Losing a Hand

Abstract

Amputation of a hand results in profound synaptic reorganisations in the brain cortex. The cortical representational area of the amputated hand is at first ‘silent’ but rapidly becomes invaded by adjacent cortical areas. Cortical reorganisations can result in phantom sensation, a feeling that the lost hand is still there. Phantom sensation can sometimes be combined with severe phantom pain. Mirror treatment, based on an illusion that the lost hand is still attached, may be an effective way of treating severe phantom pain. Amputated fingers or hands can often be microsurgically replanted (reattached to the body). When a replanted hand is reinnervated, it resumes its correct position in the brain cortex. The salamander is unique among animals since it can spontaneously regenerate an amputated extremity. It has been suggested that the mechanism behind this phenomenon is based on an interaction of stem cell-like cells at the amputation level interacting with a specific Schwann cell-produced protein (nAG). If these mechanisms could 1 day be applied to humans, it would open up a totally new landscape for treating amputations.