Multisensory integration of social signals by a pathway from the basal amygdala to the auditory cortex in maternal mice

Abstract

ABSTRACTSocial encounters are inherently multimodal events, yet how and where social cues of distinct modalities merge and interact in the brain is poorly understood. For example, when their pups wander away from the nest, mother mice use a combination of vocal and olfactory signals emitted by the pups to locate and retrieve them. Previous work revealed the emergence of multisensory interactions in the auditory cortex (AC) of both dams and virgins who co-habitate with pups (‘surrogates’). Here we identify a neural pathway that integrates information about odors with responses to sound. We found that a scattered population of glutamatergic neurons in the basal amygdala (BA) projects to the AC and responds to odors, including the smell of pups. These neurons also exhibit increased activity when the surrogate female is searching for pups. Finally, we show that selective optogenetic activation of BA-AC neurons modulates responses to pup calls, and that this modulation switches from predominantly suppressive to predominantly excitatory after maternal experience. This supports an underappreciated role for the amygdala in directly shaping sensory representations in an experience-dependent manner. We propose that the BA-AC pathway integrates olfaction and audition to facilitate maternal care, and speculate that it may carry valence information to the AC.