Evoked cerebral responses to noxious thermal stimuli in humans

Brief pulses of Laser emitted radiant heat were used to induce cutaneous painful sensations in human volunteers. Accurate timing of the stimuli permitted recording of scalp averaged evoked potentials. A late negative-positive component of the EP which correlated in amplitude with the subjective sensation was observed in four subjects. The latency of this component (130-160 msec) correlated with stimulus intensity.