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Impact of Attention and Intention on Visual Representations
Dr. Carol Colby
Tuesday, March 09, 2010, 01:00pm - 02:00pm
Carnegie Mellon University, Neuroscience and Center For the Neural Basis of Cognition
Visual perception is produced by the interaction of incoming sensory signals and top down cognitive and motor signals. When a visual stimulus requires attention, the amplitude of response in parietal neurons in strengthened. This enhancement occurs regardless of the kind of response the monkey will make. In contrast to attention, intention can shift the spatial location to which a neuron is sensitive. Spatial integration of visual information across saccades is achieved both by shifting the location of the receptive field and by updating stored memory traces. This "remapping" is initiated by a corollary discharge of the eye movement command, which provides information about the intention to make a saccade.
Remapping is accomplished not by a single brain area but by the participation of parietal, frontal and extrastriate cortex as well as subcortical structures. This neural circuitry is distinguished by significant redundancy and plasticity, suggesting that the updating of salient stimuli is fundamental for spatial stability and visuospatial behavior. These findings provide new evidence that a unified and stable representation of visual space is constructed by a redundant circuit, comprised of cortical as well as subcortical pathways, with a remarkable capacity for reorganization.