Bedtime is one of the most important parts of the day for the brain. The latest studies show that when we slumber, the brain performs important housekeeping tasks that clear away the debris of the day’s work and help reset and restore nerve networks so they are ready to operate again at full capacity when we wake.
But a lack of sleep deprives the brain of this essential rest period, and our ability to get through the day might be compromised. In a small study published in the journal Radiology, a team of Chinese and European researchers report a more detailed analysis of how insomnia can affect specific types of brain nerves in parts of the brain that regulate cognition, emotion and sensory processes.
The researchers compared the brain images of 23 people with insomnia and 30 healthy controls. They specifically focused on white matter volume, which represents nerve cells that are coated in a special protein called myelin that improves their ability to send signals to one another. Earlier brain imaging studies had suggested that people with insomnia have differences in certain parts of the brain that could be connected to inadequate myelin. So Shumei Li from the Guangdong No. 2 Provincial People’s Hospital and her colleagues compared white matter function among people with insomnia and those who slept well.
They found that people with insomnia—defined as trouble sleeping for over a month that’s associated with daytime sleepiness and sleep disturbances—had significantly less white matter connectivity, especially between areas that control sleep and wakefulness, than those without insomnia. Li speculates that this disruption in signals between these regions was triggered by thinning of the myelin surrounding the neurons, which resulted in less chatter among them.
In fact, 83%, or five of the six major nerve tracts that the scientists analyzed, were reduced among people with insomnia. Most were concentrated in the right part of the brain, where emotions and many thinking functions are regulated, as well as where sensory information like sight, smell and touch are processed.
Li says that more studies are needed to explain what might be causing the brain differences in people with insomnia, but the results hint at a starting point.