Scope of a technique for electrical stimulation of human brain, spinal cord, and muscle.

Brief high-voltage electrical shocks from a special low-output-resistance stimulator, delivered through electrodes on the skin, can excite human muscle directly (not by way of the nerves) and can also excite the motor cortex, the visual cortex, and the spinal cord. Possible applications of the technique include measurement in muscle disorders of the latency relaxation and of the excitability and contractility of muscle without the interposition of nerve fibres or the neuromuscular junction; measurement of conduction velocity in the pyramidal tract; and the detection of neuropathy in the nerves to the external sphincter ani.