Cravings for social interactions affect the same area of the brain hit by hunger pangs after a long absence of nosh, researchers at the Massachusetts Institute of Technology have found.
In a quest to understand the effects of social isolation during a global pandemic, the researchers recruited a group of 40 subjects to undergo a 10-hour session of isolation from in-person and online social interactions. They also had to endure the same time fasting as part of the study.
After each session, those taking part in the study viewed images of social interactions, such as people laughing, smiling and physical proximity while having their brains analysed with a magnetic resonance imaging scanner. They were also shown pictures of creamy cheesy pasta and fresh berries in the illustration used in the journal Nature Neuroscience. As a control, they were additionally presented with pictures of flowers.
Brain scans revealed that the same midbrain region associated with reward and novelty responses consistent with dopaminergic activity – substantia nigra pars compacta and ventral tegmental – showed greater responses to social images after isolation and to food images after fasting.
"After isolation, social cues evoke neural signatures of craving. In primates, aversive motivation – a negative state such as hunger or pain that motivates behavior to relieve the state – is represented in the SN/VTA24 and the SN/VTA is activated by craving for food and for drugs of addiction," the paper said.
However, the cravings resulting from social isolation were specific to those social stimuli, research associate Dr Livia Tomova and her colleagues found.
The researchers said they hoped the study could help contribute to a greater understanding of the impact of social isolation during a period when it has, to some extent, been mandated by governments to mitigate the spread of the SARS-CoV-2 virus.
"A vital question is how much, and what kinds of, positive social interaction is sufficient to fulfil our social needs and thus eliminate the neural craving response," the paper said. "Technological advances offer incessant opportunities to be virtually connected with others, despite physical separations. Yet, some have argued that using social media only exacerbates subjective feelings of isolation.
"The potential for virtual interactions to fulfil social needs is particularly relevant when large populations are required to self-isolate, for example during a global pandemic.
"This unprecedented upheaval in people's social routines emphasized the need for a better understanding of human social needs and the neural mechanisms underlying social motivation." ®