Brain Biology and Social Interaction

In animal and human research studying effects of social isolation, various brain structures have been identified that experience change in response to a lack of social interaction. While this area of research is not studied enough yet for us to know whether the relationships between the two are cause-and-effect, scientists have been able to link and shine a light on how physical isolation and loneliness can impair brain function.

The brain can be split into lobes and other categories, and there are different structures inside the brain that play different roles. Here are some brain structures and their roles:

PREFRONTAL CORTEX:

• located at the front of the frontal lobe, it is used for many complex behaviours like planning, impulse control, predicting likely events and personality development.
• In some studies, people who are lonely have been found to have reduced brain volumes in the prefrontal cortex, involved in important in decision making and social behavior

HIPPOCAMPUS:

• A curved seahorse-shaped organ, it supports memory, learning, navigation and space perception. It receives information and could play a role in Alzheimer's disease.
• People and other animals experiencing isolation have smaller hippocampi and reduced concentrations of a certain protein (BDNF), both associated with impaired learning and memory. Some studies indicate that levels of the stress hormone cortisol, which affects and is regulated by the hippocampus, are higher in isolated animals.

AMYGDALA:

• Two small almond-shaped structures, located under each half (hemisphere) of the brain. The amygdalae regulate emotion and memory and are associated with the brain's reward system, stress, and the "fight or flight" response when someone perceives a threat.
• Researchers found a correlation between the size of a person's social network and the volume of their amygdala. More evidence suggests the amygdalae tend to be smaller in people who are lonely, and in young adults with greater depressive symptoms.