All events

Uncovering the Boundaries of Olfactory Perception

Lecture
Date:
Monday, April 19, 2021
Hour: 15:00 - 16:00
Location:
Aharon Ravia (PhD Thesis Defense)
|
Prof. Noam Sobel Lab, Dept of Neurobiology Prof. David Harel Lab, Dept of Computer Science and Applied Mathematics WIS

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

New insights on continuous attractor neural networks

Lecture
Date:
Tuesday, April 20, 2021
Hour: 12:30
Location:
Prof. Yoram Burak
|
Racah Institute of Physics and Edmond and Lily Safra Center for Brain Sciences The Hebrew University of Jerusalem

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

Neural correlates of future weight loss reveal a possible role for brain-gastric interactions

Lecture
Date:
Tuesday, April 27, 2021
Hour: 12:30 - 13:30
Location:
Prof. Galia Avidan
|
Dept of Psychology Ben Gurion University of the Negev

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

To be announced

Lecture
Date:
Tuesday, May 4, 2021
Hour: 12:30
Location:
Ivan E de Araujo
|
Mt. Sinai Hospital

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

To be announced

Lecture
Date:
Tuesday, May 11, 2021
Hour: 12:30
Location:
Nancy Kanwisher
|
MIT

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

to be announced

Lecture
Date:
Tuesday, May 18, 2021
Hour: 12:30
Location:
Lin Dayu
|
NYU

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

To be announced

Lecture
Date:
Tuesday, May 25, 2021
Hour: 12:30
Location:
Adam Packer
|
Oxford University

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

To be announced

Lecture
Date:
Tuesday, June 1, 2021
Hour: 12:30
Location:
Adi Mizrahi
|
ELSC

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

To be announced

Lecture
Date:
Tuesday, June 8, 2021
Hour: 12:30
Location:
Prof. Yadin Dudai
|
Neurobiology Dept, WIS

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

To be announced

Lecture
Date:
Tuesday, June 15, 2021
Hour: 12:30
Location:
Gily Ginosar
|
Neurobiology Dept, WIS

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

To be announced

Lecture
Date:
Tuesday, June 22, 2021
Hour: 12:30
Location:
Talma Hendler
|
TAU

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

Brain plasticity: Regulation and Modulation

Conference
Date:
Monday, May 16, 2022
Hour: 08:00 - 18:00
Location:
David Lopatie Conference Centre

All events

Uncovering the Boundaries of Olfactory Perception

Lecture
Date:
Monday, April 19, 2021
Hour: 15:00 - 16:00
Location:
Aharon Ravia (PhD Thesis Defense)
|
Prof. Noam Sobel Lab, Dept of Neurobiology Prof. David Harel Lab, Dept of Computer Science and Applied Mathematics WIS

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

New insights on continuous attractor neural networks

Lecture
Date:
Tuesday, April 20, 2021
Hour: 12:30
Location:
Prof. Yoram Burak
|
Racah Institute of Physics and Edmond and Lily Safra Center for Brain Sciences The Hebrew University of Jerusalem

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

Neural correlates of future weight loss reveal a possible role for brain-gastric interactions

Lecture
Date:
Tuesday, April 27, 2021
Hour: 12:30 - 13:30
Location:
Prof. Galia Avidan
|
Dept of Psychology Ben Gurion University of the Negev

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

To be announced

Lecture
Date:
Tuesday, May 4, 2021
Hour: 12:30
Location:
Ivan E de Araujo
|
Mt. Sinai Hospital

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

To be announced

Lecture
Date:
Tuesday, May 11, 2021
Hour: 12:30
Location:
Nancy Kanwisher
|
MIT

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

to be announced

Lecture
Date:
Tuesday, May 18, 2021
Hour: 12:30
Location:
Lin Dayu
|
NYU

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

To be announced

Lecture
Date:
Tuesday, May 25, 2021
Hour: 12:30
Location:
Adam Packer
|
Oxford University

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

To be announced

Lecture
Date:
Tuesday, June 1, 2021
Hour: 12:30
Location:
Adi Mizrahi
|
ELSC

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

To be announced

Lecture
Date:
Tuesday, June 8, 2021
Hour: 12:30
Location:
Prof. Yadin Dudai
|
Neurobiology Dept, WIS

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

To be announced

Lecture
Date:
Tuesday, June 15, 2021
Hour: 12:30
Location:
Gily Ginosar
|
Neurobiology Dept, WIS

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

To be announced

Lecture
Date:
Tuesday, June 22, 2021
Hour: 12:30
Location:
Talma Hendler
|
TAU

Zoom link to join- https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

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All events

Brain plasticity: Regulation and Modulation

Conference
Date:
Monday, May 16, 2022
Hour: 08:00 - 18:00
Location:
David Lopatie Conference Centre