Scientists may finally be able to explain why sleep deprivation is linked to chronic pain. A new mouse study suggests that nerve damage disrupts certain brain cells during sleep, and this sudden excitement can lead to chronic pain. Studies suggest that stopping it can help relieve pain.
People with chronic pain often experience sleep disturbances such as: insomniaand evidence suggests that poor sleep quality is a major risk factor for developing chronic pain in the first place. We don’t yet know the nature of sleep problems, their exact causes, or the long-term consequences.” Alban Latremoliere (opens in new tab)An assistant professor of neurosurgery and neuroscience at Johns Hopkins Medical School, he was not involved in the new research.
“We often hear about the ‘vicious cycle’ where pain interferes with sleep, which in turn makes it worse, but the biological pathways involved are very elusive,” Latremoliere told Live Science in an email. Told.A mouse study published in the journal on Monday (January 23) Nature Neuroscience (opens in new tab)he said, will begin to unravel the inner workings of one of these mysterious pathways.
This research focuses on neuropathic pain resulting from injury or disease of nerves that relay sensory information from the body to the nerves. brainResearchers have studied mouse One of the sciatic nerves, the main nerve that runs from the spinal cord to the hind legs, is damaged. It is explained that two of his three branches of nerves that feed into his legs were damaged, causing the skin supplied by the remaining branches to become hypersensitive. Guangyang (opens in new tab)senior author of the study and associate professor of anesthesiology at Columbia University Irving Medical Center in New York City.
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“It mimics human neuropathic pain associated with peripheral nerve injury,” Yang told Live Science in an email.
The team analyzed brain activity in rodents before and after injury and found distinct changes in areas of the wrinkled cortex that receive sensory data from the hind limbs. Brain cells with pyramidal bodies, aptly named pyramidal neurons, became progressively more active several weeks after injury as pain in mice entered the chronic phase. It peaked during non-rapid eye movement sleep (NREM), when sleep occurs.
Why were these pyramidal neurons confused? The team pinpointed the anterior basal ganglia, a cluster of neurons lodged deep in the front of the brain, to be responsible.
The team found that the activity of this cell cluster also increased after injury, causing the cells to send the chemical messenger acetylcholine to the cerebral cortex. Through a chain reaction, this action effectively lifted the destruction of pyramidal neurons and shifted them into overdrive.
This change in brain activity was associated with altered sensitivity to pain in mice, where once-painless stimuli suddenly became painful. In a series of experiments, the researchers found that this pain could be alleviated by blocking the hyperactivity of various cells in the brain pathways they had discovered.
“Inhibition of this pathway during NREM sleep, but not in the wakeful state, corrects neuronal hyperactivation and reduces pain,” the researchers wrote in their study.
Ultimately, this line of research may lead to new treatments for humans with chronic pain, but this initial study was in mice, which is somewhat limiting.
“We believe that the same problems observed in mice are likely to occur in humans, but their exact profile and distribution may vary from patient to patient.” circadian rhythm It differs from that of nocturnal rodents, said Latremoliere. He added that he is interested in investigating whether this newly discovered pathway contributes to other types of chronic pain, such as pain associated with cancer or chemotherapy.
Yang and her colleagues aim to study whether their results carry over to humans. Current research raises the idea that chronic pain may be ‘encoded’ in the brain during sleep, unlike the way memories are hardwired into the brain during sleep, she said in Live. told Science.
“The knowledge that remodeling of neural circuits during sleep plays an important role in the formation of chronic pain is highly relevant for pain therapy,” she said.
