Stathmin reveals dissociable roles of the basolateral amygdala in parental and social behaviors

Innate parental behaviors and adult social interactions are essential for survival of the individual along with the species as a whole. Because these behaviors require threat assessment of the environment, it is plausible that they are regulated by the amygdala-associated neural circuitry of fear. However, the amygdala is not a single anatomic and functional unit, and nuclei of the amygdala have multiple inter- and intra-connections. This poses a question as to the exact role of different amygdala nuclei in these behaviors and the mechanisms involved. The basolateral complex of the amygdala nuclei (BLA) is particularly interesting in this regard: although the BLA role in forming memories for learned fear is established, the BLA role in innate behaviors is not well understood. We recently demonstrated that mice without an inhibitor of microtubules, stathimin, a gene enriched in BLA-associated circuitry, have deficiency in innate and learned fear. Here we show that the deficiency in fear processing in stathmin(-/-) females leads to improper threat assessment, which in turn affects innate parental care and adult social interactions. Profound deficiency is observed in maternal behavior of stathmin(-/-) females: they lack motivation for retrieving pups and are unable to choose a safe location for nest-building. Remarkably, stathmin(-/-) females have an enhancement in social interactions. BLA lesions in WT mice produce similar effects in maternal and social behaviors, confirming vital BLA participation. The findings implicate stathmin as the critical molecular component linking the BLA-associated neural circuitry with innate parental behaviors and adult social interactions.