Background

Functional imaging studies have associated dystonia with abnormal activation in motor and sensory brain regions. Commonly used techniques such as functional magnetic resonance imaging impose physical constraints, limiting the experimental paradigms. Functional near-infrared spectroscopy (fNIRS) offers a new noninvasive possibility for investigating cortical areas and the neural correlates of complex motor behaviors in unconstrained settings.

Methods

We compared the cortical brain activation of patients with focal upper-limb dystonia and controls during the writing task under naturalistic conditions using fNIRS. The primary motor cortex (M1), the primary somatosensory cortex (S1), and the supplementary motor area were chosen as regions of interest (ROIs) to assess differences in changes in both oxyhemoglobin (oxy-Hb) and deoxyhemoglobin (deoxy-Hb) between groups.

Results

Group average activation maps revealed an expected pattern of contralateral recruitment of motor and somatosensory cortices in the control group and a more bilateral pattern of activation in the dystonia group. Between-group comparisons focused on specific ROIs revealed an increased activation of the contralateral M1 and S1 cortices and also of the ipsilateral M1 cortex in patients.

Conclusions

Overactivity of contralateral M1 and S1 in dystonia suggest a reduced specificity of the task-related cortical areas, whereas ipsilateral activation possibly indicates a primary disorder of the motor cortex or an endophenotypic pattern. To our knowledge, this is the first study using fNIRS to assess cortical activity in dystonia during the writing task under natural settings, outlining the potential of this technique for monitoring sensory and motor retraining in dystonia rehabilitation.

中文翻译：

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局灶性上肢肌张力障碍书写过程中的运动皮层激活：一项 fNIRS 研究

背景

功能成像研究表明，肌张力障碍与运动和感觉大脑区域的异常激活有关。功能性磁共振成像等常用技术会施加物理限制，从而限制了实验范式。功能性近红外光谱 (fNIRS) 为研究皮层区域和不受约束的环境中复杂运动行为的神经相关性提供了一种新的非侵入性可能性。

方法

我们使用 fNIRS 在自然条件下比较了局灶性上肢肌张力障碍患者和对照组在写作任务期间的皮质脑激活。初级运动皮层 (M1)、初级躯体感觉皮层 (S1) 和辅助运动区被选为感兴趣区域 (ROI)，以评估氧合血红蛋白 (oxy-Hb) 和脱氧血红蛋白 (deoxy-Hb) 变化的差异组之间。

结果

组平均激活图显示了对照组中运动和躯体感觉皮层对侧募集的预期模式和肌张力障碍组中更双边的激活模式。以特定 ROI 为重点的组间比较显示，患者对侧 M1 和 S1 皮质以及同侧 M1 皮质的激活增加。

结论

肌张力障碍中对侧 M1 和 S1 的过度活动表明任务相关皮层区域的特异性降低，而同侧激活可能表明运动皮层的原发性疾病或内表型模式。据我们所知，这是第一项使用 fNIRS 在自然环境下评估写作任务期间肌张力障碍患者的皮质活动的研究，概述了该技术在监测肌张力障碍康复中感觉和运动再训练的潜力。