Dynamic network interactions among distinct brain rhythms as a hallmark of physiologic state and function.

Brain rhythms are associated with a range of physiologic states, and thus, studies have traditionally focused on neuronal origin, temporal dynamics and fundamental role of individual brain rhythms, and more recently on specific pair-wise interactions. Here, we aim to understand integrated physiologic function as an emergent phenomenon of dynamic network interactions among brain rhythms. We hypothesize that brain rhythms continuously coordinate their activations to facilitate physiologic states and functions. We analyze healthy subjects during sleep, and we demonstrate the presence of stable interaction patterns among brain rhythms. Probing transient modulations in brain wave activation, we discover three classes of interaction patterns that form an ensemble representative for each sleep stage, indicating an association of each state with a specific network of brain-rhythm communications. The observations are universal across subjects and identify networks of brain-rhythm interactions as a hallmark of physiologic state and function, providing new insights on neurophysiological regulation with broad clinical implications. Lin & Liu et al. analyze EEG recordings and report that each sleep stage is characterized by a specific ensemble of coupling profiles and a network of brain-rhythm communications. Their work challenges the current paradigm of understanding physiologic states through distinct or dominant brain rhythms and identifies networks of brain-rhythm interactions as a signature of physiologic state and function.