Areas of the human brain activated by ambient visual motion, indicating three kinds of self-movement

In a positron emission tomography (PET) study, a very large visual display was used to simulate continuous observer roll, yaw, and linear movement in depth. A global analysis based on all three experiments identified brain areas that responded to the three conditions’ shared characteristic of coherent, wide-field motion versus incoherent motion. Several areas were identified, in the posterior-inferior temporal cortex (Brodmann area 37), paralimbic cortex, pulvinar, and midbrain tegmentum. In addition, occipital region KO was sensitive to roll and expansion but not yaw (i.e., coherent displays containing differential flow). Continuous ambient motion did not activate V5/MT selectively. The network of sites responding specifically to coherent motion contrasted with the extensive, contiguous activation that both coherent and incoherent motion elicited in visual areas V1, V2, and V3. The coherent motion mechanisms, furthermore, extended beyond the traditional dorsal pathway proposed to account for visual motion processing, and included subcortical and limbic structures, which are implicated in polysensory processing, posture regulation, and arousal.