Motion-responsive regions of the human brain

Functional magnetic resonance imaging was used to map motion responsive reg ions of the human brain by contrasting passive viewing of moving and statio nary randomly textured patterns. Regions were retained as motion responsive if they reached significance either in the group analysis or in the majori ty of hemispheres in single-subject analysis. They include well-known regio ns, such as V1, hMT/V5+, and hV3A, but also several occipito-temporal, occi pito-parietal, parietal, and frontal regions. The time course of the activa tion was similar in most of these regions. Motion responses were nearly ide ntical for binocular and monocular presentations. Flicker-induced-activatio n introduced a dichotomy amongst these motion responsive regions. Early occ ipital and occipito-temporal regions responded well to flicker, while flick er responses gradually vanished as one moved to occipito-parietal and then parietal regions. Finally, over a more than four-fold range, stimulus diame ter had little effect on the motion activations, except in V1.