Spatiotemporal Decomposition of Whole-Brain Alpha Traveling Waves

Spontaneously emerging traveling waves are present within the spatiotemporal patterns of alpha-band EEG oscillations, but current analysis methods are limited in parsing 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 EEG alpha oscillations into directionally independent traveling waves. For the first time, we systematically characterized propagating components in alpha-band resting-state EEG as a combination of rotational, longitudinal, and horizontal traveling wave patterns. The intensity, directionality, and morphological characteristics of these wave patterns account for the differences between cognitive states during rest and consciousness levels under sedation. Moreover, our WOCCA decomposition encompassed the state transition dynamics captured by EEG Microstate Analysis, a conventional analysis framework for alpha waves. These results not only established a novel approach for identifying and analyzing traveling waves but also provided evidence for the relationship between wave directionality and cooperative interactions in brain network.