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Nonoscillatory coding and multiscale representation of very large environments in the bat hippocampus by Tamir Eliav and There is Chemistry in Social Chemistry by Inbal Ravreby

Date:
26
Tuesday
October
2021
Lecture / Seminar
Time: 12:30-13:30
Location: Gerhard M.J. Schmidt Lecture Hall
Lecturer: Tamir Eliav, Prof. Nachum Ulanovsky Lab and Inbal Ravreby, Prof. Noam Sobel Lab, Dept of Brain Sciences
Organizer: Department of Brain Sciences
Details: Student Seminar-Dept of Brain Sciences
Abstract: Nonoscillatory coding and multiscale representation of very large environments i ... Read more Nonoscillatory coding and multiscale representation of very large environments in the bat hippocampus Abstract: The hippocampus plays a key role in memory and navigation, and forms a cognitive map of the world: hippocampal ‘place cells’ encode the animal’s location by activating whenever the animal passes a particular region in the environment (the neuron’s ‘place field’). Over the last 50 years of hippocampal research, almost all studies have focused on rodents as animal models, using small laboratory experimental setups. In my research, I explored hippocampal representations in a naturalistic settings, in a unique animal model – the bat. My talk will outline two main stories: (i) In rodents, hippocampal activity exhibits ‘theta oscillations’. These oscillations were proposed to support multiple functions, including memory and sequence formation. However, absence of clear theta in bats and humans has questioned these proposals. Surprisingly, we found that in bats hippocampal neurons exhibited nonoscillatory phase-coding. This highlights the importance of phase-coding, but not oscillations per se, for hippocampal function across species – including humans. (ii) Real-world navigation requires spatial representation of very large environments. To investigate this, we wirelessly recorded from hippocampal dorsal CA1 neurons of bats flying in a long tunnel (200 meters). Place cells displayed a multifield multiscale code: Individual neurons exhibited multiple place fields of diverse sizes, ranging from 0.6 to 32 meters, and the fields of the same neuron differed up to 20-fold in size. Theoretical analysis showed that the multiscale code allows representing large environments with much better accuracy than other codes. Thus, by increasing the spatial scale, we uncovered a neural code that is radically different from classical spatial codes. Together, these results highlight the power of the comparative approach, and demonstrate that studying the brain under naturalistic settings and behavior enables discovering new unknown aspects of the neural code. There is Chemistry in Social Chemistry Abstract: Non-human terrestrial mammals constantly sniff themselves and each-other, and based on this decide who is friend or foe. Humans also constantly sniff themselves and each-other, but the functional significance of this behavior is unknown. Given that humans seek friends who are similar to themselves, we hypothesized that humans may be smelling themselves and others to subconsciously estimate body-odor similarity, and that this may then promote friendship. To test this hypothesis, we recruited non-romantic same-sex friend dyads who had initially bonded instantaneously, or so called click-friends, and harvested their body-odor. In a series of experiments, we then found that objective ratings obtained with an electronic nose, and subjective ratings obtained from independent human smellers, converged to suggest that click-friends smell more similar to each other than random dyads. To then estimate whether this similarity was merely a consequence of friendship, or a driving force of friendship, we recruited complete strangers, smelled them with an electronic nose, and engaged them in non-verbal same-sex dyadic interactions. Remarkably, we observed that dyads who smelled more similar had better dyadic interactions. In other words, we could predict social bonding with an electronic nose. This result implies that body-odor similarity is a causal factor in social interaction, or in other words, there is indeed chemistry in social chemistry.
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Special Guest Seminar

Date:
02
Tuesday
November
2021
Lecture / Seminar
Time: 10:00-11:00
Title: Self-organized morphogenesis of a stem-cell derived human neural tu
Location: https://weizmann.zoom.us/j/91871920099?pwd=Qm1kZzc2emV3cGQyekthNWFCOThWdz09
Lecturer: Dr. Eyal Karzbrun
Organizer: Department of Molecular Genetics

Brain plasticity: Regulation and Modulation

Date:
16
Monday
May
2022
-
17
Tuesday
May
2022
Conference
Time: 08:00 - 18:00
Location: David Lopatie Conference Centre
Organizer: Department of Brain Sciences

    Past

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    Time and experience dependent evolution of hippocampal memory codes

    Date:
    11
    Monday
    October
    2021
    Lecture / Seminar
    Time: 13:30-14:30
    Lecturer: Nitzan Geva (PhD Defense)
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/98861083979?pwd=Q1FmbDBYNHR2QnN ... Read more Zoom link to join: https://weizmann.zoom.us/j/98861083979?pwd=Q1FmbDBYNHR2QnNKSUNpeHlLdm94dz09 Meeting ID: 988 6108 3979 Password: 682422
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    Abstract: Hippocampal place cells fire in a spatially selective manner and are thought to ... Read more Hippocampal place cells fire in a spatially selective manner and are thought to support the formation of a cognitive-map that allows the association of an event to its spatial context. It has long been thought that within familiar spatial contexts, such cognitive maps should be stable over time, and that individual place cells should retain their firing properties. However, recent findings have demonstrated that hippocampal spatial codes gradually change over timescales of minutes to weeks. These finding raised several fundamental questions: What are the contributions of the passage of the time and the amount of experience to the observed drift in hippocampal ensemble activity? To what extent are different aspect of place code stability affected by time and experience? To address these questions, I conducted a series of Ca2+ imaging experiments in which mice repeatedly explored familiar environments. Different environments were visited at different intervals, which allowed distinguishing between the contribution of time and experience to code stability. I found that time and experience differentially affected distinct aspects of hippocampal place codes: changes in activity rates were mostly affected by time, whereas changes in spatial tuning was mostly affected by experience. These findings suggest that different biological mechanisms underlie different aspects of representational drift in the hippocampus. These findings add to the growing body of research suggesting that representational drift is an inherent property of neural networks in vivo, and point to the different candidate mechanisms that could underlie this drift. https://weizmann.zoom.us/j/98861083979?pwd=Q1FmbDBYNHR2QnNKSUNpeHlLdm94dz09 Meeting ID: 988 6108 3979 Password: 682422
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    Episodic Memory from First Principles

    Date:
    07
    Thursday
    October
    2021
    Lecture / Seminar
    Time: 14:00-15:00
    Lecturer: Michelangelo Naim (PhD Oral Defense)
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/99774936375?pwd=QUhMTG56UkJkd3l ... Read more Zoom link to join: https://weizmann.zoom.us/j/99774936375?pwd=QUhMTG56UkJkd3l1bUJ1ZDhhTTlEUT09 Meeting ID: 997 7493 6375 Password: 402616
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    Abstract: Our everyday conscious memories are an intricate network of images and associati ... Read more Our everyday conscious memories are an intricate network of images and associations, constituting a record of our personal experiences that is continuously updated through an active organization of new information within the context of previous experience. Recollection is similarly recreative, and the course of remembering is determined by the nature of our memory organization. This type of memory is called episodic memory, and is therefore a multifaceted process involving a synthesis of episodic representations with our framework of general semantic knowledge that mediates our capacity for recollection. It is therefore typically considered to be too complex to be described by physics-style universal mathematical laws. In this thesis we characterize some of the processes governing episodic recall and point out the basic principles behind them. More specifically, we propose a search process governing recall of unconnected events, mathematically computed recall capacity and tested the resulting relationship in dedicated experiments. Next, we proposed how structured information may be encoded in the human brain and compared model predictions with available experimental data. In both cases experimental data were consistent with proposed mechanisms. Since time is an essential part of episodic memory we also studied the interaction between absolute and ordinal time representation in the brain. We found that ordinal information take precedence in the inference about absolute event times. Overall, the results presented in this thesis opens opportunity that complicated cognitive processes can be described by universal mathematical laws. Zoom link to join: https://weizmann.zoom.us/j/99774936375?pwd=QUhMTG56UkJkd3l1bUJ1ZDhhTTlEUT09 Meeting ID: 997 7493 6375 Password: 402616
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    Merging of cues and hunches by the mouse cortex

    Date:
    05
    Tuesday
    October
    2021
    Lecture / Seminar
    Time: 12:30-13:00
    Lecturer: Prof. Matteo Carandini
    Organizer: Department of Brain Sciences
    Details: Zoom link: https://weizmann.zoom.us/j/95406893197?pwd=REt5L1g3SmprMUhrK3dpUDJVe ... Read more Zoom link: https://weizmann.zoom.us/j/95406893197?pwd=REt5L1g3SmprMUhrK3dpUDJVeHlrZz09 Meeting ID: 954 0689 3197 Password: 750421 Host: Dr. Takashi Kawashima takashi.kawashima@weizmann.ac.il tel: 2995
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    Abstract: Everyday decisions are often based on both external cues and internal hunches. H ... Read more Everyday decisions are often based on both external cues and internal hunches. How does the brain put these together? We addressed this question in mice trained to make decisions based on combinations of sensory cues and history of reward value or probability. While mice made these decisions, we recorded from thousands of neurons throughout the brain and causally probed the roles of cortical areas. The results are not what we thought based on textbook notions of how the brain works. This talk is based on work led by Nick Steinmetz, Peter Zatka-Haas, Armin Lak, and Pip Coen, in the laboratory I share with Kenneth Harris. Zoom link: https://weizmann.zoom.us/j/95406893197?pwd=REt5L1g3SmprMUhrK3dpUDJVeHlrZz09 Meeting ID: 954 0689 3197 Password: 750421
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    Deciphering the role of brain- resident and infiltrating myeloid cells in Alzheimer’s disease

    Date:
    19
    Sunday
    September
    2021
    Lecture / Seminar
    Time: 14:00-15:30
    Lecturer: Raz Dvir-Szternfeld (PhD Thesis Defense)
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/97303536627?pwd=YXFQZUozb1hhMS9xY ... Read more Zoom link to join: https://weizmann.zoom.us/j/97303536627?pwd=YXFQZUozb1hhMS9xY3BzOFJPZU1Vdz09 Meeting ID: 973 0353 6627 Password: 503277
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    Abstract: Alzheimer’s disease (AD) is an age-related neurodegenerative disorder, which i ... Read more Alzheimer’s disease (AD) is an age-related neurodegenerative disorder, which is the most common cause of dementia. Among the key hallmarks of AD are neurofibrillary tangles, abnormal amyloid beta (A) aggregation, neuroinflammation and neuronal loss; altogether manifested in progressive cognitive decline. Numerous attempts were made to arrest or slow disease progression by directly targeting these factors, with a limited successes in having a meaningful effect on cognition. In the recent years, the focus of AD research has been extended towards exploring the local and systemic immune response. Yet, the role of the two main myeloid populations, the central nerve system (CNS) resident immune cells, microglia and blood-borne monocyte-derived macrophages (MDM) remain unclear. In my PhD, together with members of the teams, using behavioral, immunological, biochemical and single-cell resolution molecular techniques, we deciphered the distinct role of microglia and MDM in transgenic mouse models of AD pathology. Using single cell RNA sequencing (scRNA-seq) in 5xFAD amyloidosis mouse model, we have identified a new state of microglia, which we named disease associated microglia (DAM) that were found in close proximity to A plaques. The full activation of these cells was found to be dependent on Triggering receptor expressed on myeloid cells 2 (TREM2), a well-known risk factor in late onset AD. To get an insight to the role of MDM relative to microglia, we used an experimental paradigm of boosting the systemic immunity by modestly blocking the inhibitory immune checkpoint pathway, PD-1/PD-L1, which was previously shown to be beneficial in ameliorating AD in 5xFAD mice, via facilitating homing of MDM to the brain. We found that the same treatment is efficient also in mouse model of tauopathy and that the MDM homing to the brain following the treatment expressed a unique set of scavenger molecules, including macrophage scavenger receptor 1 (MSR1). We found that MDM expressing MSR1 are essential for the disease modification. Using the same immune-modulatory treatment in a mouse model deficient in TREM2 (Trem2-/-5xFAD) and thus in DAM, allowed us to distinguish between the contribution to the disease modification of MDM and DAM. We found, that MDM display a Trem2-independent role in the cognitive improvement. In both Trem2-/-5xFAD and Trem2+/+5xFAD mice the treatment effect on behavior was accompanied by a reduction in the levels of hippocampal water-soluble Aβ1-42, a fraction of A that contains toxic oligomers. In Trem2+/+5xFAD mice, the same treatment seemed to activate additional Trem2-dependent mechanism, that could involve facilitation of removal of Aβ plaques by DAM or by other TREM2-expressing microglia. Collectively, our finding demonstrates the distinct role of activated microglia and MDM in therapeutic mechanism of AD pathology. They also support the approach of empowering the immune system to facilitate MDM mobilization as a common mechanism for treating AD, regardless of primary disease etiology and TREM2 genetic polymorphism.
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    Vision and Robotics Seminar

    Date:
    15
    Sunday
    August
    2021
    Lecture / Seminar
    Time: 09:00-10:30
    Title: Algebraic Characterization of Relational Camera Pose Measurements in Multiple Images
    Lecturer: Yoni Kasten
    Organizer: Faculty of Mathematics and Computer Science
    Details: Structure from Motion (SfM) deals with recovering camera parameters and 3D scene ... Read more Structure from Motion (SfM) deals with recovering camera parameters and 3D scene structure from collections of 2D images. SfM is commonly solved by minimizing the non-covex, bundle adjustment objective, which generally requires sophisticated initialization. In this talk I will present two approaches to SfM: the first approach involves averaging of essential or fundamental matrices (also called bifocal tensors). Since the bifocal tensors are computed independently from image pairs they are generally inconsistent with any set of n cameras.
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    Abstract: Structure from Motion (SfM) deals with recovering camera parameters and 3D scene ... Read more Structure from Motion (SfM) deals with recovering camera parameters and 3D scene structure from collections of 2D images. SfM is commonly solved by minimizing the non-covex, bundle adjustment objective, which generally requires sophisticated initialization. In this talk I will present two approaches to SfM: the first approach involves “averaging” of essential or fundamental matrices (also called “bifocal tensors”). Since the bifocal tensors are computed independently from image pairs they are generally inconsistent with any set of n cameras. We provide a complete algebraic characterization of the manifold of bifocal tensors for n cameras and present an optimization framework to project measured bifocal tensors onto the manifold. Our second approach is an online approach: given n-1 images, I_1,...,I_{n-1}, whose camera matrices have already been recovered, we seek to recover the camera matrix associated with an image I_n . We present a novel solution to the six-point online algorithm to recover the exterior parameters associated with I_n. Our algorithm uses just six corresponding pairs of 2D points, extracted each from I_n and from any of the preceding n-1 images, allowing the recovery of the full six degrees of freedom of the n'th camera, and unlike common methods, does not require tracking feature points in three or more images. We present experiments that demonstrate the utility of both our approaches. If time permits, I will briefly present additional recent work for solving SfM using deep neural models.
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    Principles of functional circuit connectivity: Insights from the zebrafish optic tectum

    Date:
    04
    Wednesday
    August
    2021
    Lecture / Seminar
    Time: 10:30
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Prof. German Sumbre
    Organizer: Department of Brain Sciences
    Details: Host: Dr. Takashi Kawashima takashi.kawashima@weizmann.ac.il tel: 2995
    Abstract: Spontaneous neuronal activity in sensory brain regions is spatiotemporally struc ... Read more Spontaneous neuronal activity in sensory brain regions is spatiotemporally structured, suggesting that this ongoing activity may have a functional role. Nevertheless, the neuronal interactions underlying these spontaneous activity patterns, and their biological relevance, remain elusive. We addressed these questions using two-photon and light-sheet Ca2+ imaging of intact zebrafish larvae to monitor the fine structure of the spontaneous activity in the zebrafish optic tectum (the fish's main visual center. We observed that the spontaneous activity was organized in topographically compact assemblies, grouping functionally similar neurons rather than merely neighboring ones, reflecting the tectal retinotopic map. Assemblies represent all-or-none-like sub-networks shaped by competitive dynamics, mechanisms advantageous for visual detection in noisy natural environments. Furthermore, the spontaneous activity structure also emerged in “naive” tecta (tecta of enucleated larvae before the retina connected to the tectum). We thus suggest that the formation of the tectal network circuitry is genetically prone for its functional role. This capability is an advantageous developmental strategy for the prompt execution of vital behaviors, such as escaping predators or catching prey, without requiring prior visual experience. Mutant zebrafish larvae for the mecp2 gene display an abnormal spontaneous tectal activity, thus representing an ideal control to shed light on the biological relevance of the tectal functional connectivity. We found that the tectal assemblies limit the span of the visual responses, probably improving visual spatial resolution.
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    Inferring Mars' Surface Winds by Analyzing the Global Distribution of Barchan Dunes using a Convolutional Neural Network

    Date:
    29
    Tuesday
    June
    2021
    Lecture / Seminar
    Time: 10:00-11:00
    Location: https://weizmann.zoom.us/j/7621438333?pwd=c0lpdlQzYSthellXWG9rZnM0ZDRFZz09
    Lecturer: Lior Rubanenko
    Organizer: Department of Earth and Planetary Sciences
    Abstract: Sand seas on Mars are riddled with eolian landforms created by accumulating sand ... Read more Sand seas on Mars are riddled with eolian landforms created by accumulating sand particles. When the sand supply is limited and the wind is approximately unidirectional, these landforms take the shape of crescentic barchan dunes, whose slip-faces are approximately perpendicular to the dominant wind direction, and their horns are oriented downwind. The morphology of barchan dunes is thus routinely used to infer wind conditions on Mars by manually analyzing aerial or satellite imagery. Despite the effectiveness of this technique on a local scale, employing it on a global scale remained challenging thusfar - as manually outlining individual dunes globally is impractical, and automatic detection methods have been largely ineffective at accurately segmenting dunes in images. Here we use Mask R-CNN, an instance segmentation convolutional neural network, to detect and outline dunes globally on Mars in images obtained by the Mars Reconnaissance Orbiter Context Camera (MRO CTX). We measure the morphometrics of dunes from their detected outlines, and infer the direction of the winds that formed them. By comparing the global wind distribution we derived to a global climate model, we study Mars' past and recent climate, and constrain global sand mobility thresholds which offer insight into the erosion and dust lifting capabilities of the atmosphere of the Red Planet.
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    Yes I Can ! Neural indicators of self-views and their motivational value

    Date:
    22
    Tuesday
    June
    2021
    Lecture / Seminar
    Time: 12:30
    Lecturer: Prof. Talma Hendler
    Organizer: Department of Brain Sciences
    Details: Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: Positive view of oneself is central for social motivation and emotional well-b ... Read more Positive view of oneself is central for social motivation and emotional well-being. Such views largely depend on the known positive-bias of social feedbacks, as well as on the value one gives to social attributes such as power or affiliation. Diminished positive self views are a common denominator in depression and social anxiety, suggesting a transdiagnostic biomarkers, yet its neural mechanism is unclear. My talk will describe a series of studies using multiscale imaging and behavioral accounts and their modeling to address the interaction between self related cognition, motivation and learning from experience. Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Representation of 3D space in the mammalian brain: From 3D grid cells in flying bats to 3D perception in flying humans

    Date:
    15
    Tuesday
    June
    2021
    Lecture / Seminar
    Time: 12:30
    Lecturer: Gily Ginosar
    Organizer: Department of Brain Sciences
    Details: Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: While our world is three-dimensional (3D), spatial perception is most often stud ... Read more While our world is three-dimensional (3D), spatial perception is most often studied in animals and humans navigating across 2D surfaces. I will present two cases in which the consideration of the 3D nature of the world has led us to surprising results. The first case regards the neural recording of mammalian grid cells. Grid cells that are recorded over 2D surfaces create a hexagonal-shaped repetitive lattice, which inspired many theoretical studies to investigate the pattern’s mechanism and function. Upon recording in bats flying through 3D space, we found that grid cells did not exhibit a hexagonal global lattice, but rather showed a local order – with grid-fields exhibiting fixed local distances. Our results in 3D strongly argue against most of the prevailing models of grid-cell function, and we suggest a unified model that explains the results in both 2D and 3D. The second case regards the perception of 3D space in humans. Different behavioral studies have shown contradicting evidence of human perception of 3D space being either isotropic or vertically compressed. We addressed this question using human experts in 3D motion and navigation – fighter pilots – studied in a flight simulator. We considered two aspects of the perception of 3D space: surrounding space and travelled space. We show that different aspects of the perception of space are shaped differently with experience: whereas the perception of the 3D surrounding space was vertically compressed in both expert and non-expert subjects, fighter pilots exhibited isotropic perception of travelled space, whereas non-expert subjects retained a distorted perception. Together, our research sheds light on the differences and similarities between the coding of 3D versus 2D space, in both animals and humans. Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Synthetic and Natural Plasticity in the Auditory Cortex

    Date:
    01
    Tuesday
    June
    2021
    Lecture / Seminar
    Time: 12:30
    Lecturer: Prof. Adi Mizrahi
    Organizer: Department of Brain Sciences
    Details: Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: We often study plasticity of highly synthetic environments that may not necessar ... Read more We often study plasticity of highly synthetic environments that may not necessarily form the substrate of more realistic conditions. We study sensory systems using both synthetic and more natural forms of plasticity in hope to find common brain mechanisms. On one hand we study perceptual and category learning and on the other hand parental plasticity; both in the auditory and olfactory systems. Using mice we exploit the available experimental toolkit to reveal anatomical, physiological and behavioral manifestation of plasticity in both synthetic and more natural conditions. I will discuss our efforts to study auditory plasticity in the context of mother-infant bonding, an interaction that rapidly develops following parturition. Specifically, I will describe how pup vocalizations are represented in the brain of naïve mice and in mothers, when they first start caring for their newborn pups. I will also share our recent efforts to study perceptual and category learning of synthetic (both simple and complex) environments. Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    The interaction of valence and information gain during learning, perception and decision-making

    Date:
    27
    Thursday
    May
    2021
    Lecture / Seminar
    Time: 11:00-12:30
    Lecturer: Ido Toren (PhD Thesis Defense)
    Organizer: Department of Brain Sciences
    Details: Neurobiology Students & Postdocs Seminar Zoom link to join: https://weizmann. ... Read more Neurobiology Students & Postdocs Seminar Zoom link to join: https://weizmann.zoom.us/j/92234357805?pwd=aVkrR21CSUVtVS9tSEJYRDkwOFRidz09 Meeting ID: 922 3435 7805 Password: 648092
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    Abstract: Decision making is a fundamental ability to human life. Even the simplest decisi ... Read more Decision making is a fundamental ability to human life. Even the simplest decision we make requires integration of multiple factors in our brain, such as prior knowledge, information from the environment, emotions and many more. Despite many years of research and numerous important and ground-breaking findings on how learning and decision-making are generated in our brain, a lot of knowledge is still required for a comprehensive understanding of it. My research initiated from the motivation to understand the unique contribution of valence (rewards and punishments) – when presented as feedback during learning – to perception and decision-making. For that purpose, I studied multiple groups of individuals under different experimental conditions created to elucidate behavioral and neural responses to rewards and punishments. I asked how prediction errors (PE, the difference between expected and received outcomes) bias the perception of time, and how valence and information from feedback, factors that are often indistinguishable, differently guide decision making in a multi-choice environment. Using functional MRI and computational models, I found that positive and negative PEs, known to drive learning, bias the perception of time in opposite directions. Positive PEs induce change in the perceived time so it seems longer compared to a neutral condition (no PE). In contrast, when a negative PE is detected, time is perceived to be shorter. My results identify the Putamen, a structure that receives dopaminergic projections and is involved in time perception, as the brain region that likely drives this bias and underlies the interaction between time perception and prediction-errors. In addition, I demonstrated that knowing the outcome valence in advance can enable an information-based decision making, namely one that is not affected by the valence itself and is driven only by the information available in the environment. Because uncertainty regarding choice increases when more options are available to choose from, a ‘right’ feedback provides more information to the learning process, compared to a ‘wrong’ feedback. This was accompanied by a differential activation in the ACC, PFC and striatum. Importantly, in this context, punishment avoidance is equally rewarding, and indeed I found that choice behavior and the neural networks underlying choice and feedback processing are similar in the two scenarios – for punishments and rewards. Overall, my work develops and suggests computational and neural mechanisms for specific roles of the information carried by prediction-errors. These findings can enhance our understanding of the fundamental roles of valence and information gain during learning and decision making. Zoom link to join: https://weizmann.zoom.us/j/92234357805?pwd=aVkrR21CSUVtVS9tSEJYRDkwOFRidz09 Meeting ID: 922 3435 7805 Password: 648092
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    Technologies for all-optical interrogation of neural circuits in behaving animalsTechnologies for all-optical interrogation of neural circuits in behaving animals

    Date:
    25
    Tuesday
    May
    2021
    Lecture / Seminar
    Time: 12:30
    Lecturer: Dr. Adam Packer
    Organizer: Department of Brain Sciences
    Details: Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: Neural circuits display complex spatiotemporal patterns of activity on the milli ... Read more Neural circuits display complex spatiotemporal patterns of activity on the millisecond timescale during behavior. Understanding how these activity patterns drive behavior is a fundamental problem in neuroscience, and remains a major challenge due to the complexity of their spatiotemporal dynamics. The ability to manipulate activity in genetically defined sets of neurons on the millisecond timescale using optogenetics has provided a powerful new tool for making causal links between neuronal activity and behavior. I will discuss novel approaches that combine simultaneous two-photon calcium imaging and two-photon targeted optogenetic photostimulation with the use of a spatial light modulator (SLM) to provide ‘all-optical’ readout and manipulation of the same neurons in vivo. This approach enables reading and writing of activity in neural circuits with single-cell resolution and single action potential precision during behavior. I will describe the power, limitations and future potential of this approach; and discuss how it can be used to address many important problems in neuroscience, including transforming our search for the neural code and the links between neural circuit activity and behavior. Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Neural mechanisms of aggression

    Date:
    18
    Tuesday
    May
    2021
    Lecture / Seminar
    Time: 15:00-16:00
    Lecturer: Prof. Lin Dayu
    Organizer: Department of Brain Sciences
    Details: Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: Aggression is an innate social behavior essential for competing for resources, s ... Read more Aggression is an innate social behavior essential for competing for resources, securing mates, defending territory and protecting the safety of oneself and family. In the last decade, significant progress has been made towards an understanding of the neural circuit underlying aggression using a set of modern neuroscience tools. Here, I will talk about our recent progress in the study of aggression. Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Using Deep Nets to Understand Visual Recognition in Mind and Brain

    Date:
    11
    Tuesday
    May
    2021
    Lecture / Seminar
    Time: 15:00-16:00
    Lecturer: Prof. Nancy Kanwisher
    Organizer: Department of Brain Sciences
    Details: zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: In this talk I will describe two ongoing lines of work from my lab that use deep ... Read more In this talk I will describe two ongoing lines of work from my lab that use deep nets to better understand visual recognition and its neural and computational basis in the brain, by testing precise computational models against fMRI data from the ventral visual pathway, and by providing clues into why face recognition works the way it does in the human mind and brain. Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Neuropixels probes - two stories about development and use

    Date:
    06
    Thursday
    May
    2021
    Lecture / Seminar
    Time: 12:30-13:30
    Lecturer: Dr. Michael Okun
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068
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    Abstract: The first part of the presentation will describe the Neuropixels 2.0 probe, focu ... Read more The first part of the presentation will describe the Neuropixels 2.0 probe, focusing on its ability to stably record from the same neurons across days and weeks in chronically implanted mice. The second part will describe the effects of psychedelic and intrinsic brain state transitions on the firing rates of neuronal populations, as revealed by high count Neuropixels recordings. Zoom link: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Prof. Ilan Lampl ilan.lampl@weizmann.ac.il tel: 3179
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    The Vagus Nerve and Physiology of Reward and Digestion

    Date:
    04
    Tuesday
    May
    2021
    Lecture / Seminar
    Time: 15:00
    Lecturer: Prof. Ivan E de Araujo
    Organizer: Department of Brain Sciences
    Details: Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: The presentation will discuss recent evidence supporting a role for the gut-br ... Read more The presentation will discuss recent evidence supporting a role for the gut-brain axis in controlling brain circuits involved in reward. It will be argued that sensory neurons of vagus nerve function as reward neurons. Via defined brainstem targets, vagal signals dopaminergic brain reward circuits in midbrain. The mapping of these circuits opens a window into how signals generated by internal body organs give rise to motivated and emotional behaviors. Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Vision and Robotics Seminar

    Date:
    29
    Thursday
    April
    2021
    Lecture / Seminar
    Time: 10:15-11:30
    Title: Robustifying neural networks
    Lecturer: Raja Giryes
    Organizer: Faculty of Mathematics and Computer Science
    Abstract: In this talk I will survey several techniques to make neural networks more robus ... Read more In this talk I will survey several techniques to make neural networks more robust. While neural networks achieve groundbreaking results in many applications, they depend strongly on the availability of good training data and the assumption that the data in the test time will resemble the one at train time. In this talk, we will survey different techniques that we developed for improving the network robustness and/or adapting it to the data at hand.
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    Neural correlates of future weight loss reveal a possible role for brain-gastric interactions

    Date:
    27
    Tuesday
    April
    2021
    Lecture / Seminar
    Time: 12:30-13:30
    Lecturer: Prof. Galia Avidan
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: Lifestyle dietary interventions are an essential practice in treating obesity, h ... Read more Lifestyle dietary interventions are an essential practice in treating obesity, hence neural factors that may assist in predicting individual treatment success are of great significance. Here, in a prospective, open-label, three arms study, we examined the correlation between brain resting-state functional connectivity measured at baseline and weight loss following 6 months of lifestyle intervention in 92 overweight participants. We report a robust subnetwork composed mainly of sensory and motor cortical regions, whose edges correlated with future weight loss. This effect was found regardless of intervention group. Importantly, this main finding was further corroborated using a stringent connectivity-based prediction model assessed with cross-validation thus attesting to its robustness. The engagement of senso-motor regions in this subnetwork is consistent with the over-sensitivity to food cues theory of weight regulation. Finally, we tested an additional hypothesis regarding the role of brain-gastric interaction in this subnetwork, considering recent findings of a cortical network synchronized with gastric activity. Accordingly, we found a significant spatial overlap with the subnetwork reported in the present study. Moreover, power in the gastric basal electric frequency within our reported subnetwork negatively correlated with future weight loss. This finding was specific to the weight loss related subnetwork and to the gastric basal frequency. These findings should be further corroborated by combining direct recordings of gastric activity in future studies. Taken together, these intriguing results may have important implications for our understanding of the etiology of obesity and the mechanism of response to dietary intervention as well as to interoceptive perception. Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Physics-guided machine-learning parameterizations of subgrid processes for climate modeling

    Date:
    26
    Monday
    April
    2021
    Lecture / Seminar
    Time: 14:00
    Location: https://weizmann.zoom.us/j/7621438333?pwd=c0lpdlQzYSthellXWG9rZnM0ZDRFZz09
    Lecturer: Janni Yuval
    Organizer: Department of Earth and Planetary Sciences
    Abstract: Global climate models represent small-scale processes, such as clouds and convec ... Read more Global climate models represent small-scale processes, such as clouds and convection, using subgrid models known as parameterizations. Traditional parameterizations are usually based on simplified physical models, and inaccuracies in these parameterizations are a main cause for the large uncertainty in climate projections. One alternative to traditional parameterizations is to use machine learning to learn new parameterizations which are data driven. However, machine-learning parameterizations might violate physical principles and often lead to instabilities when coupled to an atmospheric model. I will show how machine learning algorithms, such as neural networks and random forests, can be used to learn new parameterizations from the output of a three-dimensional high-resolution atmospheric model, while obeying physical constraints such as energy conservation. Implementing these parameterizations in the atmospheric model at coarse resolution leads to stable simulations that replicate the climate of the high-resolution simulation, and capture important statistics such as precipitation extremes. I will also discuss how machine-learning parameterizations can give further insights into the parameterization problem. Specifically, I will show that failures of machine-learning parameterizations can be used to better understand the relationship between large-scale fields and subgrid processes.
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    Vision and Robotics Seminar

    Date:
    22
    Thursday
    April
    2021
    Lecture / Seminar
    Time: 10:15-11:30
    Title: A New Theory of Adversarial Examples in Machine Learning
    Lecturer: Adi Shamir
    Organizer: Faculty of Mathematics and Computer Science
    Abstract: The extreme fragility of deep neural networks when presented with tiny perturbat ... Read more The extreme fragility of deep neural networks when presented with tiny perturbations in their inputs was independently discovered by several research groups in 2013. Due to their mysterious properties and major security implications, these adversarial examples had been studied extensively over the last eight years, but in spite of enormous effort they remained a baffling phenomenon with no clear explanation. In particular, it was not clear why a tiny distance away from almost any cat image there are images which are recognized with a very high level of confidence as cars, planes, frogs, horses, or any other desired class, why the adversarial modification which turns a cat into a car does not look like a car at all, and why a network which was adversarially trained with randomly permuted labels (so that it never saw any image which looks like a cat being called a cat) still recognizes most cat images as cats. The goal of this talk is to introduce a new theory of adversarial examples, which we call the Dimpled Manifold Model. It can easily explain in a simple and intuitive way why they exist and why they have all the bizarre properties mentioned above. In addition, it sheds new light on broader issues in machine learning such as what happens to deep neural networks during regular and during adversarial training. Experimental support for this theory, obtained jointly with Oriel Ben Shmuel and Odelia Melamed, will be presented and discussed in the last part of the talk.
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    New insights on continuous attractor neural networks

    Date:
    20
    Tuesday
    April
    2021
    Lecture / Seminar
    Time: 12:30
    Lecturer: Prof. Yoram Burak
    Organizer: Department of Brain Sciences
    Details: Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: One of the most fundamental concepts in theoretical neuroscience is that of an a ... Read more One of the most fundamental concepts in theoretical neuroscience is that of an attractor neural network, in which recurrent synaptic connectivity constraints the joint activity of neurons into a highly restricted repertoire of population activity patterns. In continuous attractor networks, these activity patterns span a continuous, low-dimensional manifold. I will survey two recent works from my group that are related to this concept. The first work is concerned with fixational eye drifts, a form of eye motion that occurs between saccades and is characterized by smooth, yet random, diffusive-like motion. This motion is tiny compared to saccadic eye motion, yet it is highly consequential for high-acuity vision. Even though fixational drift has been identified at least as early as the 19th century, its mechanistic origins have remained completely unknown. We hypothesize that the main drive for fixational drifts arises in diffusive motion along a line-attractor memory network - the oculomotor network, which is responsible for maintaining a fixed activation of the ocular muscles between saccades. I will present evidence in support of this hypothesis, coming from electrophysiology in monkeys and from theoretical modeling. The second work is concerned with the ability of a single recurrent neural network to express activity patterns that span multiple yet distinct continuous manifolds, a question that has been of interest in the context of spatial coding, across multiple environments, in area CA3 of the hippocampus. Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Uncovering the Boundaries of Olfactory Perception

    Date:
    19
    Monday
    April
    2021
    Lecture / Seminar
    Time: 15:00-16:00
    Lecturer: Aharon Ravia (PhD Thesis Defense)
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/93360836031?pwd=dDZEdTQ1QUkxUVVONV ... Read more Zoom link to join: https://weizmann.zoom.us/j/93360836031?pwd=dDZEdTQ1QUkxUVVONVErVm9CcUJWQT09 Meeting ID: 933 6083 6031 Password: 591230
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    Abstract: The question of how to measure a smell has troubled scientists for over a centur ... Read more The question of how to measure a smell has troubled scientists for over a century. It was none other than Alexander Graham Bell that raised the challenge: "we have very many different kinds of smells, all the way from the odor of violets and roses up to asafoetida. But until you can measure their likenesses and differences you can have no science of odor”. Such a measure of smell can be naturally derived from a model of olfactory perceptual quality space, and several such models have recently been put forth. These typically rely on finding mathematical rules that link odorant structure to aspects of odor perception. Here, I collected 49,788 perceptual odor estimates from 199 participants, and built such a model, finalizing a physicochemical measure of smell. This measure, expressed in radians, predicts real-world odorant pairwise perceptual similarity from odorant structure alone. Using this measure, I met Bell's challenge by accurately predicting the perceptual similarity of rose, violet and asafoetida, from their physicochemical structure. Next, based on thousands of comparisons, I identified a cutoff in this measure, below 0.05 radians, where discrimination between pairs of mixtures becomes highly challenging. To assess the usefulness of this measure, I investigated whether it can be used to create olfactory metamers, namely non-overlapping molecular compositions that share a common percept. Characterizing the link between physical structure and ensuing perception in vision and audition, and the creation of perceptual entities such as metamers, was important towards understanding their underlying dimensionality, brain mechanisms, and towards their ultimate digitization. I suggest that olfactory metamers can similarly aid these goals in olfaction. Zoom link to join: https://weizmann.zoom.us/j/93360836031?pwd=dDZEdTQ1QUkxUVVONVErVm9CcUJWQT09 Meeting ID: 933 6083 6031 Password: 591230
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    Dissecting the functional organization of sensory neurons in gut-brain communication

    Date:
    13
    Tuesday
    April
    2021
    Lecture / Seminar
    Time: 12:30
    Lecturer: Dr. Henning Fenselau
    Organizer: Department of Brain Sciences
    Details: Zoom link to join-https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUd ... Read more Zoom link to join-https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: Sensory neurons relay gut-derived signals to the brain, and thereby contribute ... Read more Sensory neurons relay gut-derived signals to the brain, and thereby contribute to systemic energy and glucose homeostasis regulation. However, the relevant sensory neuronal populations innervating the gut along with the pertaining underlying functional neurocircuits remain poorly understood. Advances in this field have been impeded by the challenges associated with targeting distinct sensory neurons of vagal and spinal origin in a cell-type-specific manner, thereby making the accurate determination of their function highly difficult. We employ a combinatorial set of modern molecular systems neuroscience tools and novel mouse genetic approaches to elucidate the role of molecularly defined sensory neurons in feeding behavior and glucose metabolism, and map their downstream neurocircuits in the brain. The overarching goal of our studies is to gain greater insights into the integral components of sensory neurons as gut-to-brain connectors in controlling metabolism. Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Uncovering Olfactory Perception Boundaries

    Date:
    25
    Thursday
    March
    2021
    Lecture / Seminar
    Time: 15:00-16:00
    Lecturer: Aharon Ravia (PhD Thesis Defense)
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/93360836031?pwd=dDZEdTQ1QUkxUVVONV ... Read more Zoom link to join: https://weizmann.zoom.us/j/93360836031?pwd=dDZEdTQ1QUkxUVVONVErVm9CcUJWQT09 Meeting ID: 933 6083 6031 Password: 591230
    Close details
    Abstract: The question of how to measure a smell has troubled scientists for over a centur ... Read more The question of how to measure a smell has troubled scientists for over a century. It was none other than Alexander Graham Bell that raised the challenge: "we have very many different kinds of smells, all the way from the odor of violets and roses up to asafoetida. But until you can measure their likenesses and differences you can have no science of odor”. Such a measure of smell can be naturally derived from a model of olfactory perceptual quality space, and several such models have recently been put forth. These typically rely on finding mathematical rules that link odorant structure to aspects of odor perception. Here, I collected 49,788 perceptual odor estimates from 199 participants, and built such a model, finalizing a physicochemical measure of smell. This measure, expressed in radians, predicts real-world odorant pairwise perceptual similarity from odorant structure alone. Using this measure, I met Bell's challenge by accurately predicting the perceptual similarity of rose, violet and asafoetida, from their physicochemical structure. Next, based on thousands of comparisons, I identified a cutoff in this measure, below 0.05 radians, where discrimination between pairs of mixtures becomes highly challenging. To assess the usefulness of this measure, I investigated whether it can be used to create olfactory metamers, namely non-overlapping molecular compositions that share a common percept. Characterizing the link between physical structure and ensuing perception in vision and audition, and the creation of perceptual entities such as metamers, was important towards understanding their underlying dimensionality, brain mechanisms, and towards their ultimate digitization. I suggest that olfactory metamers can similarly aid these goals in olfaction. Zoom link to join: https://weizmann.zoom.us/j/93360836031?pwd=dDZEdTQ1QUkxUVVONVErVm9CcUJWQT09 Meeting ID: 933 6083 6031 Password: 591230
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    Dissecting the Alzheimer’s brain: from disease single cells to cellular communities

    Date:
    09
    Tuesday
    March
    2021
    Lecture / Seminar
    Time: 12:30-13:30
    Lecturer: Prof. Naomi Habib
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: Alzheimer’s disease (AD) is one of the most pressing global medical issues t ... Read more Alzheimer’s disease (AD) is one of the most pressing global medical issues to date with no effective therapeutic strategies. Despite extensive research much remains unknown regarding the crosstalk between brain cells and the role of non-neuronal cells in the progression of Alzheimer’s disease (AD). We use single nucleus RNA-sequencing and machine learning algorithms to build detailed cellular maps of mice and human brain and to follow molecular changes in each cell type along disease progression. Our maps revealed new disease associated states in glia cells as well as unique multi-cellular communities linked to AD. Specifically, we found a link between populations of disease-associated astrocytes (DAAs), microglia, oligodendrocytes and GABAergic neurons to AD related traits in mouse models and in post-mortem human brains. Expanding the data analysis across multiple cell types, we found co-occurrences of cellular populations across individuals, which we define as multi-cellular communities. Among these communities we discovered a unique cellular community linked to cognitive decline and Alzheimer’s disease pathology. These new insights are shaping our understanding of the unique cellular environment of the Alzheimer’s disease brains. Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    “Beyond mapping: perturbation as the key to understanding function”

    Date:
    04
    Thursday
    March
    2021
    Lecture / Seminar
    Time: 09:30-10:30
    Lecturer: Dr. Michal Ramot
    Organizer: Department of Molecular Chemistry and Materials Science
    Abstract: Zoom link: https://weizmann.zoom.us/j/94322871667?pwd=NXkvODRXWVZlbW9hSEtScHN1M ... Read more Zoom link: https://weizmann.zoom.us/j/94322871667?pwd=NXkvODRXWVZlbW9hSEtScHN1M0F4dz09 passcode: 870711 Neuroimaging has allowed us to map the correlations between brain activation, and external stimuli or behaviour. Yet these correlations can only hint at the function of the brain regions involved. In order to more casually investigate these relationships between brain and behaviour, we must perturb the brain, and see what changes this brings about in behaviour. I will provide a framework for doing so through covert neurofeedback. This technique allows us to perturb brain networks by reinforcing desired network states directly, through a reward orthogonal to the networks being trained. Yet a prerequisite for such a test of function and causality, is a strong hypothesis regarding the purported link between a specific network and behaviour. We must therefore also develop better behavioural tools, in order to establish such links.
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    Using Ultra-High Field MRI to Study the Human Brain

    Date:
    04
    Thursday
    March
    2021
    Lecture / Seminar
    Time: 09:00-10:00
    Location: ZOOM
    Lecturer: Dr. Edna Furman-Haran and Dr. Tali Weiss
    Organizer: Department of Life Sciences Core Facilities

    How People Decide What They Want to Know: Information-Seeking and the Human Brain

    Date:
    02
    Tuesday
    March
    2021
    Lecture / Seminar
    Time: 14:30-15:30
    Lecturer: Prof. Tali Sharot
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: The ability to use information to adaptively guide behavior is central to intell ... Read more The ability to use information to adaptively guide behavior is central to intelligence. A vital research challenge is to establish how people decide what they want to know. In this talk I will present our recent research characterizing three key motives of information seeking. We find that participants automatically assess (i) how useful information is in directing action, (ii) how it will make them feel, and (iii) how it will influence their ability to predict and understand the world around them. They then integrate these assessments into a calculation of the value of information that guides information-seeking or its avoidance. These diverse influences are captured by separate brain regions along the dopamine reward pathway and are differentially modulated by pharmacological manipulation of dopamine function. The findings yield predictions about how information-seeking behavior will alter in disorders in which the reward system malfunctions. We test these predictions using a linguistic analysis of participants’ web searches ‘in the wild’ to quantify their motives for seeking information and relate those to reported psychiatric symptoms. Finally, using controlled behavioral experiments we show that the three motives for seeking information follow different developmental trajectories that are consistent with what would be predicted from our neuroimaging data. Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Memristors in the Neuromorphic Era

    Date:
    23
    Tuesday
    February
    2021
    Lecture / Seminar
    Time: 12:30-13:30
    Lecturer: Prof. Shahar Kvatinsky
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: Memristive technologies are attractive candidates to replace conventional memo ... Read more Memristive technologies are attractive candidates to replace conventional memory technologies and can also be used to combine data storage and computing to enable novel non-von Neumann computer architecture. One such non-von Neumann computer architecture is neuromorphic computing, where brain-inspired circuits are built for massive parallelism and in-place computing. This talk focuses on neuromorphic computing with memristors. I will show how we can get inspiration from the brain to build electronic circuits that are energy efficient and perform both inference and training extremely fast and efficient. We will see that this approach can be used not only to accelerate machine learning applications, but also for novel mixed-signal circuits and for near-sensor processing. Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    On places and borders in the brain

    Date:
    09
    Tuesday
    February
    2021
    Lecture / Seminar
    Time: 12:00-13:00
    Lecturer: Prof. Dori Derdikman
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: While various forms of cells have been found in relation to the hippocampus cogn ... Read more While various forms of cells have been found in relation to the hippocampus cognitive map and navigation system, how these cells are formed and what is read from them is still a mystery. In the current lecture I will talk about several projects which tackle these issues. First, I will show how the formation of border cells in the cognitive map is related to a coordinate transformation, second I will discuss the interaction between the reward system (VTA) and the hippocampus. Finally, I will describe a project using place cells as a proxy for associative memory for assessing deficits in Alzheimer's disease. Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Layers of primary visual cortex as a window into internal models about predicted and simulated environments

    Date:
    26
    Tuesday
    January
    2021
    Lecture / Seminar
    Time: 12:30-13:30
    Lecturer: Prof. Lars Muckli
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: Normal brain function involves the interaction of internal processes with incomi ... Read more Normal brain function involves the interaction of internal processes with incoming sensory stimuli. We have created a series of brain imaging experiments (using 7T fMRI) that sample internal models and feedback mechanisms in early visual cortex. Primary visual cortex (V1) is the entry-stage for cortical processing of visual information. We can show that there are 3 information counter-streams concerned with: (1) retinotopic visual input, (2) top-down predictions of internal models generated by the brain, and (3) top-down imagery acting independently of the perception and prediction loop. Internal models amplify and disamplify incoming information, but there is also mental imagery not interfering with visual perception. Our results speak to the conceptual framework of predictive coding. Healthy brain function will strike a balance between the precision of prediction and prediction update based on prediction error. Our results incorporate state of the art, layer-specific ultra-high field fMRI and other imaging techniques. We argue that fMRI with its capability of measuring dendritic energy consumption is sensitive to activity in different parts of layer spanning neurons, enriching our computational understanding of counter stream brain mechanisms. Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    The Adaptive Brain - Inaugural Weizmann-Columbia Brain Symposium

    Date:
    25
    Monday
    January
    2021
    -
    28
    Thursday
    January
    2021
    Conference
    Time: 16:00 - 20:30
    Location: Zoom Webinar

    What can fishes teach us about the brain?

    Date:
    19
    Tuesday
    January
    2021
    Lecture / Seminar
    Time: 12:30
    Lecturer: Prof. Ronen Segev
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068
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    Abstract: Fishes have diverged in evolution from the mammalian linage some 450 million yea ... Read more Fishes have diverged in evolution from the mammalian linage some 450 million years ago and as a result fishes’ brain structure is different from the fundamental design of the mammalian, reptilian and avian brains. This raises the question what can we learn from the ability of fishes to solve different tasks. I will discuss how aspects navigation is implemented in the goldfish brain. Zoom link: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068
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    The Cortical-Hippocampal Interplay during Episodic Memory Retrieval in Humans

    Date:
    19
    Tuesday
    January
    2021
    Lecture / Seminar
    Time: 10:00-11:00
    Lecturer: Yitzhak Norman (PhD Thesis Defense)
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/92146113977?pwd=VmhuMEhBcTRYZDNWMV ... Read more Zoom link to join: https://weizmann.zoom.us/j/92146113977?pwd=VmhuMEhBcTRYZDNWMVJ4bGJrR0lIdz09 Meeting ID: 92146113977 Password: 803220
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    Abstract: One of the most remarkable functions of the human brain is the ability to recall ... Read more One of the most remarkable functions of the human brain is the ability to recall a personal experience from the past and reenact it vividly in our mind, in a way that allows us to reflect upon the memory and derive from it relevant information that can guide our future behavior. My doctoral research explored the neuronal mechanisms that enable this core cognitive function in the human brain. Using rare electrophysiological recordings obtained from neurosurgical patients for clinical purposes I investigated and characterized the complex bidirectional interactions that occur between the hippocampus and the cerebral cortex during retrieval of conscious, reportable memories. My results are twofold. I first show that 1-2 seconds before the onset of individual recollections the hippocampus elicits transient electrical oscillations known as Sharp Wave Ripples (SWRs). Such oscillatory events have been extensively studied in animal models in recent years and were shown to reflect massive synchronization events during which millions of pyramidal neurons on the hippocampus output pathway fire simultaneously. My results demonstrate that the SWR events are selective to memory contents and play a major role in coordinating the re-activation of hippocampal-neocortical memory representations during retrieval. I show a tight coupling between SWR events and visual cortex activation, and reveal a massive peri-ripple activation of the default mode network. Second, I show that the cortex uses a flexible, goal-directed, "baseline shift" mechanism that allows the imposition of predefined boundaries on spontaneous recollections. Specifically, the results demonstrate that when free recall is limited to a particular category, the average neuronal activity level in cortical sites that represent the targeted category is steadily and significantly enhanced throughout the free recall period. Such steady-state excitatory enhancement is likely to introduce a category-specific bias in the cortical input arriving at the hippocampus, which may facilitate the reactivation of memory traces belonging to the targeted category and not others. Altogether, the results place hippocampal SWRs firmly as a central mechanism in the retrieval of human declarative memory. They demonstrate a central role for SWRs in coordinating the hippocampus-cortical dialogue during recollection and point to a flexible "baseline shift" mechanism that can account for the remarkable ease and precision by which we can constrain this dialogue to support retrieval goals. Zoom link to join: https://weizmann.zoom.us/j/92146113977?pwd=VmhuMEhBcTRYZDNWMVJ4bGJrR0lIdz09 Meeting ID: 92146113977 Password: 803220
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    Vision and Robotics Seminar

    Date:
    07
    Thursday
    January
    2021
    Lecture / Seminar
    Time: 12:15-13:30
    Title: Decoding visual experience from brain activity
    Lecturer: Guy Gaziv
    Organizer: Faculty of Mathematics and Computer Science
    Details: Deep Learning introduced powerful research tools for studying visual representat ... Read more Deep Learning introduced powerful research tools for studying visual representation in the human brain. Here, we harnessed those tools for two branches of research: 1. The primary branch focuses on brain decoding: reconstructing and semantically classifying observed natural images from novel (unknown) fMRI brain recordings. This is a very difficult task due to the scarce supervised “paired” training examples (images with their corresponding fMRI recordings) that are available, even in the largest image-fMRI datasets. We present a self-supervised deep learning approach that overcomes this barrier. This is obtained by enriching the scarce paired training data with additional easily accessible “unpaired” data from both domains (i.e., images without fMRI, and fMRI without images). Our approach achieves state-of-the-art results in image reconstruction from fMRI responses, as well as unprecedented large-scale (1000-way) semantic classification of never-before-seen classes. 2. The secondary branch of research focuses on face representation in the human brain. We studied whether the unique structure of the face-space geometry, which is defined by pairwise similarities in activation patterns to different face images, constitutes a critical aspect in face perception. To test this, we compared the pairwise similarity between responses to face images of human-brain and of artificial Deep Convolutional Neural Networks (DCNN) that achieve human-level face recognition performance. Our results revealed a stark match between neural and intermediate DCNN layers' face-spaces. Our findings support the importance of face-space geometry in enabling face perception as well as a pictorial function of high-order face-selective regions of the human visual cortex. https://weizmann.zoom.us/j/94895425759?pwd=RTh3VkMyamJOay96N3hDcWg0eFpqUT09
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    Abstract: Deep Learning introduced powerful research tools for studying visual representat ... Read more Deep Learning introduced powerful research tools for studying visual representation in the human brain. Here, we harnessed those tools for two branches of research: 1. The primary branch focuses on brain decoding: reconstructing and semantically classifying observed natural images from novel (unknown) fMRI brain recordings. This is a very difficult task due to the scarce supervised "paired" training examples (images with their corresponding fMRI recordings) that are available, even in the largest image-fMRI datasets. We present a self-supervised deep learning approach that overcomes this barrier. This is obtained by enriching the scarce paired training data with additional easily accessible "unpaired" data from both domains (i.e., images without fMRI, and fMRI without images). Our approach achieves state-of-the-art results in image reconstruction from fMRI responses, as well as unprecedented large-scale (1000-way) semantic classification of never-before-seen classes. 2. The secondary branch of research focuses on face representation in the human brain. We studied whether the unique structure of the face-space geometry, which is defined by pairwise similarities in activation patterns to different face images, constitutes a critical aspect in face perception. To test this, we compared the pairwise similarity between responses to face images of human-brain and of artificial Deep Convolutional Neural Networks (DCNN) that achieve human-level face recognition performance. Our results revealed a stark match between neural and intermediate DCNN layers' face-spaces. Our findings support the importance of face-space geometry in enabling face perception as well as a pictorial function of high-order face-selective regions of the human visual cortex. https://weizmann.zoom.us/j/94895425759?pwd=RTh3VkMyamJOay96N3hDcWg0eFpqUT09
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    Diffusion properties of intracellular metabolites: compartment specific probes for cell structure and physiology

    Date:
    05
    Tuesday
    January
    2021
    Lecture / Seminar
    Time: 12:30-13:30
    Lecturer: Prof. Itamar Ronen
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: Diffusion weighted MRI (DWI) is the main neuroimaging modality used in non-invas ... Read more Diffusion weighted MRI (DWI) is the main neuroimaging modality used in non-invasive investigations of tissue microstructure, and provides quantitative cytomorphological information on a spatial scale well below the nominal resolution of MRI. The main limitation of DWI is its lack of compartmental specificity, as its “reporter molecule” is water, ubiquitous in all tissue compartments and cell types. Brain metabolites are mostly confined to the intracellular space, and their concentrations vary across cell types. Several metabolites give rise to quantifiable magnetic resonance spectroscopy (MRS) signatures, and are thus considered as compartment-specific and sometimes cell-specific markers. Sensitization of MRS to diffusion results in a set of diffusion properties for a variety of intracellular metabolites, from which microstructural information specific to the intracellular space can be obtained. A proper choice of experimental settings can be used to investigate properties that range from cytoplasmic viscosity and tortuosity of the intracellular space, to overall cell morphological features. The specificity of some metabolites to different cell types such as neurons and astrocytes opens the way to studying morphological properties of different cell populations and monitoring their modulation by physiological changes in health and disease. The presentation will introduce methodological concepts of diffusion-weighted MRS, followed by simple examples that demonstrate the unique ability of diffusion-weighted MRS to characterize cell-type specific structural features. Special emphasis will be bestowed on experimental and modelling frameworks that merge the specificity of diffusion-weighted MRS with the sensitivity of DWI to gain insights on tissue microstructure beyond what each method can separately provide. Zoom link to join:https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Chemosignals are a form of human social communication

    Date:
    24
    Thursday
    December
    2020
    Lecture / Seminar
    Time: 15:00-16:00
    Lecturer: Eva Mishor (PhD Thesis Defense)
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/98031517872?pwd=U0EvNG5EdGJBL24zW ... Read more Zoom link to join: https://weizmann.zoom.us/j/98031517872?pwd=U0EvNG5EdGJBL24zWmpKUlY1akdnZz09 Meeting ID: 980 3151 7872 Password: 976632
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    Abstract: Although animals are known to heavily rely on chemical signals for intraspecies ... Read more Although animals are known to heavily rely on chemical signals for intraspecies communication, the matter of human chemical communication remains greatly contentious. I will present evidence supporting the claim that humans, just like other animals, rely on bodily-odors to effectively navigate the social world. First, I will present a quantification of people’s overt olfactory-sampling behavior. Of approximately 400 respondents, 94% acknowledged engaging in smelling their close relationships, and approximately 60% acknowledged sniffing strangers. Next, we tested if this olfactory information is employed for socially-relevant behavioral decisions, such as trust, a key element in human socialization. We found that subliminal exposure to body-odor increased implicit trustworthiness attributed to anthropomorphic non-humans. Finally, I will describe the effect of a specific body-volatile, Hexadecanal (HEX), on human impulsive aggression. Using validated behavioral paradigms, we observed a remarkable dissociation: sniffing HEX blocked aggression in men, but triggered aggression in women. Using functional brain imaging, we uncovered a pattern of brain activity mirroring behavior: In both men and women, HEX increased activity in an area implicated in the perception of social cues. Hex then modulated functional connectivity in a brain network implicated in aggressive behavior in a sex-dependent manner. Altogether, the thesis puts forward the hypothesis that chemosignals are a form of human social communication. Under this premise, human sampling behavior of self and others’ body-volatiles provides one with important information that, in turn, affects behaviors central to human society, such as trust and aggression. Zoom link to join: https://weizmann.zoom.us/j/98031517872?pwd=U0EvNG5EdGJBL24zWmpKUlY1akdnZz09 Meeting ID: 980 3151 7872 Password: 976632
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    Behavioural signatures of a developing neural code

    Date:
    22
    Tuesday
    December
    2020
    Lecture / Seminar
    Time: 12:30-13:30
    Lecturer: Prof. Lilach Avitan
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laU ... Read more Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: During early life the neural code must develop to appropriately transform sensor ... Read more During early life the neural code must develop to appropriately transform sensory inputs into behavioural outputs. However little is known about how developments in neural representations directly impact on behaviour. By combining behavioural analysis with 2-photon calcium imaging at multiple timepoints from 4 to 15 dpf in the optic tectum of developing zebrafish larvae, we demonstrate a link between the maturity of neural coding in the visual brain and developmental changes in visually-guided behavior. We show that visually-driven hunting behavior improves from 4 to 15 days post-fertilization, becoming faster and more accurate. During the same period population activity in parts of the optic tectum refines, improving decoding and information transmission for particular spatial positions. Together these results show that developmental signatures of an emerging neural code can be directly related to observable properties of behaviour. Please click the link below to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    The hyperpolarized brain: What can we add to cerebral metabolism with hyperpolarized MR probes?

    Date:
    17
    Thursday
    December
    2020
    Lecture / Seminar
    Time: 09:30-10:30
    Lecturer: Dr. Mor Mishkovsky
    Organizer: Department of Molecular Chemistry and Materials Science

    Coding in the ever-changing world: a mechanistic view of retinal dynamic computation of motion

    Date:
    16
    Wednesday
    December
    2020
    Lecture / Seminar
    Time: 14:00-15:00
    Lecturer: Lea Ankri (PhD Thesis Defense)
    Organizer: Department of Brain Sciences
    Details: Students & Postdocs Seminar Zoom link to join: https://weizmann.zoom.us/j/9105 ... Read more Students & Postdocs Seminar Zoom link to join: https://weizmann.zoom.us/j/91058452206?pwd=UFpBZkVrM1luUSttSGZUTHRiNUg5dz09 Meeting ID: 910 5845 2206 Password: 229240
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    Abstract: The world around us is barely stable. To maintain constancy of perception, neuro ... Read more The world around us is barely stable. To maintain constancy of perception, neuronal circuits adopt multiple mechanisms, each carefully tailored to grant the system with computational fidelity in the face of variable stimuli, yet to enable flexibility of computation in certain contexts. During my PhD I investigated the mechanisms that underlie retinal direction-selectivity. Using electrophysiology and modelling approaches, I will show how several mechanisms cooperate to maintain stability in the circuit’s response to moving objects carrying distinct characteristics. This stability is compromised when the retina is confronted by a repetitive light-adapting stimulus that changes the receptive field of cells in several layers of the circuit. Intriguingly, these changes in the cells’ receptive field expose antagonistic center-surround organization of direction coding: the center receptive field supports response to one direction, while the surround supports response to the opposite direction. Center-surround antagonism is thought to enhance spatial discrimination, but this is the first evidence for its contribution to retinal direction selectivity. This provides an example of how the retina elegantly implements computational motifs that are reminiscent of those found in higher brain regions, using just a handful of cell types, already at the first station of the visual system. (If you are not from the neuroscience field, please check out THIS). Zoom link to join: https://weizmann.zoom.us/j/91058452206?pwd=UFpBZkVrM1luUSttSGZUTHRiNUg5dz09 Meeting ID: 910 5845 2206 Password: 229240
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    Short and prolonged dynamics of taste processing in health and disease

    Date:
    08
    Tuesday
    December
    2020
    Lecture / Seminar
    Time: 12:30-13:30
    Lecturer: Dr. Anan Moran
    Organizer: Department of Brain Sciences
    Details: Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUU ... Read more Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: The brain is rife with feedback connections within and between its regions, whic ... Read more The brain is rife with feedback connections within and between its regions, which almost inevitably should give rise to dynamic activity in the underlying neuronal populations. In the taste system of awake rats, neurons sequentially transition between activity states that correlate with taste perceptions such as identity, palatability, and novelty. In my talk I will present the current knowledge regarding taste information processing in the taste system and will add our recent description of sub-second novelty information transmission through a new circuit. Next, I will present unpublished data showing the dynamic changes in neuronal activity as taste memory is acquired and consolidated across 12 hours in behaving rats. Last, I will show how taste learning helps us investigating the early, pre-pathological, stages of Alzheimer’s disease. Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    The brain as a central regulator of immunity

    Date:
    03
    Thursday
    December
    2020
    Lecture / Seminar
    Time: 14:00-15:00
    Lecturer: Prof. ASYA ROLLS
    Organizer: Dwek Institute for Cancer Therapy Research
    Details: https://weizmann.zoom.us/j/5065402023?pwd=a3Z6KzRCU0xJaUFoM2Y5emZwZm1oZz09

    Thesis defense by Jung-Seok Kim (Prof. Steffen Jung's lab)will lecture on "Dissecting functional contributions of microglia and non-parenchymal brain macrophages using a binary transgenic approach"

    Date:
    17
    Tuesday
    November
    2020
    Lecture / Seminar
    Time: 11:00
    Title: Zoom seminar: https://weizmann.zoom.us/j/98854734357?pwd=ODlIazByNDZiMnRLa3lIYWkvOTNpUT09 Password: 879770
    Location: https://weizmann.zoom.us/j/98854734357?pwd=ODlIazByNDZiMnRLa3lIYWkvOTNpUT09 Password: 879770
    Lecturer: Jung-Seok Kim
    Organizer: Department of Immunology
    Details: Zoom seminar: https://weizmann.zoom.us/j/98854734357?pwd=ODlIazByNDZiMnRLa3lIY ... Read more Zoom seminar: https://weizmann.zoom.us/j/98854734357?pwd=ODlIazByNDZiMnRLa3lIYWkvOTNpUT09 Password: 879770
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    Special guest seminar with Dr. Yosef Kaplan Dor

    Date:
    16
    Monday
    November
    2020
    Lecture / Seminar
    Time: 16:00
    Title: “Sleep loss and the gut”
    Location: https://weizmann.zoom.us/j/96213472011?pwd=cWJaVHZhbGpibDJWZ2I4MDRMMEhQUT09
    Lecturer: Dr. Yosef Dor Kaplan
    Organizer: Department of Molecular Genetics
    Details: Give the world’s most promising young scientists the means to follow their dre ... Read more Give the world’s most promising young scientists the means to follow their dream, and discoveries will come. Supporting newly recruited faculty members provides them what they need to flourish.
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    Abstract: Sleep is ubiquitous in the animal kingdom, but its function has been a mystery. ... Read more Sleep is ubiquitous in the animal kingdom, but its function has been a mystery. Besides its importance for the brain, sleep appears to play an essential physiological role, emphasized by the fact that severe sleep loss can be lethal. The cause of this lethality was unknown. We found that extreme sleep deprivation results in high levels of reactive oxygen species (ROS) that trigger oxidative stress specifically in the gut of flies and mice. Using flies, we show that neutralization of intestinal ROS prevents premature death of sleep-deprived animals, suggesting a causal link between ROS accumulation in the gut and lethality upon sleep loss. What may explain the observed phenomena? Could it teach us about the normal, daily function of sleep? In the second part of my talk, I will present our current attempts and preliminary data aiming at answering these questions.
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    Seeing the big picture - time scales of automatic prediction in temporal and frontal cortex

    Date:
    10
    Tuesday
    November
    2020
    Lecture / Seminar
    Time: 12:30
    Lecturer: Prof. Leon Y. Deouell
    Organizer: Department of Brain Sciences
    Details: Via Zoom https://weizmann.zoom.us/j/97861867679?pwd=eGljSXY2OUJPZXphN1B3ai9SNkh ... Read more Via Zoom https://weizmann.zoom.us/j/97861867679?pwd=eGljSXY2OUJPZXphN1B3ai9SNkhzQT09 Meeting ID: 978 6186 7679 Password: 904406 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070
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    Abstract: According to the hierarchical predictive-coding framework, regularities in the e ... Read more According to the hierarchical predictive-coding framework, regularities in the environment are used by the nervous system for predicting the input, and deviations from this prediction are transmitted as ‘prediction errors’. However, regularities may be based on more than one dimension and may be based on different time windows. Multiple predictions, sometimes contradicting, may be formed simultaneously and it is not clear how the brain deals with this situation. I will present evidence from scalp and intracranial EEG (in humans) showing that different parts of auditory cortex and frontal cortices are involved in predictions in multiple time scales for the same events. These predictions do not obey a simple hierarchy.
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    Immune therapy for Alzheimer’s disease and Dementia: From the bench to the bedside

    Date:
    03
    Tuesday
    November
    2020
    Lecture / Seminar
    Time: 12:30
    Lecturer: Prof. Michal Schwartz
    Organizer: Department of Brain Sciences
    Details: Seminar on Zoom https://weizmann.zoom.us/j/93371812582?pwd=VEpIZHB1U0QwMWNhY05F ... Read more Seminar on Zoom https://weizmann.zoom.us/j/93371812582?pwd=VEpIZHB1U0QwMWNhY05FWWtZcVZnQT09 Meeting ID: 933 7181 2582 Password: 610265
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    Abstract: With increased life expectancy, the incidence of patients suffering from Alzheim ... Read more With increased life expectancy, the incidence of patients suffering from Alzheimer’s disease (AD) and dementia has been steadily increasing. Currently, there is not a single treatment that can change the diseases course. Our team, over more than two decades, has demonstrated that the brain needs support from the immune system for its life-long functional plasticity and repair. Furthermore, using immunological and immunogenomic tools, we demonstrated that in AD, the immune system dysfunctions and perpetuates the pathology. Based on these observations and numerous others, we proposed that boosting the systemic immune system might facilitate mobilization of immune cells to help the brain. We found that the optimal way to activate such a reparative immune response is by reducing the restraints on the immune system, by blocking the PD-1/PD-L1 inhibitory immune checkpoint pathway. This therapy facilitates translocation of phagocytic cells to the brain; based on their transcriptomic profile, we demonstrated that these cells express molecules that can uniquely remove the toxic forms of misfolded proteins plaques, dead cells, and cell debris, and can thereby rescue synapses, change the disease course and improve brain function. Overall, our results indicate that targeting systemic and local immune cells rather than brain-specific disease-escalating factors provides a multi-dimensional disease-modifying therapy for AD and dementia, regardless of the primary disease etiology. Our approach is under an expedited development process towards clinical trial.
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    Physical Aspects of Language: Memory, Correlations and Structure in Text and Conversation

    Date:
    13
    Thursday
    August
    2020
    Colloquium
    Time: 11:15-12:30
    Location: https://weizmann.zoom.us/j/92790893230?pwd=VlRjVzkvaGZ5YWRvcXFGWXVXZ3dXdz09
    Lecturer: Elisha Moses
    Organizer: Faculty of Physics
    Abstract: The conversion of ideas and thoughts into a linear train of words that represent ... Read more The conversion of ideas and thoughts into a linear train of words that represents them constitutes a channel of communication that we call language. The capacity for language is a relatively recent evolutionary development in humans, and according to the theory of language established by Chomsky, humans are born with a universal “internal grammar” that enables verbal communication. Although this idea is still controversial, it has support from genetic research: Certain mutations in a gene called FOXP2 significantly impair the ability for grammar. As a natural phenomenon stemming from genes and the brain, language should thus be amenable to the tools of analysis that physics employs with other natural phenomena. We present three studies on the role of memory and correlations in language. In the first, we investigate the correlation network of words in written texts to identify a hierarchy structures that harnesses memory to bind topics of interest (‘concepts’). In the second study, we see how concepts are established by the existence of loops in a network of words linked by their definitions in a dictionary. Finally, we discuss recent work on how the music, or prosody, adds information to the text. We show that as we convert words into verbal utterances, our short-term memory creates chunks that are then spoken by the vocal chords and muscles. Our approach applies feature-based recognition, which has been extremely successful in image processing, to spoken language. Application to computerized analysis of emphasis in conversation and to the construction of a ‘prosodic dictionary’ will be discussed.
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    ClearSight™: A portable system that uses diffusion NMR to probe the margins of excised tumors

    Date:
    16
    Thursday
    July
    2020
    Lecture / Seminar
    Time: 09:30-10:30
    Lecturer: Dr. Saul Stokar
    Organizer: Clore Institute for High-Field Magnetic Resonance Imaging and Spectroscopy
    Abstract: Zoom link: https://weizmann.zoom.us/j/91154950215?pwd=ZkRsTWJzL1AzMWpNbFVSVUF4d0 ... Read more Zoom link: https://weizmann.zoom.us/j/91154950215?pwd=ZkRsTWJzL1AzMWpNbFVSVUF4d05zQT09 Password: 388848 Diffusion NMR weighted NMR and MRI are very powerful techniques for investigating microscopic details about tissue architecture, either normal or in a diseased state. In addition to its traditional use in diagnosing stroke and ischemic injury in the brain, in recent years DWI has been used to diagnose various kinds of cancer, including breast, prostate and lung cancers. In this seminar we will present an overview of a novel portable system that uses DWI to check whether the margins of excised breast tumors are tumor-free. This is extremely important both for the patient and the hospital, since it obviates the need to perform additional surgery if the subsequent pathology indicates the presence of tumor on the margin of the excised tissue, something that occurs today in up to 25% of breast-conserving surgeries. We shall provide an overview of diffusion MRI, the unique challenges of performing MRI in or near the operating theater, the architecture of ClearCut's system, computer simulations of its performance and an overview of the clinical results obtained to date.
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    High-dimensional geometry of visual cortex

    Date:
    25
    Thursday
    June
    2020
    Lecture / Seminar
    Time: 16:00
    Lecturer: Dr. Carsen Stringer
    Organizer: Department of Brain Sciences
    Details: Online seminar link: https://www.crowdcast.io/e/neuromath-carsen Host: Prof.M ... Read more Online seminar link: https://www.crowdcast.io/e/neuromath-carsen Host: Prof.Misha Tsodyks Contact:Pritish Patil: pritish.patil@weizmann.ac.il
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    Abstract: Interpreting high-dimensional datasets requires new computational and analytical ... Read more Interpreting high-dimensional datasets requires new computational and analytical methods. We developed such methods to extract and analyze neural activity from 20,000 neurons recorded simultaneously in awake, behaving mice. The neural activity was not low-dimensional as commonly thought, but instead was high-dimensional and obeyed a power-law scaling across its eigenvalues. We developed a theory that proposes that neural responses to external stimuli maximize information capacity while maintaining a smooth neural code. We then observed power-law eigenvalue scaling in many real-world datasets, and therefore developed a nonlinear manifold embedding algorithm called Rastermap that can capture such high-dimensional structure.
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    Sparsity-based Methods for Rapid MRI

    Date:
    25
    Thursday
    June
    2020
    Lecture / Seminar
    Time: 09:30-10:30
    Lecturer: Dr. Efrat Shimron
    Organizer: Clore Institute for High-Field Magnetic Resonance Imaging and Spectroscopy
    Abstract: Zoom Lecture: https://weizmann.zoom.us/j/99058507421 Magnetic Resonance Ima ... Read more Zoom Lecture: https://weizmann.zoom.us/j/99058507421 Magnetic Resonance Imaging (MRI) is a superb imaging modality that provides high-quality images of the human body. However, one of its major limitations is the long acquisition time, which hinders the MRI clinical use. The acquisition time can be shortened by acquiring less data; however, this requires suitable methods for accurate image reconstruction from subsampled data, which is acquired with a sub-Nyquist rate. In this seminar, four novel methods for image reconstruction from subsampled data will be presented. These methods build upon the well-established frameworks of Parallel Imaging (PI) and Compressed Sensing (CS), utilize a-priori knowledge about data sparsity, and address current limitations of PI-CS methods. The first two methods accelerate static MRI scans by introducing the Convolution-based Reconstruction (CORE) framework, which offers a parameter-free non-iterative reconstruction. Experiments with in-vivo 7T brain data demonstrated that these methods perform comparably to the well-established GRAPPA and l1-SPIRiT methods, with the advantage of shorter computation times and reduced need for parameter calibration. The next two developed methods accelerate dynamic MRI scans that provide temperature monitoring in High Intensity Focused Ultrasound (MRgHIFU) thermal ablation treatments. The developed methods enable rapid MR monitoring by reconstructing temperature changes from subsampled data. Validation experiments were performed with in-vivo data from clinical treatments of prostate cancer in humans; these showed that the proposed methods significantly outperform two state-of-the-art methods in the temperature reconstruction task
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    Mean-field models for finite-size populations of spiking neurons

    Date:
    08
    Monday
    June
    2020
    Lecture / Seminar
    Time: 10:00
    Lecturer: Dr. Tilo Schwalger
    Organizer: Department of Brain Sciences
    Details: ONLINE SEMINAR Please click the link below to join: https://www.crowdcast.io/e ... Read more ONLINE SEMINAR Please click the link below to join: https://www.crowdcast.io/e/dr--tilo-schwalger/register Host: Prof.Misha Tsodyks. Pritish Patil: pritish.patil@weizmann.ac.il
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    Abstract: Firing-rate (FR) or neural-mass models are widely used for studying computations ... Read more Firing-rate (FR) or neural-mass models are widely used for studying computations performed by neural populations. Despite their success, classical firing-rate models do not capture spike timing effects on the microscopic level such as spike synchronization and are difficult to link to spiking data in experimental recordings. For large neuronal populations, the gap between the spiking neuron dynamics on the microscopic level and coarse-grained FR models on the population level can be bridged by mean-field theory formally valid for infinitely many neurons. It remains however challenging to extend the resulting mean-field models to finite-size populations with biologically realistic neuron numbers per cell type (mesoscopic scale). In this talk, I present a mathematical framework for mesoscopic populations of generalized integrate-and-fire neuron models that accounts for fluctuations caused by the finite number of neurons. To this end, I will introduce the refractory density method for quasi-renewal processes and show how this method can be generalized to finite-size populations. To demonstrate the flexibility of this approach, I will show how synaptic short-term plasticity can be incorporated in the mesoscopic mean-field framework. On the other hand, the framework permits a systematic reduction to low-dimensional FR equations using the eigenfunction method. Our modeling framework enables a re-examination of classical FR models in computational neuroscience under biophysically more realistic conditions.
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    Individual differences in decision-making under uncertainty: a neuroeconomic approach

    Date:
    19
    Tuesday
    May
    2020
    Lecture / Seminar
    Time: 12:30
    Lecturer: Prof. Ifat Levy
    Organizer: Department of Brain Sciences
    Details: Please click the link below to join: https://weizmann.zoom.us/j/95012439251 ... Read more Please click the link below to join: https://weizmann.zoom.us/j/95012439251 (This meeting will be a “regular” Zoom meeting and not a “webinar”) Host: Dr. Meital Oren meital.oren@weizmann.ac.il tel: 6479
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    Abstract: Individuals differ substantially in their attitudes to uncertainty: some avoid i ... Read more Individuals differ substantially in their attitudes to uncertainty: some avoid is at all costs, while others are tolerant of, or even seek, uncertainty. These differences are important, because uncertainty is everywhere – how we cope with uncertainty can have significant implications for our mental health and quality of life. I will describe a series of studies in which we characterize individual differences in decision-making under uncertainty, and use these characterizations to study the neural mechanisms of decision-making under uncertainty and variations in these mechanisms in mental illness.
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    Developmental Club Series

    Date:
    06
    Wednesday
    May
    2020
    Lecture / Seminar
    Time: 10:00
    Title: Cholesterol and the brain: how the intriguing evolution of cholesterol synthesis in animals shaped their nervous system
    Location: Arthur and Rochelle Belfer Building for Biomedical Research
    Lecturer: Dr. Amir Sapir
    Organizer: Department of Molecular Genetics

    From Cognition to Depression: Using Magnetic Resonance Spectroscopy to Study In-vivo Neurochemistry

    Date:
    03
    Tuesday
    March
    2020
    Lecture / Seminar
    Time: 12:30
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Dr. Assaf Tal
    Organizer: Department of Brain Sciences
    Details: Host: Dr. Meital Oren meital.oren@weizmann.ac.il tel: 6479 For assistance wit ... Read more Host: Dr. Meital Oren meital.oren@weizmann.ac.il tel: 6479 For assistance with accessibility issues, please contact naomi.moses@weizmann.ac.il
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    Abstract: Magnetic Resonance Spectroscopy (MRS) can be used to measure the in-vivo concent ... Read more Magnetic Resonance Spectroscopy (MRS) can be used to measure the in-vivo concentrations of several metabolites in the brain non-invasively. I will present our work using MRS to study two aspects of brain metabolism. First, I'll talk about our work on functional MRS, whereby we look at neurochemical changes during or after learning or function. In the second half of the talk, I will focus on new methods we're developing in the lab, and in particular on our ability to measure the thermal relaxation times of metabolites, which probe specific cellular and subcellular microenvironments. I will present some preliminary data showing where and how this could be useful.
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    Molecular Genetics special guest seminar

    Date:
    27
    Thursday
    February
    2020
    Lecture / Seminar
    Time: 11:00-12:00
    Title: “Transsynaptic mapping and manipulation of neural circuits by trans-Tango”
    Lecturer: Prof. Gilad Barnea
    Organizer: Department of Molecular Genetics
    Abstract: I will present trans-Tango, a new technique for anterograde transsynaptic circui ... Read more I will present trans-Tango, a new technique for anterograde transsynaptic circuit tracing and manipulation that we have established in fruit flies. At the core of trans-Tango is a synthetic signaling pathway that is introduced into all neurons in the animal. This pathway converts receptor activation at the cell-surface into reporter expression through site-specific proteolysis. Specific labeling is achieved by presenting a tethered ligand at the synapses of genetically defined neurons, thereby activating the pathway in their postsynaptic partners. Activation of the pathway culminates in expression of a reporter that can be visualized. Because our system is modular, it can be easily adapted to experiments in which the properties of specific circuits are modified and the functional consequences are analyzed. We first validated trans-Tango in the Drosophila olfactory system and then implemented it in the gustatory system, where projections beyond the firstorder receptor neurons are not well characterized. We identified second-order neurons within the sweet and bitter circuits and revealed that they target brain areas involved in neuromodulation with similar but distinct projection patterns. I will also present experiments in which we use trans-Tango in functional analysis of the gustatory circuits. Using our studies in flies as proof of concept, we are currently establishing an equivalent technique for labeling circuits in vertebrate models, such as mice and zebrafish. These experiments establish trans-Tango as a flexible platform for comprehensive transsynaptic analysis of neural circuits.
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    Synaptic markers in the reward system for the predisposition to overeat

    Date:
    25
    Tuesday
    February
    2020
    Lecture / Seminar
    Time: 12:30
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Dr. Yonatan Kupchik
    Organizer: Department of Brain Sciences
    Details: Host: Dr. Meital Oren meital.oren@weizmann.ac.il tel: 6479 For assistance wit ... Read more Host: Dr. Meital Oren meital.oren@weizmann.ac.il tel: 6479 For assistance with accessibility issues, please contact naomi.moses@weizmann.ac.il
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    Abstract: Obesity is a complex disease with its roots in the physiology of various brain c ... Read more Obesity is a complex disease with its roots in the physiology of various brain circuits. Although much progress has been made in understanding the disease, the most fundamental question remains unanswered – why do we overeat? As Clifford Saper (Harvard) points out, “if feeding were controlled solely by homeostatic mechanisms, most of us would be at our ideal body weight, and people would consider feeding like breathing or elimination, a necessary but unexciting part of existence”. Clearly this is not the case; hedonic eating has come increasing under the spotlight in recent years as a main driver of obesity. As food becomes more and more rewarding, could overeating be driven by a pathological search for reward? In my talk I will demonstrate that chronic diet of highly-palatable food changes the physiology of the reward system and that mice that gained the most weight differ from those that gained the least weight in the physiology of two regions of the reward system – the nucleus accumbens and the ventral pallidum. Furthermore, I will show that long term plasticity in the ventral pallidum may be an innate marker for the predisposition to overeat palatable food.
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    Developmental Club Series 2019-20

    Date:
    12
    Wednesday
    February
    2020
    Lecture / Seminar
    Time: 10:00
    Title: Visualizing neural activity: from intracellular signaling to whole-brain network From whole-brain landscape to millisecond dynamics
    Location: Arthur and Rochelle Belfer Building for Biomedical Research
    Lecturer: Dr. Takashi Kawashima
    Organizer: Department of Molecular Genetics

    A common neuronal mechanism underlying free and creative behavior in the human brain

    Date:
    11
    Tuesday
    February
    2020
    Lecture / Seminar
    Time: 12:30
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Prof. Rafael Malach
    Organizer: Department of Brain Sciences
    Details: Host: Dr. Meital Oren meital.oren@weizmann.ac.il tel: 6479 For assistance w ... Read more Host: Dr. Meital Oren meital.oren@weizmann.ac.il tel: 6479 For assistance with accessibility issues, please contact naomi.moses@weizmann.ac.il
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    Abstract: Free behavior is likely the most fundamental and essential aspect of human life. ... Read more Free behavior is likely the most fundamental and essential aspect of human life. It underlies our unique ability to self-generate actions and come up with creative and original solutions. Yet, the brain mechanism that drives such free and creative behaviors remains unknown. In my talk I will present experimental findings supporting the hypothesis that ultra-slow spontaneous (resting state) activity fluctuations are a central and ubiquitous mechanism underlying all types of free behavior. Traces of slow resting state fluctuations can account for the intriguing observation that free behaviors of all types- from generating names to free recall of visual images- are invariably preceded by a wave of slow (1-4 seconds) activity buildup. This buildup can be observed in BOLD-fMRI, intracranial recording of single neurons and more recently, in the massive hippocampal bursts called Sharp Wave Ripples. Could the similar slow dynamics of the spontaneous fluctuations and the anticipatory buildup preceding free behaviors be a mere coincidence? Crucially, I will present evidence that individual differences in the waveforms of spontaneous fluctuations measured during are significantly correlated to the shape of the buildup wave anticipating free and creative events. The critical role of spontaneous activity fluctuations in generating creative decisions is reminiscent of the use of stochastic noise in optimizing solutions in network models.
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    Whole-brain fMRI of the Behaving Mouse

    Date:
    04
    Tuesday
    February
    2020
    Lecture / Seminar
    Time: 12:30
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Prof. Itamar Kahn
    Organizer: Department of Brain Sciences
    Details: Host: Dr. Meital Oren meital.oren@weizmann.ac.il tel: 6479 For assistance wit ... Read more Host: Dr. Meital Oren meital.oren@weizmann.ac.il tel: 6479 For assistance with accessibility issues, please contact naomi.moses@weizmann.ac.il
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    Abstract: Functional MRI is used pervasively in human brain research, enabling characteriz ... Read more Functional MRI is used pervasively in human brain research, enabling characterization of distributed brain activity underlying complex perceptual and cognitive processes. However, heretofore this technique has been limited in utility in rodents. I will present whole-brain functional imaging of head-fixed mice performing go/no-go odor discrimination in a platform allowing precise odor-delivery system, non-invasive sniff recordings and lick detection, detailing the brain regions subserving this behavior from the naïve state to task proficiency including learning of rule reversal. I will briefly discuss efforts to expand the mouse fMRI platform to additional modalities and conclude by describing the prospects of this approach more broadly.
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    PhD Thesis Defense - Spatial and temporal integration in perceptual calibration

    Date:
    30
    Thursday
    January
    2020
    Lecture / Seminar
    Time: 10:30
    Location: Nella and Leon Benoziyo Building for Brain Research
    Lecturer: Ron Dekel (PhD Thesis Defense)
    Organizer: Department of Brain Sciences
    Details: Students & Postdocs Seminar Benoziyo Brain Research Building Room 113 For ... Read more Students & Postdocs Seminar Benoziyo Brain Research Building Room 113 For assistance with accessibility issues, please contact naomi.moses@weizmann.ac.il
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    Abstract: Processing of a visual stimulus depends on previous and surrounding stimulations ... Read more Processing of a visual stimulus depends on previous and surrounding stimulations. For example, how an orientation detail is perceived depends on previous and surrounding orientation content. The influence of such context, temporal and spatial, is postulated to be beneficial, but the involved mechanism(s) as well as the behavioral relevance are not fully understood. Here, using behavioral experiments that measure how context integrates in space and time, we argue that context changes how statistical decisions are made by the visual system. Most importantly, we find that several context-dependent perceptual biases, such as visual illusions and aftereffects, are much reduced with increasing reaction time. To account for this, we consider a simple yet general explanation: prior and noisy decision-related evidence are integrated serially, with evidence and noise accumulating over time (as in the standard drift diffusion model). With time, owing to noise accumulation, the prior effect is predicted to diminish. This theory suggests a single-process alternative to the intuitive notion of dual brain systems (the so-called System 1 and System 2), and quantitatively predicts several known properties of perceptual bias, such as the order-of-magnitude variation in measured bias magnitudes between individuals.
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    New methods for identifying latent manifold structure from neural data

    Date:
    28
    Tuesday
    January
    2020
    Lecture / Seminar
    Time: 14:00
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Prof. Jonathan Pillow
    Organizer: Department of Brain Sciences
    Details: Prof. Jonathan Pillow is visiting as a Guest of "Students-Invited Lecture Series ... Read more Prof. Jonathan Pillow is visiting as a Guest of "Students-Invited Lecture Series in Brain Sciences" and will give 2 seminars. For more details please contact: Aharon Ravia tel: 6273 aharon.ravia@weizmann.ac.il For accessibility issues, please contact naomi.moses@weizmann.ac.il
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    Abstract: An important problem in neuroscience is to identify low-dimensional structure un ... Read more An important problem in neuroscience is to identify low-dimensional structure underlying noisy, high-dimensional spike trains. In this talk, I will discuss recent advances for tackling this problem in single and multi-region neural datasets. First, I will discuss the Gaussian Process Latent Variable Model with Poisson observations (Poisson-GPLVM), which seeks to identify a low-dimensional nonlinear manifold from spike train data. This model can successfully handle datasets that appear high-dimensional with linear dimensionality reduction methods like PCA, and we show that it can identify a 2D spatial map underlying hippocampal place cell responses from their spike trains alone. Second, I will discuss recent extensions to Poisson-spiking Gaussian Process Factor Analysis (Poisson-GPFA), which incorporates separate signal and noise dimensions as well as a multi-region model with coupling between latent variables governing activity in different regions. This model provides a powerful tool for characterizing the flow of signals between brain areas, and we illustrate its applicability using multi-region recordings from mouse visual cortex.
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    Identification of similarities in archaeological collections using deep learning algorithms: a Levantine case study

    Date:
    23
    Thursday
    January
    2020
    Lecture / Seminar
    Time: 11:30-12:30
    Location: Nella and Leon Benoziyo Building for Biological Sciences
    Lecturer: Avi Resler
    Abstract: Artefacts that are found in archaeological excavations are often recognized by e ... Read more Artefacts that are found in archaeological excavations are often recognized by experts, who compare their appearance to other labeled objects that they have seen before or present in archaeological catalogs. Since this procedure may be subjective, scientific methods that aid archaeologists have become increasingly popular. We have developed two machine learning tools which capture the similarity between two artefacts or similarities between groups of artefacts based on their RGB images. For the first antique recognition tool, we used face recognition deep neural network architecture, to measure the "archaeological" distance between images. In the second community detection tool, we aggregate similarities between images and measure the distance between assemblages - i.e., group of images. Based on that we applied a network-theory community detection algorithm, to find groups of archaeological sites that are linked to each other. To test our methods, we used a highly diverse dataset of Israeli antiques. This dataset is a good case study due to geographical proximity between archaeological sites and the presence of artefacts from a wide range of archaeological ages.
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    Visualizing activity dependent signaling dynamics in intact neuronal circuits

    Date:
    21
    Tuesday
    January
    2020
    Lecture / Seminar
    Time: 12:30-13:30
    Title: Joint Seminar - Dept. of Neurobiology & Biomolecular Sciences
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Dr. Tal Laviv - Joint Seminar - Dept. of Neurobiology & Biomolecular Sciences
    Organizer: Department of Biomolecular Sciences
    Abstract: Sensory experience can change the structure and function of neurons in the brain ... Read more Sensory experience can change the structure and function of neurons in the brain over a wide range of timescales, from milliseconds-second modulation of synaptic activity to long-lasting alterations of genetic programs, lasting minutes to hours. While conversion of synaptic activity into long-lasting nuclear signaling is vital for learning and neuronal development, we still lack a clear understanding of its basic operating principles. To address this, I will describe recent advancements using two-photon fluorescence lifetime imaging and new biosensors which allowed us to image the activity of CREB, an activity-dependent transcription factor important for synaptic plasticity, at single cell resolution in awake mice. Simultaneous imaging of CREB and Ca2+ in the visual cortex permitted us to explore how sensory deprivation (dark-rearing) can modulate the sensitivity and duration of CREB activity to sensory-evoked Ca2+ elevations. Future work using this approach will allow us to unravel synapse to nucleus signaling dynamics underlying experience-dependent plasticity in the brain.
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    Visualizing activity dependent signaling dynamics in intact neuronal circuits

    Date:
    21
    Tuesday
    January
    2020
    Lecture / Seminar
    Time: 12:30
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Dr. Tal Laviv
    Organizer: Department of Brain Sciences
    Details: Joint Seminar-Depts of Neurobiology & Biomolecular Sciences Hosts: Prof. Ro ... Read more Joint Seminar-Depts of Neurobiology & Biomolecular Sciences Hosts: Prof. Rony Paz rony.paz@weizmann.ac.il tel: 6216 (Neurobiology) Prof. Rivka Dikstein rivka.dikstein@weizmann.ac.il tel: 2117 (Biomolecular Sciences) For assistance with accessibility issues, please contact naomi.moses@weizmann.ac.il
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    Abstract: Sensory experience can change the structure and function of neurons in the bra ... Read more Sensory experience can change the structure and function of neurons in the brain over a wide range of timescales, from milliseconds-second modulation of synaptic activity to long-lasting alterations of genetic programs, lasting minutes to hours. While conversion of synaptic activity into long-lasting nuclear signaling is vital for learning and neuronal development, we still lack a clear understanding of its basic operating principles. To address this, I will describe recent advancements using two-photon fluorescence lifetime imaging and new biosensors which allowed us to image the activity of CREB, an activity-dependent transcription factor important for synaptic plasticity, at single cell resolution in awake mice. Simultaneous imaging of CREB and Ca2+ in the visual cortex permitted us to explore how sensory deprivation (dark-rearing) can modulate the sensitivity and duration of CREB activity to sensory-evoked Ca2+ elevations. Future work using this approach will allow us to unravel synapse to nucleus signaling dynamics underlying experience-dependent plasticity in the brain.
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    Brain Health Molecules Mechanisms and Disease

    Date:
    19
    Sunday
    January
    2020
    -
    20
    Monday
    January
    2020
    Conference
    Time: 08:00

    Denise Cai: Linking memories across time and by Tristan Shuman: Breakdown of spatial coding and interneuron synchronization in epileptic mice

    Date:
    09
    Thursday
    January
    2020
    Lecture / Seminar
    Time: 14:30-15:30
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Denise Cai and Tristan Shuman
    Organizer: Department of Brain Sciences
    Details: Back-to-back Talk (1-hour long in total) Host: Prof. Nachum Ulanovsky nachum. ... Read more Back-to-back Talk (1-hour long in total) Host: Prof. Nachum Ulanovsky nachum.ulanovksy@weizmann.ac.il tel: 6301 For assistance with accessibility issues, please contact naomi.moses@weizmann.ac.il
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    Abstract: Denise Cai: Linking memories across time The compilation of memories, collecte ... Read more Denise Cai: Linking memories across time The compilation of memories, collected and aggregated across a lifetime defines our human experience. My lab is interested in dissecting how memories are stored, updated, integrated and retrieved across a lifetime. Recent studies suggest that a shared neural ensemble may link distinct memories encoded close in time. Using in vivo calcium imaging (with open-source Miniscopes in freely behaving mice), TetTag transgenic system, chemogenetics, electrophysiology and novel behavioral designs, we tested how hippocampal networks temporally link memories. Multiple convergent findings suggest that contextual memories encoded close in time are linked by directing storage into overlapping hippocampal ensembles, such that the recall of one memory can trigger the recall of another temporally-related memory. Alteration of this process (e.g. during aging, PTSD, etc) affect the temporal structure of memories, thus impairing efficient recall of related information. Tristan Shuman: Breakdown of spatial coding and interneuron synchronization in epileptic mice Temporal lobe epilepsy causes severe cognitive deficits yet the circuit mechanisms that alter cognition remain unknown. We hypothesized that the death and reorganization of inhibitory connections during epileptogenesis may disrupt synchrony of hippocampal inhibition. To test this, we simultaneously recorded from CA1 and dentate gyrus (DG) in pilocarpine-treated epileptic mice with silicon probes during head-fixed virtual navigation. We found desynchronized interneuron firing between CA1 and DG in epileptic mice. Since hippocampal interneurons control information processing, we tested whether CA1 spatial coding was altered in this desynchronized circuit using a novel wire-free Miniscope. We found that CA1 place cells in epileptic mice were unstable and completely remapped across a week. This place cell instability emerged ~6 weeks after status epilepticus, well after the onset of chronic spontaneous seizures and interneuron death. Finally, our CA1 network model showed that desynchronized inputs can impair information content and stability of CA1 place cells. Together, these results demonstrate that temporally precise intra-hippocampal communication is critical for spatial processing and hippocampal desynchronization contributes to spatial coding deficits in epileptic mice.
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    Vision and Robotics Seminar

    Date:
    09
    Thursday
    January
    2020
    Lecture / Seminar
    Time: 12:15-13:30
    Title: Beyond Accuracy: Neural Networks Show Similar Learning Dynamics Across Architectures
    Location: Jacob Ziskind Building
    Lecturer: Daphna Weinshall
    Organizer: Faculty of Mathematics and Computer Science,Department of Computer Science and Applied Mathematics,Department of Mathematics
    Details: One of the unresolved questions in deep learning is the nature of the solutions ... Read more One of the unresolved questions in deep learning is the nature of the solutions that are being discovered. We investigated the collection of solutions reached by the same neural network (NN) architecture, with different random initialization of weights and random mini-batches. These solutions are shown to be rather similar -- more often than not, each train and test example is either classified correctly by all NN instances, or by none at all. Furthermore, all NNs seem to share the same learning dynamics, whereby initially the same train and test examples are correctly recognized by the learned model, followed by other examples that are learned in roughly the same order. When extending the investigation to heterogeneous collections of NN architectures, once again examples are seen to be learned in the same order irrespective of architecture, although the more powerful architecture may continue to learn and thus achieve higher accuracy. Finally, I will discuss cases where this pattern of similarity breaks down, which show that the reported similarity is not an artifact of optimization by gradient descent.
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    Imaging deep: sensory and state coding in subcortical circuits

    Date:
    09
    Thursday
    January
    2020
    Lecture / Seminar
    Time: 11:00
    Location: Gerhard M.J. Schmidt Lecture Hall
    Lecturer: Dr. Jan Grundemann
    Organizer: Department of Brain Sciences
    Details: Host: Dr. Yaniv Ziv yaniv.ziv@weizmann.ac.il tel: 4275 For assistance with ... Read more Host: Dr. Yaniv Ziv yaniv.ziv@weizmann.ac.il tel: 4275 For assistance with accessibility issues, please contact naomi.moses@weizmann.ac.il
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    Abstract: Internal states, including affective or homeostatic states, are important behavi ... Read more Internal states, including affective or homeostatic states, are important behavioral motivators. The amygdala is a key regulator of motivated behaviors, yet how distinct internal states are represented in amygdala circuits is unknown. Here, by longitudinally imaging neural calcium dynamics across different environments in freely moving mice, we identify changes in the activity levels of two major, non-overlapping populations of principal neurons in the basal amygdala (BA) that predict switches between exploratory and non-exploratory (defensive, anxiety-like) states. Moreover, the amygdala broadcasts state information via several output pathways to larger brain networks, and sensory responses in BA occur independently of behavioral state encoding. Thus, the brain processes external stimuli and internal states orthogonally, which may facilitate rapid and flexible selection of appropriate, state-dependent behavioral responses.
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    Example 1 for internal event node

    Date:
    08
    Monday
    May
    2017
    -
    10
    Wednesday
    May
    2017
    Retreat
    Time: 10:00 - 12:30
    Location: David Lopatie Conference Centre ...
    Organizer: Department of ...

    Example 2 for internal event node

    Date:
    08
    Monday
    May
    2017
    -
    10
    Wednesday
    May
    2017
    Retreat
    Time: 10:00 - 12:30
    Location: David Lopatie Conference Centre ...
    Organizer: Department of ...