Lead/Lag directionality is not generally equivalent to causality in nonlinear systems: Comparison of phase slope index and conditional mutual information

0585428 - ÚI 2025 RIV NL J - Journal Article
Arinyo i Prats, Andreu - López-Madrona, V. J. - Paluš, Milan
Lead/Lag directionality is not generally equivalent to causality in nonlinear systems: Comparison of phase slope index and conditional mutual information.
Neuroimage. Roč. 292, 15 April 2024 (2024), č. článku 120610. ISSN 1053-8119. E-ISSN 1095-9572
R&D Projects: GA ČR(CZ) GF21-14727K
Institutional support: RVO:67985807
Keywords : Coupling directionality * Cross-frequency coupling * Conditional mutual information * Phase slope index * EEG * Nonlinear systems
OECD category: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8)
Impact factor: 5.7, year: 2022
Method of publishing: Open access
https://doi.org/10.1016/j.neuroimage.2024.120610

Applications of causal techniques to neural time series have increased extensively over last decades, including a wide and diverse family of methods focusing on electroencephalogram (EEG) analysis. Besides connectivity inferred in defined frequency bands, there is a growing interest in the analysis of cross-frequency interactions, in particular phase and amplitude coupling and directionality. Some studies show contradicting results of coupling directionality from high frequency to low frequency signal components, in spite of generally considered modulation of a high-frequency amplitude by a low-frequency phase. We have compared two widely used methods to estimate the directionality in cross frequency coupling: conditional mutual information (CMI) and phase slope index (PSI). The latter, applied to infer cross-frequency phase–amplitude directionality from animal intracranial recordings, gives opposite results when comparing to CMI. Both metrics were tested in a numerically simulated example of unidirectionally coupled Rössler systems, which helped to find the explanation of the contradictory results: PSI correctly estimates the lead/lag relationship which, however, is not generally equivalent to causality in the sense of directionality of coupling in nonlinear systems, correctly inferred by using CMI with surrogate data testing.
Permanent Link: https://hdl.handle.net/11104/0353138