Differences in high-definition transcranial direct current stimulation over the motor hotspot versus the premotor cortex on motor network excitability
Differences in high-definition transcranial direct current stimulation over the motor hotspot versus the premotor cortex on motor network excitability
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DOI：
10.1038/s41598-019-53985-7
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发表时间：
2019-11-26
影响因子：
4.6
通讯作者：
Liew, Sook-Lei
中科院分区：
文献类型：
--
作者：
Lefebvre, Stephanie;Jann, Kay;Liew, Sook-Lei
经颅直流电刺激（tDCS）放置在运动热点（被认为代表初级运动皮层（M1））调节运动网络兴奋性的有效性是高度可变的。运动前皮质，特别是背侧运动前皮质（PMd），可能是一个有前途的替代目标，以可靠地调节运动兴奋性，因为它影响运动控制跨多个途径，一个独立的M1和一个直接连接到M1。这项双盲、安慰剂对照的初步研究旨在使用高清晰度tDCS（HD-tDCS）与同步功能性磁共振成像（fMRI）来区分兴奋运动区和运动前区。HD-tDCS应用于运动热点或运动前皮质，表现出皮质运动兴奋性变化的高个体间变异性。然而，在运动前皮质的HD-tDCS导致更多的响应者和更大的变化，在当地的fMRI为基础的复杂性比HD-tDCS的运动热点。此外，对单个运动热点解剖位置的分析显示，尽管使用了运动热点的规范定义，但在超过一半的参与者中，运动热点并不位于解剖学M1边界之上。刺激部位的这种异质性可能导致tDCS结果的变异性。总之，这些初步研究结果提供了新的考虑，以提高tDCS的可靠性。
The effectiveness of transcranial direct current stimulation (tDCS) placed over the motor hotspot (thought to represent the primary motor cortex (M1)) to modulate motor network excitability is highly variable. The premotor cortex-particularly the dorsal premotor cortex (PMd)-may be a promising alternative target to reliably modulate motor excitability, as it influences motor control across multiple pathways, one independent of M1 and one with direct connections to M1. This double-blind, placebo-controlled preliminary study aimed to differentially excite motor and premotor regions using high-definition tDCS (HD-tDCS) with concurrent functional magnetic resonance imaging (fMRI). HD-tDCS applied over either the motor hotspot or the premotor cortex demonstrated high inter-individual variability in changes on cortical motor excitability. However, HD-tDCS over the premotor cortex led to a higher number of responders and greater changes in local fMRI-based complexity than HD-tDCS over the motor hotspot. Furthermore, an analysis of individual motor hotspot anatomical locations revealed that, in more than half of the participants, the motor hotspot is not located over anatomical M1 boundaries, despite using a canonical definition of the motor hotspot. This heterogeneity in stimulation site may contribute to the variability of tDCS results. Altogether, these preliminary findings provide new considerations to enhance tDCS reliability.