Dabaghian, Y. | Search bioRxiv

bioRxiv2024

Theta oscillons in behaving rats

Recently discovered constituents of the brain waves--the oscillons--provide high-resolution representation of the extracellular field dynamics. Here we study the most robust, highest-amplitude oscillons that manifest in actively behaving rats and generally correspond to the traditional{theta} -waves. We show that the resemblances between{theta} -oscillons and the conventional{theta} -waves apply to the ballpark characteristics--mean frequencies, amplitudes, and bandwidths. In addition, both hippocampal and cortical oscillons exhibit a number of intricate, behavior-attuned, transient properties that suggest a new vantage point for understanding the{theta} -rhythms structure, origins and functions. We demonstrate that oscillons are frequency-modulated waves, with speed-controlled parameters, embedded into a noise background. We also use a basic model of neuronal synchronization to contextualize and to interpret the observed phenomena. In particular, we argue that the synchronicity level in physiological networks is fairly weak and modulated by the animals locomotion.

neuroscience↗

bioRxiv2022

Pattern dynamics and stochasticity of the brain rhythms

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 waves characteristic and abnormal behaviors, such as atypical periodicity or excessive clustering, and demonstrate coupling between the patterns dynamics and the animals location, speed and acceleration. Specifically, we studied patterns of{theta} and{gamma} waves, and Sharp Wave Ripples, and observed speed-modulated changes of the waves cadence, an antiphase relationship between orderliness and acceleration, as well as spatial selectiveness of patterns. Further-more, 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.

neuroscience↗