Every person perceives pain and temperature differently. But why this happens has yet to be fully explained. Studies have shown that differences between individuals in perceiving pain caused by heat are linked to variations in neurophysiology. TWRI Senior Scientist Dr. Karen Davis, together with her trainees Dr. Nathalie Erpelding and Massieh Moayedi, have expanded this concept by investigating the relationship between pain and temperature sensitivity and the thickness of grey matter—tissue in the brain that contains neurons related to sensory,  motor and cognitive information—in different regions of the brain associated with perception of these sensations.

Eighty subjects underwent psychophysical examinations to determine their sensitivity to detect cool and warm temperatures, as well as their pain threshold for cold and hot temperatures—characteristics of thermal and pain sensitivity. The thickness of grey matter in the regions of the brain associated with pain and temperature perception was measured in these subjects, through high-resolution magnetic resonance imaging.

The study found that differences between subjects in their ability to sense temperature and perceive pain was associated with the thickness of grey matter in the brain regions that control sensory perception, pain control and integration of sensory and motor control. Commenting on these findings, Dr. Davis says, “Genetic, psychological and environmental factors all contribute to individual differences in pain and temperature perception. Our data indicates that grey matter thickness in key brain regions provides a neural basis for individual pain and temperature sensitivity.”

Cortical thickness correlates of pain and temperature sensitivity. Erpelding N, Moayedi M, Davis KD. Pain. 2012 April 17. [Pubmed abstract]

This research was supported by the Canadian Institutes of Health Research and the Fonds National de la Recherche Luxembourg.