Posteroanterior Cervical Transcutaneous Spinal Cord Stimulation: Interactions with Cortical and Peripheral Nerve Stimulation

This study explores how stimulating the spinal cord through the skin (TSCS) interacts with brain and nerve stimulation to potentially improve hand function, especially in individuals with spinal cord injuries. A unique TSCS setup was used where the electrical current was applied from the front to the back of the neck. The researchers measured muscle responses in the hand when TSCS was combined with stimulation of the motor cortex (the brain area controlling movement) or the median nerve (a major nerve in the arm). The timing of these combined stimulations was varied to see how it affected the muscle responses. The findings suggest that TSCS, when timed correctly with brain stimulation, can enhance the communication between the brain, spinal cord, and hand muscles. This could potentially lead to new rehabilitation strategies for individuals with spinal cord injuries.

• 1
  Subthreshold TSCS facilitates hand muscle responses to motor cortex stimulation, with a tendency toward greater facilitation when TSCS is timed to arrive at cervical synapses simultaneously or up to 10 milliseconds after cortical stimulus arrival.
• 2
  Single pulses of subthreshold TSCS had no effect on the amplitudes of median H-reflex responses or F-wave responses.
• 3
  Suprathreshold TSCS interfered with F-wave transmission when TSCS was timed to arrive at cervical motor neurons 10 ms prior to retrograde F-wave arrival, indicating collisional interference.