CO2 laser radiant heat pulses activate C nociceptors in man.

Cerebral potentials evoked by noxious CO2 laser stimuli in man have been referred to nociceptive A delta units. This paper shows 1) that ultra short (5 - 50 ms) high power (less than or equal to 50 W) CO2 laser skin stimuli are able to activate nociceptive C units in man, and 2) that these C nociceptors have to be assumed to terminate in the very superficial skin layer (less than or equal to 300 microns depth).