Switching between dimensions, locations, and responses: the role of the left frontopolar cortex.

We review event-related fMRI data regarding the role of the left lateral frontopolar cortex (LFPC) in attentional switching processes. We found LFPC activation when subjects had to reallocate attentional resources, either between visual dimensions (color and motion) or between locations. However, LFPC activation during these dimension or location switches was observed only when subjects had to counteract stimulus-driven attention to an invalid dimension or location. LFPC was not activated following changes of stimulus-response associations. Further experiments will have to show whether LFPC is actively involved in the reallocation of attentional resources or whether it rather has a monitoring function. Copyright 2001 Academic Press.