The results obtained for M9, M15 and M16 suggested that other modules might distinguish additional cell types or functional elements of the human brain. We set out to characterize other identified modules using five complementary approaches. First, modules were cross-referenced with published data that have been associated with specific cell types or functional systems relevant to the brain30-37, as described above (Supplementary Table 7). Second, modules were searched for commonly used markers of specific cell types with strong evidence of module membership (Supplementary Tables 3-6 and Supplementary Fig. 4 online). To normalize comparisons across networks, we refer to module membership in terms of its rank (RMM = rank |module membership|). Third, we searched modules for over-represented functional categories of genes using all of the available categorical systems in the EASE software package38 (Supplementary Table 8 online). Fourth, modules were characterized on the basis of gene expression patterns in the adult mouse brain using the Allen Brain Atlas31 (Supplementary Fig. 5 online). Fifth, we correlated module eigengenes with available sample information such as cortical area, age or gender. Using these approaches,
