The Spatial Features Of Pain: Mapping The Extent Of Experimental Pain

• Published in: The journal of pain Vol. 24; no. 4; p. 55
• Main Authors: Adamczyk, Waclaw, Jackson, Catherine, Schulze, Geraldine, Goldschneider, Kenneth, Kashikar-Zuck, Susmita, King, Christopher D., Coghill, Robert C.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.04.2023
• ISSN: 1526-5900
• DOI: 10.1016/j.jpain.2023.02.166

The literature regarding mechanisms of the spread of pain is sparse and inconclusive. In this current experiment we offer novel insights into this problem. Here, we tested the hypothesis that more intense noxious stimuli lead to greater extent of perceived pain. 14 healthy volunteers took part in this investigation wherein three different noxious (45, 47 and 49°C) and one innocuous (43°C) intensity stimuli were used. Also, four different intensities of visual stimuli displayed on the target bodily area were utilized as a control. Participants provided pain (and light) intensity ratings using computerized Visual Analogue Scale (VAS) as well as pain (and light) size ratings. In the size rating procedure, participants "matched” the size of the square displayed on the screen with the extent of pain (or light) which they experienced. The stimulated area exposed to heat (16´16mm) was identical to the size of visual control stimuli. Initial inspection of the data revealed the following observations: First, the dispersion of values describing the extent of pain was 700% greater than corresponding values of the size of visual stimuli. Second, a gradient of the extent of pain was detected while inspecting responses to different noxious temperatures with subjects at the extremes reporting the expanse of pain as being 30.63 times greater than the actual size of the probe. These observations likely echo the complex patterns of neuronal activity at the spinal cord level previously shown in animals. Inferential statistics are pending at the time of submission as more subjects are being enrolled. CCHMC Research Innovation and Pilot (RIP) award, NIH NS39426 (RCC) grant.