Peripersonal

Peripersonal is an adjective describing the region of space immediately surrounding the body. In common and scientific usage, the term is most often paired with peripersonal space, referring to the space within arm’s reach that can be acted upon or perceived in close proximity to the body. This concept is contrasted with extrapersonal space, which lies beyond reach, and with interpersonal space, which concerns social distances between people.

In neuroscience and psychology, peripersonal space is considered a multisensory representation that integrates tactile information from the skin with visual and sometimes auditory information about stimuli near the body. Neurons coding for peripersonal space have been identified in motor and parietal areas of the brain, such as ventral premotor and parietal regions, where stimuli near the body can modify responses to touch. These representations help coordinate action, such as reaching, grasping, or defensive reactions, and they are influenced by the position of the limbs and the observer’s context.

Peripersonal space is dynamic and adaptable. It can expand or contract with tool use, experience, or emotional state. For example, using a tool can extend the body’s reachable space so that stimuli at the tool’s end are treated as if they are near the body. It can also be reshaped by learning, development, and certain clinical conditions.

Researchers study peripersonal space using behavioral tasks that combine tactile and visual stimuli, reaction-time measurements, and neuroimaging. Understanding its properties informs fields ranging from neuroscience and psychology to robotics and rehabilitation.