title: Evaluation of Phase-Amplitude Coupling in Resting State Magnetoencephalographic Signals: Effect of Surrogates and Evaluation Approach.
abstract: Phase-amplitude coupling (PAC) plays an important role in neural communication and computation. Interestingly, recent studies have indicated the presence of ubiquitous PAC phenomenon even during the resting state. Despite the importance of PAC phenomenon, estimation of significant physiological PAC is challenging because of the lack of appropriate surrogate measures to control false positives caused by non-physiological PAC. Therefore, in the present study, we evaluated PAC phenomenon during resting-state magnetoencephalography (MEG) signal and considered various surrogate measures and computational approaches widely used in the literature in addition to proposing new ones. We evaluated PAC phenomenon over the entire length of the MEG signal and for multiple shorter time segments. The results indicate that the extent of PAC phenomenon mainly depends on the surrogate measures and PAC computational methods used, as well as the evaluation approach. After a careful and critical evaluation, we found that resting-state MEG signals failed to exhibit ubiquitous PAC phenomenon, contrary to what has been suggested previously.
authors.affiliation: Center for Biosignals, Korea Research Institute of Standards and Science Daejeon, South Korea.
authors.forename: Bakul
authors.initials: B
authors.lastname: Gohel
authors.affiliation: Center for Biosignals, Korea Research Institute of Standards and Science Daejeon, South Korea.
authors.forename: Sanghyun
authors.initials: S
authors.lastname: Lim
authors.affiliation: Center for Biosignals, Korea Research Institute of Standards and Science Daejeon, South Korea.
authors.forename: Min-Young
authors.initials: MY
authors.lastname: Kim
authors.affiliation: Center for Biosignals, Korea Research Institute of Standards and Science Daejeon, South Korea.
authors.forename: Kyung-Min
authors.initials: KM
authors.lastname: An
authors.affiliation: Center for Biosignals, Korea Research Institute of Standards and Science Daejeon, South Korea.
authors.forename: Ji-Eun
authors.initials: JE
authors.lastname: Kim
authors.affiliation: Center for Biosignals, Korea Research Institute of Standards and Science Daejeon, South Korea.
authors.forename: Hyukchan
authors.initials: H
authors.lastname: Kwon
authors.affiliation: Center for Biosignals, Korea Research Institute of Standards and Science Daejeon, South Korea.
authors.forename: Kiwoong
authors.initials: K
authors.lastname: Kim
keywords: cross-frequency coupling; magnetoencephalography; phase-amplitude coupling; resting state