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Lookup NU author(s): Dr Demetris Soteropoulos
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
During everyday actions there is a need to be able to withhold movements until the most appropriate time. This motor inhibition is likely to rely on multiple cortical and subcortical areas, but the primary motor cortex (M1) is a critical component of this process. However, the mechanisms behind this inhibition are unclear, and in particular the role of the corticospinal system, which is most often associated with driving muscles and movement. In order to address this, recordings were made from identified corticospinal (PTNs, n=94) and corticomotoneuronal (CM, n=16) cells from the primary motor cortex during an instructed delay reach to grasp task. The task involved the animals withholding action for ~2s until a GO cue, after which they were allowed to reach and perform the task for a food reward. Analysis of the firing of cells in M1 during the delay period revealed that as a population, non-CM PTNs showed significant suppression in their activity during the cue and instructed delay periods, while CM cells instead showed a facilitation during the preparatory delay. Analysis of cell activity during movement also revealed that a substantial minority of PTNs (27%) showed suppressed activity during movement, a response pattern more suited to cells involved in withholding rather than driving movement. These results demonstrate the potential contributions of the M1 corticospinal system to withholding of actions and highlight that suppression of activity in M1 during movement preparation is not evenly distributed across different neural populations.
Author(s): Soteropoulos DS
Publication type: Article
Publication status: Published
Journal: Journal of Neurophysiology
Year: 2018
Volume: 119
Issue: 4
Pages: 1538-1555
Print publication date: 01/04/2018
Online publication date: 18/04/2018
Acceptance date: 01/01/2018
Date deposited: 26/02/2018
ISSN (print): 0022-3077
ISSN (electronic): 1522-1598
Publisher: American Physiological Society
URL: https://doi.org/10.1152/jn.00639.2017
DOI: 10.1152/jn.00639.2017
PubMed id: 29357454
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