Project Summary/Abstract
Chemosensory systems contribute extensively to social behavior in humans and other mammals,
including mice, a predominant animal model for diseases and disorders that impact human social
function. We propose to study the neural circuitry of the accessory olfactory system in order to better
understand how this system extracts information from chemical messages and informs social
behavior. Without improved understanding of these processes, we risk making mistakes in the
interpretation of studies seeking new therapies for diseases and disorders involving social behavior.
The activity of excitatory projection neurons called mitral cells (MCs) in the first neural circuit in the
accessory olfactory system, called the accessory olfactory bulb (AOB), strongly influences
reproductive physiology and social behavior. AOB mitral cell activity is tightly controlled by several
types of GABAergic interneurons: juxtaglomerular cells, external granule cells, and internal granule
cells (IGCs). We and others have identified that AOB IGCs undergo experience-dependent plasticity
following chemosensory social behaviors. We will investigate the hypothesis that these cells, and
perhaps other AOB interneurons, are involved in social behavior plasticity.
We will use multiple physiological techniques to investigate cellular and synaptic physiology in
AOB interneurons that undergo experience-dependent plasticity. We will investigate how experience-
dependent plasticity modulates interneuron excitability, morphology, and gene transcription. We will
determine how interneuron plasticity influences MC chemosensory tuning in vivo and ex vivo using
chemogenetics, optogenetics, and live calcium imaging. Finally, we will investigate the impacts of
inhibitory plasticity on brain-wide patterns of neuronal activation and social behavior during repeated
social encounters. Combined, these studies will fill major gaps in our understanding of chemosensory
information processing, experience-dependent plasticity, and mammalian social behavior.