Three-dimensional Map of Lumbar Spinal Cord Motor Function for Intraspinal Microstimulation in Rats

Intraspinal microstimulation is an effective method to rebuild motor function after spinal cord injury. However, in the implementation, available map of stimulation sites is lacking for reference. The location of electrode implantation can only be determined through multiple stimulation, causing secondary damage to the spinal cord. Therefore, in this paper, SD rats were chosen as the research subject, and the intraspinal microstimulation was used to perform three-dimensional scanning electrical stimulation on the lumbar spinal cord that controls the hindlimb motion. The site coordinates and corresponding threshold current that can induce motion of hip, knee and ankle joints were recorded. In order to reduce the individual variances and improve the universality and applicability of the map, the results of 6 groups were normalized, and three-dimensional map of spinal motor function were drawn in the same coordinate system. The overlap of the distribution area of the same motion in each group was defined as the core region. The threshold current of all sites were analyzed statistically to obtain the most appropriate range of current intensity required to induce hindlimb motion. Using appropriate current for intraspinal microstimulation in the core region can selectively induce desired hindlimb motion, greatly improving the accuracy and reliability of electrode implantation.