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 LTC) may underlie cognitive impairments including memory deficits and blackouts that are common in chronic AUD patients [123,124,125,126]. Interestingly, using the same sample AUD subjects, we reported reduced bilateral hippocampal volume which was also associated poor visual memory performance [16]. The finding that partly supports the current findings is from the only available eLORETA based FC study on AUD [59], where the authors reported theta band hyperconnectivity in hippocampal sub-networks among the dense connections in a small sample of craving, drug-resistant, relapsed AUD individuals (N = 11). Primary involvement of theta band may also assume significance in the context of our finding that the highest number of hippocampal connections were observed in the theta band (Figure 5, panel b), while another study reported that hippocampal atrophy was correlated with EEG theta power in elderly subjects with a range of cognitive impairment [127]. Similarly, impaired hippocampal connectivity associated with memory deficits were also reported in Alzheimer’s disease [128], temporal lobe epilepsy
