Spatially patterned excitatory neuron subtypes and projections of the claustrum

The claustrum is a functionally and structurally complex brain region, whose very spatial extent remains debated. Histochemical-based approaches typically treat the as relatively narrow anatomical region that primarily projects to neocortex, whereas circuit-based can suggest broader containing projections neocortex other regions. Here, in mouse, we took bottom-up cell-type-specific approach complement possibly unite these seemingly disparate conclusions. Using single-cell RNA-sequencing, found comprises two excitatory neuron subtypes are differentiable from surrounding cortex. Multicolor retrograde tracing conjunction with 12-channel multiplexed situ hybridization revealed core-shell arrangement of subtypes, well differential downstream targets. Thus, distinct molecular projection properties, patterns reflect narrower claustral extents debated previous research. This subtype-specific heterogeneity likely shapes functional complexity claustrum.