To test for overall significance of gene‐expression enrichment in alpha oscillation power, we used the online tool FUMA (Watanabe et al., 2017). We extracted the top 500 genes from the gene‐based association (Cz and occipital alpha), which were matched against genes significantly up‐ or downregulated in each GTEx tissue compared to the average of other tissues (i.e., differentially expressed genes determined by a Bonferroni‐corrected t test). Significance of enrichment was determined by the hypergeometric test with Bonferroni correction. Figure 3 shows that brain derived tissues are almost invariably significant, and much more so than other tissues. Other tissues—less clearly related to brain oscillations—also show significant enrichment (heart, whole blood, pancreas, tibial nerve, and liver). This is largely attributed to pleiotropy. However, causal effects and spurious relations cannot be excluded.
