HUMAN PREFRONTAL LESIONS INCREASE DISTRACTIBILITY TO IRRELEVANT SENSORY INPUTS

NEUROLOGICAL patients with focal lesions in either the dorsolateral prefrontal cortex, temporal-parietal junction or the posterior hippocampus, and control subjects, were tested on a task requiring short-term retention of environmental sounds. Subjects had to indicate whether initial and subsequent test sounds were identical in two conditions. The initial and test sounds were separated by either either a silent period varying from 4 to 12.69 (no-distractor condition) or a series of irrelevant tones (distracter condition). Prefrontal patients were significantly impaired by distracters at all delays, hippocampal patients were impaired only at longer delays, while temporal-parietal patients performed similar to controls. The findings suggest that dorsolateral prefrontal cortex is crucial for gating of distracting information during delay tasks.