Abstract
Neurophysiological research (Eifuku & Wurtz, 1998, Journal of Neurophysiology) has identified MST as a potential site for the detection of scene-relative movement. Using fMRI we investigated the role of area hMST in the same task in humans. First using standard localisers we identified hMT+, hMST and hMT, along with disparity sensitive, motion sensitive, and retinotopic regions. Next we confirmed that pure object movement (a moving object viewed from a stationary viewpoint) activated the same network of motion-sensitive areas as pure self-movement (movement of a viewpoint through a rigid scene). We then attempted to isolate areas specialised for scene-relative movement. Observers viewed (through anaglyph stereo glasses) twenty-five 3D objects randomly positioned within a volume in peripersonal space, directly ahead. Amongst the scene objects was a target object that was identified by a significant difference in size. We simulated the lateral translation of the observer and a compensatory counter-rotation of the head to maintain fixation on the centre of the volume of objects. We compared BOLD response (15 second period box-car) when the target object was a part of the rigid scene against when the target object moved independently of the scene. There was some variation in individuals' responses, but the results suggest a central role for hMST.