Variation of cerebrospinal fluid in specific regions regulates focality in transcranial direct current stimulation.
Variation of cerebrospinal fluid in specific regions regulates focality in transcranial direct current stimulation.
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DOI：
10.3389/fnhum.2022.952602
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发表时间：
2022
影响因子：
2.9
通讯作者：
中科院分区：
文献类型：
--
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传统上，经颅直流电刺激（tDCS）旨在将到达目标感兴趣区域（ROI）的电流集中。聚焦可通过剂量-靶-测定指数（DTDI）进行量化。尽管有统一的tDCS设置，一些人接受焦点刺激（高DTDI），而另一些人表现出焦性降低（“非焦性”）。每个ROI下方的脑脊液（CSF）、灰质（GM）和白质（WM）的体积控制脑内tDCS电流分布，从而调节病灶。确定区分重点群体和非重点群体的区域音量参数。300名年龄性别匹配的成年人的t1加权脑图像被分为三个相等的组——(a)青年（20≤× < 40岁），(b)中年（40≤× < 60岁）和(c)老年（60≤× < 80岁）。在每一组中，分别模拟(1)F3和右眶上区（F3- rso）以及(2)CP5和Cz （CP5-Cz）电极的半球间和半球内蒙太奇，分别针对左背外侧前额叶皮层（DLPFC）和顶叶下叶（IPL）。模拟两种电流剂量（1和2 mA）的蒙太奇。对于模拟tDCS配置（蒙太奇和剂量）的每个个体头部，计算每个感兴趣区域（ROI）的电流密度及其DTDI。将个体分为(1)病灶型（DTDI≥0.75）和(2)非病灶型（DTDI < 0.75）两组。测定所有roi的CSF、GM和WM的区域体积。对于每个tDCS配置和ROI，进行了三个3-way方差分析，考虑(i) GM, (ii) WM和（iii） CSF作为因变量（DV）。年龄、性别、焦点组为受试者间因素。对于给定的ROI，如果3个DV中的任何一个显示出涉及焦点组的重要主效应或交互作用，则该ROI被归类为“焦点ROI”。区域性脑脊液是病灶的主要决定因素。对于F3-RSO蒙太奇，年龄与病灶在左尾状核有交互作用（p < 0.05），病灶组脑脊液体积较大。病灶性ROI的CSF体积与目标ROI （DLPFC）电流密度呈正相关（r ~ 0.16, p < 0.05）。对于半球内CP5-Cz蒙太奇，在左侧中央前回和中央后回观察到显著（p < 0.05）的主要影响，焦点组显示脑脊液体积较小。脑脊液体积与左IPL电流密度呈负相关（r ~ -0.16, p < 0.05）。目前两种剂量的结果是一致的。脑脊液引导tDCS电流在电极之间流动，聚焦roi就像电流的储存器。焦点ROI在通道中的位置决定了目标ROI处的刺激强度。对于半球间F3-RSO的病灶刺激，病灶感兴趣区域的邻近保留了目标感兴趣区域的电流密度（DLPFC）。相比之下，对于半球内蒙太奇（CP5-Cz），焦点ROI的远端位置降低了目标处的电流密度（IPL）。
Conventionally, transcranial direct current stimulation (tDCS) aims to focalize the current reaching the target region-of-interest (ROI). The focality can be quantified by the dose-target-determination-index (DTDI). Despite having a uniform tDCS setup, some individuals receive focal stimulation (high DTDI) while others show reduced focality (“non-focal”). The volume of cerebrospinal fluid (CSF), gray matter (GM), and white matter (WM) underlying each ROI govern the tDCS current distribution inside the brain, thereby regulating focality. To determine the regional volume parameters that differentiate the focal and non-focal groups. T1-weighted images of the brain from 300 age-sex matched adults were divided into three equal groups- (a) Young (20 ≤ × < 40 years), (b) Middle (40 ≤ × < 60 years), and (c) Older (60 ≤ × < 80 years). For each group, inter and intra-hemispheric montages with electrodes at (1) F3 and right supraorbital region (F3-RSO), and (2) CP5 and Cz (CP5-Cz) were simulated, targeting the left- Dorsolateral Prefrontal Cortex (DLPFC) and -Inferior Parietal Lobule (IPL), respectively. Both montages were simulated for two current doses (1 and 2 mA). For each individual head simulated for a tDCS configuration (montage and dose), the current density at each region-of-interest (ROI) and their DTDI were calculated. The individuals were categorized into two groups- (1) Focal (DTDI ≥ 0.75), and (2) Non-focal (DTDI < 0.75). The regional volume of CSF, GM, and WM of all the ROIs was determined. For each tDCS configuration and ROI, three 3-way analysis of variance was performed considering- (i) GM, (ii) WM, and (iii) CSF as the dependent variable (DV). The age group, sex, and focality group were the between-subject factors. For a given ROI, if any of the 3 DV’s showed a significant main effect or interaction involving the focality group, then that ROI was classified as a “focal ROI.” Regional CSF was the principal determinant of focality. For interhemispheric F3-RSO montage, interaction effect (p < 0.05) of age and focality was observed at Left Caudate Nucleus, with the focal group exhibiting higher CSF volume. The CSF volume of focal ROI correlated positively (r ∼ 0.16, p < 0.05) with the current density at the target ROI (DLPFC). For intrahemispheric CP5-Cz montage, a significant (p < 0.05) main effect was observed at the left pre- and post-central gyrus, with the focal group showing lower CSF volume. The CSF volume correlated negatively (r ∼ –0.16, p < 0.05) with current density at left IPL. The results were consistent for both current doses. The CSF channels the flow of tDCS current between electrodes with focal ROIs acting like reservoirs of current. The position of focal ROI in the channel determines the stimulation intensity at the target ROI. For focal stimulation in interhemispheric F3-RSO, the proximity of focal ROI reserves the current density at the target ROI (DLPFC). In contrast, for intrahemispheric montage (CP5-Cz), the far-end location of focal ROI reduces the current density at the target (IPL).
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影响因子：
1.3
作者：
COLLINS, DL;NEELIN, P;EVANS, AC
通讯作者：
EVANS, AC
影响因子：
7.7
作者：
Brunoni, Andre Russowsky;Nitsche, Michael A.;Bolognini, Nadia;Bikson, Marom;Wagner, Tim;Merabet, Lotfi;Edwards, Dylan J.;Valero-Cabre, Antoni;Rotenberg, Alexander;Pascual-Leone, Alvaro;Ferrucci, Roberta;Priori, Alberto;Boggio, Paulo Sergio;Fregni, Felipe
通讯作者：
Fregni, Felipe
影响因子：
3.2
作者：
Astrom, Mattias;Lemaire, Jean-Jacques;Wardell, Karin
通讯作者：
Wardell, Karin
影响因子：
4.8
作者：
Cabral-Calderin, Yuranny;Weinrich, Christiane Anne;Schmidt-Samoa, Carsten;Poland, Eva;Dechent, Peter;Baehr, Mathias;Wilke, Melanie
通讯作者：
Wilke, Melanie
影响因子：
2.7
作者：
Akhtari, M;Bryant, HC;Sutherling, WW
通讯作者：
Sutherling, WW