Spatial extinction and its relation to mechanisms of normal attention

Abstract

AbstractThis chapter addresses the various clinical manifestations of extinction and relates these to relevant data on attentional limits in normal subjects. It then offers an overview of recent findings from studies of extinction that have focused on cross-modal interactions, the influences of temporally asynchronous stimulation, motor competition, and perceptual grouping, and links these results where possible to relevant behavioral, neurophysiological, and brain imaging data. It concludes by considering the possible sites of brain damage that give rise to extinction, and suggests some fruitful avenues for future research. The studies reviewed show that competitive interactions provide a significant mechanism for the selective processing of sensory inputs in the normal brain. They also provide evidence that spatial extinction following unilateral brain damage reflects the outcome of biased competition between simultaneous contralesional and ipsilesional stimuli. The use of functional magnetic resonance imaging (fMRI) and event-related potentials has already begun to reveal the brain basis for unconscious processing in extinction.