Development and neural diversity of septal nuclei

Septal nuclei in the basal forebrain have critical roles in regulating emotional states including fear, anxiety, and aggression. Dysfunction of septal neurons is thought to play a significant role in the pathophysiology of a variety of psychiatric disorders including schizophrenia, bipolar disorder and depression. The septum can be classified into medial (MS)and lateral (LS) regions. The medial septum is composed of cholinergic, GABAergic and glutamatergic neurons that primarily project to the hippocampus. The lateral septum is composed of a diverse array of GABAergic projection neurons that have reciprocal connections with numerous brain regions known to regulate emotional and motivational states. It is currently unclear how septal neuronal diversity and circuit wiring are specified during development. Using molecular genetics and single-cell/nuclei RNA-seq we have begun to unravel the developmental logic for producing diverse neural cell types in the septum. Our future work is focused on understanding the specific contribution of developmentally specified neural cell types in the regulation of internal states carried out by the septum.