Evoked cerebral potential correlates of C-fibre activity in man.
CO2 laser emitted radiant heat pulses of 20 ms duration were used to activate predominantly slowly conducting nociceptive cutaneous afferents in man. Stimuli of two-fold individual pain threshold caused stinging and burning pain and elicited cerebral potentials with latencies consistent with A delta-fibre activity. After preferential block of the myelinated nerve fibres by pressure only the burning pain remained with significantly increased reaction time (about 1433 ms). The A delta-fibre-induced evoked potential components disappeared, and a marked ultralate positive component became visible with mean peak latency of 1260 ms, consistent with C-fibre activity.
D000344:Afferent Pathways / Q000503:physiopathology; D001921:Brain / Q000503:physiopathology*; D004558:Electric Stimulation; D004569:Electroencephalography; D005071:Evoked Potentials; D006801:Humans; D007834:Lasers; D010146:Pain / Q000503:physiopathology*; D012867:Skin / Q000294:innervation*