# LFP beta amplitude is predictive of mesoscopic spatio-temporal phase patterns

## TL;DR

This study characterizes various spatial phase patterns of beta oscillations in motor cortex LFPs and links their occurrence and dynamics to amplitude changes and behavioral states during a reach-to-grasp task.

## Contribution

It introduces a comprehensive classification of beta phase patterns and reveals their relationship with amplitude and behavioral epochs in motor cortex recordings.

## Key findings

- Beta amplitude correlates with specific phase patterns.
- Wave propagation accelerates with increasing amplitude.
- Pattern occurrence varies with behavioral epochs.

## Abstract

Beta oscillations observed in motor cortical local field potentials (LFPs) recorded on separate electrodes of a multi-electrode array have been shown to exhibit non-zero phase shifts that organize into a planar wave propagation. Here, we generalize this concept by introducing additional classes of patterns that fully describe the spatial organization of beta oscillations. During a delayed reach-to-grasp task in monkey primary motor and dorsal premotor cortices we distinguish planar, synchronized, random, circular, and radial phase patterns. We observe that specific patterns correlate with the beta amplitude (envelope). In particular, wave propagation accelerates with growing amplitude, and culminates at maximum amplitude in a synchronized pattern. Furthermore, the occurrence probability of a particular pattern is modulated with behavioral epochs: Planar waves and synchronized patterns are more present during movement preparation where beta amplitudes are large, whereas random phase patterns are dominant during movement execution where beta amplitudes are small.