Why some people are more sensitive to pain

Researchers have shown that the brain structure may hold the clue to why everyone feels pain differently.

Study's senior author Robert Coghill from Wake Forest Baptist Medical Center found that individual differences in the amount of grey matter in certain regions of the brain are related to how sensitive different people are to pain.

The brain is made up of both grey and white matter. Grey matter processes information much like a computer, while white matter coordinates communications between the different regions of the brain.

The research team investigated the relationship between the amount of grey matter and individual differences in pain sensitivity in 116 healthy volunteers.

Pain sensitivity was tested by having participants rate the intensity of their pain when a small spot of skin on their arm or leg was heated to 120 degrees Fahrenheit. After pain sensitivity testing, participants underwent MRI scans that recorded images of their brain structure.

It was found that subjects with higher pain intensity ratings had less grey matter in brain regions that contribute to internal thoughts and control of attention.

Areas of the posterior parietal cortex play an important role in attention. Individuals who can best keep their attention focused may also be best at keeping pain under control, Coghill said.

The study was published in the journal Pain.