Similar nociceptive afferents mediate psychophysical and electrophysiological responses to heat stimulation of glabrous and hairy skin in humans

摘要: The ability to perceive and withdraw rapidly from noxious environmental stimuli is crucial for survival. When heat are applied primate hairy skin, first pain sensation mediated by type-II A-fibre nociceptors (II-AMHs). In contrast, the reported absence of II-AMH microneurographical responses when hand palm has led notion that II-AMHs lacking in this glabrous skin. aim study was assess effect skin stimulation on neural transmission nociceptive inputs elicited different kinds thermal heating. We recorded psychophysical EEG brain radiant (laser-evoked potentials, LEPs) contact (contact heat-evoked CHEPs) delivered dorsum normal volunteers. Brain were analysed at a single-trial level, using an automated approach based multiple linear regression. Laser same energy remarkably similar ratings LEPs. This finding provides strong evidence does exist suggests afferents, with physiological properties II-AMHs, mediate humans. employed, significantly higher nominal temperature had be order achieve those obtained following stimulation, CHEPs longer latencies (N2 wave, +25%; P2 +24%) smaller amplitudes −40%; −44%) than stimulation. Irrespective stimulated territory, always (hairy N2 +75%; +56%) −42%; −19%) These findings consistent thickness-dependent delay attenuation waveform nociceptor depth conductive heating applied, suggest previously lack could have been result search bias consequent use long-wavelength (i.e. CO2 laser) as procedure.