ATTENTION-RELATED MODULATION OF ACTIVITY IN PRIMARY AND SECONDARY AUDITORY-CORTEX

WE investigated the effects of auditory attention on brain activity us ing functional magnetic resonance imaging. Subjects listened to three word lists, three times each, and were instructed to count the number of times they heard a target word during two of these presentations. F or the third, they listened to the words without counting. All subject s showed significant areas of activation in auditory cortex during the listening conditions compared to rest. There was significantly more a ctivation and a larger area of activation, particularly in association cortex, in the left temporal lobe during counting of targets compared to the no-target conditions, with a similar trend in the right hemisp here. These results provide evidence of an attention-related enhanceme nt of both activation magnitude and extent in auditory cortex.