Linking electrophysiological brain activity to neurological and psychiatric liability genes: Large-scale collaborative studies by the ENIGMA-EEG group.
The ENIGMA-EEG working group was established to enable large scale international collaborations among cohorts who investigate the genetics of brain function measured with electroencephalography (EEG). The collaboration resulted in the currently largest genome-wide association study of oscillatory brain activity in EEG recordings by meta-analyzing the results across five participating cohorts’ results. Our endeavor has resulted in the first genome-wide significant hits for oscillatory brain function, and significant genes that were previously associated with psychiatric disorders. Our results have provided insight into the influence that psychitaric liability genes have on the functioning brain. In this overview, we also highlight how we have tackled methodological issues surrounding genetic meta-analysis of EEG features, and identify possible sources of heterogeneity across cohorts, which could affect the results of our meta-analysis. We discuss the importance of harmonizing EEG signal processing, cleaning, and feature extraction. Finally, we explain our selection of EEG features to be investigated in our future studies, e.g. temporal dynamics of oscillations and the connectivity network based on synchronization of oscillations. We argue that these represent some of the most important characteristics of the functioning brain. We conclude that disentangling the genetics of EEG will elucidate effects that genes have on brain function, as well as pathways from genes to neurological and psychiatric disorders.