All events, All years

Hippocampal pathology and pathophysiology in the development of temporal lobe epileptogenesis

Lecture
Date:
Sunday, March 24, 2024
Hour: 11:00 - 12:00
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Robert S. Sloviter
|
The Neuroscience Institute MRC 245 Morehouse School of Medicine, Atlanta GA

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.

Dimensionality bottleneck uncovers simple action selection rules in hunting zebrafish

Lecture
Date:
Tuesday, March 19, 2024
Hour: 12:30 - 13:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Dr. Lilach Avitan
|
Edmond and Lily Safra Center for Brain Sciences The Hebrew University of Jerusalem

Animal movements are complex, high-dimensional, and lead to many different consequences. Thus, efficiently quantifying the behavior and uncovering the underlying representation used by the animal pose a great challenge. Tracking freely behaving zebrafish larvae using a high-speed camera and analyzing their movements, we reveal that zebrafish movements can be described using exactly two parameters. Mapping all possible two-dimensional movement representations, we identified the representation used by the fish. We show that fish do not trivially represent distance and angles as separate parameters, but rather mix them nonlinearly. Moreover, when hunting, this specific nonlinear relation depends on the prey angle and further dictates a particular set of potential movements. These results uncover, for the first time, the underlying action selection principles of hunting behavior, suggesting that behind this seemingly complex behavior there is a simple and low-dimensional process.

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

Lecture
Date:
Wednesday, March 13, 2024
Hour: 15:30 - 16:30
Location:
Arthur and Rochelle Belfer Building for Biomedical Research
Linor Baliti Turgeman-PhD Thesis Defense
|
Prof. Yaniv Ziv Lab

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.

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

Lecture
Date:
Tuesday, March 12, 2024
Hour: 12:30 - 13:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Dr. Mark Shein-Idelson
|
Dept of Neurobiology, Faculty of Life Sciences Tel Aviv University

: 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.

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

Lecture
Date:
Tuesday, February 20, 2024
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Dr. Raunak Basu
|
Edmond and Lily Safra Center for Brain Sciences The Hebrew University of Jerusalem

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.

The role of the corpus callosum in interhemispheric communication

Lecture
Date:
Wednesday, February 14, 2024
Hour: 14:00 - 15:00
Location:
The David Lopatie Hall of Graduate Studies
Yael Oran-PhD Thesis Defense
|
Prof. Ilan Lampl Lab Dept of Brain Sciences

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

Mechanistic insights into ‘brainwashing’ 

Lecture
Date:
Tuesday, February 13, 2024
Hour: 12:30 - 13:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Jonathan Kipnis
|
Dept of Pathology and Immunology Washington University School of Medicine in St. Louis

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

Lecture
Date:
Tuesday, January 30, 2024
Hour: 12:30 - 13:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Gaby Maimon
|
HHMI, The Rockfeller University, NY

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.

Non-canonical circuits for olfaction

Lecture
Date:
Tuesday, January 16, 2024
Hour: 12:30 - 13:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Dr. Dan Rokni
|
Dept of Medical Neurobiology, IMRIC The Hebrew University of Jerusalem, Ein Kerem

: 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.

Immunoception: Brain Representation and Control of Immunity

Lecture
Date:
Tuesday, January 9, 2024
Hour: 13:00
Location:
Wolfson Building for Biological Research
Prof. Asya Rolls
|
HHMI-Wellcome Scholar Rappaport Institute for Medical Research TECHNION Haifa

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.

Pages

All events, All years

Hippocampal pathology and pathophysiology in the development of temporal lobe epileptogenesis

Lecture
Date:
Sunday, March 24, 2024
Hour: 11:00 - 12:00
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Robert S. Sloviter
|
The Neuroscience Institute MRC 245 Morehouse School of Medicine, Atlanta GA

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.

Dimensionality bottleneck uncovers simple action selection rules in hunting zebrafish

Lecture
Date:
Tuesday, March 19, 2024
Hour: 12:30 - 13:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Dr. Lilach Avitan
|
Edmond and Lily Safra Center for Brain Sciences The Hebrew University of Jerusalem

Animal movements are complex, high-dimensional, and lead to many different consequences. Thus, efficiently quantifying the behavior and uncovering the underlying representation used by the animal pose a great challenge. Tracking freely behaving zebrafish larvae using a high-speed camera and analyzing their movements, we reveal that zebrafish movements can be described using exactly two parameters. Mapping all possible two-dimensional movement representations, we identified the representation used by the fish. We show that fish do not trivially represent distance and angles as separate parameters, but rather mix them nonlinearly. Moreover, when hunting, this specific nonlinear relation depends on the prey angle and further dictates a particular set of potential movements. These results uncover, for the first time, the underlying action selection principles of hunting behavior, suggesting that behind this seemingly complex behavior there is a simple and low-dimensional process.

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

Lecture
Date:
Wednesday, March 13, 2024
Hour: 15:30 - 16:30
Location:
Arthur and Rochelle Belfer Building for Biomedical Research
Linor Baliti Turgeman-PhD Thesis Defense
|
Prof. Yaniv Ziv Lab

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.

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

Lecture
Date:
Tuesday, March 12, 2024
Hour: 12:30 - 13:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Dr. Mark Shein-Idelson
|
Dept of Neurobiology, Faculty of Life Sciences Tel Aviv University

: 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.

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

Lecture
Date:
Tuesday, February 20, 2024
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Dr. Raunak Basu
|
Edmond and Lily Safra Center for Brain Sciences The Hebrew University of Jerusalem

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.

The role of the corpus callosum in interhemispheric communication

Lecture
Date:
Wednesday, February 14, 2024
Hour: 14:00 - 15:00
Location:
The David Lopatie Hall of Graduate Studies
Yael Oran-PhD Thesis Defense
|
Prof. Ilan Lampl Lab Dept of Brain Sciences

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

Mechanistic insights into ‘brainwashing’ 

Lecture
Date:
Tuesday, February 13, 2024
Hour: 12:30 - 13:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Jonathan Kipnis
|
Dept of Pathology and Immunology Washington University School of Medicine in St. Louis

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

Lecture
Date:
Tuesday, January 30, 2024
Hour: 12:30 - 13:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Prof. Gaby Maimon
|
HHMI, The Rockfeller University, NY

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.

Non-canonical circuits for olfaction

Lecture
Date:
Tuesday, January 16, 2024
Hour: 12:30 - 13:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Dr. Dan Rokni
|
Dept of Medical Neurobiology, IMRIC The Hebrew University of Jerusalem, Ein Kerem

: 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.

Immunoception: Brain Representation and Control of Immunity

Lecture
Date:
Tuesday, January 9, 2024
Hour: 13:00
Location:
Wolfson Building for Biological Research
Prof. Asya Rolls
|
HHMI-Wellcome Scholar Rappaport Institute for Medical Research TECHNION Haifa

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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Challenges and Debates at the Frontiers of Brain&Cognition

Conference
Date:
Wednesday, December 25, 2013
Hour: 08:00 - 17:00
Location:
The David Lopatie Conference Centre

Optogenetics: from cells to circuits and behavior

Conference
Date:
Sunday, July 14, 2013
Hour: 08:00 - 18:00
Location:
The David Lopatie Conference Centre

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WIS-Australia Symposium on Metabolic Syndroms

Conference
Date:
Sunday, May 12, 2013
Hour: 08:00 - 16:45
Location:
The David Lopatie Conference Centre

Emotional memories and stress: from normal physiology to psychopathology

Conference
Date:
Thursday, April 25, 2013
Hour:
Location:
The David Lopatie Conference Centre

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Brain Sciences open day

Conference
Date:
Thursday, February 7, 2013
Hour: 12:30 - 16:00
Location:
The David Lopatie Conference Centre

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Inflammation: A friend & a foe

Conference
Date:
Sunday, February 3, 2013
Hour: 08:00 - 20:00
Location:
The David Lopatie Conference Centre

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Aging of the Mind:Immunity in the middle of mind/body relationship

Conference
Date:
Monday, December 3, 2012
Hour:
Location:
The David Lopatie Conference Centre

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Optogenetics symposium

Conference
Date:
Saturday, July 14, 2012
Hour:
Location:
The David Lopatie Conference Centre

90th Birthday Meeting for Prof. David Samuel

Conference
Date:
Thursday, June 28, 2012
Hour:
Location:
Michael Sela Auditorium

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Brain Sciences Open Day

Conference
Date:
Wednesday, March 7, 2012
Hour:
Location:
The David Lopatie Conference Centre

Homepage

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