The peripersonal space is thought to be represented by multimodal neurons whose receptive fields for the different modalities overlap in space. The crossmodal congruency (CC) task has been used to demonstrate a representation of peripersonal space in humans. In this task, participants judge the elevation of a touch while trying to ignore the elevation of a visual distracter. Despite this instruction, the elevation of the distracters influences performance, and most strongly so when the distracters are presented near the touched body part.
We found that the CC effect is also enhanced when the visual distracters are presented somewhere else in the peripersonal space of the body (e.g., near the foot), but not near the touched body part (e.g., the hand). We furthermore report that the spatial remapping of touch into visual coordinates in the CC task is modulated by the position of body parts which are physically connected to the touched body part (e.g. the elbow and hand).
The results of both experiments are not explained by the current conception of peripersonal space representations simply as overlapping receptive fields of different sensory modalities. Rather, they suggest interactions of the peripersonal space representations of different body parts, or a whole-body representation of peripersonal space.