A study from Canada has revealed a common theme in the brain scans of lonely people.
Researchers from McGill University say there is a particular type of signature in the brains of lonely people, which is down to variations in the volume of different regions of the organ and based on how they communicate across brain networks.
The study was based on 40,000 middle-aged and older adults, with researchers looking at the magnetic resonance imaging (MRI) data as well as genetics and psychological self-assessments of the participants.
The MRI data of those who said they often felt lonely was compared with people who did not. According to the results, there were several differences in the brains of people who reported to be lonely.
The differences were based in the area known as the default network, regions involved in inner thoughts, including thinking about others, reminiscing, imagining and future planning.
The results showed that the default networks of lonely people were wired together more robustly. The grey matter volume in regions of the default network was greater in lonely people, the study found.
Additionally, loneliness was associated with differences in the fornix, nerve fibres which carry signals from the hippocampus – a complex brain structure which has a major role in learning and memory – to the default network. The structure of this fibre tract was better preserved in lonely people, the study said.
Researcher Nathan Spreng, who was the study’s lead author, said: “In the absence of desired social experiences, lonely individuals may be biased towards internally-directed thoughts such as reminiscing or imagining social experiences. We know these cognitive abilities are mediated by the default network brain regions. So, this heightened focus on self-reflection, and possibly imagined social experiences, would naturally engage the memory-based functions of the default network.”
The study’s senior author Danilo Bzdok added: “We are just beginning to understand the impact of loneliness on the brain. Expanding our knowledge in this area will help us to better appreciate the urgency of reducing loneliness in today’s society.”
The research was published in the journal Nature Communications.