Related Experiment Video
Updated: Aug 12, 2026

Determining heat and mechanical pain threshold in inflamed skin of human subjects
Published on: January 14, 2009
Psychophysiological and psychophysical responses to experimental pain induced by two types of cutaneous thermal
V V Itskovich1, D Y Fei, S W Harkins
1Department of Biomedical Engineering, Virginia Commonwealth University, USA.
Abstract:
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. Pain quality to both forms of stimulation was consistently reported as a brief pricking or stinging sensation (first pain), occasionally followed, after a silent period, by a diffuse burning sensation (second pain). EPs to laser generated heat pulses consisted of bi- or triphasic waveforms with a large positive wave at approximately 300 ms following arm stimulation and 360 ms following stimulation of the leg. 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.
Related Concept Videos
Thermosensation
Nociception
Sensory Functions of the Skin
There are two main categories of receptors on the skin: capsulated and non-capsulated. The non-capsulated ones are mainly the pain receptors. The capsulated ones can be further categorized based on the...
Tactile and Chemical Senses
Pain

