Activate this cluster of neurons and you may never feel pain again....

The neurons in the central amygdala, the red and yellow cells are ceaga neurons, which have the function of inhibiting pain.photo source: Fan Wang Lab / Duke University article | Karl Leif Bates translation | Han Jiatong proofread | Liu Yuhang Shi Yunlei. Recently, a team from Duke University found that a small area in the brain of mice can effectively control pain perception in mice.surprisingly, this brain region turns off pain, not stimulates it.however, few people thought that the area of the brain that inhibits pain is located in the amygdala.the amygdala has always been considered to dominate negative emotions and stress responses, such as "war and flight" responses, and general anxiety.co author fan Wang, a professor of Neuroscience at the medical college, explained: "people do believe that there is a central area in the central nervous system that inhibits pain, which also explains why placebo works.but the question is, where is this area of the brain that suppresses pain.most previous studies have focused on finding areas of the brain that trigger pain, but since many brain regions are involved in this process, it is very difficult to suppress pain."prior to this work, Wang's team conducted a number of studies looking for neurons that activate rather than turn off pain.in a study in 2019, they pointed out that general anesthesia drugs can trigger slow wave sleep by activating the supraoptic nucleus in the brain.considering that sleep and pain pathways are separate, this finding provides important clues for their recent study published in nature neuroscience.the researchers found that in addition to the supraoptic nucleus, general anesthesia drugs also activated a specific group of inhibitory neurons in the central amygdala, which they named ceaga neurons.although the central amygdala of mice is relatively larger than that of humans, Wang believes that pain is suppressed in humans and mice through the same nervous system.they used some techniques to track the neural pathways activated in the mouse brain during this process, and found that ceaga neurons were associated with many brain regions.Wang said: "it's very surprising."the study group conducted mild pain stimulation on mice and located all brain regions involved in pain activation.they found that ceaga neurons could send inhibitory signals to at least 16 brain regions involved in pain perception or related emotions."pain is a complex brain response," Wang explains. "It involves pain recognition, emotion, and autonomic (involuntary neuronal) responses.it is very difficult to achieve analgesia by inhibiting all these neural processes produced in the brain, but it is easier to achieve analgesia by activating key ceaga neurons to send inhibitory signals to these brain regions."using photogenetic technology to activate ceaga neurons in mice, the researchers found that mice almost immediately stopped self soothing behaviors that relieve pain, such as licking their paws or wiping their faces.Wang recalled: "the effect was amazing, and they immediately quieted down."and when the researchers reduced the light stimulation on ceaga neurons, the mice began to act as if they had been stimulated by pain again.the research group also found that ketamine (a pain suppressing anesthetic) can inhibit pain by activating ceaga neurons.Wang said that searching for drugs that activate these nerve cells will facilitate the development of potential analgesic drugs. "Our next step is to sequence these neurons," Wang said."they hope to find specific cell surface receptors of ceaga neurons by sequencing, and design a highly specific ceaga neuronal activator to relieve pain.