Blindness to form from motion despite intact static form perception and motion detection

We studied the motion perception, including form and meaning generated by m otion, in a hemianopic patient who also bad visual perceptual impairments i n her seeing hemifeld as a result of a lesion in ventral extrastriate corte x. She was unable to recognise 2- or 3-dimensional forms, and ei en borders , generated by motion alone, failed to recognise mimed actions err the Joha nnson 'biological motion' display, and ceased to recognise people well-know n to her when they moved. I-Icr performance with static displays, although impaired, could not explain her inability to perceive shape or derive meani ng from moving displays. Unlike a motion-blind patient, she can still see a nd describe the motion, with the exception of second-order motion, but not what it creates or represents. (C) 2000 Elsevier Science Ltd. All rights re served.