Biology subjects

Coghill, R. C.

Publications and source records attributed to Coghill, R. C..

3 recordsLinked to original sources

bioRxiv2021

Processing of Pain by the Developing Brain: Evidence of Differences Between Adolescent and Adult Females

Adolescence is a sensitive period for both brain development and the emergence of chronic pain particularly in females. However, the brain mechanisms supporting pain perception during adolescence remain unclear. This study compares perceptual and brain responses to pain in female adolescents and adults to characterize pain processing in the developing brain. Thirty adolescent (ages 13-17) and thirty adult (ages 35-55) females underwent a functional MRI scan involving acute experimental pain. Participants received 12 ten-second noxious pressure stimuli which were applied to the left thumbnail at 2.5 and 4 kg/cm2, and rated pain intensity and unpleasantness on a visual analogue scale. We found a significant group-by-stimulus intensity interaction on pain ratings. Compared to adults, adolescents reported greater pain intensity and unpleasantness in response to 2.5 kg/cm2, but not 4 kg/cm2. Adolescents showed greater medial-lateral prefrontal cortex (PFC) and supramarginal gyrus activation in response to 2.5 kg/cm2, and greater medial PFC and rostral anterior cingulate responses to 4 kg/cm2. Adolescents showed augmented pain-evoked responses in the Neurologic Pain Signature and greater activation in the default mode (DMN) and ventral attention (VAN) networks. Also, the amygdala and associated regions played a stronger role in predicting pain intensity in adolescents, and activity in DMN and VAN regions more strongly mediated the relationship between stimulus intensity and pain ratings. This study provides the first evidence of augmented pain-evoked brain responses in healthy female adolescents involving regions important for nociceptive, affective and cognitive processing, in line with their augmented sensitivity to low-intensity noxious stimuli.

neuroscience↗

bioRxiv2020

DISSOCIATION BETWEEN INDIVIDUAL DIFFERENCES IN SELF-REPORTED PAIN INTENSITY AND UNDERLYING BRAIN ACTIVATION

Pain is a uniquely individual experience. Previous studies have highlighted changes in brain activation and morphology associated with inter- and intra-individual pain perception. In this study we sought to characterize brain mechanisms associated with individual differences in pain in a large sample of healthy participants (N = 101). Pain ratings varied widely across individuals. Moreover, individuals reported changes in pain evoked by small differences in stimulus intensity in a manner congruent with their pain sensitivity, further supporting the utility of subjective reporting as a measure of the true individual experience. However, brain activation related to inter-individual differences in pain was not detected, despite clear sensitivity of the BOLD signal to small differences in noxious stimulus intensities within individuals. These findings raise questions about the utility of fMRI as an objective measure to infer reported pain intensity.

neuroscience↗

bioRxiv2020

Pain sensitivity does not differ between obese and healthy weight individuals

There is emerging evidence suggesting a relationship between obesity and chronic pain. We investigated whether pain-free obese individuals display altered pain responses to acute noxious stimuli, thus raising the possibility of greater pain sensitivity and potential susceptibility for chronic pain development. Psychophysical and anthropometric data were collected from 39 individuals with an obese body mass index (BMI) classification (BMI[≥]30) and 40 age/sex-matched individuals of a healthy BMI (BMI<24.9). Since BMI may be an inaccurate index of obesity, additional anthropometric parameters of central adiposity, and percent body fat (BF%) were examined. Pain responses to supra-threshold noxious heat and cold stimuli were examined. Subjects provided pain intensity and unpleasantness ratings to noxious heat (49{degrees}C) applied at varying durations (5s, 12s, 30s) and locations (ventral forearm/lower leg). Cold pain ratings, thresholds, and tolerances were obtained following immersion of the hand in a cold-water bath (0-2{degrees}C). Between-group differences in pain responses, as well as relationships between pain responses and obesity parameters were examined. Importantly, confounds that may influence pain such as anxiety, depression, impulsivity, sleepiness, and quality of life were assessed. No between-group differences in pain sensitivity to noxious heat and cold stimuli were found. After controlling for sex, no relationships were found between BMI, central adiposity, or BF% and pain responses to noxious heat or cold stimuli. These results indicate that obesity, BF%, and central adiposity have little influence on pain sensitivity in obese individuals. Accordingly, it is unlikely that obesity alone increases susceptibility for chronic pain development via amplification of nociceptive processes.

neuroscience↗