Functional imaging of brain areas involved in the processing of coherent and incoherent wide field-of-view visual motion

The brain areas involved in processing wide field-of-view (FOV) coherent an d incoherent visual stimuli were studied using positron emission tomography (PET). The brains of nine subjects were scanned as they viewed texture pat terns moving in the roll plane. Five visual conditions were used: (1) coher ent clockwise (CW) wide-FOV (>100 degrees) roll motion; (2) coherent counte rclockwise (CCW) wide-FOV roll motion; (3) wide-FOV incoherent motion; (4) CCW motion confined to the central visual field (similar to 55 degrees); an d (5) a stationary control texture. The region most activated by the cohere nt-motion stimulus relative to the static one was the medial-occipital cort ex, whereas both the medial- and lateral-occipital cortices were activated by incoherent motion relative to a static texture. Portions of the retroins ular parietal-temporal cortex, superior insula, putamen, and vestibulocereb ellum responded specifically to the coherence of the stimulus, whereas a wi despread lateralized activation was observed upon subtracting the CW scans from the CCW scans. The results indicate separate neural regions for proces sing wide-FOV motion versus stimulus coherence.