Remodelling of sensorimotor maps in paraplegia: a functional magnetic resonance imaging study after a surgical nerve transfer

The adult mammalian brain has the capacity of reorganising its neural conne ctions in response to lesions/modifications of the peripheral and central n ervous system. We show in vivo, using functional magnetic resonance imaging (fMRI), that in paraplegics the lower-limb sensorimotor cortex is invaded by the arm representation. This functional reshaping appears to be reversib le. Indeed, surgical transfer of the ulnar nerve to the ipsilateral quadric eps and hip muscles allowed their contraction in a paraplegic patient. Duri ng fMRI, these voluntary movements activated the hip and thigh representati on in sensorimotor cortex. We suggest that the functional recovery of the l ower-limb functional maps might have been driven by the restored somatosens ory inputs from the reactivated periphery. The voluntary movements of the l ower-limbs are regained through the 're-awakening' of the corresponding sen sorimotor cortex. (C) 2001 Elsevier Science Ireland Ltd. All rights reserve d.