Differences between the sexes appeared to be greatest in the delta-gamma domain. Median delta-gamma PAC in men with AUD was broadly greater compared to unaffected men, as were all candidate clusters (M2, M3, M4, M6) and significantly greater in cluster M2. In contrast, most of the delta-gamma candidate clusters in women (W1, W6, W7) showed lower PAC in women with AUD compared to their unaffected counterparts, with significantly lower PAC found at the W6 cluster. One possible explanation for the lower PAC among women with AUD could be insufficient neural synchrony in the theta band, Lower theta EEG coherence (3–5 Hz) during resting state has been observed in women with AUD particularly at parietal brain regions (Meyers et al., 2021). If the effects of this reduced theta EEG coherence extend through parieto-frontal brain circuits, one might expect an accompanying alteration in PAC strength in recordings from frontal brain regions in the 3–5 Hz phase frequency range which would include the W6 cluster as well as W8 in the theta-alpha domain. Further investigation will be needed to test between this or other possible explanations.
