Central mechanisms underlying postural and volitional control of trunk muscles

躯干肌肉姿势和意志控制的中心机制

• 批准号: RGPIN-2019-06529
• 负责人: MasséAlarie, Hugo
• 金额: $ 2.04万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=738956
• 关键词: Central; mechanisms; underlying; postural; volitional

The aim of this research program is to better understand the role of different cortical motor areas in the control of trunk muscles. In the planned experiments, the function of cortical motor areas will be tested using cervicomedullary and transcranial magnetic stimulation (CMS/TMS). Over the next 5 years, three short-term objectives will be pursued: Objective 1: Determine the contribution of the corticospinal tract to the motor evoked potential (MEP) of the trunk muscles. Multiple pathways and levels of the central nervous system (e.g. spinal, cortical) contribute to the control of trunk muscles. CMS in combination with TMS might be used to assess the contribution of the corticospinal tract to the MEP using collision paradigm. Our hypothesis is that CMS will occlude the TMS evoked responses when timed adequately suggesting a contribution of the corticospinal tract to the MEP of trunk muscles. However, smaller occlusion of what was shown for distal muscles is possible considering that other descending pathways might contribute. Objective 2: Determine the corticospinal contribution of the supplementary motor area (SMA) and primary motor cortex (M1) in preparation of a postural and volitional task. M1 and SMA both contribute to motor control but their role might be different. SMA has been suggested to be involved in the control of postural adjustment and to project to the spinal cord through the corticospinal tract. Since trunk muscles massively contribute to postural control, SMA might influence trunk control through the corticospinal tract. Our hypothesis is that TMS over SMA will elicit larger MEP during postural task whereas TMS over M1 will produce larger MEP during volitional task. Cortical networks (rather than spinal) will drive the MEP modulation. Objective 3: Determine the contribution of SMA and M1 in the performance of a postural and volitional task. Several brain regions are involved in motor control. Repetitive TMS (rTMS) may be used to `virtually' lesion a specific area to disrupt transiently its excitability / normal functioning and assess its contribution to a specific function. This technique has been used to provide the first evidence of SMA contribution to postural adjustment. Indeed, a `virtual' lesion of the SMA using low-frequency rTMS reduced the duration of the postural adjustment during gait initiation. However, it is not known whether altering the function of M1 or SMA will influence differently the performance of a volitional or postural task. Our hypothesis is that SMA `lesion' will impact on the performance of the postural task whereas M1 `lesion' will impact on the performance of the volitional task. The effects will be mainly mediated through a change in cortical networks. Impact: Thanks to an integrated and systematic methodology, this research program will make important discoveries on the neural control of human trunk muscles in postural and volitional conditions.

该研究计划的目的是更好地了解不同皮质运动区域在躯干肌肉控制中的作用。在计划的实验中，将使用颈髓和经颅磁刺激（CMS/TMS）来测试皮质运动区的功能。在接下来的 5 年里，我们将追求三个短期目标： 目标 1：确定皮质脊髓束对躯干肌肉运动诱发电位 (MEP) 的贡献。中枢神经系统（例如脊髓、皮质）的多种途径和水平有助于躯干肌肉的控制。 CMS 与 TMS 相结合可用于使用碰撞范式评估皮质脊髓束对 MEP 的贡献。我们的假设是，当时间足够时，CMS 会阻塞 TMS 诱发的反应，这表明皮质脊髓束对躯干肌肉的 MEP 有所贡献。然而，考虑到其他下行路径可能有所贡献，远端肌肉的较小闭塞是可能的。目标 2：确定辅助运动区 (SMA) 和初级运动皮层 (M1) 在准备姿势和意志任务时对皮质脊髓的贡献。 M1 和 SMA 都有助于运动控制，但它们的作用可能不同。 SMA 被认为参与姿势调整的控制并通过皮质脊髓束投射到脊髓。由于躯干肌肉对姿势控制有很大贡献，SMA 可能通过皮质脊髓束影响躯干控制。我们的假设是，在姿势任务期间，相对于 SMA 的 TMS 会产生更大的 MEP，而相对于 M1 的 TMS 会在意志任务期间产生更大的 MEP。皮质网络（而不是脊髓）将驱动 MEP 调制。目标 3：确定 SMA 和 M1 在执行姿势和意志任务中的贡献。多个大脑区域参与运动控制。重复 TMS (rTMS) 可用于“虚拟”损伤特定区域，以暂时破坏其兴奋性/正常功能，并评估其对特定功能的贡献。该技术已被用来提供 SMA 对姿势调整贡献的第一个证据。事实上，使用低频 rTMS 对 SMA 进行“虚拟”损伤减少了步态启动过程中姿势调整的持续时间。然而，尚不清楚改变 M1 或 SMA 的功能是否会对意志或姿势任务的表现产生不同的影响。我们的假设是 SMA“损伤”将影响姿势任务的表现，而 M1“损伤”将影响意志任务的表现。这些影响主要通过皮质网络的变化来调节。影响：由于采用了综合和系统的方法，该研究项目将在姿势和意志条件下人体躯干肌肉的神经控制方面取得重要发现。