Bivariate LD score regression was used to calculate genetic correlation r G between traits. Supporting Information Figure S6 shows the genetic correlations between the EEG phenotypes. Strong and positive genetic correlations were observed among the EEG power phenotypes. Occipital and Cz alpha power correlated 1.0 (p < 1E‐80), and correlated highly with Cz beta power (r G = .67, p < 3.3E–5; and r G = .71, p < 2.8E‐9 respectively). Slow oscillatory power (delta and theta) also correlated near 1.0 (p < 1E‐20). Only the theta with beta power genetic correlation was modest and not statistically significant (p = .16). Negative correlations between peak alpha frequency and the slow oscillation power phenotypes were observed (significant for peak alpha with theta power, r G = –.73, p < 7.5E–5), and a nonsignificant positive correlation with beta power.
