Depressing loneliness – how loneliness can literally have serious effects on people is now illustrated by a neural study: Researchers have found evidence that feelings of social isolation leave certain traces in the brain of those affected. According to this, the so-called resting state network of the brain seems to have been trained. This seems to reflect how loneliness leads to increased brooding, the scientists say.
Man is a social being – excessive loneliness is not good for us. Loneliness is a major social problem that has now become even more pronounced due to social distancing in the context of the corona pandemic. Studies have already shown that loneliness-induced stress and psychological effects threaten people’s physical and mental health. Elderly people in particular are affected by being alone and its consequences: Studies have shown that feelings of loneliness are linked to an increased risk of developing neurodegenerative diseases such as Alzheimer’s. Understanding what causes loneliness in the brain could therefore also reveal ways to prevent or treat neurological diseases.
On the trail of the neural signature of loneliness
Scientists led by Nathan Spreng from McGill University in Montreal have now dedicated themselves to this research topic. To do this, they evaluated a database that contained information on brain characteristics and psychological self-assessments from 40,000 middle-aged and older adults. As the researchers report, 13.1 percent of the participants answered yes to the question “Do you often feel lonely?”. They were able to compare the results of their brain scans with the neuronal characteristics of those people who had not described themselves as lonely. In order to uncover characteristic differences, the researchers also used artificial intelligence: a computer system capable of learning automatically looked for peculiarities in the brains of lonely people.
As can be seen from the evaluations, the loneliness seems to be reflected in neural features that have to do with the so-called idle state network (default network). It is a group of brain regions that are involved in thought processes such as memories, planning for the future, imagination, and thinking about others. The researchers found that the parts of the dormant state network of lonely people have particularly intense wiring. In addition, the volume of gray matter in the brain regions involved was increased compared to the control group. The loneliness also correlated with structural features of the so-called fornix – a bundle of nerve fibers that conducts signals from the hippocampus to the resting state network. The evaluations show that this structure was more developed in lonely people.
Brooding training effect?
As the scientists explain, the results appear plausible against the background of the psychological effects of loneliness: The fact that the structure and function of the resting state network is comparatively strong could therefore be due to the fact that lonely people use their imagination particularly intensively to recall memories of the past to indulge in or develop hopeful thoughts about the future.
“In the absence of desirable social experiences, lonely individuals may be influenced by inward-looking thought processes such as remembering or imagining social experiences,” says Spreng. “We know that these cognitive skills are imparted through the brain regions involved in the resting state network. The increased focus on self-reflection and possibly imagined social experiences thus probably naturally involves the functions of this special network, ”says the neuroscientist.
As he and his colleagues emphasize, however, further investigations are now necessary in order to gain more precise insights into the relationships. In addition to the medical and psychological importance, they also emphasize the social dimension of such examinations. “We are only just beginning to understand the effects of loneliness on the brain. Expanding our knowledge in this area could also help us highlight the urgency of reducing loneliness in today’s society, ”concludes co-author Danilo Bzdok of McGill University.
Source: McGill University, Article: Nature Communications, doi: 10.1038 / s41467-020-20039-w