HOW do you react when you see somebody else in pain? Most of us can empathize with someone who has been injured or is sick – we can quite easily put ourselves “in their shoes” and understand, to some extent, what they are feeling. We can share their emotional experience, because observing their pain activates regions of the brain which are involved in processing the emotional aspects of pain.
But can seeing somebody else in pain actually cause pain in the observer? People with mirror-touch synaesthesia are known to experience touch sensations when they see others being touched, and this may also extend to pain in such individuals. There are also several anecdotal cases of patients who experience pain in the absence of noxious stimuli. And a new study by British psychologists now provides evidence that a significant minority of healthy people can also experience pain when seeing others’ injuries.
VISION is now well known to modulate the senses of touch and pain. Various studies have shown that looking at oneself being touched can enhance tactile acuity, so that one can discriminate between two pinpoints which would otherwise feel like a single sensation. And last year, researchers from the University of Oxford showed that using binoculars to make a limb look larger or smaller than it actually is can respectively enhance and diminish painful sensations.
These phenomena occur because the brain fuses stimuli from different sensory systems to generate a coherent experience of bodily sensations. The precise mechanisms are unknown, and it is also unclear whether these effects depend upon specific visual stimuli. But according to a new study from University College London, the general “context” of vison is enough to modulate pain. In the current issue of the Journal of Neuroscience, they report that merely looking at one’s hand can affect the perception of laser-induced pain, and how it is processed in the cerebral cortex. Together with earlier work, these findings point to a simple method for managing acute pain.