All events, All years

Adaptation and integration in the multimodal space map of the barn owl

Lecture
Date:
Monday, May 21, 2007
Hour: 12:00 - 13:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Dr. Yoram Gutfreund
|
Dept of Physiology & Biophysics, Faculty of Medicine, Technion, Haifa

Linking Network Archtecture to Neural Coding in the Olfactory System

Lecture
Date:
Monday, May 7, 2007
Hour: 12:00 - 13:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Dr. Roni Jortner
|
Interdisciplinary Center for Neural Computation Hebrew University of Jerusalem and Computation and Neural Systems, California Institute of Technology

Learning induces new representations of instructions and actions in the motor cortex

Lecture
Date:
Monday, April 30, 2007
Hour: 12:00 - 13:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. Eilon Vaadia
|
Dept of Physiology, Faculty of Medicine, The Hebrew University of Jerusalem

Structural analysis of serotonin transporter mechanism and regulation

Lecture
Date:
Wednesday, April 18, 2007
Hour: 12:00 - 13:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. Gary Rudnick
|
Dept of Pharmacology Yale University School of Medicine

Auditory self-perception and gating in a songbird

Lecture
Date:
Tuesday, April 17, 2007
Hour: 12:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. Richard Hahnloser
|
Institute of Neuroinformatics, UZH/ETHZ, Zurich

Vocal production and learning rely on the evaluation of auditory feedback. We use the songbird as a model system for exploring how auditory feedback in vocalizing animals is represented by auditory brain areas, and how auditory signals are gated back into premotor areas involved in song production and learning. We expose juvenile zebra finches to distorted auditory feedback and record from neurons in field L, an avian forebrain area thought to be analogous to mammalian primary auditory cortex. Most field L neurons in our ongoing study do not respond to auditory perturbation during singing, despite their motor-related firing being similar to auditory responses to playback of the bird’s own song. We argue that this behaviour of field L neurons is reminiscent of mirror neurons in primate inferior frontal cortex. In adult birds, we demonstrate modulation and gating of auditory and spontaneous cerebral activity by the thalamic nucleus uveaformis (Uva): The normal dependence of premotor-like spike patterns (bursts) on the behavioural state can be reversed by pharmacological manipulation of Uva activity. Our results show that avian thalamic relay neurons have a function that is reminiscent of a mixture of functions attributed to relay and reticular neurons in the mammalian thalamus. In summary, our findings of corollary motor discharges in auditory brain areas and of explicit thalamic gating mechanisms help to advance the understanding of auditory feedback processing and sensorimotor integration for complex learned behaviors.

guilt by association: Memory context effects, source memory, and the frontal lobes

Lecture
Date:
Monday, April 16, 2007
Hour: 12:00 - 13:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Dr. Daniel Levy
|
Gonda Brain Research Center, Bar-Ilan University & Dept of Neurobiology, WIS

As in many domains of cognition, the effects of context on memory are ubiquitous and pervasive. Even memory-impaired neurological patients and aging individuals with deficits in direct source recollection benefit from context reinstatement during retrieval. Though context effects on free and cued recall are robust, findings regarding context effects on recognition have been widely divergent. We have proposed a multifactorial model of context effects that takes into account the impact of hippocampally-based target-context binding, anterior medial temporal lobe-based additive familiarity, and frontal lobe-based strategic processes that suppress response bias to acheive mnemonic advantages. I will discuss findings from simulations and neuropsychological studies of the elderly that illustrate these factors. I will also present new data that suggest differences between temporal and spatial context and discuss their implications for memory models.

Epigenetic mechanisms in memory formation

Lecture
Date:
Sunday, April 15, 2007
Hour: 12:00 - 13:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. David Sweatt
|
Head, Neurobiology Dept and Mcknight Brain Institute, University of Alabama, Birmingham AL

Dr. Sweatt's seminar will focus on molecular mechanisms underlying learning and memory. Dr. Sweatt uses knockout and transgenic mice to investigate signal transduction mechanisms in the hippocampus, a brain region known to be critical for higher-order memory formation in animals and humans. His talk will describe transcriptional regulation in memory formation, focusing on studies of transcription factors, regulators of chromatin structure, and other epigenetic mechanisms, in order to understand the role of regulation of gene expression in synaptic plasticity and memory.

Optimal decoding of neural population responses in the primate visual cortex

Lecture
Date:
Monday, March 26, 2007
Hour: 12:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Dr. Eyal Seidemann
|
Center for Perceptual Systems and Depts. of Psychology and Neurobiology The University of Texas at Austin

How are simple perceptual decisions formed based on noisy neural signals that are distributed over large populations of neurons in early sensory cortical areas? To begin to address this fundamental question, we used a combination of real-time imaging andvelectrophysiological techniques to measure directly population responses in the primary visual cortex (V1) of monkeys while they performed a reaction-time visual detection task. We then evaluated different candidate models for detecting the target from the measured neural responses. Our analysis reveals that previously proposed methods for pooling neural responses over space and time are highly inefficient given the statistics of V1 population responses. We derived the optimal decoder of V1 responses and show that it can be approximated by simple neural circuits. Finally, we show that an optimal decoder that uses the signals from the monkey's cortex can outperform the monkey, indicating that inefficiencies at, or downstream to, V1 limit performance in simple detection tasks. The list of people I would like to meet with that I've sent to Alon is only partial. I'll be happy to meet with anyone in the Dept. that is available and is interested in meeting with me.

Medial frontal cortex involvement in error processing and delay discounting

Lecture
Date:
Monday, March 19, 2007
Hour: 12:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. Steven D. Forman
|
University of Pittsburgh, School of Medicine, Pittsburgh, PA

Background: Opiate addicts entering methadone maintenance treatment exhibit decreased medial frontal cortex activation with occurrence of error (negative) events. The strength of this error-related cortical signal correlated with discrimination performance and moment-to-moment cognitive control. In the clinical setting the strength of this signal predicted individual treatment adherence (e.g., time maintained in treatment before drop-out). While the latter finding suggests a connection between error processing and complex decisions involving choices between immediate and delayed goals, we did not have direct evidence supporting this connection. Methods: Subjects performed both the Go/NoGo task and a delay-discounting task while brain activity was monitored using event-related fMRI. Results: The medial frontal cortex region previously associated with error processing also displayed significant activation during delay discounting. Moreover, the individual strength of brain activation while processing errors correlated with that exhibited during processing decisions between immediate and delayed hypothetical rewards. Supported by NIH grant DA11721 and VA CPPF and MERIT awards.

Novel mechanisms for stress-induced hippocampal dysfunction: dendritic spines and CRH

Lecture
Date:
Monday, March 12, 2007
Hour: 12:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. Tallie Z. Baram
|
Prof. Pediatrics, Anatomy & Neurobiology and Neurology Danette Shepard Professor of Neurological Sciences, University of California at Irvine, Irvine CA

Whereas brain development is governed primarily by genetic factors, early-life experience, including stress, exerts long-lasting influence on neuronal structure and function. Baram's talk focuses on the hippocampus as the target of early-life stress because of its crucial role in learning and memory. The consequences of early-life stress on hippocampus-dependent cognitive tasks and synaptic plasticity will be described, as well as the the structural changes in dendrites and dendritic spines. New data will discuss the potential role of altered spine dynamics in the cellular mechanisms by which stress impacts the structure and function of hippocampal neurons.

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