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No evidence for spontaneous cross‐frequency phase–phase coupling in the human hippocampus
Author(s) -
Rings Thorsten,
Cox Roy,
Rüber Theodor,
Lehnertz Klaus,
Fell Juergen
Publication year - 2020
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.14608
Subject(s) - hippocampus , coupling (piping) , phase (matter) , memory consolidation , psychology , neuroscience , electroencephalography , cognition , coupling strength , physics , materials science , condensed matter physics , quantum mechanics , metallurgy
Cross‐frequency phase–phase coupling (PPC) has been suggested to play a role in cognitive processing and, in particular, in memory consolidation during sleep. Controversial results have been reported regarding the existence of spontaneous phase–phase coupling in the hippocampus. Here, we investigated this phenomenon in intracranial EEG recordings from the human hippocampus acquired during waking state and different sleep stages. We estimated the strength of interactions between different pairs of frequency bands and evaluated the statistical significance of findings using surrogates that build on different null hypotheses. Indications for spontaneous phase–phase coupling were only observed when testing with less rigorous surrogates. When requiring that all four surrogate tests be passed, however, there were no significant indications for phase–phase coupling. In conclusion, we did not detect evidence for spontaneous cross‐frequency phase–phase coupling in the human hippocampus.