Events

Abstract: At every aspect of our lives, function determines structure. Just as new roads a ... Read more At every aspect of our lives, function determines structure. Just as new roads are built between developing cities, network wires are laid to accommodate faster communication demands, and social networks form around shared goals, the brain also remodels its connectome to adapt to the continuous and dynamic changes in functional demands.The connectome refers to the functional and structural characteristics of brain connectivity, spanning from the micron level (neural circuits) to the macroscopic level (long-scale pathways). This intricate network, encompassing the white matter and beyond, facilitates the transmission of information across different brain regions. When the integrity of the connectome is compromised, brain function deteriorates. Thus, the connectome is fundamental to everything the brain does.Traditionally, without the tools to explore the connectome in vivo, it was assumed to be stable and fixed. Much of white matter research focused on mapping the geographical structure of the network and its connected areas. However, advances in magnetic resonance imaging (MRI), particularly diffusion MRI, have opened a new window into the in vivo physiology of the white matter and the connectome.By measuring the microstructural properties of white matter, researchers now have the opportunity to investigate its physiology and dynamics. This presentation will demonstrate how the connectome can be measured, outline its macro- and microstructural features, and describe its evolutionary characteristics by comparing the connectomes of 100 different mammalian species. Additionally, we will explore the role of the connectome in brain plasticity and its remarkable dynamics.Light refreshments before the seminar

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Neuromodulation of experience-dependent sexually dimorphic learning

Date:

20

Monday

January

2025

Lecture / Seminar

Time: 11:00-12:15

Location: WSOS (FGS)

Lecturer: Sonu Kurien Dr. Meital Oren Lab

Organizer: Department of Brain Sciences

Abstract: How do sex-specific evolutionary drives influence decision-making processes when ... Read more How do sex-specific evolutionary drives influence decision-making processes when facing a shared environmental cue? Given the sex biases in disease states, some of which include a significant cognitive component, it is crucial to evaluate the influence of genetic sex on brain mechanisms from the ground up. In my thesis, I investigate if and how the genetic sex affects context and experience-dependent behavioral plasticity when learning an environmental cue. By utilizing a genes-to-behavior approach, I unravel sexual dimorphism in an ethologically relevant behavioral paradigm. C. elegans males do not learn to avoid the pathogenic bacteria PA14 as efficiently and rapidly as hermaphrodites, even though the pathogenicity is perceived. I explore the neuronal representations following training that encode this dimorphism and observe a possible sensory gating mechanism. The transcriptomic and subsequent behavioral analysis revealed the influence of the neuromodulatory network on male behavior. In particular, npr-5, an ortholog of the mammalian NPY receptor, regulates male learning by modulating typical neuronal activity. Finally, we uncover that male decision-making behavior is shaped by sexual status and is regulated by npr-5. Taken together, the work portrays how shared experiences drive sex-specific plasticity in hermaphrodites and males by modulating learning to fulfill perceived evolutionary needs.

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The ESCRT machinery: an evolutionary conserved, a multi-purpose membrane remodeling deviceounced

Date:

16

Thursday

January

2025

Lecture / Seminar

Time: 15:00-16:00

Location: Nella and Leon Benoziyo Building for Biological Sciences

Lecturer: Prof. Natalie Elia

Organizer: Department of Biomolecular Sciences

Abstract: The ESCRT membrane remodeling complex, found across all life forms, exhibits a v ... Read more The ESCRT membrane remodeling complex, found across all life forms, exhibits a versatility that transcends evolutionary boundaries. From orchestrating the constriction of micron-wide tubes in cell division to facilitating the budding of 50 nm vesicles in receptor degradation, ESCRTs perform diverse functions in animal cells. In recent years, ESCRT homologs were identified in prokaryotes, highlighting a role for this protein machinery in the ancient world. We seek to understand the mechanistic principles underlying the functional diversity of the ESCRT system across evolution. Specifically, we focus on understanding how the ESCRT complex orchestrate in cells to constrict and cut membranes in eukaryotes, focusing on its role in cell division, and in prokaryotes, focusing on the recently discovered Asgard archaea. By combining high-resolution imaging with biochemical and structural studies we aim to unlock the secrets of this fundamental membrane remodeling machinery and its potential role in evolution.

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Geometric Functional Analysis and Probability Seminar

Date:

16

Thursday

January

2025

Lecture / Seminar

Time: 13:30-14:30

Title: Free boundary problems and particle systems

Location: Jacob Ziskind Building

Lecturer: Rami Atar

Organizer: Department of Mathematics

Abstract: Particle systems that can be described macroscopically via free boundary problem ... Read more Particle systems that can be described macroscopically via free boundary problems (FBP) include the $N$-branching Brownian motion (branching Brownian particles on the line with removal of the leftmost particle upon each branching), and the Atlas model (Brownian particles on the line where the leftmost particle is equipped with a positive drift). The regularity of the free boundary plays a crucial role in proving the particle system -- FBP relation, but does not hold in some natural generalizations of these models. I will describe a weak FBP formulation where control over free boundary regularity is not required in order to achieve this relation in the two cases above. I will also describe an analogous weak formulation of a ``free obstacle’' problem aimed at a branching Brownian motion with removals occurring at the most densely populated areas. This is partly based on joint works with Amarjit Budhiraja and with Leonid Mytnik and Gershon Wolansky.

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Machine Learning and Statistics Seminar

Date:

15

Wednesday

January

2025

Lecture / Seminar

Time: 11:15-12:15

Title: Algebraic Approaches and Deep Neural Models for 3D Scene Reconstruction and Camera Pose Estimation in Static and Dynamic Environments

Location: Jacob Ziskind Building

Lecturer: Yoni Kasten

Organizer: Department of Computer Science and Applied Mathematics

Abstract: This talk will explore advances in 3D scene reconstruction, focusing on approach ... Read more This talk will explore advances in 3D scene reconstruction, focusing on approaches to estimate camera poses and scene structures in challenging multiview and dynamic content scenarios. First, I will outline foundational aspects of my earlier work, where we characterized the algebraic structure of fundamental and essential matrices in multiview settings and developed deep learning methods for joint recovery of camera parameters and sparse 3D scene structures. The main part of the talk introduces TracksTo4D (NeurIPS 2024), a novel, efficient method for reconstructing dynamic 3D structures and camera motion from casual videos. TracksTo4D leverages a dedicated encoder, trained in an unsupervised way on a dataset of casual videos, that uses 2D point tracks as input to infer dynamic 3D structures and camera motion. Our architecture takes into account symmetries in the problem, enforces the reconstruction to be of low rank, and models both static and dynamic scene components. Our model demonstrates strong generalization to unseen videos from new categories, achieving accurate 3D reconstruction and camera localization through a single feed-forward pass while drastically reducing running times. Bio: Yoni Kasten is a senior research scientist at NVIDIA Research in Tel Aviv, on Prof. Gal Chechik’s team. His research in 3D computer vision focuses on algebraic characterizations of multi-camera systems and deep neural models for surface reconstruction, dynamic scene modeling, and 4D scene reconstruction. Yoni earned his PhD from the Weizmann Institute, where his work on structure from motion estimation using algebraic characterizations, supervised by Prof. Ronen Basri, received the John F. Kennedy Prize for Outstanding Doctoral Research. He also completed his M.Sc. in Computer Science at the Hebrew University of Jerusalem under the supervision of Prof. Shmuel Peleg and Prof. Michael Werman.

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The Clore Center for Biological Physics

Date:

12

Sunday

January

2025

Lecture / Seminar

Time: 12:45-14:30

Title: Rethinking Cryo-EM, by Cryo-STEM

Location: Nella and Leon Benoziyo Physics Library

Lecturer: Prof. Michael Elbaum and Dr Shahar Seifer

Organizer: Clore Center for Biological Physics

Abstract: Cryo-EM has famously revolutionized structural biology with atomic-scale resolut ... Read more Cryo-EM has famously revolutionized structural biology with atomic-scale resolution of macromolecules in 3D. The conventional protocol is based on wide-field imaging with phase contrast introduced by defocus, followed by extensive image processing and averaging from a great number of identical objects. Key assumptions break down in the extension toward 3D imaging of thicker specimens such as cells, however, and especially for interpretation of unique features.The talk will be in two parts (by Michael and Shahar). The first will introduce an alternative imaging modality by scanning a focused probe, i.e., scanning transmission electron microscopy, or STEM, which circumvents some of these constraints. New camera technologies enable recording of the entire pattern of diffraction at every pixel, called 4D STEM. Combining the imaging with tomography, we explore new methods to exploit the wave coherence for 3D reconstruction with optimal contrast and resolution. Examples include crystals of heme, intact cells and sections of cell multilayers, and bacteriophage for the latest advances. The second part will center on the physical mechanisms of electron scattering relevant to cryo-EM. Combined with an energy loss spectrometer, a 4D STEM measurement provides atomic differential cross-sections, both elastic and inelastic. The elastic part relates to de Broglie phase delay by the average electric potential. The inelastic part is mainly due to generation of plasmons and scattering by the resulting polarization. The cross-sections provide data to test new modeling approaches, as well as to develop characterization tools for biological and other organic materials.FOR THE LATEST UPDATES AND CONTENT ON SOFT MATTER AND BIOLOGICAL PHYSICS AT THE WEIZMANN, VISIT OUR WEBSITE: https://www.biosoftweizmann.com/

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Black Holes in Galaxies: Experimental Evidence & Cosmic Evolution

Date:

09

Thursday

January

2025

Colloquium

Time: 11:15-12:30

Location: Edna and K.B. Weissman Building of Physical Sciences

Lecturer: Prof. Reinhard Genzel

Organizer: Department of Particle Physics and Astrophysics

Contact: eti.shalem@weizmann.ac.il

Abstract: About a century after Albert Einstein's presentation of General Relativity and K ... Read more About a century after Albert Einstein's presentation of General Relativity and Karl Schwarzschild's first solution, have three experimental techniques made remarkable progress in proving the existence of the Schwarzschild/Kerr black hole solution. I will describe the impressive progress of high resolution near-infrared and radio imaging and interferometry, and of precision measurements of gravitational waves in the Galactic Center and other galaxies. I will then discuss what we now know about the cosmic co-evolution and growth of galaxies and black holes, and finish with the riddle of massive black holes detected by JWST only a few hundred Myrs after the Big Bang.

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The Computational and Neural Basis of Cognitive Dynamics and Diversity

Date:

08

Wednesday

January

2025

Lecture / Seminar

Time: 11:15-12:45

Location: Belfer Building

Lecturer: Dr. Roey Schurr

Organizer: Department of Brain Sciences

Abstract: Humans adapt their behavior across multiple timescales: from rapid adjustments t ... Read more Humans adapt their behavior across multiple timescales: from rapid adjustments to changing contexts to lifelong tendencies in how they approach tasks. This variation across time and individuals poses a challenge for identifying the cognitive strategies people use and the neural processes that support them. My research combines computational modeling and neuroimaging to uncover the strategies individuals use and reveal how their dynamics are reflected in neural activity and constrained by brain structure. In this talk I will present my work on computational modeling of cognitive dynamics over weeks. I will briefly describe my work on mapping of human white matter, and my current work on the computational and neural bases of creative search. I will conclude by outlining my future research aimed at uncovering the core principles that drive both the dynamics and diversity of human cognition.

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Anatomical organization of the human hippocampal system

Date:

05

Sunday

January

2025

Lecture / Seminar

Time: 11:00-12:30

Location: Belfer Building

Lecturer: Dr. Daniel Reznik

Organizer: Department of Brain Sciences

Abstract: Animal tract-tracing studies provided critical insights into the organizational ... Read more Animal tract-tracing studies provided critical insights into the organizational principles of the hippocampal system, thus deﬁning the anatomical constraints within which animal mnemonic functions operate. However, no clear framework defining the anatomical organization of the human hippocampal system exists. This gap in knowledge originates in notoriously low MRI data quality in the human medial temporal lobe (MTL) and in group-level blurring of idiosyncratic anatomy between adjacent brain regions comprising the MTL. In this talk, I will present our recent data, which overcame these longstanding challenges and allowed us to explore in detail the cortical networks associated with the human MTL, and to examine the intrinsic organization of the hippocampal-entorhinal system with unprecedented anatomical precision. Our results point to biologically meaningful and previously unknown organizational principles of the human hippocampal system. These findings facilitate the study of the evolutionary trajectory of the hippocampal connectivity and function across species, and prompt a reformulation of the neuroanatomical basis of episodic memory.

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Vision and AI

Date:

02

Thursday

January

2025

Lecture / Seminar

Time: 12:15-13:15

Title: Utilizing Pre-trained Diffusion Models for Text-based Image and Video Editing

Location: Jacob Ziskind Building

Lecturer: Vladimir Kulikov

Organizer: Department of Computer Science and Applied Mathematics

Abstract: Text-to-image (T2I) diffusion/flow models achieve state-of-the-art results in im ... Read more Text-to-image (T2I) diffusion/flow models achieve state-of-the-art results in image synthesis. Many works leverage these models for real image editing, where a predominant approach involves inverting the image into its corresponding gaussian-like noise map. However, inversion by itself is often insufficient for structure preserving edits. In our first work in this talk, termed ‘An Edit Friendly DDPM Noise Space’ [1], we present alternative latent noise maps for denoising diffusion probabilistic models (DDPMs) that do not have a standard normal distribution. These noise maps allow for perfect reconstruction of any real image, and lead to structure preserving edits, as we exemplify in our experiments. In our second work, we tackle the task of text-based video editing using T2I diffusion models. Here the main challenge lies in maintaining the temporal consistency of the original video during the edit. Many methods leverage explicit correspondence mechanisms, which struggle with strong nonrigid motion. In contrast, our method termed ‘Slicedit’ [2], introduces a fundamentally different approach, which is based on the observation that spatiotemporal slices of natural videos exhibit similar characteristics to natural images. Thus, the same T2I diffusion model that is normally used only as a prior on video frames, can also serve as a strong prior for enhancing temporal consistency by applying it on spatiotemporal slices. As we show Sliceditgenerates videos that retain the structure and motion of the original video without relying on explicit correspondence matching while adhering to the target text. Finally, in our most recent work, we will discuss ‘FlowEdit’ [3], a novel text-based image editing method that leverages the increasingly popular flow models without relying on inversion. Our method constructs an ODE that directly maps between the source and target distributions (corresponding to the source and target text prompts) and achieves a lower transport cost than the inversion approach. This leads to state-of-the-art results, as we illustrate with Stable Diffusion 3 and FLUX. [1] An Edit Friendly DDPM Noise Space: Inversion and Manipulations - CVPR24’ https://arxiv.org/abs/2304.06140 [2] Slicedit: Zero-Shot Video Editing With Text-to-Image Diffusion Models Using Spatio-Temporal Slices - ICML24’ https://arxiv.org/abs/2405.12211 [3] FlowEdit: Inversion-Free Text-Based Editing Using Pre-Trained Flow Models – under review https://arxiv.org/abs/2412.08629 Bio: Vladimir Kulikov, PhD student at the Technion, under the supervision of Prof. Tomer Michaeli. Currently studying Deep Generative Models with emphasis on Computer Vision.

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Machine Learning and Statistics Seminar

Date:

01

Wednesday

January

2025

Lecture / Seminar

Time: 11:15-12:15

Title: A Novel Outlier-Robust PCA Method with Applications to Computer Vision

Location: Jacob Ziskind Building

Lecturer: Gilad Lerman

Organizer: Department of Computer Science and Applied Mathematics

Abstract: Robust subspace recovery (RSR), or outlier-robust PCA, aims to identify a low-di ... Read more Robust subspace recovery (RSR), or outlier-robust PCA, aims to identify a low-dimensional subspace in datasets corrupted by outliers—an essential task for fundamental matrix estimation in computer vision. Despite numerous approaches, RSR faces two main challenges: heuristic methods like RANSAC often outperform mathematically rigorous approaches, and as outlier fractions grow, the problem becomes computationally intractable, with limited theoretical guarantees. We introduce the subspace-constrained Tyler's estimator (STE), which fuses Tyler's M-estimator with the fast median subspace method. Our analysis establishes that STE, when properly initialized, achieves effective subspace recovery even in challenging regimes previously lacking theoretical guarantees. We further demonstrate STE's competitive performance in fundamental matrix estimation and relate it to broader structure-from-motion (SfM) challenges. Finally, we highlight its relevance to recent advances in three-view SfM, leveraging tensor decomposition of trifocal tensors.

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The Neural Basis of Affective States

Date:

31

Tuesday

December

2024

Lecture / Seminar

Time: 12:30-14:00

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Dr. Amit Vinograd

Organizer: Department of Brain Sciences

Abstract: How does the brain regulate innate behaviors and emotional states? My researchis ... Read more How does the brain regulate innate behaviors and emotional states? My researchis driven by a vision to decode evolutionarily conserved neural circuits that regulateaffective states like aggression and anxiety. In my work, I combine deep-brain 2-photoncalcium imaging and holographic optogenetics with theoretical neuroscience approachesto unravel latent manifolds of neural activity and their dynamics. One such dynamic, lineattractors, is hypothesized to encode continuous variables such as eye position, workingmemory, and internal states. However, direct evidence of neural implementation of a lineattractor in mammals has been hindered by the challenge of targeting perturbations tospecific neurons within ensembles. In this talk, I will present our recent breakthroughsdemonstrating causal evidence for line attractor dynamics in neurons encoding anaggressive state and highlight functional connectivity within specific neuronalensembles. This work effectively bridges circuit and manifold levels, providing strongevidence of intrinsic continuous attractor dynamics in a behaviorally relevant mammaliansystem.

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Perceptual decision coding is inherently coupled to action in the mouse cortex

Date:

29

Sunday

December

2024

Lecture / Seminar

Time: 12:00-13:15

Location: Max and Lillian Candiotty Building

Lecturer: Michael Sokoletsky PhD Defense

Organizer: Department of Brain Sciences

Abstract: How do animals make perceptual decisions about sensory stimuli to guide motor ac ... Read more How do animals make perceptual decisions about sensory stimuli to guide motor actions? One hypothesis is that dedicated "perceptual decision" cells process sensory information and drive the appropriate action. Alternatively, perceptual decisions result from competition among cells driving different actions, making decisions inherently coupled to actions. To distinguish between these hypotheses, we designed a vibrotactile detection task in which mice flexibly switched between standard and reversed contingency blocks, respectively requiring them to lick after stimulus presence or absence. Optogenetic inactivation of somatosensory and secondary motor cortices reduced stimulus sensitivity without impairing the ability to lick. However, widefield and two-photon imaging found that differences in cortical activity across perceptual decisions were almost exclusively action-coupled. In addition, we identified a subset of cells that encoded the current contingency block in a gated manner, enabling mice to flexibly make decisions without relying on action-independent decision coding.

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Deep language models as a cognitive model for natural language processing in the human brain

Date:

26

Thursday

December

2024

Lecture / Seminar

Time: 12:30-13:30

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Prof. Uri Hasson

Organizer: Department of Brain Sciences

Abstract: Naturalistic experimental paradigms in cognitive neuroscience arose from a press ... Read more Naturalistic experimental paradigms in cognitive neuroscience arose from a pressure to test, in real-world contexts, the validity of models we derive from highly controlled laboratory experiments. In many cases, however, such efforts led to the realization that models (i.e., explanatory principles) developed under particular experimental manipulations fail to capture many aspects of reality (variance) in the real world. Recent advances in artificial neural networks provide an alternative computational framework for modeling cognition in natural contexts. In this talk, I will ask whether the human brain's underlying computations are similar or different from the underlying computations in deep neural networks, focusing on the underlying neural process that supports natural language processing in adults and language development in children. I will provide evidence for some shared computational principles between deep language models and the neural code for natural language processing in the human brain. This indicates that, to some extent, the brain relies on overparameterized optimization methods to comprehend and produce language. At the same time, I will present evidence that the brain differs from deep language models as speakers try to convey new ideas and thoughts. Finally, I will discuss our ongoing attempt to use deep acoustic-to-speech-to-language models to model language acquisition in children.

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Anterior-Posterior Insula Circuit Mediates Retrieval of a Conditioned Immune Response in Mice

Date:

24

Tuesday

December

2024

Lecture / Seminar

Time: 12:30-13:30

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Prof. Kobi Rosenblum

Organizer: Department of Brain Sciences

Abstract: The brain can form associations between sensory information of inner and/or oute ... Read more The brain can form associations between sensory information of inner and/or outer world (e.g. Pavlovian conditioning) but also between sensory information and the immune system. The phenomenon which was described in the last century is termed conditioned immune response (CIR) but very little is known about neuronal mechanisms subserving it. The conditioned stimulus can be a given taste and the unconditioned stimulus is an agent that induces or reduces a specific immune response. Over the last years, we and others revealed molecular and cellular mechanisms underlying taste valance representation in the anterior insular cortex (aIC). Recently, a circuit in the posterior insular cortex (pIC) encoding the internal representation of a given immune response was identified. Together, it allowed us to hypothesize and prove that the internal reciprocal connections between the anterior and posterior insula encode CIR. One can look at CIR as a noon declarative form of Nocebo effect and thus we demonstrate for the first time a detailed circuit mechanism for Placebo/Nocebo effect in the cortex.

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The Clore Center for Biological Physics

Date:

15

Sunday

December

2024

Lecture / Seminar

Time: 12:45-14:30

Title: Rationally designed functionalization of single-walled carbon nanotubes for real-time monitoring of active processes

Location: Nella and Leon Benoziyo Physics Library

Lecturer: Prof. Gili Bisker

Organizer: Clore Center for Biological Physics

Abstract: Semiconducting single-walled carbon nanotubes (SWCNTs) fluoresce in the near-inf ... Read more Semiconducting single-walled carbon nanotubes (SWCNTs) fluoresce in the near-infrared (NIR) range, which overlaps with the transparency window of biological samples, and they do not photobleach or blink. These properties make SWCNTs uniquely suited for long-term imaging and sensing applications. Using tailored surface functionalization, SWCNTs can act as dynamic optical nanosensors, transducing biochemical changes in their environment into modulations in fluorescence intensity. Owing to their intrinsic physicochemical and optical properties, SWCNTs can provide real-time, spatiotemporal information on active processes across scales, from molecular interactions to whole organism dynamics.Here, I will discuss different strategies for utilizing rationally designed functionalized SWCNTs to probe active biological processes. These include monitoring enzymatic activity, tracking supramolecular self-assembly and disassembly, and mapping in vivo processes. These findings showcase the potential of near-infrared fluorescent SWCNTs to provide insights into dynamic biological systems.LINK FOR STUDENTS INTERESTED MEETING PROF. GILI BISKER 14:30-15:15 Link FOR THE LATEST UPDATES AND CONTENT ON SOFT MATTER AND BIOLOGICAL PHYSICS AT THE WEIZMANN, VISIT OUR WEBSITE: https://www.biosoftweizmann.com/

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The Clore Center for Biological Physics

Date:

15

Sunday

December

2024

Lecture / Seminar

Time: 00:00-01:00

Title: Rationally designed functionalization of single-walled carbon nanotubes for real-time monitoring of active processes

Location: Nella and Leon Benoziyo Physics Library

Lecturer: Prof. Gili Bisker

Organizer: Clore Center for Biological Physics

Abstract: Semiconducting single-walled carbon nanotubes (SWCNTs) fluoresce in the near-inf ... Read more Semiconducting single-walled carbon nanotubes (SWCNTs) fluoresce in the near-infrared (NIR) range, which overlaps with the transparency window of biological samples, and they do not photobleach or blink. These properties make SWCNTs uniquely suited for long-term imaging and sensing applications. Using tailored surface functionalization, SWCNTs can act as dynamic optical nanosensors, transducing biochemical changes in their environment into modulations in fluorescence intensity. Owing to their intrinsic physicochemical and optical properties, SWCNTs can provide real-time, spatiotemporal information on active processes across scales, from molecular interactions to whole organism dynamics.Here, I will discuss different strategies for utilizing rationally designed functionalized SWCNTs to probe active biological processes. These include monitoring enzymatic activity, tracking supramolecular self-assembly and disassembly, and mapping in vivo processes. These findings showcase the potential of near-infrared fluorescent SWCNTs to provide insights into dynamic biological systems.LINK FOR STUDENTS INTERESTED MEETING PROF. GILI BISKER 14:30-15:15 Link FOR THE LATEST UPDATES AND CONTENT ON SOFT MATTER AND BIOLOGICAL PHYSICS AT THE WEIZMANN, VISIT OUR WEBSITE: https://www.biosoftweizmann.com/

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Unlocking ALS: Muscle Exosome Control TDP-43 Local Synthesis at the NMJced

Date:

12

Thursday

December

2024

Lecture / Seminar

Time: 15:00-16:00

Location: Nella and Leon Benoziyo Building for Biological Sciences

Lecturer: Prof. Eran Perlson

Organizer: Department of Biomolecular Sciences

Abstract: Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease characterize ... Read more Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease characterized by TDP-43 mislocalization, aggregation, and disruption of neuromuscular junctions (NMJs). We have identified a key pathological mechanism involving the accumulation of TDP-43 in axons, which impairs local protein synthesis and drives NMJ degeneration. This process is linked to dysregulated muscle-derived exosomes carrying miR-126a-5p, essential for maintaining proper nerve-muscle communication. In ALS, reduced levels of miR-126a-5p lead to abnormal TDP-43 synthesis in axons. Restoring miR-126 in vivo and in human co-culture systems provides neuroprotection. Our findings highlight a transcellular signaling axis between muscles and neurons, offering new insights into NMJ maintenance and a potential foundation for ALS therapeutic strategies.

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Neuroprotective and Anticonvulsant Effects of Cannabinoids with Neurotrauma

Date:

05

Thursday

December

2024

Lecture / Seminar

Time: 12:30-13:30

Location: Benoziyo Brain Research Building

Lecturer: Prof.Linda Friedman

Organizer: Department of Brain Sciences

Abstract: Traumatic brain (TBI) injuries result in profound local hypoperfusion, ischemia, ... Read more Traumatic brain (TBI) injuries result in profound local hypoperfusion, ischemia, chronic inflammation and refractory seizures(post-traumatic epilepsy (PTE)), and restrict drug delivery to the site of impact so that peripheral treatment alone would have limited access to the site of injury during the most critical phases of neurotrauma. Cannabidiol (CBD), the major non-psychotropic cannabinoid, has anti-convulsant, anti-inflammatory, anti-nociceptive, antioxidant, and immuno-suppressive properties not fully understood. In pre-juvenile rats, microinjection of CBD attenuated kainate(KA)-induced seizures to a greater extent than intraperitoneal injection, indicating that local drug administration was more effective. In adult rats after experimental TBI, our modified CBD-infused implant applied extradural with oil injection supplementation restored vestibulomotorand cognitive functions compared to systemic treatment alone. We questioned whether the CBD or the low concentrations of THC in the extract was responsible for behavioral and cellular recovery.We hypothesized that an optimal ratio of cannabidiol (CBD) to tetrahydrocannabinol (THC) is required to protect against neuropathological consequences following TBI greater than either substance alone. Varied CBD:THC extract concentrations were compared with hempCBD lacking THC (CBD0). Neurons, glia, and parvalbumin interneurons (PV-INs) were evaluated. Weight loss was observed following high doses of THC dominant cannabis, THC100:1. Neuroscoresand vestibulomotorperformance were restored more with CBD:THC300:1-10:1. However, THC dominant treatments resulted in early onset to spontaneous seizures post-TBI. In a non-reward T-maze, the CBD10:1group had the highest alternation rates; TBI + vehicle, CBD0, CBD1:1, and THC100:1treatment groups had the lowest. The novel object recognition memory task showed CBD300:1treated animals had the best performance, while TBI or THC100:1treated groups had the worst. The forced swim test (FST) showed immobility time was highest after TBI and lowest after THC100:1treatment. The elevated plus maze (EPM) revealed the CBD0group spent the most time in closed arms. Both tests indicate that reduced anxiety was THC dependent. All combinations resulted in reduced injury but CBD10:1and THC20:1gave the most protection and THC100:1the least. Reduced anxiety level was THC dependent but higher doses were pro-convulsant cautioning THC dosing. Reduced GFAP labeling was highest with CBD dominant cannabis supporting its neuroprotective role against inflammation. Rescue of diminished bilateral PV-INs was observed within the hippocampus and medial prefrontal cortex (mPFC) with CBD dominant treatment (CBD300, CBD0) supporting their anticonvulsant effect. Loss of PV-INs with THC dominant treatment supports their proconvulsant effect. Thus, CBD and THC have different beneficial therapeutic effects indicating an optimal concentration ratio is critical for optimal neuropathological therapeutics.Light refreshments before the seminar

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Vision and AI

Date:

05

Thursday

December

2024

Lecture / Seminar

Time: 12:15-13:15

Title: Semantic Vector Representations in the Service of Computer Vision

Location: Jacob Ziskind Building

Lecturer: Or Hirschorn

Organizer: Department of Computer Science and Applied Mathematics

Abstract: In this talk, we examine the benefits of semantic vector representations for ... Read more In this talk, we examine the benefits of semantic vector representations for computer vision, highlighting their advantages over pixel-space representations in various applications. We first consider the problem of human motion anomaly detection and demonstrate the advantage of doing that over human poses. Then, we introduce a novel category-agnostic approach, termed GraphCape, that enables pose estimation across any category. Finally, we will explore further improvements for structure-based CAPE networks, dynamically predicting useful connections. Bio: Or Hirschorn is a PhD candidate at Tel Aviv University, advised by Prof. Shai Avidan. His research interests are in developing methods for learning semantic vector representations of images and their applications for a variety of vision tasks. His MSc work won him the Weinstein scholarship for outstanding signal processing research.

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The Evolution of 7T (and Beyond) MRI in Basic Research and Clinical Practice

Date:

03

Tuesday

December

2024

Lecture / Seminar

Time: 12:30-13:30

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Prof. Noam Harel

Organizer: Department of Brain Sciences

Details: Host: Rita Schmidt rita.schmidt@weizmann.ac.il tel:9070 For accessibility iss ... Read more

Abstract: The Center for Magnetic Resonance Research (CMRR) has been at the forefront of m ... Read more The Center for Magnetic Resonance Research (CMRR) has been at the forefront of magnetic resonance imaging (MRI) innovation, pioneering ultra-high field (7 Tesla and above) technologies that are revolutionizing brain research and clinical care. This presentation will explore CMRR's groundbreaking journey, from the first functional MRI study to development of high-resolution fMRI capabilities revealing cortical columns within the human cortex. The presentation will also explore the translation of these technologies into clinical practice, with a focus on the unique visualization capabilities of 7T MRI, particularly for enhancing the precision of Deep Brain Stimulation (DBS) procedures.By exploring the progression from the 7T system to the world’s first 10.5T human MRI, this presentation will illustrate how these transformative technologies have pushed the limits of imaging science, uncovering new insights into brain function and advancing personalized clinical care at the intersection of technology, research, and medicine.

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Seminar for PhD thesis defense

Date:

05

Tuesday

November

2024

Lecture / Seminar

Time: 11:30

Title: Epithelial Tissue Regeneration by Compensatory Proliferation After Ionizing Radiation is Controlled by the Apical Caspase 9 Ortholog Dronc

Location: Arthur and Rochelle Belfer Building for Biomedical Research

Lecturer: Tslil Braun

Organizer: Department of Molecular Genetics

Contact: sandra.britton@weizmann.ac.il

Special Guest Seminar-Dr. Tamar Ben-Shaanan

Date:

29

Tuesday

October

2024

Lecture / Seminar

Time: 10:00-11:00

Location: Arthur and Rochelle Belfer Building for Biomedical Research

Lecturer: Dr. Tamar Ben-Shaanan

Organizer: Department of Molecular Neuroscience

Contact: bosmat.kariti@weizmann.ac.il

Abstract: Pain is a self-preservation mechanism, providing warning indicators associated w ... Read more Pain is a self-preservation mechanism, providing warning indicators associated with tissue damage. These indicators are perceived by nociceptive peripheral innervations with the ability to signal the brain. Nociceptive innervations are also a part of the infrastructure of various organs, yet the imprint their activity has on tissue physiology remains understudied. Here, we applied chemogenetics in mice to locally activate cutaneous TRPV1 innervations in naïve skin and found it triggered accelerated anagen onset. This was preceded by a rapid apoptosis of dermal macrophages mediated by neuropeptide calcitonin gene-related peptide (CGRP), followed by an induction of Osteopontin (Spp1)-expressing dermal fibroblasts. Spp1, an extracellular matrix protein and a hair growth promoting factor, was essential for the TRPV1-triggered induction of new regenerative cycling by dormant hair follicles. Specifically, macrophages responsiveness to CGRP was required for the changes in dermal fibroblasts. Finally, we show that epidermal abrasion induced Spp1-expressing dermal fibroblasts and hair growth via a TRPV1 neuron and CGRP dependent mechanism. Collectively, these data demonstrate a role for pain facilitating innervations in coordinating a cellular mechanism that promotes hair growth and the restoration of this important mechano- and thermo-protective barrier

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Reading Minds & Machines-AND-The Wisdom of a Crowd of Brains

Date:

25

Tuesday

June

2024

Lecture / Seminar

Time: 12:30

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Prof. Michal Irani,Prof. Michal Irani

Organizer: Department of Brain Sciences

Details: For accessibility issues:naomi.moses@weizmann.ac.il

Abstract: 1. Can we reconstruct images that a person saw, directly from his/her fMRI bra ... Read more 1. Can we reconstruct images that a person saw, directly from his/her fMRI brain recordings? 2. Can we reconstruct the training data that a deep-network trained on, directly from the parameters of the network? The answer to both of these intriguing questions is “Yes!” In this talk I will show how these can be done. I will then show how exploring the two domains in tandem can potentially lead to significant breakthroughs in both fields. More specifically: (i) I will show how combining the power of Brains & Machines can potentially be used to bridge the gap between those two domains. (ii) Combining the power of Multiple Brains (scanned on different fMRI scanners with NO shared stimuli) can lead to new breakthroughs and discoveries in Brain-Science. We refer to this as “the Wisdom of a Crowd of Brains”. In particular, we show that a Universal Encoder can be trained on multiple brains with no shared data, and that information can be functionally mapped between different brains.

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Mechano-regulation of gene expression in striated muscle

Date:

25

Tuesday

June

2024

Lecture / Seminar

Time: 10:00-11:30

Location: Nella and Leon Benoziyo Building for Biological Sciences

Lecturer: Dr. Daria Amiad-Pavlov

Organizer: Department of Biomolecular Sciences

Abstract: In recent years the cell nucleus emerged as a dynamic mechanosensor capable of s ... Read more In recent years the cell nucleus emerged as a dynamic mechanosensor capable of sensing and transducing mechanical signals into cellular responses to facilitate homeostasis and adaptation to changing environmental conditions. The constantly beating heart has a remarkable ability to adapt its structure and contractility in response to changes in mechanical load. I am introducing unique, live, and dynamic imaging approaches to investigate how nuclei in the mature heart can provide such mechano-protection and mechano-regulation of the genome. I will present a novel assay to couple cytoskeletal to nuclear strain transfer in the beating cardiomyocyte, and its further application to decipher mechanisms of nuclear damage in dilated cardiomyopathy caused by mutations in the LMNA gene (LMNA-DCM). This work pinpoints localized microtubule-dependent forces, but surprisingly not actomyosin contractility, as drivers of nuclear damage in LMNA-DCM, highlighting new therapeutic avenues. I will further discuss the role of mechanical signaling in spatial organization of the genome within the nucleus, to regulate transcriptionally active and repressed hubs, and downstream gene expression.

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Vision and AI

Date:

13

Thursday

June

2024

Lecture / Seminar

Time: 16:00-17:00

Title: Today’s “AI”-derived engineer-level models of the neural mechanisms of primate object perception, and tests of their application in non-invasive modulation of high level brain states

Lecturer: James DiCarlo

Organizer: Department of Computer Science and Applied Mathematics

Vision and AI Lecture / Seminar website

Details: ***Zoom Only***

Abstract: The human species is on a great scientific quest — to understand the neural me ... Read more The human species is on a great scientific quest — to understand the neural mechanisms of human (primate) intelligence. Recent progress in multiple subfields of brain research suggests that key next steps in this quest will result from building real-world capable, systems-level network models that aim to abstract, emulate and explain the primate neural mechanisms underlying natural intelligent behavior. In this talk, I will briefly outline the story of how neuroscience, cognitive science and computer science (“AI”) converged to create specific, image-computable, deep neural network models intended to appropriately abstract, emulate and explain the mechanisms of primate core visual object identification and categorization. Based on a large body of primate neurophysiological and behavioral data, some of these network models are currently the leading (i.e. most accurate) scientific theories of the internal mechanisms of the primate ventral visual stream and how those mechanisms support the ability of humans and other primates to rapidly and accurately infer latent world content (e.g. object identity, position, pose, etc.) from the set of pixels (image) received under typical (brief) natural viewing. While still far from complete, because these leading neuroscientific models are fully observable and machine-executable, they offer predictive and potential application power that the field’s prior conceptual models did not. I will describe two recent examples from our team. First, I will show that — relative to the gold standard of primate brains and minds — the leading models are both similarly sensitive to and similarly robust to adversarial attack at both their neural levels and their behavioral levels. Second, I will describe initial empirical tests of the closely related possibility of using such models to design spatial patterns of light energy on the retina (i.e. customized, synthetic images) to precisely, and non-invasively modulate neuronal activity deep in the primate brain. Consistent with model predictions, these tests reveal surprisingly strong and precise neural population effects. Besides being a tool for neuroscience, we see this as an exciting new application avenue of potential human clinical benefit.

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Gallery: Vision and AI Gallery

Special Guest Seminar

Date:

09

Sunday

June

2024

Lecture / Seminar

Time: 10:00-11:00

Title: Combined multimodal single-synapse profiling of synaptic activity, multiprotein composition, and translation

Location: Arthur and Rochelle Belfer Building for Biomedical Research

Lecturer: Dr. Reuven (Beny) Falkovich

Organizer: Department of Molecular Neuroscience

Contact: sivan.hoek@weizmann.ac.il

Abstract: The analog computation at the chemical synapse that underlies cognition depends ... Read more The analog computation at the chemical synapse that underlies cognition depends on a highly compartmentalized, tightly regulated, and complex network of interactions between synaptic activity and hundreds of proteins and the mechanisms that regulate them. For a top-down study of how the network operates in concert, I present a modular, versatile approach for combined imaging of multiprotein composition, activation states, ion and neurotransmitter fluxes, and mRNA translation across the same individual synapses. I will show how this approach extends to other subcellular systems such as mitochondria. I will discuss the use of Bayesian network inference to extract biological insight from high-dimensional, multimodal synapse distributions. Finally, I will present applications of this approach to identify convergent molecular phenotypes across autism and schizophrenia-associated genes, and for an in-depth study of the complex synaptic response to genetic and chemical perturbations of GluN2A.

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Memory consolidation and generalization during sleep

Date:

05

Wednesday

June

2024

Lecture / Seminar

Time: 10:00-11:00

Location: Nella and Leon Benoziyo Building for Brain Research

Lecturer: Ella Bar-Student Seminar-PhD Thesis Defense

Organizer: Department of Brain Sciences

Details: Student Seminar-PhD Thesis Defense For accessibility issues: naomi.moses@weiz ... Read more

Abstract: During sleep, our memories are reactivated and consolidated in an active process ... Read more During sleep, our memories are reactivated and consolidated in an active process that significantly influences our memory and decision-making. In this talk, I will present two studies about sleep-memory consolidation. The first study investigated sleep memory consolidation's local versus global properties within the brain. By exploiting the unique functional neuroanatomy of olfactory system, we were able to manipulate sleep oscillations and enhance memories locally within a single hemisphere during sleep. These findings underscore the local nature of sleep memory consolidation, which can be selectively manipulated within the brain, thereby creating an important link between theories of local sleep and learning. The second research explored the relationship between generalization processes and sleep, acknowledging that overgeneralization of negative stimuli and disruptions in sleep quality contribute to anxiety and PTSD disorders. Specifically, we studied participants' responses to stimuli associated with positive, negative, or neutral outcomes. Our findings revealed significant correlations between brain activity, as detected by fMRI, during the association of a stimulus with an outcome and the perceptual generalization of these stimuli. While activity in limbic brain areas was correlated with immediate negative stimulus generalization, we observed that the activation in these areas predicted recovery and positively related generalization following sleep. Moreover, we identified specific sleep oscillations correlated with this recovery generalization using high-density EEG recordings. These results highlight the crucial role of sleep in both generalization processes and the restoration of balanced responses to stimuli. Understanding these mechanisms can offer valuable insights into developing therapeutic strategies for anxiety and PTSD.

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Blood flow perturbations and its impact on brain structure and function: from microstrokes to heartbeats

Date:

04

Tuesday

June

2024

Lecture / Seminar

Time: 12:30-13:30

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Prof. Pablo Blinder

Organizer: Department of Brain Sciences

Details: Host: Dr. Yoav Livneh yoav.livneh@weizmann.ac.il For accessibility issues:n ... Read more

Vision and AI

Date:

23

Thursday

May

2024

Lecture / Seminar

Time: 12:15-13:15

Title: 3D Motion Synthesis and Control

Location: Jacob Ziskind Building

Lecturer: Sigal Raab

Organizer: Department of Computer Science and Applied Mathematics

Designing nanoparticles for biological environments: from quantum sensing to gene medicine Colloquium website

Abstract: Human motion is a fundamental attribute, underlying human actions, gestures, and ... Read more Human motion is a fundamental attribute, underlying human actions, gestures, and behavior. Research of human motion has a wide range of applications, from medical simulations, through security, to entertainment. While the domain of deep learning for RGB image analysis has received huge attention, the domain of motion manipulation using DNNs, and more recently diffusion models, is in its infancy, and holds many scientific opportunities yet to be discovered. Moreover, motion is challenging due to its irregular structure, diverse angles, and the expense and complexity of obtaining high-quality data. My research focuses on generative tasks such as motion synthesis and motion editing using deep neural networks. In the upcoming talk, I will discuss the building blocks used for motion synthesis and elaborate on various works that utilize diffusion models for synthesis and editing tasks. Each work addresses different aspects of the motion domain and involves various controls and tasks.

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Designing nanoparticles for biological environments: from quantum sensing to gene medicine

Date:

20

Monday

May

2024

Colloquium

Time: 11:00-12:15

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Prof. Petr Cigler

Organizer: Department of Chemical and Biological Physics

Contact: sarah.amzallag@weizmann.ac.il

Abstract: The use of nanoparticles in diagnostics, therapeutics and imaging has revolution ... Read more The use of nanoparticles in diagnostics, therapeutics and imaging has revolutionized these fields with new properties not available with small molecules. Nanoparticle interface provide possibilities for polyvalent and independent attachment of different molecules serving as recognition/targeting structures, optical probes, spin probes or catalysts. However, nanoparticles operating in biological environments require precise control of multiple factors related to surface chemistry and their composition. To avoid for example aggregation, off-target interactions, and protein corona formation, appropriate interface design is essential. This talk will present general nanoparticle design strategies and specific examples including nanodiamonds and lipid nanoparticles.

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Geometric Functional Analysis and Probability Seminar

Date:

16

Thursday

May

2024

Lecture / Seminar

Time: 13:30-14:30

Title: Asymptotic analysis in some problems with fractional Brownian motion

Location: Jacob Ziskind Building

Lecturer: Pavel Chigansky

Organizer: Department of Mathematics

Abstract: Some problems in the theory and applications of stochastic processes reduce to s ... Read more Some problems in the theory and applications of stochastic processes reduce to solving integral equations with their covariance operators. Usually, such equations do not have explicit solutions, but useful information can still be extracted through asymptotic analysis with respect to relevant parameters. In this talk, I will survey some recent results on such equations for processes related to the fractional Brownian motion: applications include the problem of small deviations, linear filtering, and statistical inference.

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Elizabeth Reznik GM Shouval Lab

Date:

15

Wednesday

May

2024

Lecture / Seminar

Time: 10:00-11:00

Location: Nella and Leon Benoziyo Building for Biological Sciences

Lecturer: Adi Hazak

Organizer: Department of Biomolecular Sciences

Details: Host: Ori Avinoam

Abstract: Myoblast cell fusion is essential for skeletal muscle development and regenerati ... Read more Myoblast cell fusion is essential for skeletal muscle development and regeneration. Yet, the molecular machinery that drives myoblast fusion remains incompletely understood. Myoblast cell fusion is an intricate multistep process, making it challenging to identify the specific proteins involved. Until now, no approach was available to capture fusing cells and dissect the dynamic changes in their cellular transitions. To fill this gap, we have developed a method using small-molecule inhibitors to synchronize muscle differentiation ex vivo and capture cells before, during, and after fusion. This allows us to identify and associate proteins with specific stages of muscle cell differentiation and fusion. Using this method, we have identified the Paralemmin A-kinase anchor protein (PALM2-AKAP2), a protein of unknown function, as a potential regulator of muscle regeneration. Hence, this work provides valuable data and will provide new insight into the mechanism of myoblast fusion and muscle regeneration.

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Systems Aging - A Sagol Center for Longevity Meeting

Date:

08

Wednesday

May

2024

Conference

Time: 09:00-15:00

Location: The David Lopatie Conference Centre

Contact: uri.alon@weizmann.ac.il

Vision and AI

Date:

02

Thursday

May

2024

Lecture / Seminar

Time: 12:15-13:15

Title: Quantification and Visualization of Uncertainty in Imaging Inverse Problems

Location: Jacob Ziskind Building

Lecturer: Tomer Michaeli

Organizer: Department of Computer Science and Applied Mathematics

Abstract: Uncertainty quantification and visualization is crucial for the deployment of im ... Read more Uncertainty quantification and visualization is crucial for the deployment of image restoration models in safety-critical domains, like biological and medical imaging. To date, methods for visualizing uncertainty have mainly focused on per-pixel estimates, which provide limited information. Theoretically, more natural visualizations of uncertainty could be obtained from a principal component analysis (PCA) or from some clustering of the posterior distribution. However, such approaches would require generating numerous samples from the posterior distribution as a first step, which is computationally impractical with today’s SOTA (diffusion-based) posterior samplers. In this talk I will present methods that can output a hierarchical clustering (a tree) or the principal components (PCs) of the posterior in a single forward pass of a neural network. Our methods are both more accurate and orders of magnitude faster than the naïve approach of applying clustering or PCA to posterior samples generated by a conditional generative model. I will illustrate the effectiveness of our methods on multiple inverse problems in imaging, including denoising, inpainting, super-resolution, colorization, and biological image-to-image translation. The talk will cover joint works with Elias Nehme, Omer Yair, Hila Manor and Rotem Mulayoff.

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Egr1 regulates regenerative senescence and cardiac repair

Date:

17

Wednesday

April

2024

Lecture / Seminar

Time: 14:00

Title: PhD Thesis Defense by Lingling Zhang (Prof. Eldad Tzahor Lab)

Location: Wolfson Building for Biological Research

Lecturer: Dr. Lingling Zhang

Organizer: Department of Molecular Cell Biology

Contact: michal.ovadia@weizmann.ac.il

Consciousness and the brain: comparing and testing neuroscientific theories of consciousness

Date:

16

Tuesday

April

2024

Lecture / Seminar

Time: 12:30-13:30

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Prof. Liad Mudrik

Organizer: Department of Brain Sciences

Details: Host-Dr. Yoav Livneh yoav.livneh@weizmann.ac.il tel-6230 For accessibility ... Read more

Abstract: For centuries, consciousness was considered to be outside the reach of scientifi ... Read more For centuries, consciousness was considered to be outside the reach of scientific investigation. Yet in recent decades, more and more studies have tried to probe the neural correlates of conscious experience, and several neuronally-inspired theories for consciousness have emerged. In this talk, I will focus on four leading theories of consciousness: Global Neuronal Workspace (GNW), integrated Information Theory (IIT), Recurrent Processing Theory (RPT) and Higher Order Theory (HOT). I will first shortly present the guiding principles of these theories. Then, I will provide a bird's-eye view of the field, using the results of a large-scale quantitative and analytic review we conducted, examining all studies that either empirically tested these theories or interpreted their findings with respect to at least one of them. Finally, I will describe the first results of the Cogitate consortium - an adversarial collaboration aimed at testing GNW and IIT.

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Beyond Touch: Exploring Audible Aspects of Rodent Whisking

Date:

09

Tuesday

April

2024

Lecture / Seminar

Time: 14:00-15:00

Location: Arthur and Rochelle Belfer Building for Biomedical Research

Lecturer: Ben Efron PhD Thesis Defense

Organizer: Department of Brain Sciences

Details: Zoom:Zoom: https://weizmann.zoom.us/j/95498604599?pwd=eVFqZnBJYTloWjZLOGpkMVhGM1 ... Read more

Abstract: Sensory processing is fundamental for animal adaptation and survival, linking th ... Read more Sensory processing is fundamental for animal adaptation and survival, linking them to their environments. Understanding the nervous system's integration of sensory information is crucial for comprehending behavior and cognition. This process involves integrating external cues across modalities, along with internal states, cognitive processes, and motor control, leading to complex behaviors and a nuanced understanding of the world. To facilitate research on these processes, we aimed to identify natural behaviors that produce both auditory and somatosensory stimuli, steering clear of artificial stimulus sources. We discovered that whisking, previously considered a unimodal behavior associated solely with tactile sensations, also produces sounds with distinctive acoustic features within the auditory frequency range of mice. We explored the auditory neuronal representation of sounds generated by whisking and their implications for behavioral performance. We demonstrate that sounds produced by whisking elicit diverse neuronal responses in the auditory cortex, encoding the object's identity and the mouse's whisking state, even in the absence of tactile sensations. Furthermore, we show that mice are capable of completing behavioral tasks relying solely on auditory cues generated by whisking against objects.

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Information processing in spiking networks: Converging assemblies

Date:

09

Tuesday

April

2024

Lecture / Seminar

Time: 12:30-13:30

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Prof. Eran Stark

Organizer: Department of Brain Sciences

Details: Host: Dr. Yoav Livneh yoav.livneh@weizmann.ac.il tel:6230 For accessibility i ... Read more

Abstract: How information is processed within the brain is a key question in systems neuro ... Read more How information is processed within the brain is a key question in systems neuroscience. We address the issue in spiking neuronal networks of freely moving mice. I will describe our recent findings and conclusions pertaining to three specific information processing steps: transmission, representation, and storage. First, using feedforward optogenetic injection of white noise input to a small group of adjacent neocortical excitatory cells, we find that spike transmission to a postsynaptic cell exhibits error correction, improved precision, and temporal coding. The results are consistent with a nonlinear coincidence detection model in the postsynaptic neuron. Second, by triggering input on animal kinematics, we create an artificial place field in an otherwise-silent pyramidal cell. In hippocampal region CA1 but not in the neocortex, artificial fields exhibit synthetic phase precession that persists for a full cycle. The local conversion of an induced rate code into an emerging phase code is compatible with a dual-oscillator interference model. Third, by triggering input on spontaneous spiking, we impose self-terminating spike patterns in a group of presynaptic excitatory neurons and a postsynaptic cell. The precise timing of all pre- and postsynaptic spikes has a more substantial impact on long-lasting effective connectivity than that of individual cell pairs, revealing an unexpected plasticity mechanism. We conclude that intrinsic properties of single neurons support millisecond-timescale operations, and that cortical networks are organized in functional modules which we refer to as “converging assemblies”.

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Studying Ageing and Neurodegenerative Brain with Quantitative MRI

Date:

02

Tuesday

April

2024

Lecture / Seminar

Time: 12:30-13:30

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Prof. Aviv Mezer

Organizer: Department of Brain Sciences

Details: Host: Yoav Livneh yoav.livneh@weizmann.ac.il tel:6230 For accessibility issue ... Read more

Abstract: Aging and neurodegeneration are associated with changes in brain tissue at the m ... Read more Aging and neurodegeneration are associated with changes in brain tissue at the molecular level, affecting its organization, density, and composition. These changes can be detected using quantitative MRI (qMRI), which provides physical measures that are sensitive to structural alterations. However, a major challenge in brain research is to relate physical estimates to their underlying biological sources. In this talk, I will discuss the community's efforts to use qMRI to identify biological processes that underlie changes in brain tissue. Specifically, I will highlight approaches for differentiating between changes in the concentration and composition of myelin and iron during aging. By exploring the molecular landscape of the aging and neurodegenerative brain using qMRI, we aim to gain a better understanding of these processes and potentially provide new metrics for evaluating them.

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Hippocampal pathology and pathophysiology in the development of temporal lobe epileptogenesis

Date:

24

Sunday

March

2024

Lecture / Seminar

Time: 11:00-12:00

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Prof. Robert S. Sloviter

Organizer: Department of Brain Sciences

Details: Host: Prof. Menahem Segal menahem.segal@weizmann.ac.il For accessibility issu ... Read more

Abstract: In families with febrile seizures and temporal lobe epilepsy, mutations affectin ... Read more In families with febrile seizures and temporal lobe epilepsy, mutations affecting different GABAergic mechanisms suggest that failure of chloride conductance to limit depolarization may be directly epileptogenic. This “GABAergic disinhibition” hypothesis has been discounted historically for two reasons. First, early attempts to produce hippocampal sclerosis and epilepsy simply by eliminating hippocampal GABA neurons consistently failed to do so. Second, the notion persists that because clinical epilepsy diagnosis is typically delayed for years or decades after brain injury, temporal lobe epileptogenesis should be presumed to involve a complex pathological transformation process that reaches completion during this “latent period.” Recent advances clarify both issues. Although spatially limited hippocampal GABA neuron ablation causes only submaximal granule cell hyperexcitability, more spatially extensive ablation maximizes granule cell hyperexcitability and triggers nonconvulsive granule cell status epilepticus, hippocampal sclerosis, and epilepsy. Recent studies also show that disinhibited granule cells begin to generate clinically subtle seizures immediately post-injury, and these seizures then gradually increase in duration to become clinically obvious. Therefore, rather than being a seizure-free “gestational” state of potentially interruptible epileptogenesis, the “latent period” is more likely an active epileptic state when barriers to seizure spread and clinical expression are gradually overcome by a kindling process. The likelihood that an epileptic brain state exists long before clinical diagnosis has significant implications for anti-epileptogenesis studies. The location, magnitude, and spatial extent of inherited, autoimmune, and injury-induced disinhibition may determine the latency to clinical diagnosis and establish the continuum between the benign, treatable, and refractory forms of temporal lobe epilepsy.

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Allosteric modulation of protein kinase A in individuals affected by NLPD-PKA , a neurodegenerative disease in which the RIß-L50R variant is expressed

Date:

21

Thursday

March

2024

Lecture / Seminar

Time: 15:00-16:00

Location: Nella and Leon Benoziyo Building for Biological Sciences

Lecturer: Dr. Ronit Ilouz

Organizer: Department of Biomolecular Sciences

Details: Protein Kinase A (PKA) plays a crucial role in regulating neuronal functions, an ... Read more

The Golden Approach for Overcoming Bio-Barriers: Delivering Nanomedicine to Brain and Beyond

Date:

21

Thursday

March

2024

Lecture / Seminar

Time: 14:00-15:00

Location: Max and Lillian Candiotty Building

Lecturer: Prof. Rachela Popovtzer

Organizer: Dwek Institute for Cancer Therapy Research

Contact: michalav@weizmann.ac.il

Details: Meeting URL: https://weizmann.zoom.us/j/5065402023?pwd=a3Z6KzRCU0xJaUFoM2Y5emZwZ ... Read more

A brain-computer interface for studying long-term changes of hippocampal neural codes

Date:

13

Wednesday

March

2024

Lecture / Seminar

Time: 15:30-16:30

Location: Arthur and Rochelle Belfer Building for Biomedical Research

Lecturer: Linor Baliti Turgeman-PhD Thesis Defense

Organizer: Department of Brain Sciences

Details: Student Seminar-PhD Thesis Defense

Abstract: Brain-computer interfaces (BCI), have important applications both in medicine an ... Read more Brain-computer interfaces (BCI), have important applications both in medicine and as a research tool. Typically, BCIs rely on electrode arrays to capture electrical signals, which are then processed by algorithms to translate neural activity into actions of an external device. However, these electrophysiological techniques are often inadequate for tracking large populations of the same neurons over timescales longer than ~1 day. To address this, we developed calcium imaging-based BCI for freely behaving mice, facilitating continuous recording and analysis of specific neuronal populations over extended periods. This BCI allowed investigating the long-term neuronal coding dynamics in the hippocampus, revealing changes in neuronal population activity both within and across days. I am hopeful that this BCI will advance studies on spatial cognition and long-term memory.

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Travelling waves or sequentially activated modules: mapping the granularity of cortical propagation

Date:

12

Tuesday

March

2024

Lecture / Seminar

Time: 12:30-13:30

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Dr. Mark Shein-Idelson

Organizer: Department of Brain Sciences

Details: Host: Dr. Yoav Livneh yoav.livneh@weizmann.ac.il tel:6230 For accessibility ... Read more

Abstract: : Numerous studies have identified travelling waves in the cortex and suggested ... Read more : Numerous studies have identified travelling waves in the cortex and suggested they play important roles in brain processing. These waves are most often measured using macroscopic methods that do not allow assessing wave dynamics at the single neuron scale and analyzed using techniques that smear neuronal excitability boundaries. In my talk, I will present a new approach for discriminating travelling waves from modular activation. Using this approach I will show that Calcium dynamics in mouse cortex and spiking activity in turtle cortex are dominated by modular activation rather than by propagating waves. I will then show how sequentially activating two discrete brain areas can appear as travelling waves in EEG simulations and present an analytical model in which modular activation generates wave-like activity with variable directions, velocities, and spatial patterns. I will end by illustrating why a careful distinction between modular and wave excitability profiles across scales will be critical for understanding the nature of cortical computations.

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The Clore Center for Biological Physics

Date:

03

Sunday

March

2024

Lecture / Seminar

Time: 13:15-14:30

Title: A Statistical Physics Approach to Bacteria under Strong Perturbations

Location: Nella and Leon Benoziyo Physics Library

Lecturer: Prof. Nathalie Q. Balaban

Organizer: Clore Center for Biological Physics

Details: refreshments will be served at 12:45

Abstract: Statistical physics successfully accounts for phenomena involving a large number ... Read more Statistical physics successfully accounts for phenomena involving a large number of components using a probabilistic approach with predictions for collective properties of the system. While biological cells contain a very large number of interacting components, (proteins, RNA molecules, metabolites, etc.), the cellular network is understood as a particular, highly specific, choice of interactions shaped by evolution, and therefore difficultly amenable to a statistical physics description. Here we show that when a cell encounters an acute but non-lethal stress, its perturbed state can be modelled as random network dynamics. Strong perturbations may therefore reveal the dynamics of the underlying network that are amenable to a statistical physics description. We show that our experimental measurements of the recovery dynamics of bacteria from a strong perturbation can be described in the framework of physical aging in disordered systems (Kaplan Y. et al, Nature 2021). Further experiments on gene expression confirm predictions of the model. The predictive description of cells under and after strong perturbations should lead to new ways to fight bacterial infections, as well as the relapse of cancer after treatment.

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Highly multiplexed imaging of tissues with subcellular resolution by imaging mass cytometry

Date:

29

Thursday

February

2024

Lecture / Seminar

Time: 14:00

Lecturer: Prof. Bernd Bodenmiller

Organizer: Dwek Institute for Cancer Therapy Research

Contact: michalav@weizmann.ac.il

Details: Meeting URL: https://weizmann.zoom.us/j/5065402023?pwd=a3Z6KzRCU0xJaUFoM2Y5emZw ... Read more

Immunology and Regenerative Biology Colloquium

Date:

28

Wednesday

February

2024

Lecture / Seminar

Time: 11:00-12:00

Title: Multi-Potent Lung Stem Cells for Lung Regeneration

Location: Max and Lillian Candiotty Building

Lecturer: Prof. Yair Reisner

Organizer: Department of Immunology and Regenerative Biology

Contact: ronen.alon@weizmann.ac.il

Mapping the world around us: A topology-preserved schema of space that supports goal-directed navigation

Date:

20

Tuesday

February

2024

Lecture / Seminar

Time: 12:30

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Dr. Raunak Basu

Organizer: Department of Brain Sciences

Details: Host: Dr. Yoav Livneh yoav.livneh@weizmann.ac.il For accessibility issues: na ... Read more

Abstract: Successful goal-directed navigation requires estimating one’s current position ... Read more Successful goal-directed navigation requires estimating one’s current position in the environment, representing the future goal location, and maintaining a map that preserves the topological relationship between positions. In addition, we often need to implement similar navigational strategies in a continuously changing environment, thereby necessitating certain invariance in the underlying spatial maps. Previous research has identified neurons in the hippocampus and parahippocampal cortices that fire specifically when an animal visits a particular location, implying the presence of a spatial map in the brain. However, this map largely encodes the current position of an animal and is context-dependent, whereby changing the room or shape of the arena results in a new map orthogonal to the previous one. These observations raise the question, are there other spatial maps that fulfill the cognitive requirements necessary for goal-directed navigation? Using a goal-directed navigation task with multiple reward locations, we observed that neurons in the orbitofrontal cortex (OFC) exhibit distinct firing patterns depending on the goal location, and this goal-specific OFC activity originates even before the onset of the journey. Further, the difference in the ensemble firing patterns representing two target locations is proportional to the physical distance between these locations, implying the preservation of spatial topology. Finally, carrying out the task across different spatial contexts revealed that the mapping of target locations in the OFC is largely preserved and that the maps formed in two different contexts occupy similar neural subspaces and could be aligned by a linear transformation. Taken together, the OFC forms a topology-preserved schema of spatial locations that is used to represent the future spatial goal, making it a potentially crucial brain region for planning context-invariant goal-directed navigational strategies.

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iSCAR seminar

Date:

19

Monday

February

2024

Lecture / Seminar

Time: 09:00-10:00

Title: The ultimate sacrifice? The germline regulates longevity and somatic repair in a sex-specific manner

Location: Max and Lillian Candiotty Building

Lecturer: Dr. Itamar Harel

Organizer: Department of Immunology and Regenerative Biology

Contact: karina.yaniv@weizmann.ac.il

The role of the corpus callosum in interhemispheric communication

Date:

14

Wednesday

February

2024

Lecture / Seminar

Time: 14:00-15:00

Location: The David Lopatie Hall of Graduate Studies

Lecturer: Yael Oran-PhD Thesis Defense

Organizer: Department of Brain Sciences

Details: Student Seminar-PhD Thesis Defense

Abstract: Interhemispheric communication is a comprehensive concept that involves both the ... Read more Interhemispheric communication is a comprehensive concept that involves both the synchronization of neural activity as well as the integration of sensory information across the two brain hemispheres. In this work, we explored these properties in the somatosensory system of the mouse brain. We show that during spontaneous activity in awake animals, robust interhemispheric correlations of both spiking and synaptic activities that are reduced during whisking compared to quiet wakefulness. And that the state-dependent correlations between the hemispheres stem from the state-depended nature of the corpus callosum activity. Further, to understand how sensory information is integrated across the brain's hemispheres, we studied bilateral and ipsilateral responses to passive whisker stimulation using widefield imaging and then employed a virtual tunnel environment to explore bilateral integration in active whisking

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Vision and AI

Date:

08

Thursday

February

2024

Lecture / Seminar

Time: 12:15-13:15

Title: Strong and Precise Modulation of Human Percepts via Robustified ANNs

Location: Jacob Ziskind Building

Lecturer: Guy Gaziv

Organizer: Department of Computer Science and Applied Mathematics

Abstract: The visual object category reports of artificial neural networks (ANNs) are noto ... Read more The visual object category reports of artificial neural networks (ANNs) are notoriously sensitive to tiny, adversarial image perturbations. Because human category reports (aka human percepts) are thought to be insensitive to those same small-norm perturbations — and locally stable in general — this argues that ANNs are incomplete scientific models of human visual perception. Consistent with this, we show that when small-norm image perturbations are generated by standard ANN models, human object category percepts are indeed highly stable. However, in this very same "human-presumed-stable" regime, we find that robustified ANNs reliably discover low-norm image perturbations that strongly disrupt human percepts. These previously undetectable human perceptual disruptions are massive in amplitude, approaching the same level of sensitivity seen in robustified ANNs. Further, we show that robustified ANNs support precise perceptual state interventions: they guide the construction of low-norm image perturbations that strongly alter human category percepts toward specific prescribed percepts. These observations suggest that for arbitrary starting points in image space, there exists a set of nearby "wormholes", each leading the subject from their current category perceptual state into a semantically very different state. Moreover, contemporary ANN models of biological visual processing are now accurate enough to consistently guide us to those portals. project webpage Bio: Guy is a Computer Vision postdoctoral researcher at the DiCarlo Lab at MIT, interested in the intersection between machine and human vision. His PhD focused on decoding visual experience from brain activity. His current focus is on harnessing contemporary models of primate visual cognition for neural and behavioral modulation. Guy holds a PhD in Computer Science and an MSc in Physics from The Weizmann Institute of Science, and a BSc in Physics-EECS from The Hebrew University of Jerusalem.

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Geometric Functional Analysis and Probability Seminar

Date:

01

Thursday

February

2024

Lecture / Seminar

Time: 13:30-14:30

Title: Scaling limits for growth driven by reflecting Brownian motion

Location: Jacob Ziskind Building

Lecturer: Amir Dembo

Organizer: Department of Mathematics

Abstract: In joint works with Kevin Yang, we consider a stochastic Laplacian growth model, ... Read more In joint works with Kevin Yang, we consider a stochastic Laplacian growth model, that can be viewed as a continuum version of origin-excited random walks. Here, we grow the (d 1)-dimensional manifold M(t) according to a reflecting Brownian motion (RBM) on M(t), stopped at level sets of its boundary local time. An averaging principle for the RBM characterizes the scaling limit for the leading order behavior of the interface (namely, the boundary of M(t)). This limit is given by a locally well-posed, geometric flow-type PDE, whose blow-up times correspond to changes in the diffeomorphism class of the growing set. Smoothing the interface as we inflate M(t), yields an SPDE for the large-scale fluctuations of an associated height function. This SPDE is a regularized KPZ-type equation, modulated by a Dirichlet-to-Neumann operator. For d=1 we can further remove the regularization, so the fluctuations of M(t) now have a double-scaling limit given by a singular KPZ-type equation.

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One molecular- and one circuit-level insight into cognition from studying Drosophila

Date:

30

Tuesday

January

2024

Lecture / Seminar

Time: 12:30-13:30

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Prof. Gaby Maimon

Organizer: Department of Brain Sciences

Details: Host: Yoav Livneh yoav.livneh@weizmann.ac.il tel:6230 For accessibility issue ... Read more

Abstract: A major goal of cognitive neuroscience is to clarify the functions of central br ... Read more A major goal of cognitive neuroscience is to clarify the functions of central brain regions. Over the past decade, the high-level functional architecture of a region in the middle of the insect brain––the central complex––has come into focus. I will start by briefly summarizing our understanding of the central complex as a microcomputer that calculates the values of angles and two-dimensional vectors important for guiding navigational behavior. I will then describe some recent findings on this brain region, revealing (1) how neuronal calcium spikes, mediated by T-type calcium channels, augment spatial-vector calculations and (2) how an angular goal signal is converted into a locomotor steering signal. These results provide inspiration for better understanding the roles of calcium spikes and goal signals in mammalian brains.

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Geometric Functional Analysis and Probability Seminar

Date:

25

Thursday

January

2024

Lecture / Seminar

Time: 13:30-14:30

Title: Determinants of Laplacians and heat-kernel bounds

Location: Jacob Ziskind Building

Lecturer: Renan Gross

Organizer: Department of Mathematics

Abstract: In this talk, we will smash together spanning trees, Brownian motion and negativ ... Read more In this talk, we will smash together spanning trees, Brownian motion and negative-curvature manifolds. The "tree entropy" of a converging sequence of graphs roughly counts how many spanning trees per vertex each graph has, and can be calculated using the Laplacian of the graph. A similar quantity can be defined for compact hyperbolic surfaces, but is much trickier to compute. In this talk we will discuss spectral and geometric conditions which lead to its convergence for locally-converging surfaces. The proof involves analyzing the return density of Brownian motion to the origin, averaged over the entire surface.

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Non-canonical circuits for olfaction

Date:

16

Tuesday

January

2024

Lecture / Seminar

Time: 12:30-13:30

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Dr. Dan Rokni

Organizer: Department of Brain Sciences

Details: Host: Yoav Livneh yoav.livneh@weizmann.ac.il tel: 6230 For accessibility issu ... Read more

Abstract: : I’ll describe two projects: In the first, we examined the circuitry that un ... Read more : I’ll describe two projects: In the first, we examined the circuitry that underlies olfaction in a mouse model with severe developmental degeneration of the OB. The olfactory bulb (OB) is a critical component of mammalian olfactory neuroanatomy. Beyond being the first and sole relay station for olfactory information to the rest of the brain, it also contains elaborate stereotypical circuitry that is considered essential for olfaction. In our mouse model, a developmental collapse of local blood vessels leads to degeneration of the OB. Mice with degenerated OBs could perform odor-guided tasks and even responded normally to innate olfactory cues. I will describe the aberrant circuitry that supports functional olfaction in these mice. The second project focusses on the nucleus of the lateral olfactory tract. This amygdaloid nucleus is typically considered part of the olfactory cortex, yet almost nothing is known about its function, connectivity, and physiology. I will describe our approach to studying this intriguing structure and will present some of its cellular and synaptic properties that may guide hypotheses about its function.

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How Do Muscle Fibers Grow and Regenerate?

Date:

16

Tuesday

January

2024

Lecture / Seminar

Time: 10:00-11:00

Location: Nella and Leon Benoziyo Building for Biological Sciences

Lecturer: Sharon Havusha-Laufer

Organizer: Department of Biomolecular Sciences

Abstract: The skeletal muscle tissue that allows our bodies to move, is comprised of enorm ... Read more The skeletal muscle tissue that allows our bodies to move, is comprised of enormous muscle fibers, termed myofibers. Myofibers must grow with our body and adapt to its needs throughout life. This is accomplished by adding nuclei via cell-to-cell fusion. However, the fusion mechanism is poorly understood. To gain a better understanding of the fusion and repair mechanisms I recapitulated myoblast-to-myofiber fusion in culture, which allowed me for the first time to visualize the fusion and regeneration processes at high resolution, generating the seminal observations that form the central hypothesis for my PhD.

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Immunoception: Brain Representation and Control of Immunity

Date:

09

Tuesday

January

2024

Lecture / Seminar

Time: 13:00

Location: Wolfson Building for Biological Research

Lecturer: Prof. Asya Rolls

Organizer: Department of Brain Sciences

Details: Host. Dr. Yoav Livneh yoav.livneh@weizmann.ac.il For accessibility issues: na ... Read more

Abstract: To function as an integrated entity, the organism must synchronize between behav ... Read more To function as an integrated entity, the organism must synchronize between behavior and physiology. Our research focuses on probing this synchronization through the lens of the brain-immune system interface. The immune system, pivotal in preserving the organism's integrity, is also a sensitive barometer of its overall state. I will discuss the emerging understanding of how the brain represents the state of the immune system and the specific neural mechanisms that enable the brain to orchestrate immune responses.

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Special Clore Seminar - Leenoy Meshulam

Date:

09

Tuesday

January

2024

Lecture / Seminar

Time: 12:45-13:45

Title: Bridging scales in biological systems – from octopus skin to mouse brain

Location: Nella and Leon Benoziyo Physics Building

Lecturer: Leenoy Meshulam

Organizer: Clore Center for Biological Physics

Contact: malka.avraham@weizmann.ac.il

Details: Lunch will be held at 12:15

Abstract: For an animal to perform any function, millions of cells in its body furiously i ... Read more For an animal to perform any function, millions of cells in its body furiously interact with each other. Be it a simple computation or a complex behavior, all biological functions involve the concerted activity of many individual units. A theory of function must specify how to bridge different levels of description at different scales. For example, to predict the weather, it is theoretically irrelevant to follow the velocities of every molecule of air. Instead, we use coarser quantities of aggregated motion of many molecules, e.g., pressure fields. Statistical physics provides us with a theoretical framework to specify principled methods to systematically ‘move’ between descriptions of microscale quantities (air molecules) to macroscale ones (pressure fields). Can we hypothesize equivalent frameworks in living systems? How can we use descriptions at the level of cells and their connections to make precise predictions of complex phenomena My research group will develop theory, modeling and analysis for a comparative approach to discover generalizable forms of scale bridging across species and behavioral functions. In this talk, I will present lines of previous, ongoing, and proposed research that highlight the potential of this vision. I shall focus on two seemingly very different systems: mouse brain neural activity patterns, and octopus skin cells activity patterns. In the mouse, we reveal striking scaling behavior and hallmarks of a renormalization group- like fixed point governing the system. In the octopus, camouflage skin pattern activity is reliably confined to a (quasi-) defined dynamical space. Finally, I will touch upon the benefits of comparing across animals to extract principles of multiscale function in biological systems, and propose future directions to investigate how macroscale properties, such as memory or camouflage, emerge from microscale level activity of individual cells.

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Chemical and Biological Physics Guest seminar

Date:

07

Sunday

January

2024

Lecture / Seminar

Time: 15:00

Title: Static and dynamic biophysical properties of tissue microstructure: Insights from advanced in vivo MRI

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Dr Noam Shemesh

Organizer: Department of Chemical and Biological Physics

Contact: daniella.goldfarb@weizmann.ac.il

Abstract: In living systems, the tissue micro-architecture consists of myriad cellular and ... Read more In living systems, the tissue micro-architecture consists of myriad cellular and subcellular elements whose density, size/shape distributions, composition, and permeability, endow the tissue with its biological functionality. Dynamic transport mechanisms are further critical for maintaining homeostasis and supporting diverse physiological functions such as action potentials and biochemical signaling. Still, how these biophysical properties change over time and how they couple to activity, remains largely unknown. This is mainly due to the difficulty in mapping these properties in-vivo, longitudinally, and with sufficient specificity. Magnetic Resonance Imaging (MRI), with its capacity for longitudinal studies and wealth of microscopic information leading to multiple contrast mechanisms, provides an outstanding opportunity to decipher these phenomena. In this talk I will discuss our recent advances in diffusion and functional MRI, including novel pulse sequences and biophysical modeling of diffusion processes in the microscopic tissue milieu, which provide, for the first time, the sought-after specificity for density, size, and permeability of particular (sub)cellular elements in tissues. I will show new experiments in rodents proving unique power-laws predicted from biophysical models, revealing axon density and size, as well as cell body density and size, along with validations against ground-truth histology and applications in animal models of disease. Evidence for exchange between the intracellular and extracellular space will also be given, along with a first approach for quantitatively mapping permeability in tissue. I will also introduce correlation tensor MRI (CTI), a new approach for source-separation in diffusional kurtosis, that offers surrogate markers of neurite beading effects, thereby further enhancing specificity, especially in stroke. Finally, I will touch upon dynamic modulations of neural tissue microstructure upon neural activity, and provide evidence for the existence of a neuro-morphological coupling in diffusion-weighted functional MRI signals. Future vistas and potential applications will be discussed.

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Clore Seminar-Professor Jay Fineberg

Date:

07

Sunday

January

2024

Lecture / Seminar

Time: 13:15-14:15

Title: The Fundamental Physics of the Onset of Frictional Motion: How do laboratory earthquakes nucleate?

Location: Nella and Leon Benoziyo Physics Building

Lecturer: Prof. Jay Fineberg

Organizer: Clore Center for Biological Physics

Contact: malka.avraham@weizmann.ac.il

Details: Lunch at 12:45

Abstract: Recent experiments have demonstrated that rapid rupture fronts, akin to earthqua ... Read more Recent experiments have demonstrated that rapid rupture fronts, akin to earthquakes, mediate the transition to frictional motion. Moreover, once these dynamic rupture fronts (“laboratory earthquakes”) are created, their singular form, dynamics and arrest are well-described by fracture mechanics. Ruptures, however, need to be created within initially rough frictional interfaces, before they are able to propagate. This is the reason that “static friction coefficients” are not well-defined; frictional ruptures can nucleate for a wide range of applied forces. A critical open question is, therefore, how the nucleation of rupture fronts actually takes place. We experimentally demonstrate that rupture front nucleation is prefaced by extremely slow, aseismic, nucleation fronts. These nucleation fronts, which are often self-similar, are not described by our current understanding of fracture mechanics. The nucleation fronts emerge from initially rough frictional interfaces at well-defined stress thresholds, evolve at characteristic velocity and time scales governed by stress levels, and propagate within a frictional interface to form the initial rupture from which fracture mechanics take over. These results are of fundamental importance to questions ranging from earthquake nucleation and prediction to processes governing material failure.

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Chemical and Biological Physics Guest seminar

Date:

03

Wednesday

January

2024

Lecture / Seminar

Time: 15:00-16:00

Title: Atomic arrays as programmable quantum processors and sensors

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Dr Ran Finkelstein

Organizer: Department of Chemical and Biological Physics

Contact: lucio.frydman@weizmann.ac.il

Abstract: Large arrays of trapped neutral atoms have emerged over the past few years as a ... Read more Large arrays of trapped neutral atoms have emerged over the past few years as a promising platform for quantum information processing, combining inherent scalability with high-fidelity control and site-resolved readout. In this talk, I will discuss ongoing work with arrays of Alkaline-earth atoms. These divalent atoms offer unique properties stemming largely from their long-lived metastable states, which form the basis of the optical atomic clock. I will describe the design of a universal quantum processor based on clock qubits and its application in quantum metrology, and I will address the challenge of generating and benchmarking highly entangled states in an analog quantum simulator. First, we realize scalable local control of individual clock qubits, which we utilize to extend the Ramsey interrogation time beyond the coherence time of a single atom [1]. To realize a universal quantum processor, we demonstrate record high-fidelity two-qubit entangling gates mediated by Rydberg interactions, which we combine with dynamical reconfiguration to entangle clock probes in GHZ states and perform Ancilla-based detection [2]. We then use the narrow clock transition to measure and remove thermal excitations of atoms in tweezers (a technique known as erasure conversion) and generate hyperentangled states of motion and spin [3]. In the second part of the talk, I will describe a different approach for generating large scale entangled states in an analog quantum simulator configuration [4], including error mitigation [5] and benchmarking of a 60-atom simulator [6]. Together, these show the great promise and the large variety of experiments accessed with this emerging platform. [1] A. Shaw*, R. Finkelstein*, R. Tsai, P. Scholl, T. Yoon, J. Choi, M. Endres, Multi-ensemble metrology by programming local rotations with atom movements, arxiv:2303.16885, Nature Physics in press (2023). [2] R. Finkelstein, R. Tsai, A. Shaw, X. Sun, M. Endres, A universal quantum processor for entanglement enhanced optical tweezer clocks, in preparation. [3] P. Scholl*, A. Shaw*, R. Finkelstein*, R. Tsai, J. Choi, M. Endres, Erasure cooling, control, and hyper-entanglement of motion in optical tweezers, arXiv:2311.15580 (2023). [4] J. Choi, A. Shaw, I. Madjarov, X. Xie, R. Finkelstein, J. Covey, J. Cotler, D. Mark, H.Y. Huang, A. Kale, H. Pichler, F. Brandão, S. Choi, and M. Endres, Preparing random states and benchmarking with many-body quantum chaos, Nature 617 (2023) [5] P. Scholl, A. Shaw, R. Tsai, R. Finkelstein, J. Choi, M. Endres, Erasure conversion in a high-fidelity Rydberg quantum simulator, Nature 622 (2023). [6] A. Shaw, Z. Chen, J. Choi, D.K. Mark, P. Scholl, R. Finkelstein, A. Elben, S. Choi, M. Endres, Benchmarking highly entangled states on a 60-atom analog quantum simulator, arXiv:2308.07914 (2023).

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Special Guest Seminar: Dr. Sharon Fleischer

Date:

03

Wednesday

January

2024

Lecture / Seminar

Time: 10:00-12:00

Title: Stem cell based cardiac tissue models to study the human heart in health and disease

Location: Wolfson Building for Biological Research

Lecturer: Dr. Sharon Fleischer

Organizer: Department of Molecular Cell Biology

Contact: michal.ovadia@weizmann.ac.il

A paradigm shift in GPCR recruitment and activity: GPCR Voltage Dependence Controls Neuronal Plasticity and Behavior

Date:

02

Tuesday

January

2024

Lecture / Seminar

Time: 00:00

Location: Gerhard M.J. Schmidt Lecture Hall

Lecturer: Prof. Moshe Parnas

Organizer: Department of Brain Sciences