This image shows that the black mice are sniffing each other during social interactions. Long-term social isolation during late adolescence causes hyper-sociability in female mice because of reduced expression of the parvalbumin-positive inhibitory neurons in the left orbitofrontal cortex. For more information, see the article by Jeon and Jeong et al. (pages 1555–1571). Cover image: Yi-seon Jeon.