Brain activity evoked by inverted and imagined biological motion

Previous imaging research has identified an area on the human posterior sup erior temporal sulcus (STS) activated upon viewing biological motion. The c urrent experiments explore the relationship between neural activity within this region and perceptual experience. Biological motion perception is orie ntation dependent: inverting point-light animations make them more difficul t to see. We measured activity levels within this region as observers viewe d inverted point-light animations. We also measured neural activity while o bservers imagined biological motion and compared it to that measured while observers viewed the animations. In both experiments Lye found that the BOL D response was modulated with perceptual experience. Viewing inverted biolo gical motion activated posterior STS more than scrambled motion, but less t han upright biological motion. Mental imagery of biological motion was also sufficient to activate this region in most of our observers, but the level of activity was weaker than during actual viewing of the motion animations . (C) 2001 Elsevier Science Ltd. All rights reserved.