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Electrophysiological Measurement of Noxious-evoked Brain Activity in Neonates Using a Flat-tip Probe Coupled to Electroencephalography
Published on: November 29, 2017
"First pain" in humans: convergent and specific forebrain responses.
Dagfinn A Matre1, Luis Hernandez-Garcia, Tuan D Tran
1Dept. of Work-related Musculoskeletal Disorders, National Institute of Occupational Health, Oslo, Norway. dagfinn@stami.no
Molecular Pain
|November 19, 2010
Summary
Pain perception involves distinct brain pathways. Brief heat stimuli activating Aδ (delta) fibers preferentially engage specific brain regions, differentiating "first pain" from C fiber-mediated "second pain".
Area of Science:
- Neuroscience
- Pain Research
- Sensory Physiology
Background:
- Distinguishes
- first pain
- (sharp, localized) from
- second pain
- (dull, prolonged) based on Aδ and C fiber activation, respectively.
- Investigates forebrain activation patterns for Aδ fiber-mediated heat pain.
Purpose of the Study:
- To determine if noxious heat stimuli exciting cutaneous Aδ (delta) fibers activate distinct forebrain structures.
Main Methods:
- Functional magnetic resonance imaging (fMRI) in healthy volunteers.
- Application of brief heat stimuli at two temperatures (41°C and 51°C) to the hand.
- Analysis of brain responses within predefined volumes of interest (VOI).
Main Results:
- 51°C stimuli, at pain threshold, preferentially activated Aδ (delta) fibers.
- Bilateral anterior insulae, contralateral hippocampus, and ipsilateral posterior insula showed preferential activation by Aδ (delta) fiber stimulation.
- Both Aδ (delta) and C fiber stimulation elicited responses in most VOI.
Conclusions:
- Two distinct sets of forebrain structures mediate initial sharp pain from heat stimuli.
- One set responds preferentially to Aδ (delta) fiber stimulation, the other to C fiber input.
- Findings support specific and convergent mechanisms underlying
- first pain
- sensation.
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