A converging approach to sex differences and pain : an examination of social and biological mechanisms that may account for differences between male and female pain reports

• Main Author: Currie, Alexander G. J.
• Other Authors: Mullins, Paul
• Published: Bangor University 2017
• Subjects: 150
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.731729

The Neuromatrix of Pain is a comprehensive theory that has been designed to account for a majority of mediatory processes that influence pain perception, yet one aspect that does not appear to have been explicitly considered as a predominant factor in the research is that of biological sex, despite several articles and reviews that have highlighted the importance of it. Originating as an examination of anticipatory processes, this thesis evolved to examine how males and females experience pain differently in social contexts, and possible neurometabolic differences that may account for these disparities. From the social approach, we examined the experimenter gender effect, which demonstrates that the experimenter’s sex alters pain perception. Not only were the results concurrent with previous literature, but it was demonstrated that the presence and gender of an additional observer also influences pressure-pain threshold (PPT), predominantly in males; the observer effect could operate as either an extension of the experimenter effect, or a facilitating factor to it. It was also found that, in females, the personality trait Openness correlated significantly with PPT, which may reflect previous findings of females’ coping mechanisms. From the biological approach, proton magnetic resonance spectroscopy (1H-MRS) was used to examine the neurometabolic concentrations in the insula of healthy males and females based on findings in clinical populations. While the results were not replicated, it was found that there was a significant difference between glutamate concentrations between males and females in the anterior insula (A.I.), and also that glutamate in the A.I. also correlated significantly with PPT in males. These findings demonstrate and support evidence for how males and females adopt differential anticipatory mechanisms to predict and limit potential tissue damage. Overall, this thesis provides evidence for gender differences in pain perception that holds implications for both the experimental and clinical fields of study.