This is Your Brain. This is Your Brain When you are Lonely.

By Jim Windell

           This holiday season is going to be different for many people. I know that in our family there won’t be the large Christmas Eve party that we’ve enjoyed for the past 25 years. There will be no family gathering on Christmas morning to open gifts. And there will be no New Year’s Eve parties.

            Of course, there will be Zoom interactions, text messages about our gifts and an exchange of photos on our phones. But for many people, for instance the people we usually visit during the holidays at care facilities and prisons, there will be a feeling of special isolation and – likely – the desolation of loneliness.

           As quarantining and social distancing due to COVID-19 continues, it is particularly important to understand how isolation affects our health. A new study, published in Nature Communications, shows a sort of signature in the brains of lonely people that make them distinct in fundamental ways. These distinctions are based on variations in the volume of different brain regions as well as how those regions communicate with one another across brain networks.

            For the study, 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. The researchers 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 centered 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. The study 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.

           Also, loneliness also correlated with differences in the fornix: a bundle of nerve fibers that carries signals from the hippocampus to the default network. In lonely people, the structure of this fiber tract was better preserved.

           People use the default network when remembering the past, envisioning the future or thinking about a hypothetical present. The fact that the structure and function of this network is positively associated with loneliness may be because lonely people are more likely to use imagination, memories of the past or hopes for the future to overcome their social isolation.

           According to Nathan Spreng, from The Neuro (Montreal Neurological Institute-Hospital) of McGill University, “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.”

           Spreng, the study's lead author, goes on to say, “So this heightened focus on self-reflection, and possibly imagined social experiences, would naturally engage the memory-based functions of the default network.”

           Previous studies have shown that older people who experience loneliness have a higher risk of cognitive decline and dementia, it is important to better understand how loneliness manifests itself in the brain. Knowing how loneliness impacts the brain could be a key to preventing neurological disease and developing better treatments.

           Danilo Bzdok, a researcher at The Neuro and the Quebec Artificial Intelligence Institute and the study's senior author, comments that “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.”

             To read the original article, find it with this reference:

R. Nathan Spreng, Emile Dimas, Laetitia Mwilambwe-Tshilobo, Alain Dagher, Philipp Koellinger, Gideon Nave, Anthony Ong, Julius M. Kernbach, Thomas V. Wiecki, Tian Ge, Yue Li, Avram J. Holmes, B. T. Thomas Yeo, Gary R. Turner, Robin I. M. Dunbar, & Danilo Bzdok. The default network of the human brain is associated with perceived social isolation. Nature Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-20039-w