Aromatase and its role in shaping sex-differentiated brain networks

Steroid hormone signaling drives sex-differentiated brain development and function, with the social behavior network (SBN) as a primary site of these differences. Aromatase, densely expressed in the SBN, is essential for estrogen production in the brain, shaping brain organization during development and dynamically regulating neural function and behavior throughout life. This review explores how aromatase-dependent mechanisms establish sex differences at multiple anatomical levels, from gene expression and cellular morphology to brain-wide differences in the connectivity of neural circuits. These structural differences, in cooperation with dynamic estrogen signaling, are thought to mediate sex-differences in social behavior. Advancing our understanding of how aromatase-dependent sex differences shape brain function will require grounding both new and existing findings within the heterogeneous and interconnected circuitry of the SBN.