Limb amputation is a common problem affecting the brain’s representation of the body. Most individuals with amputation have a phantom limb with which they experience touch and pain. Laurel J. Buxbaum, PsyD, and colleagues in MRRI’s Cognition and Action Laboratory are performing experiments with people experiencing phantom limb sensations that will explore two major questions.

First, there is prior evidence that the integrity of the body and of the ability to act may alter our perception of the space around the body (peripersonal space). One experiment is exploring whether having a phantom limb may change the way the brain represents the space around the body, using a task that requires people to judge whether an object is reachable or not.

Second, there is evidence that individuals with amputation who experience strong control over the movements of the phantom limb also experience reduced pain. The feeling of strong control, in turn, may result from “retargeting” of muscles of the residual limb. Following from this, Dr. Buxbaum and colleagues are using electromyography (EMG) to assess whether commands to move the foot have been remapped onto muscles that formerly controlled the upper leg.

Together, these experiments will lead to improved understanding of brain changes after amputation, and will help Dr. Buxbaum and colleagues secure grant funding for an expanded research program focusing on rehabilitation of phantom limb pain.

For more information about this research, contact MRRI Cognition and Action Lab research assistant Cortney Howard, 215-663-6035, howardco@einstein.edu.