brain's medial prefrontal cortex (MPFC), where our minds keep a map of our social circles, based on closeness. People who feel lonelier tend to feel a gap between themselves and others, which is reflected in MPFC activity.

 brain's medial prefrontal cortex (MPFC), where our minds keep a map of our social circles, based on closeness. People who feel lonelier tend to feel a gap between themselves and others, which is reflected in MPFC activity.