CORTICAL ACTIVATION IN THE HUMAN BRAIN DURING LATERAL SACCADES USING EPISTAR FUNCTIONAL MAGNETIC-RESONANCE-IMAGING

The location of the human cortical substrate underlying simple horizon tal saccadic eye movements was investigated using echoplanar functiona l magnetic resonance imaging (fMRI) in young healthy volunteers. Echop lanar imaging with signal targeting and alternating radiofrequency (EP ISTAR), a novel perfusion technique, measured signal intensity changes in one to four contiguous 10-mm slices centered to include both stria te cortex and putative frontal eye fields during horizontal saccade an d fixation conditions. Subtraction images of self-paced visually guide d saccadic versus fixation conditions showed bilateral marked and stat istically significant localized signal increases in the precentral reg ion (Brodmann areas 4, 6) and peristriate cortex (areas 17, 18, 19) an d qualitative increases in the superior medial frontal region, as iden tified by a Talairach-Tournoux generalized template in the brain slice s that were scanned. Additional parietal activation occurred during a target-guided saccade task. Our data () support the localization of th e human FEF, as identified by simple, nonexploratory saccadic eye move ments, in the precentral motor strip and premotor cortex, (ii) show in dividual variability in the exact anatomical location of saccade-relat ed activations, and (iii) confirm that the EPISTAR technique can demon strate localized signal increases during a behavioral task. (C) 1996 A cademic Press, Inc.