Pattern dynamics and stochasticity of the brain rhythms

TL;DR

This study investigates the detailed waveforms and patterns of brain rhythms, revealing their relationship with physiological functions, animal behavior, and spatial factors, providing a mesoscale perspective on brain wave dynamics.

Contribution

It introduces novel measures to analyze wave shape consistency and orderliness, linking wave patterns to behavior and spatial variables, advancing understanding of brain rhythm structure.

Findings

Wave patterns vary with animal speed and location.

Orderliness inversely correlates with irregularity and behavioral acceleration.

Patterns show spatial selectiveness and speed-modulated changes.

Abstract

Our current understanding of brain rhythms is based on quantifying their instantaneous or time-averaged characteristics. What remains unexplored, is the actual structure of the waves -- their shapes and patterns over finite timescales. To address this, we used two independent approaches to link wave forms to their physiological functions: the first is based on quantifying their consistency with the underlying mean behavior, and the second assesses "orderliness" of the waves' features. The corresponding measures capture the wave's characteristic and abnormal behaviors, such as atypical periodicity or excessive clustering, and demonstrate coupling between the patterns' dynamics and the animal's location, speed and acceleration. Specifically, we studied patterns of $\theta$ and $\gamma$ waves, and Sharp Wave Ripples, and observed speed-modulated changes of the wave's cadence, an antiphase relationship between orderliness and acceleration, as well as spatial selectiveness of patterns. Furthermore, we found an interdependence between orderliness and regularity: larger deviations from steady oscillatory behavior tend to accompany disarrayed temporal cluttering of peaks and troughs. Taken together, our results offer a complementary -- mesoscale -- perspective on brain wave structure, dynamics, and functionality.