A new study involving mice may have provided some more insights into why poor sleep and chronic pain may be linked.

According to the study, nerve injuries may cause certain brain cells to act excitedly during sleep, and this sudden excitement may lead to chronic pain onset. On a positive note, researchers say that stopping this hyperactivity during sleep could help provide significant pain relief

As we’ve talked about on the blog in the past, sleep disorders and chronic pain are closely related, but the exact nature of why certain sleep problems increase the risk of different types of chronic pain is not well understood. We’ve talked about how it can be hard to break out of the sleep-pain cycle, which theorizes that chronic pain makes it hard to fall asleep and stay asleep, and poor sleep quality can intensify pain sensations, but this recent study wanted to learn more about the exact connection between the two.

Sleep And Chronic Pain

For the study, researchers honed in on neuropathic pain, which is pain that derives from an injury or disease in the nerves that relays sensory information from the body to the brain. Researchers studied mice with injuries in one of the sciatic nerves, the large nerve that branches from the spinal cord through the hind legs. The team analyzed brain activity in the mice both before and after the sciatic nerve injury in order to see how the brain responded to this new pain. The team found that there were significant changes after the injury in the wrinkled cerebral cortex, which is the area that receives and stores sensory data from the hind legs. Moreover, certain brain cells became progressively more active in the weeks after the injury as the mice’s pain became chronic.

Perhaps most interestingly, this brain cell activity peaked during non-rapid eye movement sleep (NREM), which is when deep sleep occurs. Researchers said these neurons became hyperactive during NREM sleep as a result of an issue with the anterior nucleus basalis, a cluster of neurons located deep in the front of the brain. Researchers noted that the activity of the anterior nucleus basalis also increased after the nerve injury, and this triggered the cells to send a chemical response to the cerebral cortex. As a result of this chain reaction, the previously mentioned brain cells shifted into overdrive during NREM sleep.

This increase in brain activity was linked to an increase in pain sensitivity in mice, as researchers stated that once-painless stimuli suddenly became painful. In follow up experiments, researchers were able to relieve this pain by blocking cell hyperactivity along certain neural pathways during NREM sleep.

“Inhibition of this pathway during NREM sleep, but not wakefulness, corrects neuronal hyperactivation and alleviates pain,” the researchers concluded.

So while the study only examined mice, it does provide insights into how neural action during sleep can lead to increased pain during wake periods, and researchers are hoping that some of the findings would be similar in a human population. Future studies are sure to follow, and hopefully we continue to learn more about the connection between poor sleep and chronic pain onset.

For now, do what you can to prioritize healthy sleep if you have a chronic pain condition. Avoid caffeine late in the day, get regular exercise, go to bed around the same time each night and keep electronics out of the bedroom so that you have an ideal sleep environment. You may not be able to control what happens during NREM sleep, but you can work to break out of the sleep-pain cycle by making it easier for your body to fall asleep and stay asleep.

If you’re dealing with sleep issues as a result of your chronic pain condition, or you want help with a different pain issue, reach out to Dr. Cohn and his team today.