New brain scans indicate that instead of asking a person where their body hurts, the brain can reveal the answer on its own.

When a person feels pain in a region of their body, it is because their brain tells them so. That process is implicitly understood by scientists, particularly in the cases of sufferers of chronic pain or those who do not feel any pain at all. However, researchers never explicitly understood where the feeling of pain registered in the brain. For the first time, researchers from the University College London and the University of London have mapped it out.

The study, published in the Journal of Neuroscience, analyzed brains with functional magnetic resonance imaging machines, or fMRIs. Their technique had previously been used by scientists to discern what participants were viewing just by looking at their brain scans. Researchers used laser stimuli on seven participants to inflict pain on their right hands and each of their individual fingers. The scientists were then able to look at the brain scans and distinguish exactly which finger was in distress.

Using these brain scans, researchers were able to create a map that showed exactly which parts of the primary somatosensory cortex were being activated. The primary somatosensory cortex, located in the left hemisphere, is the part of the brain that processes bodily information.

Interestingly, researchers compared their pain map with a map generated by touch of the right hand. They found that the maps were surprisingly similar.

"The cells in the skin that respond to pain and the cells that respond to touch have very different structures and distributions, so we were surprised to find that the maps of pain and of touch were so similar in the brain," said Dr. Flavia Mancini, one of the authors of the study. "The striking alignment of pain and touch maps suggests powerful interactions between the two systems."

Researchers hope that their findings can help doctors analyze the brain for solutions for chronic pain.

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