The International journal of neuroscience
-
Evoked potentials (EPs) to noxious thermal stimulation of skin may provide information about integrity of the nociceptive afferent system and thus small afferent fiber integrity. Here we describe subjective report, EPs and response times to noxious contact thermal and laser stimuli in the same subjects. ⋯ EPs to contact heat pulses consisted of a single, scalp positive wave occurring approximately 830 ms following arm stimulation and 890 ms following leg stimulation. Both forms of noxious stimulation activated afferents with a conduction velocity consistent with that of A-delta fibers ( approximately 10 m/s) and with the psychophysical attributes of first pain.