NEURONAL RESPONSES IN THE MOTION PATHWAY OF THE MACAQUE MONKEY TO NATURAL OPTIC FLOW STIMULI

NEURONES in higher visual motion areas in the superior temporal sulcus (STS) of the macaque monkey respond to abstract random dot optic flow stimuli. Higher motion areas may not only represent, but in a next co mputational stage also analyse the flow field to determine, for instan ce, the direction of heading for navigation purposes. Real world visua l scenes differ in several aspects from these abstract optic flow stim uli. We tested tile neuronal response to naturalistic optic flow stimu li which simulated egomotion in different virtual environments and con tained different numbers of visual cues. Neuronal activity depended ma inly on the position of the focus of expansion rather than on other vi sual cues. This finding supports the hypothesis that higher motion are as within the STS analyse optic flow in natural scenes and can thus si gnal the direction of heading.