Intracranial Somatosensory Responses with Direct Spinal Cord Stimulation in Anesthetized Sheep
Figure 1
A) Axial view of the spinal cord illustrating the different stimulator positions (intradural, epidural, midline, and lateral). B) Schematic depiction of the orientation of the bipolar stimulating electrode contacts relative to the spinal cord. The contacts were oriented in parallel with the long axis of the spinal cord, with the cathode contact being rostral to the anode contact. C and D) Photographs of the sheep’s brain before and after removal of the 96 contact subdural grid (Sheep 3). E) Photograph of the spinal cord surgical field. A mounting arm (1) is attached to the spinous process and connected to the micromanipulator (3) that is adjusted via the control (2). With this device the location of the neurostimulator (4) can be varied as needed over the mid-line of the exposed dorsal spinal cord (5) and maintained in a stable position. F) A close-up view of the neurostimulator placed in contact with the pial surface at the spinal cord midline (the dura is incised and sutured open). The field is flooded with 0.9% normal saline (NSS). In this experiment, a four contact subdural strip was also carefully inserted rostrally within the subdural space to record spinal cord potentials. The leads for the subdural strip are housed inside the white cable seen running through the lower center of the photo.