经颅直流电刺激调控大脑认知功能的研究进展

经颅直流电刺激是一种非侵入式调节大脑皮层神经元活动的技术,其利用的直流电强度较低且恒定(0.5~2 mA),持续时间一般为5～30 min。近年来,经颅直流电刺激以其成本低、便携性强、调控效果突出等特点,在神经科学和神经病理学等领域得到大量的研究和应用。介绍经颅直流电刺激的生理效应和实施方式,并分别从学习和记忆、注意力、感知、情绪和决策等方面,论述经颅直流电刺激应用于大脑认知功能调控的研究现状和发展趋势。     

经颅直流电刺激治疗时颅内电场数值仿真

明确经颅直流电刺激(tDCS)治疗时颅内电场数值分布,有助于准确控制治疗处方剂量,确保颅内目标区的电场能够高于有效刺激阈值,提高治疗处方对病人治疗的有效性。本文采用商用工具软件COMSOL,完成颅内电场边值问题有限元数值解,计算出了tDCS治疗时颅内电场强度分布,并以图形化显示治疗处方在目标区域电场剂量的有效数值。本文介绍的方法可用于tDCS治疗处方方案优化研究,也可用于分析其它电刺激治疗是否形成有效刺激的电场强度。     

基于经颅电、磁刺激神经调控方法的卒中康复研究进展

肢体运动功能障碍作为卒中后的常见病症,急需有效的康复治疗手段以助其运动功能改善。近年来,诸如经颅电磁刺激等新型神经调控技术通过可逆性地调控神经系统活性,达到改善患者肢体运动功能障碍、增强康复效果的目的。本文在阐述经颅直流电刺激(transcranial direct current stimulation,tDCS)和重复经颅磁刺激(repetitive transcranial magnetic stimulation,rTMS)两种方法的作用机制基础上,对tDCS及rTMS分别在卒中后肢体运动功能康复中的神经可塑性机制、肢体运动功能康复刺激参数的研究、康复手段融合研究进行了回顾与总结,发现tDCS和rTMS均可促进患者大脑运动功能神经重组,与传统、现代技术治疗手段结合均可在运动功能康复方面发挥有效作用。而后归纳了影响二者临床应用的诸如刺激部位、tDCS最佳电流强度和rTMS最优频率等刺激参数设置不一致等问题。最后针对两种调控手段融合方式的探索性研究,展望了未来新型调控方法在临床的应用模式,为今后临床康复中面向肢体运动功能障碍的神经调控技术研究方法的设计、制定与优化提供新的技术思路。     

经颅直流电刺激治疗精神分裂症幻听疗效的meta分析

目的:探讨经颅直流电刺激(tDCS)对精神分裂症幻听的治疗效果。方法:系统检索PubMed、Embase、Cochrane Library、中国期刊全文数据库、万方、维普和中国生物医学文献数据库中关于tDCS治疗精神分裂症幻听相关的随机对照研究,检索时限为1994年1月到2020年12月,使用RevMan5.3软件进行meta分析。结果:最终纳入10项随机对照研究,共439例。Meta分析结果显示,tDCS刺激组对精神分裂症幻听症状的疗效优于对照组(MD:-2.24,95%CI:-3.59～-0.89,P<0.01),并且每天两次tDCS刺激疗效更显著(MD:-2.41,95%CI:-3.78～-1.03,P<0.001);随访分析中tDCS刺激与空白刺激差异无统计学意义(P>0.05);两组各项不良反应的差异均无统计学意义(P>0.05)。结论:tDCS刺激对改善精神分裂症的幻听症状有效,且安全性较高,但远期疗效还有待进一步研究。     

经颅直流电刺激下脑卒中患者脑电功率谱密度研究EI北大核心CSCD

经颅直流电刺激(tDCS)已成为卒中后康复治疗的新手段,并且逐渐被人们所接受。然而,tDCS治疗脑卒中的神经生理机制仍需进一步探讨。本文纳入了30例大脑左侧受损的脑卒中患者,随机分为tDCS真刺激组(15例)和tDCS伪刺激组(15例)。采集两组受试者刺激前、后的静息态脑电(EEG)信号,分析对比刺激前、后EEG信号δ、θ、α和β频带的功率谱密度差异,并计算了δ/α功率比值(DAR)。结果发现,真刺激后δ频带能量在左颞叶区明显降低,差异具有统计学意义(P <0.05);α频带能量在枕叶区明显增强,差异具有统计学意义(P <0.05);θ和β频带能量在整个脑区的差异不具有统计学意义(P> 0.05)。伪刺激前、后δ、θ、α和β频带能量在整个脑区的差异不具有统计学意义(P> 0.05)。另一方面,真刺激后脑卒中患者的DAR值明显降低,差异具有统计学意义(P <0.05),伪刺激后DAR值差异不具有统计学意义(P> 0.05)。本研究在一定程度上揭示了tDCS治疗脑卒中的神经生理机制。     

经颅刺激对脑功能的调节作用

文章分析经颅刺激技术的发展趋势,为研究者及相关仪器开发者提供参考。首先对3种刺激技术(经颅磁刺激、经颅直流电刺激、经颅超声刺激)在物理指标及生物作用特性等方面进行了横向分析、比较;然后以经颅磁刺激为例,从文献计量学的角度分析了其在神经、精神疾病的应用范围及发展趋势。经颅刺激技术已经被应用于30多种疾病的临床治疗或研究,相关的临床研究文献数量也以稳定的速度持续增长。经颅超声刺激具有更加精确的空间分辨率、与功能性磁共振成像技术兼容性良好等优势,有望成为和经颅磁刺激相媲美的脑功能调节技术。     

经颅直流电刺激干预工作记忆的脑功能网络研究

工作记忆是高级认知功能的重要基础,为探索经颅直流电刺激(tDCS)对工作记忆的影响及具体机制,招募18位被试参加实验,采集被试在伪/阳极/阴极tDCS刺激后三图、四图以及五图记忆负载任务中的行为数据(准确率、反应时长)与脑电信号.首先根据行为数据对工作记忆能力进行评估,再利用不同通道之间脑电信号的相关性,构建各状态下的...     

阳极经颅直流电刺激对脑卒中患者脑功能网络的影响

经颅直流电刺激(tDCS)在脑卒中治疗中应用潜力巨大,但其作用效应仍不明确。本研究基于脑电图(EEG)和图论分析探讨阳极tDCS干预对脑卒中患者的作用效应。对15例脑卒中患者施加阳极tDCS真刺激和伪刺激,以随机顺序间隔一周进行两次刺激,每次采集刺激前和刺激后静息态EEG信号。对每次采集的EEG信号,采用皮尔逊相关系数等分析方法研究各个导联间的关联性特征参数。基于分析结果,构建患者刺激前、后的脑功能网络,并分析网络特征参数的变化。结果显示,真刺激后脑功能网络的平均度、平均聚类系数、全局效率以及“小世界”属性值较刺激前均显著增大(P<0.05),特征路径长度显著减小(P<0.05),而伪刺激组相关参数变化未见显著差异(P>0.05)。结果表明,阳极tDCS干预对卒中后恢复性治疗具有积极影响,为其临床应用提供了实验依据。     

经颅直流电刺激对下肢耐力表现影响的系统综述

下肢疲劳是影响运动表现的重要因素之一,如何提升下肢在耐力运动过程中的抗疲劳能力是人体运动生物力学研究领域的重点。本文对经颅直流电刺激(transcranial direct current stimulation, tDCS)干预下肢耐力表现的相关文献进行系统综述,总结tDCS干预下肢耐力表现的效果,分析影响因素及潜在机制。结果发现：tDCS干预对下肢整体耐力表现有显著影响,对膝关节耐力表现的影响无统一定论,研究人员认为tDCS可提高初级运动皮层兴奋性从而降低辅助运动区激活,在耐力运动中产生更低的主观感觉疲劳分级,但却无法影响耐力运动中肌肉疼痛感知,且各研究中刺激方案不一,可能是部分原因。本研究可为探究tDCS提升耐力表现的中枢机制、针对不同人群制定康复和运动训练方案及开发新型刺激设备以增强人体抗疲劳能力提供理论依据。     

高精度经颅直流电刺激研究热点的可视化分析

背景:近年来,高精度经颅直流电刺激因其非侵入性调控大脑功能的潜在益处而备受关注,但目前仍未有研究对其进行可视化分析。目的:对高精度经颅直流电刺激相关研究进行可视化分析,探索研究现状及热点趋势。方法:从Web of Science(WOS)核心合集数据库中检索2010-01-01/2023-05-06发表的与高精度经颅直流电刺激相关的英文文献,应用VOSviewer软件对纳入文献的来源期刊、国家/地区、作者、机构、被引文献和关键词进行可视化分析并绘制知识图谱,探索该领域的研究现状及热点。结果与结论:①共纳入336篇文献,高精度经颅直流电刺激的发文量逐年增加。其中,美国的发文量最多(141篇),被引次数为4221,中国发文量仅次于美国(70篇),被引次数为401。②《Brain Stimulation》是发文量最多的期刊(28篇),Marom Bikson是发文量最多的作者(37篇),纽约市立大学城市学院是发文量最多的机构(35篇)。③运动皮质、调控、工作记忆、兴奋性及背外侧前额叶是该领域出现频次排名前5的关键词。近5年的热点关键词主要包括注意力缺陷/多动症、脑网络及刺激强度等。④目前,高精度经颅直流电刺激领域的研究文献数量相对较少,但总体呈现上升趋势,这反映出该领域具备较大的研究潜力。预计该领域的研究将持续聚焦于高精度经颅直流电刺激在认知精神类疾病的应用,并基于脑网络进一步揭示其作用于运动皮质及背外侧前额叶等靶点的治疗机制。     

Transcranial direct current stimulation and repetitive transcranial magnetic stimulation in consultation-liaison psychiatry

Patients with clinical diseases often present psychiatric conditions whosepharmacological treatment is hampered due to hazardous interactions with theclinical treatment and/or disease. This is particularly relevant for majordepressive disorder, the most common psychiatric disorder in the generalhospital. In this context, nonpharmacological interventions could be usefultherapies; and, among those, noninvasive brain stimulation (NIBS) might be aninteresting option. The main methods of NIBS are repetitive transcranialmagnetic stimulation (rTMS), which was recently approved as a nonresearchtreatment for some psychiatric conditions, and transcranial direct currentstimulation (tDCS), a technique that is currently limited to research scenariosbut has shown promising results. Therefore, our aim was to review the mainmedical conditions associated with high depression rates, the main obstacles fordepression treatment, and whether these therapies could be a useful interventionfor such conditions. We found that depression is an important and prevalentcomorbidity in a variety of diseases such as epilepsy, stroke, Parkinson''sdisease, myocardial infarction, cancer, and in other conditions such aspregnancy and in patients without enteral access. We found that treatment ofdepression is often suboptimal within the above contexts and that rTMS and tDCStherapies have been insufficiently appraised. We discuss whether rTMS and tDCScould have a significant impact in treating depression that develops within aclinical context, considering its unique characteristics such as the absence ofpharmacological interactions, the use of a nonenteral route, and as anaugmentation therapy for antidepressants.     

Modulating lexical and semantic processing by transcranial direct current stimulation

Here we aim to evaluate the ability of transcranial direct current stimulation (tDCS), which is applied over Wernicke’s area and its right homologue, to influence lexical decisions and semantic priming and establish an involvement for temporo-parietal areas in lexical and semantic processing. Thirty-two subjects (17 women) completed a lexical decision task and a semantic priming task while receiving 20 min of bilateral tDCS stimulation (right anodal/left cathodal or left anodal/right cathodal stimulation) or sham stimulation. We hypothesized that right anodal/left cathodal stimulation over temporo-parietal areas would selectively interrupt the typical lexical processing dominance of the left hemisphere and facilitate mediated priming, while left anodal/right cathodal stimulation would selectively facilitate lexical processing and direct priming. Results showed impaired lexical processing under right anodal/left cathodal stimulation in comparison with sham and left anodal/right cathodal stimulation. Results are discussed in light of previous findings and hemispheric lateralization models.     

一种可实现动物清醒状态下施加经颅直流电刺激的方法

目的:建立一种适用于小型实验动物,特别是啮齿类动物清醒状态下施加经颅直流电刺激(transcranial direct currentstimulation,t DCS)的方法以满足实验室研究的需要。方法:根据实验需要自行设计并制备杯状电极及配套电极-电路连接装置;通过骨水泥和颅钉联合固定的方法将刺激电极固定于目标脑区对应的颅骨表面;连接刺激通路、调节刺激参数,并开始对实验动物施加清醒t DCS刺激,在刺激过程中检测电流和电压变化并观察实验动物的反应;通过与传统金属电极比较证明该方法在长期饲养和多次刺激时的可靠性。结果:成功制备符合实验要求且规格一致的杯状电极与电极-电路连接装置;成功通过骨水泥及颅钉联合固定的方法将刺激电极长期固定于目标脑区对应的颅骨表面;实现动物清醒状态下t DCS刺激,刺激期间电流稳定,动物未出现神经精神行为异常;比较该杯状电极与传统电极发现,为了达到预订刺激电流强度,传统金属电极组需要更高的输出电压(P0.01),并且杯状电极在固定牢固性、刺激电流稳定性和操作简易性等方面明显高于传统金属电极,同时杯状电极重复利用度明显高于金属电极。结论:本方法制备的杯状电极可以满足小型实验动物长期、多次清醒t DCS刺激的需要,与传统金属电极相比具有明显优势。     

Transcranial direct current stimulation modulates motor responses evoked by repetitive transcranial magnetic stimulation

Introduction

Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are non-invasive techniques able to induce changes in corticospinal excitability. In this study, we combined rTMS and tDCS to understand possible interactions between the two techniques, and investigate whether they are polarity dependent.

Materials and methods

Eleven healthy subjects participated in the study. Each patient underwent both anodal and cathodal conditioning tDCS in two separate sessions; brief 5 Hz-rTMS trains were delivered over the primary motor cortex at an intensity of 120% the resting motor threshold (RMT) before tDCS (T0), immediately after (T1) and 10 min after current offset (T2). We then analysed changes induced by cathodal and anodal tDCS on TMS variables.

Results

Our results showed that in both anodal and cathodal sessions, the motor evoked potential (MEP) amplitude increased significantly in size before stimulation (T0). Conversely, after anodal tDCS, the MEP facilitation measured at T1 and T2 was absent, whereas after cathodal tDCS it was preserved.

Conclusions

Our findings provide new direct neurophysiological evidence that tDCS influences primary motor cortex excitability.     

Manipulation of phosphene thresholds by transcranial direct current stimulation in man

Transcranial direct current stimulation (tDCS) can modulate the excitability of the human motor cortex, as revealed by the amplitude of the motor-evoked potentials (MEP). The aim of our study has been to produce localized changes of cerebral excitability of the visual cortex in the intact human by weak anodal and cathodal stimulation. For quantification of current-induced excitability changes, we measured phosphene threshold (PT) using short trains of 5-Hz transcranial magnetic stimulation (TMS) pulses in nine healthy subjects before, immediately after, 10 min, and 20 min after the end of tDCS. PTs are suggested as representative values of visual cortex excitability changes. Reduced PT was detected immediately and 10 min after the end of anodal stimulation, while cathodal stimulation resulted in an opposite effect. Our results show that tDCS elicits a transient, reversible excitability alteration of the visual cortex, thus representing a promising tool for neuroplasticity research. Electronic Publication     

Transcranial direct current stimulation modulates motor responses evoked by repetitive transcranial magnetic stimulation

The Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) may be a core component in the common molecular pathways for drug addiction. Moreover, studies using animal models of drug addiction have demonstrated that changing CaMKII activity or expression influences animals' responses to the drugs of abuse. Here, we explored the roles of CaMKII in the nucleus accumbens (NAc) shell in the extinction and reinstatement of morphine-seeking behavior. Rats were trained to obtain intravenous morphine infusions through poking hole on a fixed-ratio one schedule. Selective CaMKII inhibitor myristoylated autocamtide-2-inhibitory peptide (myr-AIP) was injected into the NAc shell of rats after the acquisition of morphine self-administration (SA) or before the reinstatement test. The results demonstrated that injection of myr-AIP after acquisition of morphine SA did not influence morphine-seeking in the following extinction days and the number of days spent for reaching extinction criterion. However, pretreatment with myr-AIP before the reinstatement test blocked the reinstatement of morphine-seeking behavior induced by morphine-priming. Our results strongly indicate that CaMKII activity in the NAc shell is essential to the relapse to morphine-seeking.     

Anodal transcranial direct current stimulation of prefrontal cortex enhances working memory

Previous studies have claimed that weak transcranial direct current stimulation (tDCS) induces persisting excitability changes in the human motor cortex that can be more pronounced than cortical modulation induced by transcranial magnetic stimulation, but there are no studies that have evaluated the effects of tDCS on working memory. Our aim was to determine whether anodal transcranial direct current stimulation, which enhances brain cortical excitability and activity, would modify performance in a sequential-letter working memory task when administered to the dorsolateral prefrontal cortex (DLPFC). Fifteen subjects underwent a three-back working memory task based on letters. This task was performed during sham and anodal stimulation applied over the left DLPFC. Moreover seven of these subjects performed the same task, but with inverse polarity (cathodal stimulation of the left DLPFC) and anodal stimulation of the primary motor cortex (M1). Our results indicate that only anodal stimulation of the left prefrontal cortex, but not cathodal stimulation of left DLPFC or anodal stimulation of M1, increases the accuracy of the task performance when compared to sham stimulation of the same area. This accuracy enhancement during active stimulation cannot be accounted for by slowed responses, as response times were not changed by stimulation. Our results indicate that left prefrontal anodal stimulation leads to an enhancement of working memory performance. Furthermore, this effect depends on the stimulation polarity and is specific to the site of stimulation. This result may be helpful to develop future interventions aiming at clinical benefits.Felipe Fregni and Paulo S. Boggio contributed equally to this work.     

Increased short latency afferent inhibition after anodal transcranial direct current stimulation

Transcranial direct current stimulation (tDCS), a technique for central neuromodulation, has been recently proposed as possible treatment in several neurological and psychiatric diseases. Although shifts on focal brain excitability have been proposed to explain the clinical effects of tDCS, how tDCS-induced functional changes influence cortical interneurones is still largely unknown. The assessment of short latency afferent inhibition (SLAI) of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS), provides the opportunity to test non-invasively interneuronal cholinergic circuits in the human motor cortex. The aim of the present study was to assess whether anodal tDCS can modulate interneuronal circuits involved in SLAI. Resting motor threshold (RMT), amplitude of unconditioned MEPs and SLAI were assessed in the dominant hemisphere of 12 healthy subjects (aged 21-37) before and after anodal tDCS (primary motor cortex, 13min, 1mA). SLAI was assessed delivering electrical conditioning stimuli to the median nerve at the wrist prior to test TMS given at the interstimulus interval (ISI) of 2ms. Whereas RMT and the amplitude of unconditioned MEPs did not change after anodal tDCS, SLAI significantly increased. In conclusion, anodal tDCS-induced effects depend also on the modulation of cortical interneuronal circuits. The enhancement of cortical cholinergic activity assessed by SLAI could be an important mechanism explaining anodal tDCS action in several pathological conditions.