Optimal stimulus duration for extracranial cortical stimulation.

Motor cortex stimulation is a new testing area in which either electrical or magnetic fields are used to produce transcranial stimulation of the underlying brain. The resulting signals, recorded from the spinal cord, peripheral nerves, or muscles, are monitored by electromyographic and evoked potential techniques. This report considers the issues in effective stimulation with minimal noxious sensation. Short duration pulses are optimal for electrical fields, and electrodeless stimulation with magnetic fields also makes use of short duration pulses.