Institute for General Kinesiology and Exercise Science, Faculty of Sport Science, University of Leipzig, Leipzig, 04109, Germany.
Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, 04103, Germany.
Sci Rep. 2018 Jun 15;8(1):9178. doi: 10.1038/s41598-018-27471-5.
Mirror Activity (MA) describes involuntarily occurring muscular activity in contralateral homologous limbs during unilateral movements. This phenomenon has not only been reported in patients with neurological disorders (i.e. Mirror Movements) but has also been observed in healthy adults referred to as physiological Mirror Activity (pMA). However, despite recent hypotheses, the underlying neural mechanisms and structural correlates of pMA still remain insufficiently described. We investigated the structural correlates of pMA during isometric contractions of hand muscles with increasing force demands on a whole-brain level by means of voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS). We found significant negative correlations between individual tendencies to display pMA and grey matter volume (GMV) in the right anterior cingulate cortex (ACC) as well as fractional anisotropy (FA) of white matter (WM) tracts of left precuneus (PrC) during left (non-dominant) hand contractions. No significant structural associations for contractions of the right hand were found. Here we extend previously reported functional associations between ACC/PrC and the inhibtion of intrinsically favoured mirror-symmetrical movement tendencies to an underlying structural level. We provide novel evidence that the individual structural state of higher order motor/executive areas upstream of primary/secondary motor areas might contribute to the phenomen of pMA.
镜像活动（MA）描述了在单侧运动中，对侧同源肢体中不自主发生的肌肉活动。这种现象不仅在神经障碍患者中被报道（即镜像运动），也在健康成年人中被观察到，称为生理性镜像活动（pMA）。然而，尽管最近有了假设，但 pMA 的潜在神经机制和结构相关性仍描述不足。我们通过基于体素的形态计量学（VBM）和基于束的空间统计学（TBSS），在全脑水平上，对手部肌肉进行等长收缩，以增加力的要求，研究了 pMA 的结构相关性。我们发现，在进行左手（非优势手）手部收缩时，个人显示 pMA 的倾向与右侧前扣带皮层（ACC）的灰质体积（GMV）以及左侧楔前叶（PrC）的白质（WM）束的各向异性分数（FA）之间存在显著的负相关。而在进行右手收缩时，没有发现显著的结构相关性。在这里，我们将之前报道的 ACC/PrC 与内在偏好镜像对称运动趋势的抑制之间的功能关联扩展到了一个潜在的结构水平。我们提供了新的证据，表明主要/次要运动区上游的更高阶运动/执行区的个体结构状态可能有助于 pMA 的现象。
