Coherence between all pairs of channels was computed as follows: 1) the first 20 s of each recording was discarded, to allow electrode impedances to settle, 2) the magnitude squared coherence was estimated over the next 4 min of data using Welch's averaged, modified periodogram method, using 2 s epochs with 50% overlap, 3) coherence estimates were then averaged within frequency bands for delta (1–3 Hz), theta (4–7 Hz), alpha1 (8–9 Hz), alpha2 (10–12 Hz), beta1 (13–17 Hz), beta2 (18–30 Hz), gamma1 (31–40 Hz), and gamma2 (41–50 Hz). EEG theta, alpha, and beta have been previously studied in neurofeedback treatments (Congedo et al., 2004, Sokhadze et al., 2008) and have been shown to alter EEG resting state networks following alcohol consumption (Lithari et al., 2012). fMRI BOLD signals are thought to arise from the summed neural activities of several oscillatory EEG networks, particularly gamma (Whitman et al., 2013). Therefore, in this paper we focused on theta, alpha, beta, and gamma bands. For these bands, the upper-half of the resulting coherence matrix (excluding the diagonal) was rearranged into a single vector
