that established markers of oligodendrocytes (for example, PLP1, MAG, OLIG2, MOG, MOBP, CNP), astrocytes (for example, GFAP, GJA1, GLUL, GLUD1, SLC1A2, AQP4) and neurons (for example, MAP2, MAP1B, SYT1, NRXN1, SLC1A1 and NRCAM) were all correctly determined to be significant members of M9, M15 and M16, respectively, in all four networks (Supplementary Tables 3-6). These results indicate that M9, M15 and M16 consist of genes that are preferentially expressed in oligodendrocytes, astrocytes and neurons, respectively, relative to other cell types in the brain, and suggest that covariance in these modules is related to the absolute quantities of these cell types that were present in each sample.
