What Loneliness Looks Like in the Brain

TUESDAY, Dec. 29, 2020 (HealthDay News) -- As COVID-19 continues to spread and people face more isolation than usual, researchers are noting the impact of loneliness on the brain.

A new study from McGill University in Montreal found a tell-tale signature in the brains of lonely people. Specifically, they discovered variations in the volume of different brain regions and how those regions communicate across brain networks.

"We are just beginning to understand the impact of loneliness on the brain," study senior author Dr. Danilo Bzdok said in a McGill news release. He's a researcher at the university's Montreal Neurological Institute-Hospital.

Loneliness is increasingly being recognized as a major health problem. Understanding how it manifests in the brain could be key to preventing neurological disease and developing better treatments, the researchers said. Other studies have shown that older people who experience loneliness have a higher risk of dementia and declining thinking skills.

For this study, MRI data, genetics and psychological self-assessments were used to study loneliness in 40,000 middle-aged and older adults whose information was included in the UK Biobank. Researchers compared data from those who expressed loneliness with those who did not.

They found surprising differences in what is known as the default network. These are brain regions involved in our innermost thoughts, such as reminiscing, future planning, imagining and thinking about others.

In lonely people, gray matter volume in the default network was greater and their default networks were more strongly wired together.

The fornix -- a bundle of nerve fibers that carries signals to the default network from the hippocampus, a brain structure involved in learning and memory -- was also better preserved in lonely people, the study found.

That suggests lonely people may be more likely to use their imagination, memories of the past or hopes for the future to overcome social isolation.

"We know these cognitive abilities are mediated by the default network brain regions," said lead author Nathan Spreng, director of McGill's Laboratory of Brain and Cognition. "So this heightened focus on self-reflection, and possibly imagined social experiences, would naturally engage the memory-based functions of the default network."

The findings were published Dec. 15 in the journal Nature Communications.

More information

AARP offers tips for combating loneliness during the pandemic.

SOURCE: McGill University, news release, Dec. 15, 2020