Pain perception of noxious thermal stimulus changes via a central mechanism

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Pain perception of noxious thermal stimulus changes via a central mechanism

A combination of filtering and amplification mechanisms in the nervous system is involved in the attention and behavioural response to essential stimulus features. The interpretation of analogous processes in pain perception is comparatively primitive, chiefly for processing of time-varying stimuli. The pain perception temporarily amplifies abrupt thermal stimulus changes portraying a mechanism for nociceptive temporal contrast enhancement (TCE). So far, TCE in pain has been primarily explored in the context of “offset analgesia” and a single stimulus pattern. A non-linear model with perceptual feedback precisely stimulates the phenomenon for TCE however, the mechanism is unknown.

The study mentioned here was executed to investigate if a mechanism in the central nervous system underlies thermal TCE. The model used in this study efficiently predicted an optimal stimulus, incorporating a transient temperature offset (step-up/step-down), with maximal TCE. It caused psychophysically verified substantial decrements in pain response (“offset-analgesia”; mean analgesia: 85%) in 20 subjects. Further, the two thermoses were used to deliver the stimulus; one provided the longer duration baseline temperature pulse and the other superimposing a short higher temperature pulse. The two stimuli were applied concurrently either near or far on the same arm, or on opposite arms. The spatial separation across multiple peripheral receptive fields guaranteed that the combined stimulus timecourse was first reconstituted in the central nervous system. After ipsilateral stimulus cessation on the high-temperature thermode, but before termination of the low-temperature stimulus features of TCE were noticed both for individual subjects and in group-mean responses.

It was thus concluded that a central integration mechanism is sufficient to induce painful thermal TCE. It is an essential step in transforming transient afferent nociceptive signals into a stable pain perception.

Source:

Sci Rep. 2017 Jun 20;7(1):3894

Link to the source:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5478630/

Original title of article:

A central mechanism enhances pain perception of noxious thermal stimulus changes

Authors

B. Petre et. al

SearchTags: 
Exploratory, Pain, Nervous System, Analgesia
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