Abnormal Changes in Motor Cortical Maps in Humans with Spinal Cord Injury

This study investigates how the brain's motor cortex, which controls movement, changes after a spinal cord injury (SCI). Researchers used transcranial magnetic stimulation (TMS) to map the motor cortex in people with SCI and compared it to healthy individuals. The study found that at rest, the motor cortex maps were larger in people with SCI. However, during voluntary muscle contraction, the motor cortex map area decreased in people with SCI, while it increased in healthy individuals. The researchers also found that sensory input plays a role in this reorganization. When sensory input was increased via muscle-tendon vibration, the motor cortex map area increased in people with SCI during voluntary contraction.

• 1
  Motor maps were larger in SCI (22.3 cm2) compared with control (12.6 cm2, P < 0.001) participants at rest.
• 2
  Motor map area increased during voluntary contraction of the FDI (120.7%) and further increased during contraction of the BB (143.9%) compared with rest in control subjects; however, motor map area decreased during voluntary contraction of the FDI (69.5%) and further decreased during contraction of the BB (55.5%) in individuals with SCI.
• 3
  SCI participants with larger decreases in map area during voluntary contraction of the FDI were those with larger sensory deficits in the hand and 10 minutes of hand muscle-tendon vibration increased motor map area.