[Brain potentials following painful stimulation in humans].
When a CO2 laser beam is applied to the skin, subjects feel a "pin-prick" sensation. We have investigated somatosensory evoked potentials following CO2 laser stimulation (laser SEP) in normal subjects, and confirmed that signals following CO2 laser stimulation ascend through A-delta fibers and the spinothalamic tract. Its conduction velocity is approximately 10 m/s. Change in pain perception produced by the application of movement and various modalities of sensation to areas adjacent to, and remote from, the painful stimulus was investigated by means of laser SEPs. We investigated pain SEPs and conventional electrically stimulated SEPs in patients with various neurological diseases including peripheral neuropathies, syringomyelia, multiple sclerosis and HTLV-I-associated myelopathy (HAM), and found a good correlation between laser SEP findings and the degree of impairment of pain-temperature sensations. Laser SEPs could be used to find subclinical abnormalities in some patients.
Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
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D000328:Adult; D001921:Brain / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory; D006801:Humans; D007834:Lasers; D010146:Pain / Q000503:physiopathology*; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis / Q000503:physiopathology; D010812:Physical Stimulation