Cervical intraspinal microstimulation evokes robust forelimb movements before and after injury

This study explores the use of intraspinal microstimulation (ISMS) to restore movement in paralyzed limbs after spinal cord injury. ISMS involves stimulating the spinal cord to activate motor neurons and muscles. The researchers examined how cervical ISMS could evoke forelimb movements in rats both before and after a contusion injury to the cervical spinal cord. They looked at which muscles were activated and what movements were produced by the stimulation. The results showed that ISMS could still evoke forelimb movements after the spinal cord injury, suggesting its potential for reanimating arm and hand function following such injuries. There was a temporary shift towards certain types of movements (extension) after the injury, but the patterns of movement generally returned to normal over time.

• 1
  ISMS evoked movements at a similar percentage of sites from spinally-intact animals and from animals tested at each of the three time points after spinal cord injury.
• 2
  Three weeks after injury, the distribution of ISMS-evoked movements changed to predominately movements of the elbow (56.3±11.8%), with decreased shoulder (2.0±1.7%) and wrist movements (0.2± 0.2 %; p < 0.05).
• 3
  Multiple muscles were often coactivated by cervical ISMS at threshold intensities sufficient for producing a single forelimb movement.