Insomnia may cause damage to the brain’s communication networks, according to a study published online in the journal Radiology. Apparently, insomniacs have a significantly reduced thalamus and white matter integrity in several parts on the right side of their brains.

According to Shumei Li from the Department of Medical Imaging at Guangdong No. 2 Provincial People’s Hospital in Guangzhou, China, these white matter tracts are crucial for cognitive and sensorimotor functions as well as sleep regulation and wakefulness and its damage could result to impaired brain regions communication.

The damage on the thalamus and the brain’s largest white matter structure, known as the corpus callosum, is related to the duration of insomnia and depression. Li suggests that “the involvement of the thalamus in the pathology of insomnia is particularly critical since the thalamus houses important constituents of the body’s biological clock.”


Figure 1 shows the distribution of the six whole WM tracts in the brain. ALIC = anterior limb of the internal capsule, ACR = anterior corona radiata, BCC = body of the corpus callosum, PLIC = posterior limb of the internal capsule, R = right side of the brain, SCR = superior corona radiata, SLF = superior longitudinal fasciculus. Credit: Radiological Society of North America

The researchers studied 23 patients with primary insomnia and 30 healthy participants. These participants were given with the Pittsburgh Sleep Quality Index, the Insomnia Severity Index, the Self-Rating Anxiety Scale, and the Self-Rating Depression Scale to assess their mental health and sleep patterns.

They analysed the water movement along the white matter tracts through a brain magnetic resonance imaging or MRI with a technique called diffusion tensor imaging (DTI). Tracking the water movement helps identify the tract integrity alterations.

“We used a new method called Tract-Based Spatial Statistics that is highly sensitive to the microstructure of the white matter tract and provides multiple diffusion measures,” Li explains.

Unlike the healthy participants, those with insomnia have reduced white matter integrity in some of their right-brain parts, as well as their thalami. They also speculate that the white matter deterioration stems from myelin loss, the protective cover of nerve fibres.

However, the researchers assert that they only showed the link between insomnia and white matter integrity. They suggest more studies are still needed to further understand this mechanism and to confirm this cause and effect.