# Characterization of Sexual Dimorphism in the Brain

> **NIH NIH R01** · STANFORD UNIVERSITY · 2020 · $90,052

## Abstract

Project Summary
Social interactions are powerfully modulated by internal physiological state and future goals. The goal of our
project is a functional and molecular characterization of the mammalian bed nucleus of the stria terminalis
(BNST), with a focus on its medial division posteromedial compartment (BNSTmpm). The BNSTmpm is sexually
dimorphic across many mammalian species, and it has been implicated in a diversity of social interactions in
both sexes and physiological responses. Consistent with these observations, BNSTmpm neurons express the
enzyme aromatase that converts testosterone or related androgens into estrogens; aromatase activity is
essential for wildtype sexual differentiation of the brain and behavior in both sexes in rodents and many other
animals. However, the function of aromatase in different brain regions in adult animals remains poorly
characterized. The research goals of the diversity supplement fit within the goals of the parent project, and in
particular they are focused on a subset of the specific aims. We have identified a small subset of BNSTmpm
neurons that are activated upon mating in females. In aim 1 of the supplement, we will use FosTrap to label
these neurons and use fiber photometry to understand the specific components of mating that activate these
cells. We will next use chemogenetic actuators to test if these mating-activated BNSTmpm neurons are
necessary or sufficient for female reproductive behaviors. In aim 2 of the supplement, we will specifically delete
aromatase in BNSTmpm neurons to test its functional contribution to sexually dimorphic social interactions and
physiology in both sexes. In summary, the studies proposed for the diversity supplement fit within the
overarching goals of the parent project.
Health Relatedness: Neurodegenerative and psychiatric conditions often reflect dysfunction of neural circuitry
at a gross or microscopic level, and these remain poorly understood and therapeutically intractable. The BNST
is a critical node linking amygdalar, hypothalamic, and cortical networks in the regulation of social interactions,
response to various stressors, and reward pathways. Our proposed studies will shed light on the connectivity
and functions of a subset of BNST neurons in the two sexes, thereby leading to an advance in basic scientific
understanding of this region and the neural circuits within which it functions in health, and it may ultimately
provide insights into future therapeutic or diagnostic applications for mental illness and common
neurodegenerative conditions.

## Key facts

- **NIH application ID:** 10166218
- **Project number:** 3R01NS049488-14S1
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** Nirao Mahesh Shah
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $90,052
- **Award type:** 3
- **Project period:** 2020-07-01 → 2022-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10166218

## Citation

> US National Institutes of Health, RePORTER application 10166218, Characterization of Sexual Dimorphism in the Brain (3R01NS049488-14S1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10166218. Licensed CC0.

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