Abstract
The most prominent characteristic of motor cortex is its activation during movement execution, but it is also active when we simply imagine movements in the absence of actual motor output. Despite decades of behavioural and imaging studies, it is unknown how the specific activity patterns and temporal dynamics in motor cortex during covert motor imagery relate to those during motor execution. Here we recorded intracortical activity from the motor cortex of two people who retain some residual wrist function following incomplete spinal cord injury as they performed both actual and imagined isometric wrist extensions. We found that we could decompose the population activity into three orthogonal subspaces, where one was similarly active during both action and imagery, and the others were active only during a single task type—action or imagery. Although they inhabited orthogonal neural dimensions, the action-unique and imagery-unique subspaces contained a strikingly similar set of dynamic features. Our results suggest that during motor imagery, motor cortex maintains the same overall population dynamics as during execution by reorienting the components related to motor output and/or feedback into a unique, output-null imagery subspace.
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Data availability
Given the potential sensitivity concerns, deidentified data from this study are posted on DABI, a repository for data related to the National Institutes of Health Brain Research Through Advancing Neurotechnologies Initiative. The data for this specific sub-project can be found at https://doi.org/10.18120/70gm-a975 and are available upon request. A portion of the data included in this paper (action conditions only) was used in a previous publication61.
Code availability
The code central to the results presented in this manuscript is publicly available at https://github.com/pitt-rnel/action_imagery.
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Acknowledgements
We thank N. Copeland and Mr. Dom for their continued efforts and commitment to this study. We also thank the research team, especially D. Harrington for regulatory management as well as C. Schoenewald, J. Ting, D. Sarma, A. Sethi and J. Weiss for their help with data collection. The research reported in this publication was supported by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health under award numbers UH3NS107714 and U01NS108922. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
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B.M.D. designed the task and collected the data. B.M.D., R.H.C. and S.M.C. contributed to the analysis. All authors contributed to the interpretation of the results. B.M.D. wrote the manuscript, with input from all authors.
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Dekleva, B.M., Chowdhury, R.H., Batista, A.P. et al. Motor cortex retains and reorients neural dynamics during motor imagery. Nat Hum Behav 8, 729–742 (2024). https://doi.org/10.1038/s41562-023-01804-5
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DOI: https://doi.org/10.1038/s41562-023-01804-5