To illustrate the value of these data in understanding the functional organization of neurotransmission, we examined the 740 genes identified in the human excitatory postsynaptic density (PSD12), and in particular those that varied in their neuroanatomical distribution. Thirty-one per cent of PSD genes showed highly regional differential expression (Supplementary Methods 2 and Supplementary Table 3) (fold change >5 between any pair of 170 structures, false discovery rate <0.01), a significantly greater percentage than that observed across all genes (21%, P < 10−6, Mann–Whitney U-test). As expected, many synapse-associated Gene Ontology (GO) categories13 were enriched in this gene set, even relative to the PSD genes as a whole, including synapse (GO: 0045202), synaptic vesicle (GO: 0008021), synaptic transmission (GO: 0007268), neurophysiological process (GO: 0050877) and receptor activity (GO: 0004872).
