We set out to investigate the organization of the transcriptome in the human brain by applying weighted gene coexpression network analysis (WGCNA)18 to four microarray data sets generated from 160 human brain control samples. Two cortical data sets were assembled to provide independent validation of gene coexpression relationships across individuals and microarray platforms and two data sets consisting of samples from either caudate nucleus or cerebellum were assembled to enable comparisons across brain regions. Data set 1 (CTX) consisted of 67 samples from 67 individuals representing four cortical areas4,6,7 and data set 2 (CTX_95) consisted of 42 samples from 32 individuals representing six cortical areas2,5,19-22. Data set 3 (CN) consisted of 27 samples from 27 individuals taken from the head of the caudate nucleus and data set 4 (CB) consisted of 24 samples from 24 individuals taken from cerebellar hemisphere6 (detailed sample information can be found in Supplementary Table 1 online). All samples from CTX, CN and CB were analyzed using Affymetrix U133A microarrays, whereas samples from CTX_95 were analyzed using Affymetrix U95A/v2 microarrays. To ensure the highest possible level
