Functional specializations within endothelial, glial, and other non-neuronal cell classes could be ubiquitous features of the adult mouse brain, or could be enriched in particular brain regions. We compared the relative abundance of cells from each region within fibroblast-like and endothelial subclusters (Figure 2F)(results for other non-neuronal classes in Data S4H). While endothelial subpopulations had similar abundances across regions, fibroblast-like subpopulations exhibited different contributions from cortical and subcortical areas: the cortex and hippocampus contributed disproportionately to the population that more strongly expressed genes with membrane-transport functions (subcluster 6), while collagen-expressing cell populations (subclusters 2 and 3) came largely from the basal ganglia and thalamus (Figure 2F).
