Electroencephalography and clinical neurophysiology
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Electroencephalogr Clin Neurophysiol · Mar 1989
Pain-related somatosensory evoked potentials following CO2 laser stimulation in man.
Pain-related somatosensory evoked potentials (SEPs) following CO2 laser stimulation were analyzed in normal volunteers. Low power and long wavelength CO2 laser stimuli to the hand induced a sharp pain which was associated with a large positive component, P320, recorded over the scalp. Amplitude decreased and latency increased with reduction in stimulus intensity and subjective pain feeling. ⋯ No potential corresponding to P320 could be recorded following electrical or mechanical tactile stimulation. We consider P320 to be generated by impulses arising from pain stimuli and ascending through A delta fibers. We propose the thalamus as a generator source from considering its scalp topography, but pain-specific cognition or perception may also be involved in generating this potential.