Shared Mapping of Own and Others' Bodies in Visuotactile Bimodal Area of Monkey Parietal Cortex

TLDR

The parietal cortex integrates visual and somatosensory signals and contains mirror neurons that map others’ actions onto the self, yet how it represents others’ bodies and aligns self and other body representations remains unclear. The study aimed to determine whether visuotactile neurons in simian parietal cortex encode both the monkey’s own and others’ body parts. Researchers recorded visuotactile bimodal neurons in ventral intraparietal area and area 7b while monkeys observed visual or tactile stimuli applied to experimenter’s body parts. Bimodal neurons with body‑anchored receptive fields responded to visual stimuli on corresponding experimenter body parts and had peripersonal visual RFs within ~30 cm, indicating that the brain uses self representation as a reference for perceiving others’ bodies and may support spatial matching for action recognition and imitation.

Abstract

Parietal cortex contributes to body representations by integrating visual and somatosensory inputs. Because mirror neurons in ventral premotor and parietal cortices represent visual images of others' actions on the intrinsic motor representation of the self, this matching system may play important roles in recognizing actions performed by others. However, where and how the brain represents others' bodies and correlates self and other body representations remain unclear. We expected that a population of visuotactile neurons in simian parietal cortex would represent not only own but others' body parts. We first searched for parietal visuotactile bimodal neurons in the ventral intraparietal area and area 7b of monkeys, and then examined the activity of these neurons while monkeys were observing visual or tactile stimuli placed on the experimenter's body parts. Some bimodal neurons with receptive fields (RFs) anchored on the monkey's body exhibited visual responses matched to corresponding body parts of the experimenter, and visual RFs near that body part existed in the peripersonal space within approximately 30 cm from the body surface. These findings suggest that the brain could use self representation as a reference for perception of others' body parts in parietal cortex. These neurons may contribute to spatial matching between the bodies of the self and others in both action recognition and imitation.