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What does the Pulvinar tell us about Visual Perception?| old_uid | 9159 |
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| title | What does the Pulvinar tell us about Visual Perception? |
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| start_date | 2010/10/15 |
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| schedule | 14h30 |
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| online | no |
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| details | invité par Frédéric Chavane |
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| summary | It is generally considered that sensory signals reaching primary sensory areas through thalamic nuclei are further processed along direct cortico-cortical pathways in a hierarchical manner (with parallel processing existing within these pathways). This model of sensory processing does not take into account the existence of multiple reciprocal connections between cortical areas and thalamic nuclei. A fundamental question remains unresolved and corresponds to the long-term objective of my laboratory: what are the functions of these transthalamic cortico-cortical pathways? To address this question, we must first define the properties of the thalamic nuclei involved in these pathways, and in particular, the main higher-order visual thalamic nucleus, the pulvinar. This structure lies over the dorsolateral posterior thalamus and runs along the medial edge of the lateral geniculate nucleus (LGN). Through evolution, the pulvinar, in parallel with the expansion of the neocortex, has undergone a considerable increase in size, and has established extensive reciprocal connections with virtually all visual cortical areas. The pulvinar complex receives its primary visual afferents through descending pathways from layer V cortical neurons of the primary visual cortex and not from ascending retinal projections. For this reason, the pulvinar complex must be considered as a higher-order nucleus, as opposed to a first-order nucleus, such as the LGN, which receives its driving afferents from the retina. Response characteristics of neurons in the pulvinar complex reflect the presence of the prominent descending cortical inputs and therefore resemble those of cortical rather than subcortical neurons. I this talk, I will describe some higher-order properties of LP-pulvinar cells and provide evidence that |
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| responsibles | Riehle |
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