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  • Date:09MondayDecember 2019

    The temporal structure of the code of large neural populations

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    Time
    10:30
    Location
    Nella and Leon Benoziyo Building for Brain Research
    Lecturer
    Ehud Karpas (PhD Thesis Defense)
    Elad Schneidman Lab, Dept of Neurobiology, WIS
    Organizer
    Department of Neurobiology
    Contact
    DetailsShow full text description of Students & Postdocs Seminar Benoziyo Brain Research ...»
    Students & Postdocs Seminar

    Benoziyo Brain Research Building Room 113

    For assistance with accessibility issues, please contact naomi.moses@weizmann.ac.il

    AbstractShow full text abstract about Studying the neural code deals with trying to understand how...»
    Studying the neural code deals with trying to understand how information is stored and processed in the brain, searching for basic principles of this "language". The study of population codes aims to understand how neural populations collectively encode information, and to map interactions between neurons. Previous studies explored the firing rates of single cells and how they evolve with time. Other studies have shown that neural populations are correlated and explored spatial activity patterns of large groups. In this work we combine these approaches, and study population activity of large groups of neurons, and how they evolve with time.

    We studied the fine temporal structure of spiking patterns of groups of up to 100 simultaneously recorded units in the prefrontal cortex of monkeys performing a visual discrimination task. We characterized the population activity using 10 ms time bins and found that population activity patterns (codebooks) were strongly shaped by spatial correlations. Further, using a novel extension of models which describe spatio-temporal population activity patterns, we show that temporal sequences of population activity patterns have strong history-dependence. Together, the large impact of spatial and temporal correlations makes the observed sequences of activity patterns many orders of magnitude more likely to appear than predicted by models that ignore these correlations and rely only on the population rates.

    Surprisingly, despite these strong correlations, decoding behavior using models that were trained ignoring these correlations perform as well as decoders that were trained to capture these correlations. The difference in the role of correlations in population encoding and decoding suggests that one of the goals of the complex encoding scheme in the prefrontal cortex may be to create a code that can be read by simple downstream decoders that do not have to learn correlations.
    Lecture
  • Date:09MondayDecember 2019

    Principles of Protein Assembly in Cells

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    Time
    11:00 - 12:15
    Location
    Gerhard M.J. Schmidt Lecture Hall
    Lecturer
    Dr. Emmanuel Levy
    Dept. of Structural Biology, WIS
    Organizer
    Faculty of Chemistry
    Contact
    Colloquia
  • Date:09MondayDecember 2019

    Computer Science Seminar

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    Time
    11:15 - 13:00
    Title
    Clustering: How hard is it to classify data?
    Location
    Jacob Ziskind Building
    Room 155
    Lecturer
    Karthik C.S
    Tel Aviv University
    Organizer
    Faculty of Mathematics and Computer Science
    Seminar
    Contact
    DetailsShow full text description of Two popular objectives optimized in clustering algorithms ar...»
    Two popular objectives optimized in clustering algorithms are k-means and k-median. The k-means (resp. k-median) problem in the L_p-metric is specified by n points as input and the goal is to classify the input point-set into k clusters such that the k-means (resp. k-median) objective is minimized. The best-known inapproximability factor in literature for these NP-hard problems in L_p-metrics were well-below 1.01. In this talk, we take a significant step to improve the hardness of approximating these problems in various L_p-metrics.
    Lecture
  • Date:09MondayDecember 2019

    Trapped on the ribosome: exploring the chemical biology of translational control

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    Time
    14:00 - 15:00
    Location
    Gerhard M.J. Schmidt Lecture Hall
    Lecturer
    Prof. Jack Taunton
    Dept. of Cellular and Molecular Pharmacology, University of California, San-Francisco
    Organizer
    Department of Structural Biology
    Contact
    Lecture
  • Date:09MondayDecember 2019

    A quantitative footprint of irreversibility in the absence of observable currents

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    Time
    14:15
    Location
    Edna and K.B. Weissman Building of Physical Sciences
    Room A
    Lecturer
    Gili Bisker
    TAU
    Organizer
    Department of Physics of Complex Systems
    Statistical Physics Seminar
    Contact
    AbstractShow full text abstract about Time irreversibility is the hallmark of nonequilibrium dissi...»
    Time irreversibility is the hallmark of nonequilibrium dissipative processes. Detecting dissipation is essential for our basic understanding of the underlying physical mechanism, however, it remains a challenge in the absence of observable directed motion, flows, or fluxes. Additional difficulty arises in complex systems where many internal degrees of freedom are inaccessible to an external observer. In living systems, for example, the dissipation is directly related to the hydrolysis of fuel molecules such as adenosine triphosphate (ATP), whose consumption rate is difficult to directly measure in many experimental setups. In this talk, I will introduce a novel approach to detect time irreversibility and estimate the entropy production from time-series measurements, even in the absence of observable currents. This method can be implemented in scenarios where only partial information is available and thus provides a new tool for studying nonequilibrium phenomena.


    1. G. Bisker et al. Inferring broken detailed balance in the absence of observable currents,
    Nature Communications, 10(1), 1-10 (2019)
    2. G. Bisker et al. Hierarchical Bounds on Entropy Production Inferred from Partial
    Information, Journal of Statistical Mechanics: Theory and Experiment (9), 093210 (2017)
    Lecture
  • Date:10TuesdayDecember 2019

    Molecular errors and evolvability

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    Time
    11:00 - 12:00
    Location
    Gerhard M.J. Schmidt Lecture Hall
    Lecturer
    Prof. Joanna Masel
    Ecology and Evolutionary Biology, The University of Arizona, USA
    Organizer
    Department of Structural Biology
    Contact
    Lecture
  • Date:10TuesdayDecember 2019

    Special Guest Seminar: Prof. Yair Reisner will lecture on "Hematopoietic and lung stem cell transplantation across major genetic barriers."

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    Time
    11:00 - 12:00
    Location
    Wolfson Building for Biological Research
    Auditorium
    Lecturer
    Prof. Yair Reisner
    Head, Stem Cell Research; Dep. Stem Cell Transplantation & Cellular Therapy; MD Anderson Cancer Center; Houston, Texas.
    Organizer
    Department of Immunology
    Contact
    Lecture
  • Date:10TuesdayDecember 2019

    Transposable elements as drivers of structural and functional variations in wheat genome

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    Time
    11:30 - 12:30
    Location
    Nella and Leon Benoziyo Building for Biological Sciences
    Auditorium
    Lecturer
    Prof. Khalil Kashkush
    Dept. of Life Sciences, Faculty of Natural Sciences, Ben-Gurion University of the Negev
    Organizer
    Department of Plant and Environmental Sciences
    Homepage
    Contact
    DetailsShow full text description of Hosts: Dr. Cathy Bessudo and Dr. Hadas Zehavi...»
    Hosts: Dr. Cathy Bessudo and Dr. Hadas Zehavi
    Lecture
  • Date:10TuesdayDecember 2019

    Tracking proteins' conformations inside cells with Gd(III) spin labels

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    Time
    14:00 - 15:00
    Location
    Helen and Milton A. Kimmelman Building
    Dov Elad Room
    Lecturer
    Prof. Daniella Goldfarb
    Department of Chemical and Biological Physics, WIS
    Organizer
    Department of Structural Biology
    Contact
    Lecture
  • Date:11WednesdayDecember 2019

    Developmental Club Series 2019-20

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    Time
    10:00
    Title
    Uncovering the basis of axonal guidance receptor multifunctionality
    Location
    Arthur and Rochelle Belfer Building for Biomedical Research
    Botnar Auditorium
    Lecturer
    Prof. Avraham Yaron
    Organizer
    Department of Molecular Genetics
    Developmental Club
    Contact
    Lecture
  • Date:12ThursdayDecember 2019

    In vivo multimodality imaging of immune-vascular interactions in cardiovascular disease

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    Time
    10:00 - 11:00
    Location
    Perlman Chemical Sciences Building
    Room 404
    Lecturer
    Prof. Katrien Vandoorne
    Eindhoven University of Technology (The Netherlands), Department of Biomedical Engineering, Soft Tissue Engineering
    Organizer
    Department of Materials and Interfaces
    The Helen and Martin Kimmel Institute for Magnetic Resonance
    Contact
    AbstractShow full text abstract about Cardiovascular disease is a result of genetic and environmen...»
    Cardiovascular disease is a result of genetic and environmental risk factors that together generate arterial and cardiac pathologies. Blood vessels connect multiple organ systems throughout the entire body allowing organs to interact via circulating messengers. Multimodality imaging achieves integration of these interfacing systems’ distinct processes, quantifying interactions that contribute to cardiovascular disease. Noninvasive multimodality imaging techniques are emerging tools that can further our understanding of this complex and dynamic interplay. Multichannel multimodality imaging including optics, CT, PET and MRI, are particularly promising because they can simultaneously sample multiple biomarkers. As the opportunities provided by imaging expand, mapping interconnected systems will help us decipher the complexity of cardiovascular disease and monitor novel therapeutic strategies.
    Lecture
  • Date:12ThursdayDecember 2019

    Magic Angle Bilayer Graphene - Superconductors, Orbital Magnets, Correlated States and beyond

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    Time
    11:15 - 12:30
    Location
    Edna and K.B. Weissman Building of Physical Sciences
    Auditorium
    Lecturer
    Dmitri K. Efetov
    ICFO
    Organizer
    Faculty of Physics
    Contact
    DetailsShow full text description of 11:00 Coffee, Tea and more ...»
    11:00 Coffee, Tea and more
    AbstractShow full text abstract about When twisted close to a magic relative orientation angle nea...»
    When twisted close to a magic relative orientation angle near 1 degree, bilayer graphene has flat moire superlattice minibands that have emerged as a rich and highly tunable source of strong correlation physics, notably the appearance of superconductivity close to interaction-induced insulating states. Here we report on the fabrication of bilayer graphene devices with exceptionally uniform twist angles. We show that the reduction in twist angle disorder reveals insulating states at all integer occupancies of the four-fold spin/valley degenerate flat conduction and valence bands, i.e. at moire band filling factors nu = 0, +(-) 1, +(-) 2, +(-) 3, and reveals new superconductivity regions below critical temperatures as high as 3 K close to - 2 filling. In addition we find novel orbital magnetic states with non-zero Chern numbers. Our study shows that symmetry-broken states, interaction driven insulators, and superconducting domes are common across the entire moire flat bands, including near charge neutrality. We further will discuss recent experiments including screened interactions, fragile topology and the first applications of this amazing new materials platform.
    Colloquia
  • Date:12ThursdayDecember 2019

    Geometric Functional Analysis and Probability Seminar

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    Time
    13:30 - 15:30
    Title
    Existence of persistence exponent for Gaussian stationary functions
    Location
    Jacob Ziskind Building
    Room 155
    Lecturer
    Naomi Feldheim
    BIU
    Organizer
    Faculty of Mathematics and Computer Science
    Faculty of Mathematical Sciences Seminar, Department of Computer Science and Applied Mathematics
    Faculty of Mathematical Sciences Seminar, Department of Mathematics
    Faculty of Mathematical Sciences Seminar
    Contact
    DetailsShow full text description of Let Z(t) be a Gaussian stationary function on the real line,...»
    Let Z(t) be a Gaussian stationary function on the real line, and fix a level L
    Lecture
  • Date:12ThursdayDecember 2019

    TAM Tyrosine Kinase Receptor Signaling in Cancer: Unexpected Roles in the Tumor microenvironment

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    Time
    14:00 - 15:00
    Location
    Max and Lillian Candiotty Building
    Auditorium
    Lecturer
    Prof. Tal Burstyn-Cohen
    Organizer
    Department of Biological Regulation
    Contact
    Lecture
  • Date:15SundayDecember 201917TuesdayDecember 2019

    1st Israeli ISAC Flow Cytometry workshop

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    Time
    All day
    Organizer
    Department of Life Sciences Core Facilities
    Contact
    Lecture
  • Date:15SundayDecember 201919ThursdayDecember 2019

    Selected Problems in Z-Pinch Physics

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    Time
    08:00 - 08:00
    Location
    Edna and K.B. Weissman Building of Physical Sciences
    Drory Auditorium
    Chairperson
    Tal Queller
    Contact
    Conference
  • Date:15SundayDecember 2019

    China-Weizmann Symposium on Scientific Cooperation

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    Time
    09:00 - 18:00
    Location
    David Lopatie Conference Centre
    President's Auditorium
    Chairperson
    Eli Pollak
    Contact
    Conference
  • Date:15SundayDecember 2019

    Evaporation from the ocean: A new Lagrangian model and its application to observations

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    Time
    11:00
    Location
    Sussman Family Building for Environmental Sciences
    M. Magaritz Seminar Room
    Lecturer
    Natan Paldor
    The Hebrew University of Jerusalem
    Organizer
    Department of Earth and Planetary Sciences
    Contact
    Lecture
  • Date:15SundayDecember 2019

    Topological defects in the actin cytoskeleton as organizing centers of Hydra morphogenesis

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    Time
    11:00 - 12:00
    Location
    Perlman Chemical Sciences Building
    Room 404
    Lecturer
    Prof. Kinneret Keren
    Physics Department, Technion
    Organizer
    Department of Materials and Interfaces
    Soft Matter and Biomaterials
    Contact
    AbstractShow full text abstract about Morphogenesis is one of the most remarkable examples of biol...»
    Morphogenesis is one of the most remarkable examples of biological self-organization. Despite substantial progress, we still do not understand the organizational principles underlying the convergence of this process, across scales, to form viable organisms. We focus on the mechanical aspects of morphogenesis using Hydra, a small multicellular fresh-water animal, as a model system. Hydra has a simple body plan and is famous for its ability to regenerate its whole body from small tissue segments. I will show that the nematic order of the supra-cellular actin fibers in regenerating Hydra defines a coarse-grained field, whose dynamics provide an effective description of the morphogenesis process, with the topological defects in the nematic order acting as effective organizing centers. I will further describe our attempts to directly probe the influence of mechanics on morphogenesis, by applying various external mechanical constraints on regenerating Hydra.
    Lecture
  • Date:15SundayDecember 2019

    Faculty Seminar

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    Time
    11:15 - 13:00
    Title
    Representation, inference and design of multicellular systems
    Location
    Jacob Ziskind Building
    Room 155
    Lecturer
    Mor Nitzan
    Harvard University
    Organizer
    Faculty of Mathematics and Computer Science
    Faculty of Mathematical Sciences Seminar, Department of Computer Science and Applied Mathematics
    Faculty of Mathematical Sciences Seminar, Department of Mathematics
    Faculty of Mathematical Sciences Seminar
    Contact
    DetailsShow full text description of The past decade has witnessed the emergence of single-cell t...»
    The past decade has witnessed the emergence of single-cell technologies that measure the expression level of genes at a single-cell resolution. These developments have revolutionized our understanding of the rich heterogeneity, structure, and dynamics of cellular populations, by probing the states of millions of cells, and their change under different conditions or over time. However, in standard experiments, information about the spatial context of cells, along with additional layers of information they encode about their location along dynamic processes (e.g. cell cycle or differentiation trajectories), is either lost or not explicitly accessible. This poses a fundamental problem for elucidating collective tissue function and mechanisms of cell-to-cell communication.
    In this talk I will present computational approaches for addressing these challenges, by learning interpretable representations of structure, context and design principles for multicellular systems from single-cell information. I will first describe how the locations of cells in their tissue of origin and the resulting spatial gene expression can be probabilistically inferred from single-cell information by a generalized optimal-transport optimization framework, that can flexibly incorporate prior biological assumptions or knowledge derived from experiments. Inference in this case is based on an organization principle for spatial gene expression, namely a structural correspondence between distances of cells in expression and physical space, which we hypothesized and supported for different tissues. We used this framework to spatially reconstruct diverse tissues and organisms, including the fly embryo, mammalian intestinal epithelium and cerebellum, and further inferred spatially informative genes. Since cells encode multiple layers of information, in addition to their spatial context, I will also discuss several approaches for the disentanglement of single-cell gene expression into distinct biological processes, based on ideas rooted in random matrix theory and manifold learning. I will finally discuss how these results can be generalized to reveal principles underlying self-organization of cells into multicellular structures, setting the foundation for the computationally-directed design of cell-to-cell interactions optimized for specific tissue structure or function.
    Lecture

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