Transcriptional and Spatial Resolution of Cell Types in the Mammalian Habenula

Summary The habenula complex is appreciated as a critical regulator of motivated and pathological behavioral states via its output to midbrain nuclei. Despite this, transcriptional definition of cell populations that comprise both the medial (MHb) and lateral habenular (LHb) subregions in mammals remain undefined. To resolve this, we performed single-cell transcriptional profiling and highly multiplexed in situ hybridization experiments of the mouse habenula complex in naïve mice and those exposed to an acute aversive stimulus. Transcriptionally distinct neuronal cell types identified within the MHb and LHb, were spatially defined, and differentially engaged by aversive stimuli. Cell types identified in mice, also displayed a high degree of transcriptional similarity to those previously described in zebrafish, highlighting the well conserved nature of habenular cell types across the phylum. These data identify key molecular targets within habenula cell types, and provide a critical resource for future studies.