Everyone occasionally experiences sleepless nights of tossing and turning, waking up exhausted in dreary. For an insomniac, however, these experiences are not only regular, recent MRI scans suggest that there may be a connection between the sleeping disorder and irregularities in the brain communication networks.
In a recent study of insomniacs published online in Radiology, researchers from the Department of Medical Imaging at Guangdong No. 2 Provincial People’s Hospital in Guangzhou, China, found reduced white matter in the thalamus, which regulates consciousness, sleep and alertness, and in the limbic system, which supports functions like emotion, behavior, motivation, long-term memory, and olfaction.
“White matter tracts are bundles of axons – or long fibers of nerve cells – that connect part of the brain to another,” said coauthor Shumei Li in a press release. She added: “If white matter tracts are impaired, communication between brain regions is disrupted.”
Li and her colleagues recruited 23 primary insomnia patients – those whose sleeplessness is not attributable to a medical, psychiatric, or environmental cause – and 30 healthy controls. All the participants answered questionnaires about the quality of their sleep and their levels of anxiety and depression.
The findings revealed that insomnia patients had signigicantly reduced white matter integrity in several parts of the right brain, including the body corpus callosum – the largest white matter structure of the brain – and the right thalamus. Researchers linked the reduced activity of the body corpus callosum to more severe insomnia and depression scored in the patients.
“The brain is like a car with the engine of a Ferrari but the brakes of a bicycle. It performs extremely well switching gears and racing forward, but it suffers from an ability to slow down. This can be most obvious during bedtime,” she told Medical Daily .
Previous brain imaging studies have linked primary insomnia to brain abnormalities in young and middle-aged adults. A 2008 paper found that patients who have primary insomnia for more than six months showed a 30 percent reduction in gamma-aminobutyric acid, whose purpose is to decrease overall activity in many areas of the brain, helping to shut it down, especially when it’s time to sleep. This could be why insomniacs commonly complain that their minds keep racing and won’t quiet down at night.
This constant “on” state is one of hyperarousal, with unusually high levels of cortisol, metabolic activity, and sympathetic activity when insomniacs are both awake and asleep, according to Dr. David Brown, a sleep psychologist at the Children’s Medical Center in Dallas.
Brown believes the biggest problem with insomnia is that it is not a single entity.
“There are many types of insomnia and many different causes. Insomnia severity may be short lived and acute, or chronic,” he told Medical Daily. “Some insomnias show difficulty falling to sleep, some have difficulty staying asleep, some wake too early and cannot get back to sleep.”
Source: Li S, Tian J, Bauer A et al. Reduced Integrity of Right Lateralized White Matter in Patients with Primary Insomnia: A Diffusion-Tensor Imaging Study. Radiology. 2016. Original Article