Brain Center that can Shut Off Pain

Jun 1, 2020 by Iris Dawn Tabangcora

Pain control remains a challenge in modern medicine because several brain regions process pain. In order for specific pain management to be successful, all of these regions need to be shut off. Recently, a research team from Duke University discovered a small brain region that profoundly shuts pain off by itself. It is also located in an unexpected region tied to negative emotional responses and anxiety: the amygdala.

Researchers claimed that placebos work because there is a central region in the brain that relieves pain. However, it is not known where it is in the brain. This research is the first of its kind, as previous studies have focused on regions that can turn pain on. It was inspired by the team’s study last year on neurons that can be activated instead of being suppressed by general anesthetics.

Photo credit: Road Trip with Raj

A specific subset of neurons found in the central amygdala was found to be activated by general anesthesia. These are now called CeAga neurons. CeA stands for central amygdala while ga stands for activation by general anesthesia. While mice have a larger central amygdala compared to humans, researchers claimed that pain control systems work the same.

Furthermore, it was found out that CeAga neurons were connected to as many as 16 pain-processing brain centers upon giving mild pain stimulus to mice. All of these brain centers received inhibitory input from the CeAga neurons. Dampening these signals by shutting off these brain centers would be difficult but if innovations are made to enhance the natural inhibitory capacity of these CeAga neurons to dampen pain processing, it would be more robust.

Using optogenetics technology, researchers observed that mice instantly stop showing self-caring behaviors like licking and rubbing when CeAga neurons were activated. On the other hand, when these neurons were dampened, mice were observed to be experiencing the pain again.

The next step would be to explore possible drugs that can activate these cells to suppress pain instantaneously.
 

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