Resolving whole-brain alpha traveling waves across brain states

Spontaneously emerging traveling waves are present within the spatiotemporal patterns of alpha-band EEG oscillations, but current analysis methods are limited in resolving the diversity of global wave structures and their correlation with brain functions. To address this limitation, we constructed a rigorous mathematical framework, Weakly Orthogonal Conjugate Contrast Analysis (WOCCA), which decomposes the whole-brain neural oscillations into traveling waves with independent directionality. Propagating patterns in alpha-band resting-state EEG are resolved as a combination of rotational, longitudinal, and horizontal traveling wave components. The intensity, directionality, and morphological characteristics of these wave components account for the differences between cognitive states during rest and the rapidly changing dynamics of consciousness levels during sedation. Moreover, the WOCCA decomposition encompassed the state transition dynamics captured by EEG Microstate Analysis, a conventional analysis framework for alpha waves. These results not only established an effective technique for resolving and analyzing traveling waves but also provided evidence for the relationship between wave directionality and cooperative interactions in brain network.