Abnormal changes in motor cortical maps in humans with spinal cord injury

The functional role of motor cortical reorganization following spinal cord injury (SCI) remains largely unknown. Here, we tested motor maps in a hand muscle at rest and during voluntary contraction of the hand with and without voluntary contraction of a proximal arm muscle. Motor map area in participants with SCI decreased during hand voluntary contraction and further decreased during additional contraction of a proximal arm muscle compared with rest. In contrast, motor map area in controls increased during the same motor tasks. Participants with SCI with more severe sensory deficits in the hand showed larger decreases in motor map area. Ten minutes of hand muscle-tendon vibration increased the motor map area during voluntary contraction in SCI participants. These novel findings suggest that abnormal changes in motor cortical maps during voluntary contraction after SCI can be reshaped by sensory input, knowledge that can have implications for rehabilitation.