The researchers found that the pain neurons could be "completely" turned off

neurons Image copyright Stock imageA team at Duke University in the UNITED States has found that a small area of the mouse's brain can profoundly control the animal's pain.
surprised that the brain center was able to turn off the pain, not the pain. It is located in an unexpected area of an anti-pain center, the Amygdala, which is often considered a "home base" for negative emotions and reactions, such as combat or escape responses and common anxieties.
believe there is a central place to relieve pain, which is why placebos work," he said. "The question is which part of the brain is the center that stops pain, " said Wang Fan, senior author of the paper and distinguished professor of neurobiology at Duke University School of Medicine. Most
previous studies have focused on which areas pain stimulates. "But there are a lot of areas that are dealing with pain, and you have to turn them all off to stop the pain. The center can turn off the pain on its own. The
is a follow-up to early research by Wang Fan's lab, which looked at neurons that were activated rather than suppressed during general anaesthetic. In a 2019 study, the authors found that general anaesthetic promotes slow-wave sleep by activating the visual nuclei of the brain. But sleep and pain are separate, an important clue to the new discovery, which was published online online in Nature Neuroscience.
researchers found that general anaesthetic also activates a group of inhibitory neurons in the middle of the amygdala, which they call "CeAga neurons" (CeA stands for "central amygdala" and ga for general anaesthetic activation). The central amygdala of mice is larger than that of humans, but Wang fan says there is no reason to think that people's pain control systems are different.
using the lab's first technique to track the pathways of activated neurons in mice, the team found that CeAga was connected to many different regions of the brain. "It's amazing." Wang Fan said.
by giving mice a slight pain stimulation, the researchers were able to map out all the pain-activated brain regions. They found that at least 16 brain centers processed pain sensations or emotional information, receiving inhibited input from CeAga.
" pain is a complex brain reaction. Wang Fan said. It includes sensory discernment, emotional and autonomous (involuntary nervous system) responses. It is very difficult to treat pain by suppressing all these processes in many areas of the brain. But it is more efficient to activate a key node that naturally sends suppressive signals to these pain processing areas.
using a technique called photogenetics to activate a small number of cells in the brain using light, researchers found that by activating CeAga neurons, they were able to stop the self-care behavior of mice when they felt uncomfortable. When the light is turned on to activate the pain-resistant center, the licking of the paws or the wipe of the face "disappears completely".
" is too significant. Wang Fan said, "They will immediately stop licking their paws or wiping their faces." The
when scientists inhibited the activity of these CeAga neurons, the mice reacted as if the temporary damage had become intense or painful again. They also found that low doses of ketamine, an anaesthetic that produces sensations but blocks pain, activate the CeAga hub and do not work without it.
are looking for drugs that activate these cells to suppress pain as potential painkillers in the future, Wang Fan said.
"The other thing we're trying to do is sort these cells. She said. The researchers hope to find a gene in these special cells that is a rare or unique cell surface receptor that activates these neurons and relieves pain with a very specific drug.