Left Cathodal Trans-Cranial Direct Current Stimulation of the Parietal Cortex Leads to an Asymmetrical Modulation of the Vestibular-Ocular Reflex
Left Cathodal Trans-Cranial Direct Current Stimulation of the Parietal Cortex Leads to an Asymmetrical Modulation of the Vestibular-Ocular Reflex
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DOI：
10.1016/j.brs.2013.07.002
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发表时间：
2014-01-01
影响因子：
7.7
通讯作者：
Bronstein, Adolfo M.
中科院分区：
文献类型：
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作者：
Arshad, Qadeer;Nigmatullina, Yuliya;Bronstein, Adolfo M.
顶叶内的多感觉视觉前庭皮质区对于空间定向非常重要，并且可能对于前庭眼反射（VOR）的下行调制非常重要。功能成像和病变研究表明，前庭皮质处理主要位于非优势顶叶。然而，前庭处理中半球间顶叶平衡的作用知之甚少。因此，我们测试是否实验诱导的不对称性，右与左顶叶兴奋性调节前庭功能。VOR功能进行了评估，在右利手正常受试者在热量耳冲洗（30摄氏度），之前和之后，经颅直流电刺激（tDCS）施加双侧顶叶皮层。双侧tDCS，阳极在右侧，阴极在左侧顶骨区域，导致VOR的显著不对称调制，在右侧热量灌注期间反应高度抑制（即，缓慢相眼球震颤）。相比之下，我们没有观察到VOR调制过程中，无论是阴极刺激的右顶叶皮层或假tDCS条件。单侧tDCS的应用表明，左阴极刺激在诱导观察到的VOR调制中至关重要。我们发现，顶叶半球间平衡的破坏可以引起前庭功能的不对称。这是第一个报告使用神经调制显示右半球优势的前庭皮质处理。(C)2014作者爱思唯尔公司出版All rights reserved.
Multi-sensory visuo-vestibular cortical areas within the parietal lobe are important for spatial orientation and possibly for descending modulation of the vestibular-ocular reflex (VOR). Functional imaging and lesion studies suggest that vestibular cortical processing is localized primarily in the non-dominant parietal lobe. However, the role of inter-hemispheric parietal balance in vestibular processing is poorly understood. Therefore, we tested whether experimentally induced asymmetries in right versus left parietal excitability would modulate vestibular function. VOR function was assessed in right-handed normal subjects during caloric ear irrigation (30 degrees C), before and after trans-cranial direct current stimulation (tDCS) was applied bilaterally over the parietal cortex. Bilateral tDCS with the anode over the right and the cathode over the left parietal region resulted in significant asymmetrical modulation of the VOR, with highly suppressed responses during the right caloric irrigation (i.e. rightward slow phase nystagmus). In contrast, we observed no VOR modulation during either cathodal stimulation of the right parietal cortex or SHAM tDCS conditions. Application of unilateral tDCS revealed that the left cathodal stimulation was critical in inducing the observed modulation of the VOR. We show that disruption of parietal inter-hemispheric balance can induce asymmetries in vestibular function. This is the first report using neuromodulation to show right hemisphere dominance for vestibular cortical processing. (C) 2014 The Authors. Published by Elsevier Inc. All rights reserved.