Scientists have uncovered a previously unknown cluster of brain cells that may help explain differences in social behavior between males and females. The small neural circuit appears to function like an on/off switch, showing a striking pattern of activity that differs sharply by sex, an unusually clear contrast compared with most known brain sex differences, which tend to be more subtle and overlapping. Researchers also found that the circuit’s activity shifts with social and reproductive status, suggesting the brain may use this mechanism to adapt behavior across key life stages.

The new study was led by Dr. Tamar Licht and Dr. Dan Rokni from the Institute of Medical Research Israel-Canada (IMRIC) at the Hebrew University of Jerusalem and is published in the Proceedings of the National Academy of Sciences.