A spinal stimulator that can regulate hindlimb movements using monopolar stimulation has not been developed yet. Nevertheless, in a previous study, we found a specific central pattern generator site on the right side of the rat spinal cord. By stimulating these sites with certain pulse signals, the alternating movement of the hindlimb can be obtained using fewer electrodes. Therefore, in this research, considering the specific central pattern generator site as the target, functional electrical stimulation was performed on rats with spinal cord injury using monopolar stimulation. Angle sensors were used to track and capture the knee joint angle data of the right hindlimb; thus, the mapping relationship between the voltage amplitude and the knee angle parameters was established. Based on this relationship, the rats' hindlimb were controlled. Compared with the traditional spinal stimulator, the proposed approach increases the gait feedback, requires fewer electrodes, and simplifies the timing of stimulation. The rats with spinal cord injury were subjected to stimulation training for half an hour every day for 28 consecutive days. The Basso, Beattie and Bresnahan score showed that 76% of the health level could be achieved on the 28th day. Finally, somatosensory evoked potential analysis showed that the measurement results were close to the standard value on the 28th day. This study lays a foundation for future rehabilitation research on the hindlimb.
Keywords: Central pattern generator; functional electrical stimulation; gait feedback and control; monopolar stimulation.