Septal Stimulation Inhibits Spinal Cord Dorsal Horn Neuronal Activity
Hagains, Christopher E
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Deep Brain Stimulation is a useful technique for relieving chronic pain in patients that have exhausted their options. The septum has been a target for such treatment. The purpose of this study was to determine if electrical stimulation in the medial septum diagonal band of broca (MSDB) would reduce nociceptive neuronal activity in the spinal cord of rats. This interest was addressed using a Grass Stimulator to stimulate the MSDB on one side of the brain while recording mostly wide dynamic range neurons in the lumbar region of the spinal cord. Neuronal activity was initiated by graded mechanical stimulation of the hind paws (brush, pressure, and pinch). Responses to pressure were significantly reduced in both sides of the spinal cord by 1V, 5V, 10V, and 20V, 100Hz, and 0.1 ms duration MSDB stimulation. Responses to pinch in the spinal cord were significantly reduced bilaterally by 1V, 5V, 10V, and 20V, 100Hz, and 0.1 ms duration. However, there was no change in responses to brush. Additionally, inhibition scores were calculated and used to examine the extent of inhibition for each parameter of electrical stimulation. These data suggested that 5V was adequate for achieving optimal inhibition. The ratio of stimulation-on and stimulation-off was also compared within each segment of mechanical stimulation. These results indicated that neuronal responses were being inhibited when the stimulation was on. In summary, it is concluded that unilateral stimulation of the MSDB produces bilateral inhibition of spinal cord dorsal horn neuronal responses to noxious mechanical stimuli.