Among the 29 significant DMN connections identified by the RF model, 13 of them (~45%) were bilateral parahippocampal connections to prefrontal (PFC and ACC), temporal (LTC) and parietal (IPL) regions, and thus formed a hub region. These 13 hippocampal connections represented all frequencies (i.e., one in delta, four in theta, three in alpha, three in beta, and two in gamma band) and 12 of these connections, except the R.PHG–L.ACC beta band connection, were hyperconnected in AUD individuals. It should be mentioned that it is the parahippocampal region that links the DMN connections with the medial temporal lobe memory system [122]. Therefore, this finding of hyperconnected hippocampal hub may suggest either a noisy communication across hippocampal sub-networks or an upregulated connectivity pattern representing overcompensation for the existing neural damage and memory impairments due to chronic drinking. In our earlier study using structural MRI, Pandey et al. [16] reported smaller volume in several regions, including bilateral hippocampi, in AUD individuals compared to controls. Therefore, it is possible that damage to hippocampal connectivity to other regions of higher cortical functions (PFC, ACC, and
