Motor cortex latent dynamics encode spatial and temporal arm movement parameters independently.

Colins Rodriguez, Andrea; Perich, Matthew G; Miller, Lee; Humphries, Mark D

Abstract

The fluid movement of an arm requires multiple spatiotemporal parameters to be set independently. Recent studies have argued that arm movements are generated by the collective dynamics of neurons in motor cortex. An untested prediction of this hypothesis is that independent parameters of movement must map to independent components of the neural dynamics. Using a task where three male monkeys made a sequence of reaching movements to randomly placed targets, we show that the spatial and temporal parameters of arm movements are independently encoded in the low-dimensional trajectories of population activity in motor cortex: each movement’s direction corresponds to a fixed neural trajectory through neural state space and its speed to how quickly that trajectory is traversed. Recurrent neural network models show that this coding allows independent control over the spatial and temporal parameters of movement by separate network parameters. Our results support a key prediction of the dynamical systems view of motor cortex, and also argue that not all parameters of movement are defined by different trajectories of population activity.

Citation

Colins Rodriguez, A., Perich, M. G., Miller, L., & Humphries, M. D. (2024). Motor cortex latent dynamics encode spatial and temporal arm movement parameters independently. Journal of Neuroscience, 44(35), Article e1777232024. https://doi.org/10.1523/JNEUROSCI.1777-23.2024

• Journal Article Type: Article
• Acceptance Date: Jul 17, 2024
• Online Publication Date: Jul 26, 2024
• Publication Date: Aug 28, 2024
• Deposit Date: Oct 18, 2024
• Publicly Available Date: Oct 21, 2024
• Journal: Journal of Neuroscience
• Electronic ISSN: 1529-2401
• Publisher: Society for Neuroscience
• Peer Reviewed: Peer Reviewed
• Volume: 44
• Issue: 35
• Article Number: e1777232024
• DOI: https://doi.org/10.1523/JNEUROSCI.1777-23.2024
• Public URL: https://nottingham-repository.worktribe.com/output/38365984
• Publisher URL: https://www.jneurosci.org/content/44/35/e1777232024