Perceptual and motor mechanisms for mental rotation of human hands

We measured brain potentials from human subjects performing a mental rotati on task requiring right-left judgments of misoriented hands, and a control task requiring palm-back judgments of the same stimuli. High-density, 128-c hannel event-related potentials (ERPs) were recorded from 16 normal, right- handed subjects. There was a main effect of task at five different latencie s: 148 ms (occipital), 180 ms (parietal), 388 ms (vertex), 556 ms (central- parietal), and 900 ms. (vertex). Source estimations derived from topographi c data indicate that frontal brain. regions were strongly activated after 3 00 ms in the control task, but not until about 900 ms in the rotation task. We conclude that the neural computations underlying mental hand rotation m ay be recruited from relatively early stages of visuo-perceptual analysis; these early computations influence subsequent processing within a parietal- prefrontal system for the integration of perception with action. (C) 2001 L ippincott Williams & Wilkins.