Sexually Dimorphic Cellular Architecture and Neural Circuity of ovBNST Proenkephalin Neurons.

Sexual dimorphism in the brain underlies behavioral differences between sexes. The bed nucleus of the stria terminalis (BNST) is a complex nucleus that differs between males and females, but the sexual dimorphism in cytoarchitecture and the connectome of its oval subdivision (ovBNST) remains largely unexplored. By combining snRNA-seq and transgenic labeling, we found a higher density of ovBNST proenkephalin (ovBNST(PENK)) neurons in male than female mice. Anatomically, we virally mapped the efferents and afferents of ovBNST(PENK) neurons, finding reciprocally dimorphic connections with the hypothalamus and striatum. Gene enrichment analysis suggests that ovBNST(PENK) neurons are modulated by the upstream dopamine pathway. Functionally, by applying caspase-3-mediated depletion of ovBNST(PENK) neurons, we found that loss of these neurons enhanced locomotor activity in male but not female mice, without altering the anxiety-like phenotypes in either sex. Our study may pave the way for a better understanding of the anatomical and functional profiles of ovBNST(PENK) neurons from a sexually dimorphic perspective.