Comparison of Phase Synchronization Measures for Identifying Stimulus-Induced Functional Connectivity in Human Magnetoencephalographic and Simulated Data

Kenji Yoshinaga; Masao Matsuhashi; Tatsuya Mima; Hidenao Fukuyama; Ryosuke Takahashi; Takashi Hanakawa; Akio Ikeda

doi:10.3389/fnins.2020.00648

Comparison of Phase Synchronization Measures for Identifying Stimulus-Induced Functional Connectivity in Human Magnetoencephalographic and Simulated Data

Front Neurosci. 2020 Jun 19:14:648. doi: 10.3389/fnins.2020.00648. eCollection 2020.

Authors

Kenji Yoshinaga^{1

2}, Masao Matsuhashi³, Tatsuya Mima⁴, Hidenao Fukuyama⁵, Ryosuke Takahashi¹, Takashi Hanakawa^{2

6}, Akio Ikeda³

Affiliations

¹ Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
² Department of Advanced Neuroimaging, Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan.
³ Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
⁴ Graduate School of Core Ethics and Frontier Sciences, Ritsumeikan University, Kyoto, Japan.
⁵ Research and Educational Unit of Leaders for Integrated Medical System, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, Japan.
⁶ Department of Integrated Neuroanatomy and Neuroimaging, Kyoto University Graduate School of Medicine, Kyoto, Japan.

Abstract

Phase synchronization measures are widely used for investigating inter-regional functional connectivity (FC) of brain oscillations, but which phase synchronization measure should be chosen for a given experiment remains unclear. Using neuromagnetic brain signals recorded from healthy participants during somatosensory stimuli, we compared the performance of four phase synchronization measures, imaginary part of phase-locking value, imaginary part of coherency (ImCoh), phase lag index and weighted phase lag index (wPLI), for detecting stimulus-induced FCs between the contralateral primary and ipsilateral secondary somatosensory cortices. The analyses revealed that ImCoh exhibited the best performance for detecting stimulus-induced FCs, followed by the wPLI. We found that amplitude weighting, which is related to computing both ImCoh and wPLI, effectively attenuated the influence of noise contamination. A simulation study modeling noise-contaminated periodograms replicated these findings. The present results suggest that the amplitude-dependent measures, ImCoh followed by wPLI, may have the advantage in detecting stimulus-induced FCs.

Keywords: amplitude coherence; cross-periodogram; functional connectivity; phase synchronization; somatosensory system.