Sex-dependent cortico-amygdala circuits controlling emotion recognition
In social species, the ability to recognize others emotional states is essential for appropriate social interactions, yet it often declines with age and is impaired in various neurodevelopmental and neurodegenerative disorders. While emotion recognition has been characterized in both humans and rodents, the underlying neural circuits and how they vary by sex and age remain poorly understood. Here, we used a negative Emotional state Discrimination Task (EDT) in TRAP2 transgenic mice to map brain regions engaged during negative emotion recognition in young and aged animals. Young male and female mice successfully discriminated emotionally altered conspecifics, recruiting the basolateral amygdala (BLA) and medial orbitofrontal cortex (MO) in a sex-specific manner. Fiber photometry revealed distinct activation dynamics in these regions, and chemogenetic inhibition of bidirectional BLA-MO projections abolished emotion recognition in male but not female mice. Notably, young human participants also showed sex-specific recruitment of BLA and OFC during negative facial emotion recognition. Moreover, aging selectively impaired emotion recognition in male mice, coinciding with reduced BLA activity. Remarkably, chemogenetic activation of BLA in aged male mice rescued this deficit. Together, these findings identify a sex-dependent BLA-MO circuit as a conserved neural substrate for emotion recognition and demonstrate that age-related impairments can be reversed through targeted circuit-level intervention.