Our results converge with previous findings from our lab by Watrous and colleagues38 who used a similar behavioral paradigm with intracranial EEG in human patients to show increased global connectivity across the frontal, medial temporal, and parietal lobes, with the MTL acting as a hub, during successful spatiotemporal retrieval. Previous findings have suggested similarities between low-frequency band oscillatory coherence and functional connectivity measured using fMRI49, and corresponding results from our two studies (global increases in functional interactions for correct versus incorrect retrieval) are also consistent with the idea that low-frequency oscillatory coherence and function connectivity, measured via BOLD time series correlations, may carry similar types of information. Complementary to the current results, Watrous and colleagues found that spatial and temporal retrieval arose from common anatomical but frequency-specific subnetworks, with somewhat limited regional specificity distinguishing between spatial and temporal order retrieval. While iEEG affords high spectrotemporal resolution compared to fMRI, fMRI provides potentially greater anatomical precision with greater ease of sampling a large number of brain hubs, including the hippocampus, which we did not sample in the Watrous et al. study.
