Using Scanning Machines

Brain scans have made great progress in the last few years, which has enabled scientists to look more closely at a brain and to learn how it works. One of the subjects that is being studied is this manner is pain. To understand where pain originates in the brain, or how pain is generated and modulated, tests subjects are placed in a scanner and subjected to mild pain experiences.

This can be done by a mild electric current, needle pricks or the administration of capsaicin (the substance that gives peppers their ‘hotness’) on the skin. By using stimuli whose duration can be controlled, it can be judged how the brain deals with persisting pain.

Finding the Matrix

With the help of these brain scans, researchers can uncover which brain areas play a role in the processing of pain signals. So, the ‘black box’ of pain can be opened. The initial expectation was to find a single area that would be the main culprit, some sort of primary pain cortex.

But it turned out it was nothing like that. A lot of different areas are involved in the processing and regulating of pain. The process looks more like a network than a control center, which is why it is now known as the pain matrix.

Parts of the Matrix

Even though there are still a lot of questions concerning which part of the matrix does what, some initial clues have been found, which might elucidate the function of certain brain areas in processing and generating pain.

• The amygdala, which consists out of two almond shaped structures deep in the brain, play an large role in the generating of fear and probably do the same for pain. Maybe this can all be understood from the perspective of being alert in situations where danger looms.
• The prefrontal cortex, located in the front of the brain, is probably important in our conscious reactions to pain, as it is mainly responsible for the higher control functions.

While many questions still remain, now there are ways to pear into the black box of pain. Through a greater understanding of pain, it might become possible to deal with it more appropriately.

References

• Bingel, U. & Tracey, I. (2008). Imaging CNS Modulation of Pain in Humans. Physiology. 23(6), pp. 371 – 380.
• Tracey, I. & Mantyh, P.W. (2007). The Cerebral Signature for Pain Perception and Its Modulation. Neuron. 55(3), pp. 377 – 391.
• Wiech, K.; Ploner, M. & Tracey, I. (2008). Neurocognitive aspects of pain perception. Trends in Cognitive Science. 12(8), pp. 306 – 313.