Prefrontal modulation of visual processing in humans

Single neuron, evoked potential and metabolic techniques show that attentio n influences visual processing in extrastriate cortex. We provide anatomica l, electrophysiological and behavioral evidence that prefrontal cortex regu lates neuronal activity in extrastriate cortex during visual discrimination . Event-related potentials (ERPs) were recorded during a visual detection t ask in patients with damage in dorsolateral prefrontal cortex. Prefrontal d amage reduced neuronal activity in extrastriate cortex of the lesioned hemi sphere. These electrophysiological abnormalities, beginning 125 ms after st imulation and lasting for another 500 ms, were accompanied by behavioral de ficits in detection ability in the contralesional hemifield. The results pr ovide evidence for intrahemispheric prefrontal modulation of visual process ing.