Neuronal heterogeneity in the medial septum and diagonal band of Broca: classes and continua

Abstract

SUMMARYThe medial septum and diagonal band of Broca is known for its diverse populations of cholinergic, GABAergic, and glutamatergic neurons and their behaviorally relevant functions. Behavioral studies and cell-specific manipulations within this region have underscored its involvement in a diverse array of mouse behaviors, implying the presence of a more intricate and complex cellular landscape than previously acknowledged. In this study, we employed single-cell RNA sequencing to thoroughly characterize the heterogeneity of septal neurons. Our findings confirmed previously known neuronal classes and uncovered previously undescribed subclasses, as well as expression gradients. We identified transcriptomic identities of molecularly defined cell populations and validated the expression of cell type-specific marker genes using spatial transcriptomic datasets, mapping distinct patterns of cell distribution. Taken together, our analyses provide a comprehensive description of MSDB cell type diversity and novel marker genes to investigate the intricate neuronal composition of the medial septal region.