Brain activity associated with the rubber foot illusion.

Area of Science:

• Neuroscience
• Cognitive Science
• Somatosensation

Background:

• The internal body representation is dynamic, updated by sensory input.
• The rubber hand illusion (RHI) manipulates hand representation; its neural basis is studied.
• The rubber foot illusion (RFI) extends this to the lower limb, but neural correlates are unknown.

Purpose of the Study:

• To investigate the neural mechanisms underlying the rubber foot illusion (RFI).
• To compare brain activity during RFI with previously reported RHI activity.
• To explore implications for treating disturbed body representations.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used.
• Forty-four healthy volunteers participated.
• Participants underwent the RFI paradigm for both right and left feet.

Main Results:

• fMRI revealed significant activation in prefrontal cortex, parietal cortex, and cerebellum during RFI.
• Activation patterns for RFI were comparable to those reported for RHI.
• Conjunction analysis confirmed co-activation in medial frontal gyri, inferior parietal lobuli, and cerebellar hemispheres for both RFIs.

Conclusions:

• The RFI engages brain regions similar to the RHI, suggesting a shared neural basis for body representation.
• Co-activation in prefrontal, parietal, and cerebellar areas may underlie body representation reconstruction.
• These findings have implications for understanding and treating disorders of body representation.