Subjective image of invisible hand coded by monkey intraparietal neurons

Humans can perform purposeful band actions even blindly in the dark, perhap s using mental images of the hand. To demonstrate such subjective body imag es, this study describes the activities of bimodal (somatosensory and visua l) neurons in the monkey intraparietal cortex. Visual stimuli moving into t he space encompassing their somatosensory receptive fields (s-RFs) on the h and activated these neurons, forming visual receptive fields (v-RFs) as if coding a hand-image. After the hand was hidden by covering it with an opaqu e plate, the v-RF persisted over the plate above the invisible s-RF. Furthe rmore, when the hand was moved invisibly under the plate, the v-RF moved ov er the plate to follow the invisible s-RF. Thus, monkeys can maintain and u pdate subjective body images in the mind, and they are coded by intrapariet al bimodal neurons. NeuroReport 11:3499-3505 (C) 2000 Lippincott Williams & Wilkins.