Cerebral blood flow evidence of right frontal activation in attention demanding tasks.

Having noticed a consistent activation of right frontal areas during several visuospatial tasks, we retrospectively examined data from 121 regional cerebral blood flow (rCBF) studies conducted under a variety of conditions involving different stimuli, response modes and task requirements. These were compared to scans conducted while subjects were at rest. Significant hemispheric differences were found for all tasks combined in the frontal regions, where right flow was greater than left, especially in more demanding tasks. This finding suggests a very general role for the right hemisphere in attention or vigilance.