Friday, November 12, 2010

Reducing pain by touching ourselves

Interesting observations from Kammers et al. The abstract:
Acute peripheral pain is reduced by multisensory interactions at the spinal level. Central pain is reduced by reorganization of cortical body representations. We show here that acute pain can also be reduced by multisensory integration through self-touch, which provides proprioceptive, thermal, and tactile input forming a coherent body representation. We combined self-touch with the thermal grill illusion (TGI). In the traditional TGI, participants press their fingers on two warm objects surrounding one cool object. The warm surround unmasks pain pathways, which paradoxically causes the cool object to feel painfully hot. Here, we warmed the index and ring fingers of each hand while cooling the middle fingers. Immediately after, these three fingers of the right hand were touched against the same three fingers on the left hand. This self-touch caused a dramatic 64% reduction in perceived heat. We show that this paradoxical release from paradoxical heat cannot be explained by low-level touch-temperature interactions alone. To reduce pain, we often clutch a painful hand with the other hand. We show here that self-touch not only gates pain signals reaching the brain but also, via multisensory integration, increases coherence of cognitive body representations to which pain afferents project.


  1. One thing I've often wondered about is the way that people touch their their head, often with two hands on the back of the head when the get something important wrong, like missing a goal shot in sport. Is this the same clutching of the source of the pain?

  2. Sounds reasonable. I don't have an answer to that one.

  3. @jim - I believe that's a hard-wired reflexive hide/shame response to (the psychological part of) the agony of defeat. The physical discomfort of defeat is a plummeting drop in blood testosterone level, and is felt body-wide - especially in the midsection and not especially in the head.