Investigation of cortical neuronal reorganization for neuroprosthetics in monkeys

Whether there is neural regeneration after spinal cord injury (SCI) is a challenging scientific and clinical research topic. Extensive research efforts have been devoted to identify effective neural repair strategies to limit further neural damages following spinal cord injury and promote axonal regeneration and sprouting for recovery of voluntary functions. However, little information or effort has been reported on how cortical control being affected by spinal cord injury and adaptation in such control due to spinal cord neural repair. With the advances in chronically implantable microelectrode arrays, the cortical neuronal activities have become accessible, which enables us to investigate the important question on possible changes in cortical neuron activity patterns. We implanted four 16-channel microelectrode arrays into two monkeys´ primary motor cortical areas related to lower limb movement, and recorded cortical neuronal signals while they performed a bipedal walking on the treadmill. Comparing the neural population activity patterns from normal monkeys to that after spinal cord injury and treated with neural repair, we identified a significant increase in the synchronization among the recorded cortical neuronal population activities. This information would be critical for the development of effective and practical techniques to harness the cortical adaptation or plasticity after spinal cord injury to promote voluntary control of lower limb functions or neuroprosthetics for SCI victims who are reliant on wheelchair.