Functional imaging of executive functions.

Abstract

Executive functioning refers to cognitive processes that facilitate our adaptation to new or complex situations when action routines are not efficient. Neuropsychological studies in brain-damaged patients suggested that executive functions were predominantly dependent on prefrontal regions. However, prefrontal lesions frequently occurred in a context of more widespread brain involvement, and a dysexecutive syndrome was described in posterior cortical dementia of the Alzheimer type. Functional imaging can precisely identify brain networks involved in executive functioning. We discuss functional imaging studies that show both frontal and posterior activation during executive tasks and bring information concerning unity and diversity in executive processes.