The Pain Matrix

I find that a challenging yoga class brings a little thrill of fear to me which is not necessarily a pleasant sensation. A new study utilizing fancy brain-imaging techniques may explain the connection.

Researchers at the University of Manchester used PET scan imaging to see what parts of the brain lit up when people ached in their arthritic old knees. This technique involves injecting a person with a tagged sugar molecule called F-fluorodeoxyglucose or FDG. FDG is concentrated in neurons as they suck up sugar while at work reacting to the task at hand.

Neurobiologists already know which brain pathways activate when volunteers are pinched or kicked or however it is that researchers induce experimental pain. This same 'pain matrix' is also activated by arthritic pain. These UK scientists were surprised, however, to find that pain from degenerative joints "was associated with increased activity in the cingulate cortex, the thalamus, and the amygdala. These areas are involved in the processing of fear, emotions, and in aversive conditioning."

So if yoga induces pain in degenerating knee joints--and despite all that soothing patter from the instructor, I find it often does--aging yoginis might feel fear.