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 [129,130], and elderly individuals [131]. Although EEG source FC studies on AUD are scarce, aberrations in fMRI FC across the hippocampal connections have been reported in other related conditions such as drug addiction [132]. Finally, it should also be noted that the single beta connection that showed hypoconnectivity (R.PHG–L.ACC) (Figure 5, panel d) was also found to have hyperconnectivity in the Gamma band. Although intriguing, it is possible that the reciprocal communications across hippocampal and ACC may involve different frequencies, given that these complex, multi-level connections involve both direct and indirect pathways [133].
