Immunohistochemical localization of the corticospinal tract in normal rat spinal cord as a stereotactic guidance for implantation of microelectronic chip

In order to investigate the pick-up, the process and the regeneration of central neural signals for neural function regeneration by means of microelectronic techniques, it is necessary to do a more detailed investigation, primarily of the stereotactic anatomical bases of corticospinal tract (CST). In present study, we use a polyclonal antibody against protein kinase C gamma subspecies (PKC γ) as a specific marker of CST to reveal the precise localization of CST in rat spinal cord by immunohistochemistry. The strong PKC γ immunoreactivities in axons of CST were found in the pyramid and pyramidal decussation of medulla oblongata, and then from the cervical to lumbar spinal cord, PKC γ immunoreactivities were found to descend caudully through the white matter occupying the ventralmost portion of the posterior funiculus. At the conus medullaris, the positive reactivities of PKC γ appeared at the midline of the posterior funiculus. The area of positive reactivities of PKC γ decreased in size caudally in different spinal cord segments. These findings suggest that PKC γ immunohistochemical method can show the accurate position of corticospinal tract in rat spinal cord clearly, and provide the stereotactic anatomical bases for the microelectronic chip implantation in spinal cord.