Genes with relatively high specificity for bulk expression in every tested region of human brain14 were significantly enriched for associations (Extended Data Figure 3. Comparison with our earlier studies11,15 shows increasingly clear contrast between the enrichments in brain and non-brain tissues. More strongly than in prior studies16, from human single cell expression data17, we found associations were enriched in genes with high expression in excitatory glutamatergic neurons from cerebral cortex and hippocampus (pyramidal CA1 and CA3 cells, and granule cells of dentate gyrus) and also human cortical inhibitory interneurons (Figure 4a). In mouse single-cell RNA-seq data16, we found similar patterns of enrichments in genes with high expression in excitatory glutamatergic pyramidal neurons from the cortex and hippocampus (Figure 4b), and inhibitory cortical interneurons. We also found associations were enriched in inhibitory medium spiny neurons, the predominant cells of the striatum.
