In our life, physical pain can be unbearable at times. The human body has nerves distributed all across the body that carry the pain signal from our body parts to the Brain. This signal is what activates the pain region of our Brains, and thus we experience the pain. And this results in the awareness of our surroundings and the care taken by us before trying anything too dangerous. Now the researchers at Duke University have found a tiny area of the brain in mice that regulate the sense of pain. The pain controller has been found in an area of the brain known as the amygdala, which is an unusual place for it to be in because the amygdala is often considered the home of negative emotions and reactions. The feelings of anxiety and the urge to fight all originate here.
Another unusual thing about the discovery was that the amygdala doesn’t turn pain on, rather it shuts it down.
The research is building upon a previous study by the same researchers that had aimed to find the neurons that were activated under the influence of anaesthesia, rather than suppressed. However, there is a clear difference between pain and sleep, which is what anaesthesia induces in humans. It was found that anaesthesia activates a specific set of inhibitory neurons in the amygdala, which are called CeAga neurons( CeA stands for central amygdala & ga indicates activation by general anaesthesia). It was also found that the CeAga area was very well connected to other areas of the brain, which could be a clue as to its effectiveness in controlling pain.
Researchers have been looking for such a place in the Brain for a long time now. It is a widely held belief that such a centre exists as it is the only reasonable explanation for why placebos work. The previous studies which had focused on the relationship of pain and the brain had focused on the areas that were turned on by pain. Consequently, they had found several areas of the brain that were seemingly processing this emotion. Therefore if you had to turn it off, you would have to deal with a lot of distinct areas. Now, one region has been identified that can shut it all down, all on its own.
The discovery was made by studying the responses of mice towards pain.
By giving mice a mild pain stimulus, the researchers could map all of the pain-activated brain regions. They discovered that at least 16 brain centres known to process the sensory or emotional aspects of pain were receiving inhibitory input from the CeAga.
Using a technology called optogenetics, which uses light to activate a small population of cells in the brain, the researchers found they could turn off the self-caring behaviours a mouse exhibits when it feels uncomfortable by activating the CeAga neurons. Paw-licking or face-wiping behaviours were “completely abolished” the moment the light was switched on to activate the anti-pain centre.
The research is building towards some important underlying biological principles that could lead us to a better understanding of the Brain and perhaps help us in treating patients as well.
-Janu N Ajit
References:
Further Reading : Optogenetics Helps in Neuroprosthetic Studies https://shasthrasnehi.com/optogenetics-helps-in-neuroprosthetic/
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