DONATE MAINS

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January 26th, 14h00-15h00
(13 rue Moreau, 75012 PARIS)

Prof. Ernst Niebur  (Department of Neuroscience and Mind/Brain Institute Johns Hopkins University)

Invited by Ryad Benosman

Abstract: Visual attention is often understood as a modulatory field acting at early stages of processing, but the mechanisms that direct and fit the field to the attended object are not known. It is unlikely that neuronal structures that control the deployment of attention (like prefrontal cortex) contain detailed representations of object features. How can they then direct attention to specific objects? We show that a purely spatial attention field propagating downwards in the neuronal network responsible for perceptual organization will be reshaped, repositioned and sharpened to match the object's shape and scale. Key features of the model are neurons integrating local features into coherent (proto-)objects, excitatory feedback to the same local feature neurons which caused a proto-object's cell activation, and inhibition between incompatible interpretations both at the level of local features and at the level of proto-objects. We also extend the concept of the saliency map to proto-object based elements and we develop models of multi-modal saliency maps that integrate visual and auditory information.

 

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