Columbia scientists have identified a brain region that helps tell an animal when to attack an intruder and when to accept it into its home. This brain area, called CA2, is part of the hippocampus, a larger brain structure known to be critical for our memory of people, places, things and events. The research was published on Wednesday in Nature.
CA2 was already known to specialize in social memory, the ability to remember encounters with others. Surprisingly, the recent findings reveal that a single brain region can control both higher-order cognition, like social memory, and an innate, instinctual behavior like social aggression. Because CA2 dysfunction has been implicated in psychiatric diseases, such as schizophrenia and bipolar disorder, these results provide further support that altered CA2 function may contribute to abnormal social behaviors associated with such illnesses.
“Humans and mice are social creatures. We both engage in learned and innate social interactions that sometimes foster cooperation, and other times drive competition for mates, food and dominance. How the brain mediates these conflicting impulses has been a puzzling question,” said the paper’s senior author, Steven A. Siegelbaum, PhD, the Chair of Neuroscience at Columbia University Irving Medical Center and principal investigator at Columbia’s Zuckerman Institute. “Today’s study in mice shows us that diminutive CA2, which is made up of just a few thousand cells, acts as a nexus of social behaviors, allowing memory to influence the decision to engage in social aggression,” he continued. (more…)