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From perception to action: imaging human brain function
Conference
Sunday, December 24, 2017
Hour: 08:30 - 13:30
Location:
The David Lopatie Conference Centre
Challenging the sensory division of labor in the brain. Lessons from the deafs’ sense of rhythm and tactile braille reading in the sighted.
Lecture
Tuesday, November 7, 2017
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Challenging the sensory division of labor in the brain. Lessons from the deafs’ sense of rhythm and tactile braille reading in the sighted.
Dr. Marcin Szwed
Dept of Psychology,
Jagiellonian University, Krakow, Poland
It is established that the brain is capable of large-scale reorganization following sensory deprivation or injury. What is less clear is what are the rules that guide it. In the blind, many visual regions preserve their task specificity despite being recruited for different sensory input; ventral visual areas, for example, become engaged in auditory and tactile object-recognition. However, we are interested in two questions. First, is sensory deprivation necessary for such task-specific reorganization, or can it happen in non-deprived individuals? In this series of experiments, during 9 months we taught Braille, a tactile alphabet, to sighted individuals and observed the resulting changes with structural and functional MRI. (Siuda, Krzywicka, Bola et al, eLife, 2016). Second, we wondered whether task-specific reorganization is unique to the visual cortex, or alternatively, is it a general principle applying to other cortical areas. Here, we enrolled deaf and hearing adults into an fMRI experiment, during which they discriminated between rhythms. In hearing individuals, rhythm processing is performed mostly in the auditory domain. Our prediction was that if task-specific reorganization applies to the human auditory cortex, performing this function visually should recruit the auditory cortex in the deaf (Bola, Zimmerman et al., PNAS, 2017).
Revealing the neural correlates of behavior without behavioral measurements
Lecture
Tuesday, October 31, 2017
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Revealing the neural correlates of behavior without behavioral measurements
Dr. Alon Rubin
Senior Intern, Yaniv Ziv Lab
Department of Neurobiology, WIS
Using whiskers to gain insights into animal behaviour and motor control
Lecture
Monday, October 16, 2017
Hour: 14:30
Location:
Nella and Leon Benoziyo Building for Brain Research
Using whiskers to gain insights into animal behaviour and motor control
Dr. Robyn A. Grant
Conservation, Evolution and Behaviour Research Group
Division of Biology and Conservation Ecology
Manchester Metropolitan University, UK
Mammalian whiskers and avian rictal bristles come in a variety of shapes and sizes. Indeed, one of the most striking facial features in all mammals (excluding higher primates and humans) is the presence of whiskers. They are deployed in a wide range of tasks and environments. For example, rodents may use their whiskers to guide arboreal locomotion, whilst seals use theirs to track hydrodynamic trails of vortices shed by the fish upon which they prey (Gläser et al, 2010). Certainly, the evolution of the sense of touch is a recognised cornerstone in mammalian evolution, driving brain complexity and behavioural flexibility. While the whisker system is an established model for sensory information processing, advances in measuring whisker behaviours suggests that whisker movements are also useful for measuring aspects of motor control. Many "whisker specialists" including rodents and pinnipeds employ their whiskers by moving them actively, and all mammals (and even some birds) share a similar muscle architecture that drives the movement of the whiskers. Certainly, changes in whisker movements can indicate a loss of motor control and coordination. In this talk I will consider the anatomy and morphology of whiskers, and consider their function in a range of different species. I will suggest how whisker movements may have evolved, and how they are very important for whisker specialists.
Applying epigenetics to the study of trauma in the first and second generation
Lecture
Sunday, September 17, 2017
Hour: 10:30
Location:
Nella and Leon Benoziyo Building for Brain Research
Applying epigenetics to the study of trauma in the first and second generation
Prof. Rachel Yehuda
Director, Traumatic Stress Studies Division
Mount Sinai School of Medicine, NYC
A phylogenetic approach to decision making
Lecture
Tuesday, September 5, 2017
Hour: 12:30
Location:
Nella and Leon Benoziyo Building for Brain Research
A phylogenetic approach to decision making
Prof. Thomas Boraud, MD PhD
Directeur de Recherche CNRS,
University of Bordeaux
Speech processing in auditory cortex with and without oscillations
Lecture
Monday, September 4, 2017
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Speech processing in auditory cortex with and without oscillations
Prof. Anne-Lise Giraud
Department of Neuroscience
University of Geneva
Switzerland
Perception of connected speech relies on accurate syllabic segmentation and phonemic encoding. These processes are essential because they determine the building blocks that we can manipulate mentally to understand and produce speech. Segmentation and encoding might be underpinned by specific interactions between the acoustic rhythms of speech and coupled neural oscillations in the theta and low-gamma band. To address how neural oscillations interact with speech, we used a neurocomputational model of speech processing generating biophysically plausible coupled theta and gamma oscillations. We show that speech could be well decoded from this purely bottom-up artificial network’s low-gamma activity, when the phase of theta activity was taken into account. Because speech is not only a bottom-up process, we set out to develop another type of neurocomputational model that takes into account the influence of linguistic predictions on acoustic processing. I will present preliminary results obtained with such a model and discuss the advantage of incorporating neural oscillations in models of speech processing.
Functional dissection of decision-related activity in the primate dorsal stream
Lecture
Thursday, August 17, 2017
Hour: 12:30
Location:
Nella and Leon Benoziyo Building for Brain Research
Functional dissection of decision-related activity in the primate dorsal stream
Dr. Leor Katz
University of Texas at Austin
The study of perceptual decision-making is key to understanding complex cognitive behavior. Two decades of recordings in primate parietal cortex suggest that neurons in the lateral intraparietal (LIP) cortex integrate sensory evidence from upstream neurons (presumably MT) in favor of making a decision. However, the causal role of LIP in decision-making had not been tested directly.
In this talk, I will present recent experiments that tested whether area LIP—which exhibits strong decision-related activity—is causally related to perceptual decision-making. In contrast to the generally accepted model, we found that inactivation in area LIP had no measurable impact on decision-making behavior (despite having exerted effects in a control task). This finding suggests that strong decision-related activity does not guarantee a causal role in decision-making. To better understand the MT-LIP circuit we then applied a Generalized Linear Model (GLM) to simultaneously recorded MT and LIP neurons. We found that much of MT & LIP responses may be interpreted in simple sensorimotor terms, as opposed to appealing to nuanced cognitive phenomena. These results shift our understanding of decision-related activity in the primate brain and motivate new approaches to further dissecting the circuit.
Simple integration of asymmetric inputs computes directional selectivity in Drosophila
Lecture
Tuesday, July 11, 2017
Hour: 12:30
Location:
Nella and Leon Benoziyo Building for Brain Research
Simple integration of asymmetric inputs computes directional selectivity in Drosophila
Eyal Gruntman
Postdoc, Reiser Lab, HHMI, Janelia Research Campus
The detection of visual motion is a fundamental neuronal computation that serves many critical behavioral roles, such as encoding of self-motion or figure-ground discrimination. For a neuron to extract directionally selective (DS) motion information from inputs that are not motion selective it is essential to integrate across multiple spatially distinct inputs. This integration step has been studied for decades in both vertebrate and invertebrate visual systems and given rise to several competing computational models. Recent studies in Drosophila have identified the 4th-order neurons, T4 and T5, as the first neurons to show directional selectivity. Due to the small size of these neurons, recordings have been restricted to the use of calcium imaging, limiting timescale and direct measurement of inhibition. These limitations may prevent a clear demonstration of the neuronal computation underlying DS, since it may depend on millisecond-timescale interactions and the integration of excitatory and inhibitory signals. In this study, we use whole cell in-vivo recordings and customized visual stimuli to examine the emergence of DS in T4 cells. We record responses both to a moving bar stimulus and to its components: single position bar flashes. Our results show that T4 cells receive both excitatory and inhibitory inputs, as predicted by a classic circuit model for motion detection. Furthermore, we show that by implementing a passive compartment model of a T4 cell, we can account not only for the DS response of the cell, but also for its dynamics.
Neural Representations of Natural Self Motion: Implications for Perception & Action
Lecture
Monday, July 3, 2017
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Neural Representations of Natural Self Motion: Implications for Perception & Action
Prof. Kathleen Cullen
Dept of Biomedical Engineering,
Johns Hopkins University
The vestibular system detects self-motion and in turn generates reflexes that are crucial for our daily activities, such as stabilizing the visual axis (gaze) and maintaining head and body posture. In addition, the vestibular system provides us with our subjective sense of movement and orientation in space. The loss vestibular function due to aging, injury, or disease produces dizziness, postural imbalance, and an increased risk of falls – all symptoms that profoundly impair quality of life.
In this talk, I will describe how the brain processes vestibular information in natural conditions. Notably, our work has established how early stages of processing encode vestibular stimuli and integrate them with extra-vestibular cues – for example proprioceptive and premotor information to ensure accurate perception and behaviour. Our experiments have revealed that while vestibular afferents respond identically to externally-generated and actively-generated self-motion, this is not the case at first central stage of sensory processing. Neurons mediating the vestibulo-spinal reflexes, as well as ascending thalamocortical pathways, are robustly activated during externally-generated motion, however their sensory response are cancelled during actively-generated movements. Our work has further revealed that this cancellation of actively-generated vestibular input occurs only in conditions where the actual sensory signal matches the brain’s internal estimate of the expected sensory consequences of active movement. Moreover, when unexpected vestibular inputs becomes persistent during voluntary motion, a cerebellar-based cancellation mechanism is rapidly updated to re-enable the vital distinction between self-generated and externally-applied stimulation to ensure the maintenance of posture and stable perception. In contrast, vestibular pathways mediating the vestibulo-ocular reflex, employ a different strategy. In this pathway, head velocity is robustly encoded whenever the goal is to stabilize gaze, but when the goal is to voluntarily redirect gaze an efferent copy of the gaze command suppresses the efficacy of this reflex pathway. Taken together, these findings have important implications for understanding the neural basis of perception and action during self-motion.
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A phylogenetic approach to decision making
Lecture
Tuesday, September 5, 2017
Hour: 12:30
Location:
Nella and Leon Benoziyo Building for Brain Research
A phylogenetic approach to decision making
Prof. Thomas Boraud, MD PhD
Directeur de Recherche CNRS,
University of Bordeaux
Speech processing in auditory cortex with and without oscillations
Lecture
Monday, September 4, 2017
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Speech processing in auditory cortex with and without oscillations
Prof. Anne-Lise Giraud
Department of Neuroscience
University of Geneva
Switzerland
Perception of connected speech relies on accurate syllabic segmentation and phonemic encoding. These processes are essential because they determine the building blocks that we can manipulate mentally to understand and produce speech. Segmentation and encoding might be underpinned by specific interactions between the acoustic rhythms of speech and coupled neural oscillations in the theta and low-gamma band. To address how neural oscillations interact with speech, we used a neurocomputational model of speech processing generating biophysically plausible coupled theta and gamma oscillations. We show that speech could be well decoded from this purely bottom-up artificial network’s low-gamma activity, when the phase of theta activity was taken into account. Because speech is not only a bottom-up process, we set out to develop another type of neurocomputational model that takes into account the influence of linguistic predictions on acoustic processing. I will present preliminary results obtained with such a model and discuss the advantage of incorporating neural oscillations in models of speech processing.
Functional dissection of decision-related activity in the primate dorsal stream
Lecture
Thursday, August 17, 2017
Hour: 12:30
Location:
Nella and Leon Benoziyo Building for Brain Research
Functional dissection of decision-related activity in the primate dorsal stream
Dr. Leor Katz
University of Texas at Austin
The study of perceptual decision-making is key to understanding complex cognitive behavior. Two decades of recordings in primate parietal cortex suggest that neurons in the lateral intraparietal (LIP) cortex integrate sensory evidence from upstream neurons (presumably MT) in favor of making a decision. However, the causal role of LIP in decision-making had not been tested directly.
In this talk, I will present recent experiments that tested whether area LIP—which exhibits strong decision-related activity—is causally related to perceptual decision-making. In contrast to the generally accepted model, we found that inactivation in area LIP had no measurable impact on decision-making behavior (despite having exerted effects in a control task). This finding suggests that strong decision-related activity does not guarantee a causal role in decision-making. To better understand the MT-LIP circuit we then applied a Generalized Linear Model (GLM) to simultaneously recorded MT and LIP neurons. We found that much of MT & LIP responses may be interpreted in simple sensorimotor terms, as opposed to appealing to nuanced cognitive phenomena. These results shift our understanding of decision-related activity in the primate brain and motivate new approaches to further dissecting the circuit.
Simple integration of asymmetric inputs computes directional selectivity in Drosophila
Lecture
Tuesday, July 11, 2017
Hour: 12:30
Location:
Nella and Leon Benoziyo Building for Brain Research
Simple integration of asymmetric inputs computes directional selectivity in Drosophila
Eyal Gruntman
Postdoc, Reiser Lab, HHMI, Janelia Research Campus
The detection of visual motion is a fundamental neuronal computation that serves many critical behavioral roles, such as encoding of self-motion or figure-ground discrimination. For a neuron to extract directionally selective (DS) motion information from inputs that are not motion selective it is essential to integrate across multiple spatially distinct inputs. This integration step has been studied for decades in both vertebrate and invertebrate visual systems and given rise to several competing computational models. Recent studies in Drosophila have identified the 4th-order neurons, T4 and T5, as the first neurons to show directional selectivity. Due to the small size of these neurons, recordings have been restricted to the use of calcium imaging, limiting timescale and direct measurement of inhibition. These limitations may prevent a clear demonstration of the neuronal computation underlying DS, since it may depend on millisecond-timescale interactions and the integration of excitatory and inhibitory signals. In this study, we use whole cell in-vivo recordings and customized visual stimuli to examine the emergence of DS in T4 cells. We record responses both to a moving bar stimulus and to its components: single position bar flashes. Our results show that T4 cells receive both excitatory and inhibitory inputs, as predicted by a classic circuit model for motion detection. Furthermore, we show that by implementing a passive compartment model of a T4 cell, we can account not only for the DS response of the cell, but also for its dynamics.
Neural Representations of Natural Self Motion: Implications for Perception & Action
Lecture
Monday, July 3, 2017
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Neural Representations of Natural Self Motion: Implications for Perception & Action
Prof. Kathleen Cullen
Dept of Biomedical Engineering,
Johns Hopkins University
The vestibular system detects self-motion and in turn generates reflexes that are crucial for our daily activities, such as stabilizing the visual axis (gaze) and maintaining head and body posture. In addition, the vestibular system provides us with our subjective sense of movement and orientation in space. The loss vestibular function due to aging, injury, or disease produces dizziness, postural imbalance, and an increased risk of falls – all symptoms that profoundly impair quality of life.
In this talk, I will describe how the brain processes vestibular information in natural conditions. Notably, our work has established how early stages of processing encode vestibular stimuli and integrate them with extra-vestibular cues – for example proprioceptive and premotor information to ensure accurate perception and behaviour. Our experiments have revealed that while vestibular afferents respond identically to externally-generated and actively-generated self-motion, this is not the case at first central stage of sensory processing. Neurons mediating the vestibulo-spinal reflexes, as well as ascending thalamocortical pathways, are robustly activated during externally-generated motion, however their sensory response are cancelled during actively-generated movements. Our work has further revealed that this cancellation of actively-generated vestibular input occurs only in conditions where the actual sensory signal matches the brain’s internal estimate of the expected sensory consequences of active movement. Moreover, when unexpected vestibular inputs becomes persistent during voluntary motion, a cerebellar-based cancellation mechanism is rapidly updated to re-enable the vital distinction between self-generated and externally-applied stimulation to ensure the maintenance of posture and stable perception. In contrast, vestibular pathways mediating the vestibulo-ocular reflex, employ a different strategy. In this pathway, head velocity is robustly encoded whenever the goal is to stabilize gaze, but when the goal is to voluntarily redirect gaze an efferent copy of the gaze command suppresses the efficacy of this reflex pathway. Taken together, these findings have important implications for understanding the neural basis of perception and action during self-motion.
Astrocytes generate de-novo neuronal potentiation and memory enhancement
Lecture
Tuesday, June 20, 2017
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Astrocytes generate de-novo neuronal potentiation and memory enhancement
Dr. Inbal Goshen
Edmond and Lily Safra Center for Brain Sciences
Hebrew University of Jerusalem
Clustering of dendritic activity during decision making
Lecture
Tuesday, June 13, 2017
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Clustering of dendritic activity during decision making
Dr. Boaz Mohar
Postdoctoral Associate, Karel Svoboda Lab, Janelia Research Campus, HHMI
Neighboring neurons in motor cortex exhibit diverse selectivity during sensation, movement preparation, and movement execution. Neuronal selectivity could emerge from diverse mechanisms, including selective connectivity and nonlinear interactions of synaptic inputs in dendrites. We studied dendritic integration in the anterior motor cortex of mice performing a tactile discrimination task with a delayed response (Guo and Li et al., 2014). We constructed a two-photon microscope that allows rapid (~15 Hz) imaging of up to 300 µm of contiguous dendrite while resolving calcium transients in individual dendritic spines. Two galvanometers and a remote focusing mirror (Botcherby et al., 2008) steer 16 kHz lines (24 µm extent) produced by a resonant mirror arbitrarily in three dimensions. Pyramidal neurons were labeled sparsely with GCaMP6f in transgenic mice. We imaged spine and dendritic calcium transients, as well as somatic calcium transients associated with action potentials. We developed methods to computationally remove the influence of backpropagating action potentials (bAPs), which allowed us to quantify the selectivity of spines and dendritic segments during sensation, movement preparation, and movement execution. Nearby spines and dendritic segments share similar selectivity (length constant of signal correlation, ~30 µm). This clustering was more often seen in distal than in proximal dendrites. Using a measure of local autocorrelation, we also found that this reflects distinct “hotspot” locations on the dendrite where nearby dendrite and spines are co-active in time. Hotspot selectivity was correlated with the behavioral selectivity of somatic spikes, suggesting that these locations may have privileged influence over the output of the cell.
Behavioral and neural bases of social decision-making in non-human primates
Lecture
Thursday, June 8, 2017
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Behavioral and neural bases of social decision-making in non-human primates
Prof. Jean-Rene Duhamel
Institut des Sciences Cognitives Marc Jeannerod CNRS/
Universite Claude Bernard Lyon
Primates live in environments characterized by continuous, complex cycles of social interactions, where the actions of any group member necessarily influences those of the other members. This raises the question of the extent to which adaptive behavior in social encounters involves specialized mechanisms to represent others’ intentions and affective states. In my talk, I will explore this topic at the behavioral level - asking whether monkeys take into account the welfare of their conspecific when making decisions- and at the brain level - asking what type of information about a social partner is encoded by single neurons in the amygdala and anterior insula. I will try yo argue that these two structures carry neuronal mechanisms for empathy and perspective taking.
Presynaptic dysfunction in Fragile X syndrome
Lecture
Tuesday, June 6, 2017
Hour: 12:30
Location:
Gerhard M.J. Schmidt Lecture Hall
Presynaptic dysfunction in Fragile X syndrome
Prof. Vitaly Klyachko
Dept of Biomedical Engineering, Dept of Cell Biology and Physiology
Washington University School of Medicine
I will discuss our efforts towards understanding synaptic and circuit dysfunction in Fragile X syndrome, the most common heritable cause of intellectual disability and the leading genetic cause of autism. I will describe our studies identifying major presynaptic defects in excitability and neurotransmitter release in Fragile X and the role of ion channel dysregulation in these deficits. Finally, I will present evidence for a direct link between presynaptic dysregulation and specific Fragile X phenotypes in a patient.
Orbitofrontal-hippocampal interactions in decision making
Lecture
Wednesday, May 24, 2017
Hour: 16:00
Location:
Gerhard M.J. Schmidt Lecture Hall
Orbitofrontal-hippocampal interactions in decision making
Prof. Yael Niv
Princeton Neuroscience Institute and Psychology Dept
Princeton University
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