共查询到20条相似文献，搜索用时 15 毫秒
1.
F. Fregni I.C. Macedo L.N. Spezia-Adachi V.L. Scarabelot G. Laste A. Souza Paulo Roberto Stefani Sanches W. Caumo I.L.S. Torres 《Brain stimulation》2018,11(2):299-301
Background
Chronic stress (CS) is associated with a decrease in pain threshold caused by the changes in neural pain circuits. It can be associated to glucocorticoid imbalance with alterations in neural circuitry. Inhibition of stress-induced pain-related neural changes by using techniques that safely induce neuroplasticity such as transcranial direct current stimulation (tDCS) may prevent hyperalgesia triggered by CS.Objective
This study aimed to verify the effect of tDCS performed prior to CS exposure on nociceptive response.Methods
Thirty-two rats were distributed in the following groups: control; stress; sham-tDCS + stress; and tDCS + stress. Bicephalic active tDCS was performed for 8 consecutive days before the CS exposure. The pain threshold was evaluated using a hot plate and tail flick latency (TFL) tests.Results
The tDCS exposure increased the pain threshold on stressed rats.Conclusion
The data obtained indicate that the treatment with bicephalic active tDCS before chronic stress exposure prevents stress-induced hyperalgesia. 相似文献2.
Vishal Rawji Matteo Ciocca André Zacharia David Soares Dennis Truong Marom Bikson John Rothwell Sven Bestmann 《Brain stimulation》2018,11(2):289-298
Background
Measurements and models of current flow in the brain during transcranial Direct Current Stimulation (tDCS) indicate stimulation of regions in-between electrodes. Moreover, the folded cortex results in local fluctuations in current flow intensity and direction, and animal studies suggest current flow direction relative to cortical columns determines response to tDCS.Methods
Here we test this idea by using Transcranial Magnetic Stimulation Motor Evoked Potentials (TMS-MEP) to measure changes in corticospinal excitability following tDCS applied with electrodes aligned orthogonal (across) or parallel to M1 in the central sulcus.Results
Current flow models predicted that the orthogonal electrode montage produces consistently oriented current across the hand region of M1 that flows along cortical columns, while the parallel electrode montage produces non-uniform current directions across the M1 cortical surface. We find that orthogonal, but not parallel, orientated tDCS modulates TMS-MEPs. We also show modulation is sensitive to the orientation of the TMS coil (PA or AP), which is thought to select different afferent pathways to M1.Conclusions
Our results are consistent with tDCS producing directionally specific neuromodulation in brain regions in-between electrodes, but shows nuanced changes in excitability that are presumably current direction relative to column and axon pathway specific. We suggest that the direction of current flow through cortical target regions should be considered for targeting and dose-control of tDCS. 相似文献3.
Stevan Nikolin Christina Huggins Donel Martin Angelo Alonzo Colleen K. Loo 《Brain stimulation》2018,11(2):278-288
Background
Repeated sessions of transcranial direct current stimulation (tDCS) are increasingly used for therapeutic applications. However, adverse events (AEs) associated with repeated sessions have not been comprehensively evaluated.Objective
The aim of this study was therefore to evaluate the safety of repeated sessions of tDCS, examining AE risk relative to tDCS exposure. Further, to identify whether certain participant populations are particularly at risk from tDCS.Methods
A systematic review and meta-analysis included sham-controlled studies (up to June 2017) involving two or more tDCS sessions, spaced not more than a day apart. Data was extracted on AEs reported, total tDCS exposure (cumulative charge), and diagnostic groups (Healthy, Pain Disorder, Stroke, Neurocognitive Disorder, Neuropsychiatric Disorder, and Other). Univariate simple linear meta-regression analyses examined AE likelihood, comparing active and sham tDCS, with increasing exposure. Rates of AEs were compared for diagnostic groups.Results
158 studies (total 4130 participants) met inclusion criteria and were included for quantitative analyses. The incidence of AEs (examined per session, by proportion of participants, and by the number of studies reporting AEs) did not increase with higher levels of tDCS exposure. Furthermore, AE rates were not found to be greater for any diagnostic group.Conclusions
Little evidence was found to suggest that repeated sessions of active tDCS pose increased risk to participants compared to sham tDCS within the limits of parameters used to date. Increased risks associated with greater levels of exposure to tDCS, or rare and under-reported AEs, however, cannot be ruled out. 相似文献4.
Douglas Teixeira Leffa Bruna Bellaver Artur Alban Salvi Carla de Oliveira Wolnei Caumo Eugenio Horacio Grevet Felipe Fregni André Quincozes-Santos Luis Augusto Rohde Iraci L.S. Torres 《Brain stimulation》2018,11(4):743-751
Background
Transcranial direct current stimulation (tDCS) is a technique that modulates neuronal activity and has been proposed as a potential therapeutic tool for attention-deficit/hyperactivity disorder (ADHD) symptoms. Although pilot studies have shown evidence of efficacy, its mechanism of action remains unclear.Objective/Hypothesis
We evaluated the effects of tDCS on behavioral (working and long-term memory) and neurochemical (oxidative and inflammatory parameters) outcomes related to ADHD pathophysiology. We used the most widely accepted animal model of ADHD: spontaneously hypertensive rats (SHR). The selected behavioral outcomes have been shown to be altered in both ADHD patients and animal models, and were chosen for their relation to the proposed mechanistic action of tDCS.Methods
Adult male SHR and their control, the Wistar Kyoto rats (WKY), were subjected to 20?min of bicephalic tDCS or sham stimulation for 8 consecutive days. Working memory, long-term memory, and neurochemical outcomes were evaluated.Results
TDCS improved long-term memory deficits presented by the SHR. No change in working memory performance was observed. In the hippocampus, tDCS increased both the production of reactive oxygen species in SHR and the levels of the antioxidant molecule glutathione in both strains. TDCS also modulated inflammatory response in the brains of WKY by downregulating pro-inflammatory cytokines.Conclusion
TDCS had significant effects that were specific for strain, type of behavioral and neurochemical outcomes. The long-term memory improvement in the SHR may point to a possible therapeutic role of tDCS in ADHD that does not seem to be mediated by inflammatory markers. Additionally, the anti-inflammatory effects observed in the brain of WKY after tDCS needs to be further explored. 相似文献5.
Background
Transcranial direct current stimulation (tDCS) has been found to improve working memory (WM) performance in healthy participants following a single session. However, results are mixed and the overall effect size is small. Interpretation of these results is confounded by heterogeneous study designs, including differences in tDCS dose (current intensity) and sham conditions used.Aims
We systematically investigated the effect of tDCS dose on working memory using behavioural and neurophysiological outcomes.Methods
In a single-blind parallel group design, 100 participants were randomised across five groups to receive 15?min of bifrontal tDCS at different current intensities (2?mA, 1?mA, and three sham tDCS conditions at 0.034?mA, 0.016?mA, or 0?mA). EEG activity was acquired while participants performed a WM task prior to, during, and following tDCS. Response time, accuracy and an event-related EEG component (P3) were evaluated.Results
We found no significant differences in response time or performance accuracy between current intensities. The P3 amplitude was significantly lower in the 0?mA condition compared to the 0.034?mA, 1?mA and 2?mA tDCS conditions. Changes in WM accuracy were moderately correlated with changes in frontal P3 amplitude (channel Fz) following tDCS compared to baseline levels (r?=?0.34).Conclusions
Working memory was not significantly altered by tDCS, regardless of dose. The P3 amplitude showed that stimulation at 1?mA, 2?mA and a sham condition (0.034?mA) had biological effects, with the largest effect size for 1?mA stimulation. These findings indicate higher sensitivity of neurophysiological outcomes to tDCS and suggests that sham stimulation previously considered inactive may alter neuronal function. 相似文献6.
Colleen K. Loo Mustafa M. Husain William M. McDonald Scott Aaronson John P. O&#x;Reardon Angelo Alonzo Cynthia Shannon Weickert Donel M. Martin Shawn M. McClintock Adith Mohan Sarah H. Lisanby 《Brain stimulation》2018,11(1):125-133
Background
Evidence suggests that transcranial Direct Current Stimulation (tDCS) has antidepressant effects in unipolar depression, but there is limited information for patients with bipolar depression. Additionally, prior research suggests that brain derived neurotrophic factor (BDNF) Val66Met genotype may moderate response to tDCS.Objective
To examine tDCS efficacy in unipolar and bipolar depression and assess if BDNF genotype is associated with antidepressant response to tDCS.Methods
130 participants diagnosed with a major depressive episode were randomized to receive active (2.5 milliamps (mA), 30 min) or sham (0.034 mA and two 60-second current ramps up to 1 and 0.5 mA) tDCS to the left prefrontal cortex, administered in 20 sessions over 4 weeks, in a double-blinded, international multisite study. Mixed effects repeated measures analyses assessed change in mood and neuropsychological scores in participants with at least one post-baseline rating in the unipolar (N = 84) and bipolar (N = 36) samples.Results
Mood improved significantly over the 4-week treatment period in both unipolar (p = 0.001) and bipolar groups (p < 0.001). Among participants with unipolar depression, there were more remitters in the sham treatment group (p = 0.03). There was no difference between active and sham stimulation in the bipolar sample. BDNF genotype was unrelated to antidepressant outcome.Conclusions
Overall, this study found no antidepressant difference between active and sham stimulation for unipolar or bipolar depression. However, the possibility that the low current delivered in the sham tDCS condition was biologically active cannot be discounted. Moreover, BDNF genotype did not moderate antidepressant outcome.7.
Jana Wörsching Frank Padberg Stephan Goerigk Irmgard Heinz Christine Bauer Christian Plewnia Alkomiet Hasan Birgit Ertl-Wagner Daniel Keeser 《Brain stimulation》2018,11(5):998-1007
Background
Transcranial direct current stimulation (tDCS) of the prefrontal cortex (PFC) has been widely applied in cognitive neurosciences and advocated as a therapeutic intervention, e.g. in major depressive disorder. Although several targets and protocols have been suggested, comparative studies of tDCS parameters, particularly electrode montages and their cortical targets, are still lacking.Objective
This study investigated a priori hypotheses on specific effects of prefrontal-tDCS montages by using multimodal functional magnetic resonance imaging (fMRI) in healthy participants.Methods
28 healthy male participants underwent three common active-tDCS montages and sham tDCS in a pseudo-randomized order, comprising a total of 112 tDCS-fMRI sessions. Active tDCS was applied at 2?mA for 20?min. Before and after tDCS, a resting-state fMRI (RS fMRI) was recorded, followed by a task fMRI with a delayed-response working-memory (DWM) task for assessing cognitive control over emotionally negative or neutral distractors.Results
After tDCS with a cathode-F3/anode-F4 montage, RS-fMRI connectivity decreased in a medial part of the left PFC. Also, after the same stimulation condition, regional brain activity during DWM retrieval decreased more in this area after negative than after neutral distraction, and responses to the DWM task were faster, independent of distractor type.Conclusion
The current study does not confirm our a priori hypotheses on direction and localization of polarity-dependent tDCS effects using common bipolar electrode montages over PFC regions, but it provides evidence for montage-specific effects on multimodal neurophysiological and behavioral outcome measures. Systematic research on the actual targets and the respective dose-response relationships of prefrontal tDCS is warranted. 相似文献8.
Niranjan Khadka Helen Borges Adantchede L. Zannou Jongmin Jang Byunggik Kim Kiwon Lee Marom Bikson 《Brain stimulation》2018,11(5):1044-1053
Background
The adoption of transcranial Direct Current Stimulation (tDCS) is encouraged by portability and ease-of-use. However, the preparation of tDCS electrodes remains the most cumbersome and error-prone step. Here, we validate the performance of the first “dry” electrodes for tDCS. A “dry electrode” excludes 1) any saline or other electrolytes, that are prone to spread and leaving a residue; 2) any adhesive at the skin interface; or 3) any electrode preparation steps except the connection to the stimulator. The Multilayer Hydrogel Composite (MHC) dry-electrode design satisfied these criteria.Objective/Hypothesis
Over an exposed scalp (supraorbital (SO) regions of forehead), we validated the performance of the first “dry” electrode for tDCS against the state-of-the-art conventional wet sponge-electrode to test the hypothesis that whether tDCS can be applied with a dry electrode with comparable tolerability as conventional “wet” techniques?Methods
MHC dry-electrode performance was verified using a skin-phantom, including mapping voltage at the phantom surface and mapping current inside the electrode using a novel biocompatible flexible printed circuit board current sensor matrix (fPCB-CSM). MHC dry-electrode performance was validated in a human trial including tolerability (VAS and adverse events), skin redness (erythema), and electrode current mapping with the fPCB-CSM. Experimental data from skin-phantom stimulation were compared against a finite element method (FEM) model.Results
Under the tested conditions (1.5?mA and 2?mA tDCS for 20?min using MHC-dry and sponge-electrode), the tolerability was improved, and the erythema and adverse-events were comparable between the MHC dry-electrode and the state-of-the-art sponge electrodes.Conclusion
Dry (residue-free, non-spreading, non-adhesive, and no-preparation-needed) electrodes can be tolerated under the tested tDCS conditions, and possibly more broadly used in non-invasive electrical stimulation. 相似文献9.
Rosa Manenti Maria Sofia Cotelli Chiara Cobelli Elena Gobbi Michela Brambilla Danila Rusich Antonella Alberici Alessandro Padovani Barbara Borroni Maria Cotelli 《Brain stimulation》2018,11(6):1251-1262
Background
A number of non-motor symptoms occurs in Parkinson Disease (PD), cognitive decline and mood disturbances representing the most prevalent.Recent studies reported that cognitive training could potentially help to attenuate cognitive deficits in patients with PD and several researches demonstrated a beneficial effect of active transcranial Direct Current Stimulation (tDCS) over the left dorsolateral prefrontal cortex (anode over left dorsolateral prefrontal cortex, cathode over right supraorbital area) on cognitive deficits and mood disturbances.Objective
To investigate the effects of active tDCS combined with computerized cognitive training on cognition and mood disturbances in PD patients.Methods
Twenty-two patients with PD were assigned to either active tDCS plus computerized cognitive training (CCT) or sham tDCS plus CCT groups. Each patient underwent two weeks' treatment of daily application of tDCS for 25?minutes during CCT focalized on functions related with prefrontal cortex. Each patient was evaluated at baseline, after treatment and at 3-month follow-up.Results
A significant reduction of depressive symptoms was observed in the active tDCS group from baseline to post-treatment assessment and from baseline to 3-month follow-up. An improvement in cognitive performances, referring more specifically to language, attentional and executive functions, was observed in both groups post-treatment and at follow-up. However, phonemic verbal fluency showed significant greater changes from baseline in the active tDCS group.Conclusions
We concluded that cognitive training along with active tDCS is a useful combined approach in the management of mood and cognitive dysfunctions in PD. 相似文献10.
Background
There has been increased interest in the potential use of transcranial direct current stimulation (tDCS) as treatment for multiple conditions including depression, pain, and cognitive impairment. However, few studies account for the possible influence of comorbid medications when conducting tDCS research.Objective/Hypothesis
This literature review was conducted to examine what is currently known about the impact of medications on tDCS, provide recommendations for future research practices, and highlight areas where more research is needed.Methods
Key terms were searched in PubMed and Web of Science to identify studies that examine the impact of medication on tDCS effects in adults. Relevant papers' reference lists were also reviewed for thoroughness. Studies examined the effects of medication on 1 mA tDCS delivered to M1 (motor) and orbit/supraorbital (SO) area. All studies measured the effects of tDCS via MEP TMS paradigm.Results
Results of the literature review suggest multiple classes of medications, including sodium and calcium channel blockers, and medications that influence various neurotransmitter systems (GABA, dopamine, serotonin, etc.) may all impact tDCS effects on tissue excitability.Conclusions
Research to date suggests multiple classes of medications may impact tDCS effects. These results highlight the importance of documenting medication use in research subjects and carefully considering what types of medications should be allowed into tDCS trials. Many questions still remain regarding the exact mechanisms of action for tDCS and how various parameters (medication dosages, tDCS stimulation intensity, etc.) may further impact the effects of medications on tDCS. 相似文献11.
Casey S. Gilmore Patricia J. Dickmann Brent G. Nelson Greg J. Lamberty Kelvin O. Lim 《Brain stimulation》2018,11(2):302-309
Background
Impulsivity is a multidimensional personality trait observed across a variety of psychiatric disorders. Transcranial direct current stimulation (tDCS) applied over dorsolateral prefrontal cortex (DLPFC) has shown promise as an intervention to reduce impulsivity.Objective
To investigate the effects of tDCS paired with a decision-making task on risk-taking in Veterans with a clinical history of impulsive behavior.Methods
This was a randomized, single-blind, sham-controlled study. Participants performed the Balloon Analogue Risk Task (BART) while concurrently receiving either active or sham tDCS (right anodal/left cathodal over DLPFC) twice a day for five days. To evaluate generalization, the Risk Task was performed before and after the complete course of intervention. To evaluate durability, the BART and Risk Task were administered again at one and two month follow-up sessions.Results
Thirty Veterans participated: 15 received active tDCS and 15 received sham tDCS. For the trained BART task, individual growth curve analysis (IGC) examining individual variation of the growth rates over time showed no significant variations in individual trajectory changes over time (β = 0.02, p > 0.05). For the untrained Risk Task, IGC showed that the active tDCS group had a significant 46% decrease in risky choice from pre-to post-intervention, which persisted through the one and two month follow-up sessions. The sham tDCS group showed no significant change in risky choice from pre-to post-intervention.Conclusions
tDCS over DLPFC paired with a decision-making task effectively reduced risk-taking behavior in a group of Veterans with clinically-relevant impulsivity. Results suggest that this approach may be an effective neuroplasticity-based intervention for patients affected by impulsivity. 相似文献12.
Julius Fridriksson Jordan Elm Brielle C. Stark Alexandra Basilakos Chris Rorden Souvik Sen Mark S. George Michelle Gottfried Leonardo Bonilha 《Brain stimulation》2018,11(6):1276-1281
Background
Several studies, including a randomized controlled trial by our group, support applying anodal tDCS (A-tDCS) to the left hemisphere during behavioral aphasia treatment to improve outcomes. A clear mechanism explaining A-tDCS's efficacy has not been established, but modulation of neuroplasticity may be involved.Objective/hypothesis
The brain-derived neurotrophic factor (BDNF) gene influences neuroplasticity and may modulate the effects of tDCS. Utilizing data from our recently completed trial, we conducted a planned test of whether aphasia treatment outcome is influenced by interaction between A-tDCS and a single-nucleotide polymorphism of the BDNF gene, rs6265.Methods
Seventy-four individuals with chronic stroke-induced aphasia completed 15 language therapy sessions and were randomized to receive 1?mA A-tDCS or sham tDCS (S-tDCS) to the intact left temporoparietal region for the first 20?min of each session. BDNF genotype was available for 67 participants: 37 participants had the typical val/val genotype. The remaining 30 participants had atypical BDNF genotype (Met allele carriers). The primary outcome factor was improvement in object naming at 1 week after treatment completion. Maintenance of treatment effects was evaluated at 4 and 24 weeks.Results
An interaction was revealed between tDCS condition and genotype for treatment-related naming improvement (F?=?4.97, p?=?0.03). Participants with val/val genotype who received A-tDCS showed greater response to aphasia treatment than val/val participants who received S-tDCS, as well as the Met allele carriers, regardless of tDCS condition.Conclusion
Individuals with the val/val BDNF genotype are more likely to benefit from A-tDCS during aphasia treatment. 相似文献13.
L. Angius A.R. Mauger J. Hopker A. Pascual-Leone E. Santarnecchi S.M. Marcora 《Brain stimulation》2018,11(1):108-117
Background
Transcranial direct current stimulation (tDCS) has been used to enhance endurance performance but its precise mechanisms and effects remain unknown.Objective
To investigate the effect of bilateral tDCS on neuromuscular function and performance during a cycling time to task failure (TTF) test.Methods
Twelve participants in randomized order received a placebo tDCS (SHAM) or real tDCS with two cathodes (CATHODAL) or two anodes (ANODAL) over bilateral motor cortices and the opposite electrode pair over the ipsilateral shoulders. Each session lasted 10 min and current was set at 2 mA. Neuromuscular assessment was performed before and after tDCS and was followed by a cycling time to task failure (TTF) test. Heart rate (HR), ratings of perceived exertion (RPE), leg muscle pain (PAIN) and blood lactate accumulation (ΔB[La?]) in response to the cycling TTF test were measured.Results
Corticospinal excitability increased in the ANODAL condition (P < 0.001) while none of the other neuromuscular parameters showed any change. Neuromuscular parameters did not change in the SHAM and CATHODAL conditions. TTF was significantly longer in the ANODAL (P = 0.003) compared to CATHODAL and SHAM conditions (12.61 ± 4.65 min; 10.61 ± 4.34 min; 10.21 ± 3.47 min respectively), with significantly lower RPE and higher ΔB[La?] (P < 0.001). No differences between conditions were found for HR (P = 0.803) and PAIN during the cycling TTF test (P = 0.305).Conclusion
Our findings demonstrate that tDCS with the anode over both motor cortices using a bilateral extracephalic reference improves endurance performance. 相似文献14.
Pratik Y. Chhatbar Steven A. Kautz Istvan Takacs Nathan C. Rowland Gonzalo J. Revuelta Mark S. George Marom Bikson Wuwei Feng 《Brain stimulation》2018,11(4):727-733
Background
Transcranial direct current stimulation (tDCS) is a promising brain modulation technique for several disease conditions. With this technique, some portion of the current penetrates through the scalp to the cortex and modulates cortical excitability, but a recent human cadaver study questions the amount. This insufficient intracerebral penetration of currents may partially explain the inconsistent and mixed results in tDCS studies to date. Experimental validation of a transcranial alternating current stimulation-generated electric field (EF) in vivo has been performed on the cortical (using electrocorticography, ECoG, electrodes), subcortical (using stereo electroencephalography, SEEG, electrodes) and deeper thalamic/subthalamic levels (using DBS electrodes). However, tDCS-generated EF measurements have never been attempted.Objective
We aimed to demonstrate that tDCS generates biologically relevant EF as deep as the subthalamic level in vivo.Methods
Patients with movement disorders who have implanted deep brain stimulation (DBS) electrodes serve as a natural experimental model for thalamic/subthalamic recordings of tDCS-generated EF. We measured voltage changes from DBS electrodes and body resistance from tDCS electrodes in three subjects while applying direct current to the scalp at 2?mA and 4?mA over two tDCS montages.Results
Voltage changes at the level of deep nuclei changed proportionally with the level of applied current and varied with different tDCS montages.Conclusions
Our findings suggest that scalp-applied tDCS generates biologically relevant EF. Incorporation of these experimental results may improve finite element analysis (FEA)-based models. 相似文献15.
Carina França Daniel Ciampi de Andrade Manoel Jacobsen Teixeira Ricardo Galhardoni Valquiria Silva Egberto Reis Barbosa Rubens Gisbert Cury 《Brain stimulation》2018,11(2):249-260
Background
The cerebellum is involved in the pathophysiology of many movement disorders and its importance in the field of neuromodulation is growing.Objectives
To review the current evidence for cerebellar modulation in movement disorders and its safety profile.Methods
Eligible studies were identified after a systematic literature review of the effects of cerebellar modulation in cerebellar ataxia, Parkinson's disease (PD), essential tremor (ET), dystonia and progressive supranuclear palsy (PSP). Neuromodulation techniques included transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS) and deep brain stimulation (DBS). The changes in motor scores and the incidence of adverse events after the stimulation were reviewed.Results
Thirty-four studies were included in the systematic review, comprising 431 patients. The evaluation after stimulation ranged from immediately after to 12 months after. Neuromodulation techniques improved cerebellar ataxia due to vascular or degenerative etiologies (TMS, tDCS and DBS), dyskinesias in PD patients (TMS), gross upper limb movement in PD patients (tDCS), tremor in ET (TMS and tDCS), cervical dystonia (TMS and tDCS) and dysarthria in PSP patients (TMS). All the neuromodulation techniques were safe, since only three studies reported the existence of side effects (slight headache after TMS, local skin erythema after tDCS and infectious complication after DBS). Eleven studies did not mention if adverse events occurred.Conclusions
Cerebellar modulation can improve specific symptoms in some movement disorders and is a safe and well-tolerated procedure. Further studies are needed to lay the groundwork for new researches in this promising target. 相似文献16.
Donel M. Martin Shawn M. McClintock Scott T. Aaronson Angelo Alonzo Mustafa M. Husain Sarah H. Lisanby William M. McDonald Adith Mohan Stevan Nikolin John O&#x;Reardon Cynthia Shannon Weickert Colleen K. Loo 《Brain stimulation》2018,11(6):1282-1290
Background
Transcranial direct current stimulation (tDCS) has promising antidepressant effects, however, clinical trials have shown variable efficacy. Pre-treatment neurocognitive functioning has previously been identified as an inter-individual predictor of tDCS antidepressant efficacy.Objective
In this international multicentre, sham-controlled study, we investigated this relationship while also assessing the influence of clinical and genotype (BDNF Val66Met and COMT Val158Met polymorphisms) factors as predictors of response to active tDCS.Methods
The study was a triple-masked, parallel, randomized, controlled design across 6 international academic medical centers. Participants were randomized to active (2.5?mA) or sham (34?μA) tDCS for 30?min each session for 20 sessions. The anode was centered over the left dorsolateral prefrontal cortex at F3 (10/20 EEG system) and the cathode over the lateral right frontal area at F8.Results
Better pre-treatment attentional processing speed on the Ruff 2 & 7 Selective Attention Test (Total Speed: β?=?0.25, p?<?.05) and concurrent antidepressant medication use (β?=?0.31, p?<?.05) predicted antidepressant efficacy with active tDCS. Genotype differences in the BDNF Val66Metand COMT Val158Met polymorphisms were not associated with antidepressant effects. Secondary analyses revealed that only participants in the highest performing Ruff 2 & 7 Total Speed group at pre-treatment in both active and sham tDCS conditions showed significantly greater antidepressant response compared to those with lower performance at both the 2 and 4 week treatment time points (p?<?.05).Conclusions
These results suggest that high pre-treatment attentional processing speed may be relevant for identifying participants more likely to show better tDCS antidepressant response to both high (2.5?mA) and very low (34?μA) current intensity stimulation.17.
Pedro Caldana Gordon Christoph Zrenner Debora Desideri Paolo Belardinelli Brigitte Zrenner André Russowsky Brunoni Ulf Ziemann 《Brain stimulation》2018,11(5):1024-1032
Background
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique with potential for cost-effective therapeutic neuromodulation. Although positive therapeutic effects were found by stimulating the dorsolateral prefrontal cortex (DLPFC), few studies have investigated physiological effects of DLPFC-tDCS.Objectives
To investigate effects of tDCS with different parameter settings applied to the left DLPFC on cortical responses, measured by resting-state electroencephalography (rs-EEG) and transcranial magnetic stimulation (TMS)-evoked/induced EEG responses.Methods
22 healthy subjects underwent 5 tDCS sessions with different tDCS parameter settings in a double-blinded randomized crossover design (1: 1.5?mA, anode left-DLPFC, cathode right-DLPFC; 2: 1.5?mA, cathode left-DLPFC, anode right-DLPFC; 3: 0.5?mA, anode left-DLPFC, cathode right-DLPFC; 4: 1.5?mA, anode left-DLPFC, cathode left deltoid muscle; 5: sham stimulation). Rs-EEG and TMS-EEG were recorded before and after tDCS.Results
Rs-EEG power spectrum analysis showed no difference comparing baseline with post stimulation in any of the tDCS conditions. TMS-EEG evoked potential amplitude decreased in parietal cortex after 1.5?mA left-DLPFC anodal tDCS, and TMS-induced gamma and theta oscillations decreased after all conditions using left-DLPFC anodal tDCS. Left-DLPFC cathodal tDCS did not lead to significant change. None of the post-intervention changes was different when comparing the effects across conditions, including sham.Conclusions
Our study does not provide evidence that a single tDCS session results in significant changes in rs-EEG, using the current stimulation parameters. Significant changes in EEG responses to TMS pulses were observed following the anodal 1.5?mA tDCS interventions, although these changes were not statistically significant in a group comparison. 相似文献18.
Background
High frequency transcranial random noise stimulation (hf-tRNS) facilitates performance in several perceptual and cognitive tasks, however, little is known about the underlying modulatory mechanisms.Objective
In this study we compared the effects of hf-tRNS to those of anodal and cathodal tDCS in a global motion direction discrimination task. An equivalent noise (EN) paradigm was used to assess how hf-tRNS modulates the mechanisms underlying local and global motion processing.Method
Motion coherence threshold and slope of the psychometric function were estimated using an 8AFC task in which observers had to discriminate the motion direction of a random dot kinematogram presented either in the left or right visual hemi-field. During the task hf-tRNS, anodal and cathodal tDCS were delivered over the left hMT+. In a subsequent experiment we implemented an EN paradigm in order to investigate the effects of hf-tRNS on the mechanisms involved in visual motion integration (i.e., internal noise and sampling).Results
hf-tRNS reduced the motion coherence threshold but did not affect the slope of the psychometric function, suggesting no modulation of stimulus discriminability. Anodal and cathodal tDCS did not produce any modulatory effects. EN analysis in the last experiment found that hf-tRNS modulates sampling but not internal noise, suggesting that hf-tRNS modulates the integration of local motion cues.Conclusion
hf-tRNS interacts with the output neurons tuned to directions near to the directional signal, incrementing the signal-to-noise ratio and the pooling of local motion cues and thus increasing the sensitivity for global moving stimuli. 相似文献19.
Mascha van &#x;t Wout-Frank M. Tracie Shea Victoria C. Larson Benjamin D. Greenberg Noah S. Philip 《Brain stimulation》2019,12(1):41-43
Background
Facilitating neural activity using non-invasive brain stimulation may improve extinction-based treatments for posttraumatic stress disorder (PTSD).Objective/hypothesis
Here, we examined the feasibility of simultaneous transcranial direct current stimulation (tDCS) application during virtual reality (VR) to reduce psychophysiological arousal and symptoms in Veterans with PTSD.Methods
Twelve Veterans with PTSD received six combat-related VR exposure sessions during sham-controlled tDCS targeting ventromedial prefrontal cortex. Primary outcome measures were changes in skin conductance-based arousal and self-reported PTSD symptom severity.Results
tDCS + VR components were combined without technical difficulty. We observed a significant interaction between reduction in arousal across sessions and tDCS group (p = .03), indicating that the decrease in physiological arousal was greater in the tDCS + VR versus sham group. We additionally observed a clinically meaningful reduction in PTSD symptom severity.Conclusions
This study demonstrates feasibility of applying tDCS during VR. Preliminary data suggest a reduction in psychophysiological arousal and PTSD symptomatology, supporting future studies. 相似文献20.