Brain region essential for socializing identified

Researchers have determined that a small region of the hippocampus known as CA2 is essential for social memory, the ability of an animal to recognize another of the same species.

A better grasp of the function of CA2 could prove useful in understanding and treating disorders characterized by altered social behaviors, such as autism, schizophrenia, and bipolar disorder.

Recent studies have shown that different subregions of the hippocampus have different functions.

"However, the role of CA2, a relatively small region of the hippocampus sandwiched between CA3 and CA1, has remained largely unknown," senior author Steven A. Siegelbaum, PhD, professor of neuroscience and pharmacology, chair of the Department of Neuroscience, a member of the Mortimer B. Zuckerman Mind Brain Behavior Institute and Kavli Institute for Brain Science, and a Howard Hughes Medical Institute Investigator, said.

A few studies have suggested that CA2 might be involved in social memory, as this region has a high level of expression of a receptor for vasopressin, a hormone linked to sexual motivation, bonding, and other social behaviors.

To learn more about this part of the hippocampus, the researchers created a transgenic mouse in which CA2 neurons could be selectively inhibited in adult animals.

"Because several neuropsychiatric disorders are associated with altered social behaviors, our findings raise the possibility that CA2 dysfunction may contribute to these behavioral changes," Dr. Siegelbaum said.

The study was published in the journal Nature.