Response mapping for epidural spinal stimulation for the restoration of controlled hindlimb movement after spinal cord injury

Epidural spinal stimulation induces controlled muti-joint movements in the lower limbs after spinal cord injury. Though often approached as a method for eliciting locomotor movements, unilateral induced movement could enable the control of step height and duration, critical in restoring freeform locomotion with a brain machine interface post spinal cord injury. In this study, hindlimb movement was induced in the rat by electrical stimulation at the lateral aspect of the dorsal surface in the L1-L6 levels. Stimulation in the L2 and L3 segments induced hindlimb extension while the induced movement changed to hindlimb flexion when the stimulation was moved to L4 and L5. This pattern of activation was maintained in transected animals and was consistent with both mineral oil and saline hydrating the cord during stimulation. This work develops a rat model of epidural spinal stimulation for spinal cord injury.