Human brain regions involved in heading estimation.

Observer motion in a stationary visual environment results in an optic flow pattern on the retina, which in simple situations can be used to determine the direction of self motion or heading. The present study, using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), investigated the human cerebral activation pattern, elicited when subjects viewing a ground plane optic flow pattern actively judged heading. Several successive experiments controlled for visual input, visuospatial attention, and motor response effects. Results indicate that the network specifically involved in heading consists of only two motion sensitive areas: human MT/V5+, including an inferior satellite, and dorsal intraparietal sulcus area (DIPSM/L), predominantly in the right hemisphere, plus a dorsal premotor region bilaterally. These results suggest possible homologies with the dorsal part of the medial superior temporal area and area 7a in the monkey.