Rjosk Viola, Lepsien Jöran, Kaminski Elisabeth, Hoff Maike, Sehm Bernhard, Steele Christopher J, Villringer Arno, Ragert Patrick
Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany.
Department of Neurology, Max Planck Institute for Human Cognitive and Brain SciencesLeipzig, Germany; Cerebral Imaging Centre, Department of Psychiatry, Douglas Mental Health Institute, McGill UniversityMontreal, QC, Canada.
Front Hum Neurosci. 2017 Feb 6;11:54. doi: 10.3389/fnhum.2017.00054. eCollection 2017.
Mirror visual feedback (MVF) is a promising approach to enhance motor performance without training in healthy adults as well as in patients with focal brain lesions. There is preliminary evidence that a functional modulation within and between primary motor cortices as assessed with transcranial magnetic stimulation (TMS) might be one candidate mechanism mediating the observed behavioral effects. Recently, studies using task-based functional magnetic resonance imaging (fMRI) have indicated that MVF-induced functional changes might not be restricted to the primary motor cortex (M1) but also include higher order regions responsible for perceptual-motor coordination and visual attention. However, aside from these instantaneous task-induced brain changes, little is known about learning-related neuroplasticity induced by MVF. Thus, in the present study, we assessed MVF-induced functional network plasticity with resting-state fMRI (rs-fMRI). We performed rs-fMRI of 35 right-handed, healthy adults before and after performing a complex ball-rotation task. The primary outcome measure was the performance improvement of the untrained left hand (LH) before and after right hand (RH) training with MVF (mirror group [MG], = 17) or without MVF (control group [CG], = 18). Behaviorally, the MG showed superior performance improvements of the untrained LH. In resting-state functional connectivity (rs-FC), an interaction analysis between groups showed changes in left visual cortex (V1, V2) revealing an increase of centrality in the MG. Within group comparisons showed further functional alterations in bilateral primary sensorimotor cortex (SM1), left V4 and left anterior intraparietal sulcus (aIP) in the MG, only. Importantly, a correlation analysis revealed a linear positive relationship between MVF-induced improvements of the untrained LH and functional alterations in left SM1. Our results suggest that MVF-induced performance improvements are associated with functional learning-related brain plasticity and have identified additional target regions for non-invasive brain stimulation techniques, a finding of potential interest for neurorehabilitation.
镜像视觉反馈（MVF）是一种很有前景的方法，可在不进行训练的情况下提高健康成年人以及局灶性脑损伤患者的运动表现。有初步证据表明，经颅磁刺激（TMS）评估的初级运动皮层内部及之间的功能调制可能是介导观察到的行为效应的一种潜在机制。最近，使用基于任务的功能磁共振成像（fMRI）的研究表明，MVF诱导的功能变化可能不仅限于初级运动皮层（M1），还包括负责感知运动协调和视觉注意力的高阶区域。然而，除了这些即时任务诱导的大脑变化外，关于MVF诱导的与学习相关的神经可塑性知之甚少。因此，在本研究中，我们使用静息态fMRI（rs-fMRI）评估了MVF诱导的功能网络可塑性。我们对35名右利手健康成年人在执行复杂的球旋转任务前后进行了rs-fMRI。主要结局指标是在使用MVF（镜像组[MG]，n = 17）或不使用MVF（对照组[CG]，n = 18）对右手（RH）进行训练前后，未训练的左手（LH）的表现改善情况。在行为上，MG组未训练的LH表现出更好的改善。在静息态功能连接（rs-FC）方面，组间交互分析显示左视觉皮层（V1、V2）发生变化，表明MG组的中心性增加。组内比较仅显示MG组双侧初级感觉运动皮层（SM1）、左V4和左前顶内沟（aIP）有进一步的功能改变。重要的是，相关性分析显示MVF诱导的未训练LH的改善与左SM1的功能改变之间存在线性正相关。我们的结果表明，MVF诱导的表现改善与与学习相关的功能性脑可塑性有关，并确定了非侵入性脑刺激技术的额外目标区域，这一发现对神经康复具有潜在意义。
