A new study shows a sort of signature in the brains of lonely people that make them distinct in fundamental ways, based on variations in the volume of different brain regions as well as based on how those regions communicate with one another across brain networks.
A team of researchers examined the magnetic resonance imaging (MRI) data, genetics and psychological self-assessments of approximately 40,000 middle-aged and older adults who volunteered to have their information included in the UK Biobank: an open-access database available to health scientists around the world. They then compared the MRI data of participants who reported often feeling lonely with those who did not.
The researchers found several differences in the brains of lonely people. These brain manifestations were centred on what is called the default network: a set of brain regions involved in inner thoughts such as reminiscing, future planning, imagining and thinking about others. Researchers found the default networks of lonely people were more strongly wired together and surprisingly, their grey matter volume in regions of the default network was greater. Loneliness also correlated with differences in the fornix: a bundle of nerve fibres that carries signals from the hippocampus to the default network. In lonely people, the structure of this fibre tract was better preserved.
We use the default network when remembering the past, envisioning the future or thinking about a hypothetical present. The fact the structure and function of this network are positively associated with loneliness maybe because lonely people are more likely to use imagination, memories of the past or hopes for the future to overcome their social isolation.
Loneliness is increasingly being recognized as a major health problem, and previous studies have shown older people who experience loneliness have a higher risk of cognitive decline and dementia. Understanding how loneliness manifests itself in the brain could be key to preventing neurological disease and developing better treatments.
Source: McGill University