Peripersonal space around the upper and the lower limbs

Area of Science:

• Neuroscience
• Cognitive Psychology
• Human Sensory Perception

Background:

• Peripersonal space (PPS) is the region surrounding the body, characterized by enhanced multisensory integration.
• Previous research shows stronger visuo-tactile integration in near space (within PPS) compared to far space, primarily using stimuli on upper limbs, torso, and face.
• The multisensory properties of PPS surrounding the lower limbs remain largely unexplored.

Purpose of the Study:

• To investigate whether the peripersonal space surrounding the lower limbs exhibits similar multisensory integration properties as observed for upper limbs.
• To compare visuo-tactile integration for stimuli presented to the hand versus the foot within near and far space.

Main Methods:

• Participants completed a visuo-tactile crossmodal congruency task involving speeded elevation judgments.
• Tactile stimuli were presented to the dorsum of the hand and foot.
• Visual distractors were presented at spatially congruent or incongruent locations in near or far space.

Main Results:

• For hand-presented stimuli, the crossmodal congruency effect (CCE) was larger in near space than far space, confirming stronger visuo-tactile integration within PPS.
• For foot-presented stimuli, the CCE was larger for far space distractors than near space distractors.
• This indicates distinct multisensory properties for PPS surrounding the upper versus lower limbs.

Conclusions:

• The representation of peripersonal space differs systematically between upper and lower limbs.
• Multisensory integration properties within PPS are likely dependent on the specific body part and its associated potential actions.
• This suggests a body part-centric organization of peripersonal space.