All events, All years

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.

Brain functions: from basic research to clinical applications

Conference
Date:
Monday, March 12, 2007
Hour:
Location:

The perception of curvature and its neural substrate

Lecture
Date:
Monday, March 5, 2007
Hour: 12:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Dr. Ohad Ben-Shahar
|
Department of Computer Science, Ben Gurion University of the Negev

The analysis of texture patterns, and texture segregation in particular, are at the heart of visual processing. In this work we question the accepted view that the (perceptual and computational) detection of salient perceptual singularities (i.e., borders) between perceptually coherent texture regions is tightly dependent upon feature *gradients*. Specifically, we study smooth orientation-defined textures (ODTs) and show psychophysically that they exhibit striking perceptual singularities even without any outstanding gradients in their defining feature (i.e., orientation). By studying oriented patterns from a (differential) geometric point of view we then develop a theory that accurately predicts their perceptual singularities from two ODT *curvatures*. Finally, in searching for the cortical substrate of curvature computation, we show how its critical role at the perceptual level could be reflected physiologically in the functional organization of the primary visual cortex via the connectivity patterns of long range horizontal connections.

Entorhinal grid cells and hippocampal memory

Lecture
Date:
Tuesday, February 27, 2007
Hour: 12:00
Location:
Arthur and Rochelle Belfer Building for Biomedical Research
Prof. Edvard I. Moser
|
Director, Centre for the Biology of Memory, Norwegian University of Science and Technology, Trondheim, Norway

Representation in entorhinal grid cells

Lecture
Date:
Monday, February 26, 2007
Hour: 12:00
Location:
Arthur and Rochelle Belfer Building for Biomedical Research
Prof. May-Britt Moser
|
Co-director, Centre for the Biology of Memory, Norwegian University of Science and Technology, Trondheim, Norway

Structural and functional changes induced by prenatal stress

Lecture
Date:
Monday, February 19, 2007
Hour: 12:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. Marta Weinstock-Rosin
|
Department of Pharmacology, The Hebrew University of Jerusalem

Adaptive mechanisms in the auditory system

Lecture
Date:
Monday, February 12, 2007
Hour: 12:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. Merav Ahissar
|
Department of Psychology, Faculty of Social Sciences, The Hebrew University of Jerusalem

The mechanisms underlying our remarkable ability to form coherent and meaningful percepts in our complex environment are still an unresolved mystery. I propose that fast adaptive processes occurring at all levels of the processing hierarchy play a major role in this ability. I will give examples from speech perception and from tone comparison. A unique population in this respect are individuals with reading and learning disabilities. Their adaptive stimulus-specific mechanisms are impaired, with broad perceptual and cognitive consequences.

Molecular crossroads of neuronal plasticity and neuropathology

Lecture
Date:
Wednesday, February 7, 2007
Hour: 12:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. Natalia V. Gulyaeva
|
Deputy Director, Inst. of Higher Nervous Activity & Neurophysiol, Moscow Russia

Imaging synaptic development and plasticity of adult-born neurons in the mouse Olfactory Bulb

Lecture
Date:
Monday, February 5, 2007
Hour: 12:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Dr. Adi Mizrahi
|
Department of Neurobiology, The Hebrew University of Jerusalem

The mammalian brain maintains few developmental niches where neurogenesis persists into adulthood. One niche is located within the olfactory system where the olfactory bulb (OB) continuously receives newborn neurons that integrate into the network as functional interneurons. However, little is known about the mechanisms of development and function of this unique population. In this study, we set out to directly image newborn neurons and synapses by combining high resolution in vivo two-photon microscopy and lentivirus labeling. Overexpressing cytosolic GFP or a synaptic protein (PSD95-GFP) reveals the general dendritic structure and/or synaptic distributions along dendritic trees, respectively. In vivo imaging reveals the dynamic behavior of dendrites and synapses over time. Adult-born neurons were transduced at the subventricular zone and imaged in the OB where they start to mature into functional neurons. First, time-lapse imaging of newborn neurons over several days revealed that dendritic formation is highly dynamic with distinct dynamics for spiny neurons and non-spiny neurons. The dynamic nature of newborn development was not affected by sensory deprivation. Once incorporated into the network, adult-born neurons maintain significant levels of structural dynamics. This structural plasticity is local, cumulative and sustained in neurons several months after their integration. Second, synapse formation on these young cells and dendrites was verified by EM analysis of PSD95-GFP expressing cells. Using these neurons we found that early during development, synaptic distributions are highly ordered along dendritic trees. Third, these synapses continuously change locations along dendritic shafts as revealed time-lapse imaging over several days. Interestingly, these newborn neurons remain structurally dynamic months after they have been incorporated into the network. I will also discuss preliminary results where we use in vivo calcium to decipher the physiological activity of unique populations in the OB and cortex. These experiments provide an experimental model to directly study the dynamics of neuronal and synaptic development in the intact mammalian brain and provide direct evidence for the ongoing plasticity of the adult-born neuronal population.

Structure and dynamics of neuronal networks: impact on representation

Lecture
Date:
Monday, January 29, 2007
Hour: 12:00
Location:
Nella and Leon Benoziyo Building for Brain Research
Prof. Shimon Marom
|
Dept of Physiology, Faculty of Medicine, Technion

The structure of large random networks is explored using spontaneous and evoked activities recorded from a subset of individual neurons. The emerging topology is that of a complex dynamic graph. Impacts on concepts of representation are analyzed.

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