Propagating patterns of activity across motor cortex facilitate movement initiation

Abstract

Voluntary movement initiation involves the modulation of neurons in the primary motor cortex (M1) around movement onset. Yet, similar modulations of M1 activity occur during movement planning when no movement occurs. Here, we show that a sequential spatio-temporal pattern of excitability based on beta oscillation amplitude attenuation propagates across M1 prior to the initiation of reaching movements in one of two oppositely oriented directions along the rostrocaudal axis. Using spatiotemporal patterns of intracortical microstimulation, we find that reaction time increases significantly when stimulation is delivered against but not with the natural propagation orientation suggesting that movement initiation requires a precise recruitment pattern in M1. Functional connections among M1 units emerge at movement onset that are oriented along the same rostro-caudal axis but not during movement planning. Finally, we show that beta amplitude profiles can more accurately decode muscle activity when these patterns conform to the natural propagating patterns. These findings provide the first causal evidence that large-scale, spatially organized propagating patterns of cortical excitability and activity are behaviorally relevant and may be a necessary component of movement initiation. and training as well as Callum Ross, Juan Alvaro Gallego, and Raeed Chowdhury for assistance in chronic EMG implants.

Comparing apples to apples -- Using a modular and adaptable analysis pipeline to compare slow cerebral rhythms across heterogeneous datasets

“…Yet another effort is pursued to also analyze the characteristics of wave-like phenomena in other frequency regimes. For example, in alpha, beta, and gamma frequency ranges, diverse and complex wave patterns have been observed in various experiments of awake behaving animals (Balasubramanian et al, 2019;Denker et al, 2018b;Petersen et al, 2003;Senseman and Robbins, 2002;Townsend and Gong, 2018;Wu et al, 2008). A pipeline approach similar to the Cobrawap may disentangle and align some of the various reported results, methods, and terminologies.…”

The inhibitory control of traveling waves in cortical networks

“…They suggest that these waves can modulate the excitability of the cortex in such a way as to affect processing of future stimuli. More recently, [16] have suggested that propagating waves in motor cortex can facilitate the initiation of movement and [17] have shown that spontaneous propagating waves can affect perception in awake monkeys. Because of their possible roles in modulating cortical excitability in a spatially and temporally precise manner, it is important to better understand the cellular mechanisms that control these waves.…”