A brain region called the medial prefrontal cortex (mPFC) maintains a structured map of a person's social circles, based on closeness. People that struggle with loneliness often perceive a gap between themselves and others. This gap is reflected by the activity patterns of the mPFC.
The researchers had the participants think of different groups of people (self, "close others", acquaintances, and celebrities) while being scanned in an fMRI (functional magnetic resonance imaging). The perceived closeness of the subject to the imagined targets were revealed in the scans. Further, the lonelier-feeling participants had reduced perception of similarity to others in all categories.
Journal Reference:
Andrea L. Courtney, Meghan L. Meyer. Self-other representation in the social brain reflects social connection [$], Journal of Neuroscience (DOI: 10.1523/JNEUROSCI.2826-19.2020)
(Score: 3, Insightful) by Anonymous Coward on Saturday June 20 2020, @10:05PM
There's a definite difference between being "with" people and being "connected to" people. Being with people that you're not connecting to can be even more isolating than knowing that people exist somewhere out there.