CUTANEOUS LOCALIZATION OF LASER-INDUCED PAIN IN HUMANS

Localisation of painful laser-induced stimuli has been compared to loc alisation of tactile stimuli in normal humans. Laser stimulation evoke d pain of two qualities (sharp pricking pain and hot burning pain). Sh arp pricking pain was found to be localised with almost equal precisio n to tactile stimuli (13.8+/-3.4 versus 11.6+/-2.3 mm) on the dorsum o f the hand, (21.5+/-7.9 versus 20.6+/-7.5 mm) on the forearm and (15.5 +/-5.6 versus 13.8+/-5.4 mm) on the foot, respectively. There was no s ignificant difference between the ability to localise tactile stimuli and hot burning pain except on the dorsum of the hand. These results i ndicate that tactile information is not essential for the accurate loc alisation of cutaneous pain.