All events, All years

Population receptive fields in the human ventral stream and their role in face perception

Lecture
Date:
Tuesday, July 12, 2016
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Kalanit Grill-Spector
|
Dept of Psychology and Stanford Neurosciences Institute Stanford University, CA

The cortical system for processing faces is a model system for studying the functional neuroanatomy of ventral temporal cortex and its role in perception for two reasons. First, the functional organization of the cortical face system is well understood. Second, activations in ventral face-selective regions are causally related to face perception. Here, I will describe recent results from our research elucidating the computations performed by population receptive field (pRFs) in the cortical system for face perception. In contrast to predictions of classical theories, recent data from my lab reveals that computations in face-selective regions in human ventral temporal cortex can be characterized with a computational pRF model, which predicts the location and spatial extent of the visual field that is processed by the neural population in a voxel. Our research characterizes pRF properties of ventral face-selective regions revealing three main findings. First, pRFs illustrate a hierarchical organization within the face system, whereby pRFs become larger and more foveal across the ventral hierarchy. Second, attention to faces modulates pRFs in face-selective regions, consequently enhancing the representation of faces in the peripheral visual field where visual acuity is the lowest. Third, our research shows that pRF properties in face-selective regions are behaviorally relevant. We find that face perception abilities are correlated with pRF properties: participants with larger pRFs perform better in face recognition than participants with smaller pRFs. These data suggest that computations performed by pRFs in face-selective regions may form a neural basis for holistic processing necessary for face recognition. Overall, these data highlight the importance of elucidating computational properties of neural populations in ventral temporal cortex as they offer a new mechanistic understanding of high-level visual processes such as face perception.

Essential Functions of Chromatin Modifications in Prefrontal Synaptic Plasticity and Working Memory

Lecture
Date:
Tuesday, June 28, 2016
Hour: 14:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Mira Jakovcevski, PhD
|
Max Planck Institute of Psychiatry, Munich

Using Intersubject Correlation (ISC) of Dance to Study Biological Motion Processing in Autism

Lecture
Date:
Monday, June 27, 2016
Hour: 14:30
Location:
Arthur and Rochelle Belfer Building for Biomedical Research
Prof. Frank Pollick,School of Psychology,Scotland,University of Glasgow

Several recent papers have used the technique of Intersubject Correlation (ISC) of fMRI data to study differences between typical individuals and those on the autism spectrum when they watch movies while being scanned (Byrge, et al., 2015; Salmi et al., 2013; Hasson et al., 2009). In this presentation I discuss preliminary results from a study using ISC of solo dances that explored the differences in biological motion processing in autism noted previously by our lab (McKay, et al., 2012). This will include introductory discussion of ISC studies of dance that have highlighted the possible confounding effect of using edited videos composed of different camera views (Herbec et al., 2015) as well as the motion signal that appears related to regions of highest ISC (Noble et al., 2014; Jola et al., 2013).

Encoding of spatial and temporal properties of motor tics

Lecture
Date:
Tuesday, June 21, 2016
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Izhar Bar-Gad
|
Gonda Brain Research Center, Bar Ilan University

Striatal disinhibition leads to spontaneous abnormal action release manifesting as motor tics, resembling those expressed in Tourette syndrome patients. We utilized microstimulation within the motor cortex of freely-behaving rats before and after striatal disinhibition to study the spatial and temporal properties of tic expression. The spatial properties of these tics were dependent on the striatal organization while the temporal properties were dependent on the cortico-striatal activity. A data-driven computational model of cortico-striatal function closely replicated the temporal properties of abnormal action release. These converging experimental and computational findings suggest a clear functional dichotomy within the cortico-striatal network, pointing to disparate temporal (cortical) vs. spatial (striatal) encoding of action release.

The first steps in vision: cell types, circuits and repair

Lecture
Date:
Monday, June 13, 2016
Hour: 12:45
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Botond Roska
|
Friedrich Miescher Institute for Biomedical Research, Basel

Tactile discrimination with non-whisking whiskers

Lecture
Date:
Thursday, June 9, 2016
Hour: 11:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. Daniel Shulz
|
CNRS, Gif sur Yvette, France

Plasticity in Tuft Dendrites of Layer 5 pyramidal neurons

Lecture
Date:
Tuesday, June 7, 2016
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Jackie Schiller
|
Rappaport Faculty of Medicine, Technion, Haifa

Nonlinear decoding of a complex movie from the mammalian retina

Lecture
Date:
Thursday, June 2, 2016
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Gasper Tkacik
|
Institute of Science and Technology IST Austria

Sexually dimorphic neuronal connectivity established by sex-specific synapse pruning in C. elegans

Lecture
Date:
Wednesday, June 1, 2016
Hour: 15:00
Location:
Gerhard M.J. Schmidt Lecture Hall
Dr. Meital Oren-Suissa
|
Dept of Biochemistry and Molecular Biophysics, Columbia University New York, NY

Sexually reproducing animals display sex-specific behaviors wired onto dimorphic connectivity patterns in the nervous system. The mechanisms underlying the development of sexually dimorphic nervous systems that consists mainly of shared neuronal types remain largely unknown. Within the nervous system, males and females display a number of anatomical sexual dimorphisms often in the form of neurons that are present exclusively in one, but not the other sex. In this talk I will focus on sex-specific wiring of neurons that are present in both sexes, and demonstrate the sex-specific functions of sex-shared neurons in C. elegans. The key finding that I will present is that sex-specific wiring patterns are the result of sex-specific synaptic pruning events. I will show that many neurons initially form synapses in a non-discriminatory manner in both the male and hermaphrodite pattern before sexual maturation, but sex-specific pruning events result in the sex-specific maintenance of subsets of the connections. I will describe the behavioral tests taken to show that rewiring is indicative of repurposing of the function of sensory and interneuron. I will present the conserved genes I uncovered that function to determine sex-specific connectivity patterns. To summarize I will discuss how the sexual identity of individual neurons, by initiating selective synapse loss, refines the circuitry and defines sex-specific synaptic targets. This allows for diversification of behavioral outputs with a limited set of shared neurons.

Developing behavioral flexibility

Lecture
Date:
Wednesday, June 1, 2016
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Catherine Hartley
|
Weill Cornell Medical College Cornell University NY

Learning lays the foundation for motivated behavior, enabling us to recognize and respond appropriately to salient events. However, to function adaptively in a dynamic environment, we must be able to flexibly alter learned behavioral responses in accordance with our ongoing experience. In this talk, I will present studies examining at the cognitive, neural, and computational levels how the learning processes that support adaptive behavioral flexibility change over the course of development from childhood to adulthood. I will show that development confers marked changes in the cognitive representations engaged during learning and I will propose that learning about the degree of instrumental agency afforded by the environment may be a critical factor that shapes an individual’s behavioral repertoire.

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All events, All years

Tactile discrimination with non-whisking whiskers

Lecture
Date:
Thursday, June 9, 2016
Hour: 11:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. Daniel Shulz
|
CNRS, Gif sur Yvette, France

Plasticity in Tuft Dendrites of Layer 5 pyramidal neurons

Lecture
Date:
Tuesday, June 7, 2016
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Jackie Schiller
|
Rappaport Faculty of Medicine, Technion, Haifa

Nonlinear decoding of a complex movie from the mammalian retina

Lecture
Date:
Thursday, June 2, 2016
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Gasper Tkacik
|
Institute of Science and Technology IST Austria

Sexually dimorphic neuronal connectivity established by sex-specific synapse pruning in C. elegans

Lecture
Date:
Wednesday, June 1, 2016
Hour: 15:00
Location:
Gerhard M.J. Schmidt Lecture Hall
Dr. Meital Oren-Suissa
|
Dept of Biochemistry and Molecular Biophysics, Columbia University New York, NY

Sexually reproducing animals display sex-specific behaviors wired onto dimorphic connectivity patterns in the nervous system. The mechanisms underlying the development of sexually dimorphic nervous systems that consists mainly of shared neuronal types remain largely unknown. Within the nervous system, males and females display a number of anatomical sexual dimorphisms often in the form of neurons that are present exclusively in one, but not the other sex. In this talk I will focus on sex-specific wiring of neurons that are present in both sexes, and demonstrate the sex-specific functions of sex-shared neurons in C. elegans. The key finding that I will present is that sex-specific wiring patterns are the result of sex-specific synaptic pruning events. I will show that many neurons initially form synapses in a non-discriminatory manner in both the male and hermaphrodite pattern before sexual maturation, but sex-specific pruning events result in the sex-specific maintenance of subsets of the connections. I will describe the behavioral tests taken to show that rewiring is indicative of repurposing of the function of sensory and interneuron. I will present the conserved genes I uncovered that function to determine sex-specific connectivity patterns. To summarize I will discuss how the sexual identity of individual neurons, by initiating selective synapse loss, refines the circuitry and defines sex-specific synaptic targets. This allows for diversification of behavioral outputs with a limited set of shared neurons.

Developing behavioral flexibility

Lecture
Date:
Wednesday, June 1, 2016
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Catherine Hartley
|
Weill Cornell Medical College Cornell University NY

Learning lays the foundation for motivated behavior, enabling us to recognize and respond appropriately to salient events. However, to function adaptively in a dynamic environment, we must be able to flexibly alter learned behavioral responses in accordance with our ongoing experience. In this talk, I will present studies examining at the cognitive, neural, and computational levels how the learning processes that support adaptive behavioral flexibility change over the course of development from childhood to adulthood. I will show that development confers marked changes in the cognitive representations engaged during learning and I will propose that learning about the degree of instrumental agency afforded by the environment may be a critical factor that shapes an individual’s behavioral repertoire.

Encoding of spatial and temporal properties of motor tics

Lecture
Date:
Tuesday, May 31, 2016
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Izhar Bar-Gad
|
Gonda Brain Research Center, Bar Ilan University

Striatal disinhibition leads to spontaneous abnormal action release manifesting as motor tics, resembling those expressed in Tourette syndrome patients. We utilized microstimulation within the motor cortex of freely-behaving rats before and after striatal disinhibition to study the spatial and temporal properties of tic expression. The spatial properties of these tics were dependent on the striatal organization while the temporal properties were dependent on the cortico-striatal activity. A data-driven computational model of cortico-striatal function closely replicated the temporal properties of abnormal action release. These converging experimental and computational findings suggest a clear functional dichotomy within the cortico-striatal network, pointing to disparate temporal (cortical) vs. spatial (striatal) encoding of action release.

Multi-level scalable proteomic interrogation of intact biological systems

Lecture
Date:
Monday, May 30, 2016
Hour: 10:00
Location:
Arthur and Rochelle Belfer Building for Biomedical Research
Prof. Kwanghun Chung
|
Department of Chemical Engineering Institute for Medical Engineering and Science (IMES)Picower Institute for Learning and Memory Massachusetts Institute of Technology http://www.chunglab.org/

Unraveling unconventional role for astroglial connexins in synaptic strength and memory

Lecture
Date:
Sunday, May 29, 2016
Hour: 15:00
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Nathalie Rouach
|
CIRB, College de France, Paris

Astrocytes play active roles in brain physiology by dynamic interactions with neurons. Connexin 30, one of the two main astroglial gap-junction subunits, is thought to be involved in behavioral and basic cognitive processes. However, the underlying cellular and molecular mechanisms were unknown. We will show here in mice that connexin 30 controls hippocampal excitatory synaptic transmission through modulation of astroglial glutamate transport, which directly alters synaptic glutamate levels. Unexpectedly, we found that connexin 30 regulated cell adhesion and migration and that connexin 30 modulation of glutamate transport, occurring independently of its channel function, was mediated by morphological changes controlling insertion of astroglial processes into synaptic clefts. By setting excitatory synaptic strength, connexin 30 plays an important role in long-term synaptic plasticity and in hippocampus-based contextual memory. Taken together, these results establish connexin 30 as a critical regulator of synaptic strength by controlling the synaptic location of astroglial processes.

Experience-induced transcriptional networks that regulate the function of cortical circuits

Lecture
Date:
Tuesday, May 24, 2016
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Dr. Ivo Spiegel
|
Department of Neurobiology, WIS

Inhibitory neurons are critically important for the adaptation of neural circuits to sensory experience, but the molecular mechanisms by which experience controls the connectivity between different types of inhibitory neurons to regulate cortical plasticity are largely unknown. In this talk, I will present studies demonstrating that sensory experience induces in cortical vasoactive intestinal peptide (VIP)-expressing neurons a gene program that is markedly distinct from that induced in excitatory neurons and other subtypes of inhibitory neuron. I will show that is Igf1 one of several activity-regulated genes that are specific to VIP neurons, that IGF1 functions cell-autonomously in VIP neurons to increase inhibitory synaptic input onto these neurons and that VIP neuron-derived IGF1 regulates visual acuity in an experience-dependent manner, likely by promoting the inhibition of disinhibitory neurons and affecting inhibition onto cortical pyramidal neurons. I will discuss how our findings support a model by which experience-induced transcriptional networks regulate the synaptic connectivity of each type of neuron according to a circuit-wide homeostatic logic and I will propose that the analysis of the genomic mechanisms regulating these transcriptional networks will allow us to evaluate the extent to which cell-type-specific homeostatic mechanisms contribute to the function of cortical circuits.

HOW SLOW CORTICAL NEURONS MANAGE TO MAKE FAST DECISIONS

Lecture
Date:
Tuesday, May 10, 2016
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Michael Gutnick
|
Koret School of Veterinary Medicine Hebrew University of Jerusalem

Most excitatory cells in layer 4 of the mouse somatosensory cortex are spiny stellate (SpSt) neurons, which receive nearly all their excitatory input from the thalamus and from other SpSt neurons in the same barrel. Because layer 4 is the key entrance point into the cortical circuit, we assume that SpSt neurons respond rapidly to sensory input. However, these cells are very small, and there are strong theoretical reasons to suspect that their compact morphology could impair their capacity to encode high input frequencies and thus hamper the temporal fidelity of cortical processing. We use whole-cell patch clamp to measure the temporal properties of asynchronous noise in SpSt cells as compared with the much larger layer 5 pyramidal (Pyr) cells, and characterize the capabilities of both cell types to encode high frequencies in a synaptically active-like environment. We find that individual SpSt cells indeed have a much narrower dynamic range than Pyr cells when probed with inputs on a background of identical noise characteristics. However, the synaptic dynamics in SpSt cells, as evidenced by the correlation time of asynchronous noise, is slower than in Pyr neurons, and the slower correlation time of the SpSt cells is associated with significant broadening of their dynamic range. We further show that this compensatory improvement in encoding bandwidth of sensory input depends on activation of potassium conductances, as it decreases when potassium channels are pharmacologically blocked.

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