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PubMed2004

Transcranial direct current stimulation during sleep improves declarative memory.

In humans, weak transcranial direct current stimulation (tDCS) modulates excitability in the motor, visual, and prefrontal cortex. Periods rich in slow-wave sleep (SWS) not only facilitate the consolidation of declarative memories, but in humans, SWS is also accompanied by a pronounced endogenous transcortical DC potential shift of negative polarity over frontocortical areas. To experimentally induce widespread extracellular negative DC potentials, we applied anodal tDCS (0.26 mA) [correction] repeatedly (over 30 min) bilaterally at frontocortical electrode sites during a retention period rich in SWS. Retention of declarative memories (word pairs) and also nondeclarative memories (mirror tracing skills) learned previously was tested after this period and compared with retention performance after placebo stimulation as well as after retention intervals of wakefulness. Compared with placebo stimulation, anodal tDCS during SWS-rich sleep distinctly increased the retention of word pairs (p < 0.005). When applied during the wake retention interval, tDCS did not affect declarative memory. Procedural memory was also not affected by tDCS. Mood was improved both after tDCS during sleep and during wake intervals. tDCS increased sleep depth toward the end of the stimulation period, whereas the average power in the faster frequency bands (,alpha, and beta) was reduced. Acutely, anodal tDCS increased slow oscillatory activity <3 Hz. We conclude that effects of tDCS involve enhanced generation of slow oscillatory EEG activity considered to facilitate processes of neuronal plasticity. Shifts in extracellular ionic concentration in frontocortical tissue (expressed as negative DC potentials during SWS) may facilitate sleep-dependent consolidation of declarative memories.

Adult↗

PubMed2006

Testing for causality with transcranial direct current stimulation: pitch memory and the left supramarginal gyrus.

Neuroimaging studies have implicated the left supramarginal gyrus in short-term auditory memory processing, including memory for pitch. The present study investigated the causal role of the left supramarginal gyrus in short-term pitch memory by comparing the effects of cathodal transcranial direct current stimulation when applied over the left or right supramarginal gyrus with sham transcranial direct current stimulation. Only cathodal transcranial direct current stimulation over the left supramarginal gyrus had a detrimental effect on short-term pitch-memory performance in 11 adult participants. These results provide support for the important role of the left supramarginal gyrus in short-term memory for pitch information, and they further demonstrate the potential of transcranial direct current stimulation to modulate the functional contribution of a brain area to a particular cognitive process.

Analysis of Variance↗

PubMed2004

Effects of transcranial direct current stimulation over the human motor cortex on corticospinal and transcallosal excitability.

Weak transcranial direct current stimulation (tDCS) can induce long lasting changes in cortical excitability. In the present study we asked whether tDCS applied to the left primary motor cortex (M1) also produces aftereffects distant from the site of the stimulating electrodes. We therefore tested corticospinal excitability in the left and the right M1 and transcallosal excitability between the two cortices using transcranial magnetic stimulation (TMS) before and after applying tDCS. Eight healthy subjects received 10 min of anodal or cathodal tDCS (1 mA) to the left M1. We examined the amplitude of contralateral motor evoked potentials (MEPs) and the onset latency and duration of transcallosal inhibition with single pulse TMS. MEPs evoked from the tDCS stimulated (left) M1 were increased by 32% after anodal and decreased by 27% after cathodal tDCS, while transcallosal inhibition evoked from the left M1 remained unchanged. The effect on MEPs evoked from the left M1 lasted longer for cathodal than for anodal tDCS. MEPs evoked from the right M1 were unchanged whilst the duration of transcallosal inhibition evoked from the right M1 was shortened after cathodal tDCS and prolonged after anodal tDCS. The duration of transcallosal inhibition returned to control values before the effect on the MEPs from the left M1 had recovered. These findings are compatible with the idea that tDCS-induced aftereffects in the cortical motor system are limited to the stimulated hemisphere, and that tDCS not only affects corticospinal circuits involved in producing MEPs but also inhibitory interneurons mediating transcallosal inhibition from the contralateral hemisphere.

Adult↗

PubMed2006

Transcranial direct current stimulation applied over the somatosensory cortex - differential effect on low and high frequency SEPs.

OBJECTIVE: Transcranial direct current stimulation (tDCS) has an influence on the excitability of the human motor cortex measured by motor evoked potentials (MEPs) after transcranial magnetic stimulation. Low and high frequency (HFOs) components of somatosensory evoked potentials (SEPs) were studied questioning whether a comparable effect can be observed after applying tDCS to the human somatosensory cortex. METHODS: Multichannel median nerve SEPs were recorded before and after applying tDCS of 1mA over a period of 9min with the cathode placed over the somatosensory cortex and the anode over the contralateral forehead and vice versa in a second session. The source activity of the N20, N30 and HFOs was evaluated before and after application of tDCS. RESULTS: After cathodal tDCS to the somatosensory cortex we found a significant reduction of the N20 source amplitude while there was no effect after anodal stimulation. For the N30 component and HFOs no change in source activity was observed. CONCLUSIONS: Corresponding to the results for the motor cortex a sustained reduction of the excitability of the somatosensory cortex after cathodal tDCS was shown. SIGNIFICANCE: We demonstrated differential effects of tDCS on the high and low frequency components of SEPs confirming the hypothesis of locally and functionally distinct generators of these two components.

Adult↗

PubMed2026

Remotely Supervised, Home-Based Transcranial Direct Current Stimulation for Major Depressive Disorder: Systematic Review and Meta-Analysis.

BACKGROUND: Major depressive disorder affects over 280 million people worldwide, and access to effective treatment remains limited. Transcranial direct current stimulation (tDCS) is a noninvasive option, and portable devices now allow for home-based delivery under varying degrees of remote supervision. OBJECTIVE: This study aimed to systematically review and meta-analyze the efficacy, safety, feasibility, and acceptability of home-based and remotely supervised tDCS for depressive disorders. METHODS: Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 and PRISMA-S (Preferred Reporting Items for Systematic Reviews and Meta-Analyses literature search extension) guidelines, we searched MEDLINE, Embase, Web of Science, the Cochrane databases, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform up to July 2025, with backward and forward citation searching. Two reviewers independently screened records, extracted data, and assessed risk of bias (version 2 of the Cochrane risk-of-bias tool for randomized trials, Newcastle-Ottawa Scale for observational studies, and Critical Appraisal Skills Programme for qualitative studies) and certainty of evidence (Grading of Recommendations Assessment, Development, and Evaluation; GRADE). RESULTS: This review included 12 distinct studies (16 reports), of which 6 (50%) were randomized sham-controlled trials forming the meta-analytic pool. Active home-based tDCS produced a small, statistically significant improvement over sham (pooled Hedges g=0.36, 95% CI 0.06-0.66; P=.03; I2=34.3%). The effect was not robust to removal of the single largest positive trial (omitting the one study from 2025: g=0.39, 95% CI -0.12 to 0.91), and trial-level results were mixed: the 2 largest trials (one unsupervised [n=210] and one self-administered [n=141]) were negative on their primary depression outcomes, whereas the largest real-time supervised trial (n=174) was positive (between-group 95% CI 0.51-4.01; P=.01). This estimate was concordant in direction with an independent peer-reviewed meta-analysis of overlapping trials, which reported a pooled Montgomery-Åsberg Depression Rating Scale reduction (weighted mean difference -2.74, 95% CI -4.19 to -1.29) and Hamilton Depression Rating Scale reduction (weighted mean difference -2.24, 95% CI -4.16 to -1.49), attenuating to nonsignificance (P>.05) in major depressive disorder without comorbid cognitive impairment. The pooled effect fell at or near the minimal clinically important difference. GRADE certainty was moderate. Adverse events were predominantly mild: one pilot study was terminated early for skin lesions, and one nonfatal suicide attempt occurred in an unsupervised trial. CONCLUSIONS: Home-based and remotely supervised tDCS produces a small, statistically significant but clinically modest antidepressant effect that is sensitive to the inclusion of the largest positive trial, with the 2 largest trials being negative. The available controlled evidence does not establish supervision intensity as a determinant of efficacy. Current data are insufficient to recommend routine clinical adoption; adequately powered trials with standardized supervision and longer follow-up are needed.

Humans↗

PubMed2026

Exercise with motor cortex high-definition transcranial direct current stimulation enhances cardiovascular efficiency and lower-limb function in multiple sclerosis: A crossover, double-blind, and proof-of-principle study.

Combining exercise with high-definition transcranial direct current stimulation (HD-tDCS) could offer a strategy to help people with Multiple Sclerosis improve outcomes. In this crossover study, participants with MS (Expanded Disability Status Scale ≥3.0, n = 12) and controls (n = 10) completed baseline testing, followed by three randomized experimental conditions: 1) exercise+active HD-tDCS; 2) exercise+sham HD-tDCS; and 3) HD-tDCS alone. Exercise performance metrics [heart rate, work rate, heart rate-to-work rate (HR/WR) ratio, and perceived exertion] were compared across the exercise conditions. Secondary outcomes included the Symbol Digit Modalities Test (SDMT), Timed 25-Foot Walk (T25F), Nine-Hole Peg Test (9HPT), and acute symptom ratings (fatigue and pain), assessed pre-, immediately post-, and 1h-Post. Cardiovascular efficiency (HR/WR ratio) significantly improved during exercise+HD-tDCS compared to exercise alone, particularly in older MS participants (p = 0.010). SDMT declined immediately post HD-tDCS alone, 1h-post-exercise alone, and at both time points during exercise+active HD-tDCS (p < 0.05). Both groups increased walking speed only post-exercise+active HD-tDCS, while no condition affected upper-limb function (p < 0.05). These results are in line with the tDCS literature in the general population, suggesting that tDCS improves exercise performance and selectively improves engaged motor function. The trade-off between physical and cognitive outcomes underscores the importance of personalized neuromodulation strategies in neurorehabilitation to maximize therapeutic benefits while minimizing adverse effects, and warrants further large-scale, long-term investigations of this approach in MS.

Humans↗

PubMed2026

Effects of anodal transcranial direct current stimulation over the right primary motor cortex on a sequential motor finger tapping task in developmental stuttering.

INTRODUCTION: This study investigates the impact of anodal transcranial direct current stimulation (tDCS) on non-speech sequential motor practice in adults who stutter (AWS), compared to non-stuttering controls (ANS). Recent research has explored the effects of tDCS on speech fluency in stuttering. However, its effect on non-speech motor tasks has not yet been studied. METHODS: 20 AWS and 30 ANS right-handed participants were randomly assigned to anodal or sham tDCS conditions, performing a sequential finger tapping task. We targeted over the right primary motor cortex, stimulating at 2 mA for 20 min. Sequence duration and reaction time were analyzed. RESULTS: AWS analysis revealed that the anodal condition had significantly slower reaction times in the second half of the task compared to sham. For sequence durations, AWS in the anodal condition had slower overall sequence durations than the sham condition. However, there were no block-by-block differences in sequence duration. When comparing AWS and ANS, no significant differences were observed for sequence duration. However, there were significant differences in reaction time between AWS and ANS, specifically in earlier blocks. Additionally, there was no significant Group × Condition interaction. DISCUSSION: The findings suggest that anodal stimulation impeded finger sequencing in AWS, showing overall slower sequence durations and a diminishing effect on reaction times in the second half of the experiment, suggesting anodal tDCS may interact uniquely with the neural mechanisms in stuttering. Future studies should explore the effects of anodal tDCS on non-speech motor tasks to gain a broader understanding of its impact on motor control and motor learning.

Humans↗

PubMed2026

Dual Transcranial Direct Current Stimulation Modulates Hierarchical Functional Network Organization in Post-Stroke Cognitive Impairment: A Randomized Controlled Trial.

OBJECTIVE: To evaluate the clinical efficacy of dual transcranial direct current stimulation (tDCS) in patients with post-stroke cognitive impairment (PSCI) and to explore the effects on the hierarchical organization of functional brain networks, ranging from regional synchronization to inter-regional connectivity and global network topology. METHODS: In this randomized, double-blind, sham-controlled trial, 74 PSCI patients received conventional therapy alongside either active dual-tDCS (n = 38) or sham stimulation (n = 36). Active tDCS targeted the dorsolateral prefrontal cortex (DLPFC) via anodal-left/cathodal-right nodes (2.0 mA, 20 min/day, 20 sessions). The primary outcome was the Montreal Cognitive Assessment (MoCA). Secondary outcomes included the Mini-Mental Status Examination (MMSE), Stroop Test (ST), Trail Making Test (TMT), Wechsler Memory Scale (WMS), and Barthel Index (BI). A subgroup of 36 participants (18 per group) underwent resting-state functional magnetic resonance imaging (rs-fMRI) to analyze regional homogeneity (ReHo), functional connectivity (FC), and network topology. Partial correlations assessed the association between neuroimaging alterations and clinical improvements. RESULTS: The tDCS group showed significantly greater improvements in MoCA scores (tDCS: 5.74 ± 2.76 vs. sham: 2.69 ± 2.69; t = 4.799, p < 0.001) as well as in attention and memory domains compared to the sham group. The rs-fMRI changes included increased ReHo in the right middle temporal gyrus (MTG) and the left inferior frontal gyrus (IFG), and reduced FC between the right MTG-left superior frontal gyrus and left IFG-cerebellum (p < 0.05, FWE-corrected). Additionally, small-worldness and global efficiency increased (p < 0.05) with these alterations correlating with clinical recovery. Adverse events were rare and self-limiting. CONCLUSION: Dual-tDCS over bilateral DLPFC safely improves cognitive recovery in PSCI. These clinical gains are associated with rs-fMRI alterations, specifically in regional synchronization, inter-regional connectivity, and global topology, which suggest a potential biomarker for monitoring tDCS efficacy, offering a rationale for precision neuromodulation in stroke rehabilitation.

Humans↗

PubMed2001

Regional modulation of BOLD MRI responses to human sensorimotor activation by transcranial direct current stimulation.

Blood oxygenation level dependent (BOLD) MRI was used to monitor modulations of human sensorimotor activity by prior transcranial direct current stimulation (tDCS). Activation maps for a right hand sequential finger opposition task were obtained for six subjects before as well as 0-5 min and 15-20 min after a 5-min period of 1 mA cathodal and, in a separate session, anodal tDCS of the left-hemispheric motor cortex. Cathodal tDCS resulted in a global decrease of the mean number of activated pixels by 38% (P < 0.01) 0-5 min after stimulation, which reduced to 28% (P < 0.05) 15-20 min after stimulation. A region-of-interest analysis revealed a 57% decrease of activated pixels (P < 0.001) in the supplementary motor area, but no change in the hand area of the primary motor cortex. Anodal tDCS yielded a nonsignificant 5% increase of activated pixels with no regional differences. These findings support the view that reduced neuroaxonal excitability after cathodal tDCS causes reduced brain activity. However, rather than affecting the primary sensorimotor input of an active task, the process appears to dampen those responses that rely on cortico-cortical connections and related processing. Magn Reson Med 45:196-201, 2001.

Adult↗

PubMed2006

After-effects of transcranial direct current stimulation (tDCS) on cortical spreading depression.

Abnormal cortical excitability influences susceptibility to cortical spreading depression (CSD) in migraine. Because transcranial direct current stimulation (tDCS) is capable of inducing lasting changes of cortical excitability, we investigated the after-effects of tDCS on the propagation velocity of CSD in the rat. Twenty-five anesthetised rats received either anodal, cathodal or sham tDCS. The stimulation was applied for 20 min at a current strength of 200 microA after the recording of three baseline CSD measurements. Starting 5 min after tDCS, a further three CSDs were elicited and CSD velocity recorded at intervals of 20 min. tDCS and CSD recording was performed under anaesthesia with chloralose and urethane. As compared to the baseline velocity of 3.14 mm/min, anodal tDCS induced a significant increase of propagation velocity during the first post-tDCS recording (3.49 mm/min). In contrast to anodal tDCS, neither cathodal tDCS nor sham tDCS, which consisted of an initial ramped DC stimulation lasting only 20 s, showed a significant effect on CSD propagation velocity. As anodal tDCS is known to induce a lasting increase of cortical excitability in the clinical setting, our results support the notion that CSD propagation velocity reflects cortical excitability. Since cortical excitability and susceptibility to CSD is elevated in migraine patients, anodal tDCS - by increasing cortical excitability - might increase the probability of migraine attack in these patients, even beyond the end of its application.

Animals↗

PubMed2026

Effectiveness of transcranial direct current stimulation with and without positive mood induction on worry and transdiagnostic cognitive-emotional processes: A randomized controlled trial.

The present study investigated the effectiveness of transcranial direct current stimulation (tDCS), with and without positive mood induction, on worry and key transdiagnostic cognitive-emotional processes, including attentional bias, working memory, problem solving, and emotion regulation, in individuals with high levels of worry. This single-blind randomized controlled trial included 45 individuals with high levels of worry. After a structured clinical interview, participants were randomly assigned, with gender balancing, to one of three groups: (1) tDCS alone, (2) tDCS combined with positive mood induction, or (3) a sham control group. Outcome measures were administered at three time points (pretest, posttest, and one-month follow-up) and assessed attentional bias (Dot Probe Task), working memory (1-back task), problem solving (Tower of London task), emotion regulation (Gross's Emotion Regulation Questionnaire), and worry severity (Penn State Worry Questionnaire; PSWQ). Repeated-measures ANOVA showed that both active groups (tDCS alone and tDCS + positive mood induction) significantly improved attentional bias, worry, working memory, problem solving, and emotion regulation compared to controls (p < 0.05). The combined intervention produced significantly greater gains than tDCS alone in working memory, problem solving, emotion regulation (p < 0.05), and reductions in attentional bias and worry (p < 0.001). All effects persisted at one-month follow-up (p < 0.05). tDCS reduces worry and attentional bias and enhances cognition and emotion regulation in individuals with high levels of worry. The combined intervention produced larger and more sustained improvements than tDCS alone across the assessed behavioral outcomes. These findings support further investigation of combining tDCS with structured positive mood induction while the mechanisms underlying the additional benefits remain to be established.

Humans↗

PubMed2003

Facilitation of implicit motor learning by weak transcranial direct current stimulation of the primary motor cortex in the human.

Transcranially applied weak direct currents are capable of modulating motor cortical excitability in the human. Anodal stimulation enhances excitability, cathodal stimulation diminishes it. Cortical excitability changes accompany motor learning. Here we show that weak direct currents are capable of improving implicit motor learning in the human. During performance of a serial reaction time task, the primary motor cortex, premotor, or prefrontal cortices were stimulated contralaterally to the performing hand. Anodal stimulation of the primary motor cortex resulted in increased performance, whereas stimulation of the remaining cortices had no effect. We conclude that the primary motor cortex is involved in the acquisition and early consolidation phase of implicit motor learning.

Analysis of Variance↗

PubMed2026

Effects of Transcranial Direct Current Stimulation and Individualized Physical Therapy on Pain and Function in Individuals With Chronic Knee Pain: A Pilot Study.

BACKGROUND AND PURPOSE: Noninvasive brain stimulation is a promising neuromodulatory intervention for chronic pain. This study aimed to determine the impact that transcranial direct current stimulation (tDCS) in combination with individualized physical therapy (PT) has on pain and function in individuals with chronic knee pain. METHODS: This study was a preliminary pragmatic, triple-blinded, randomized, and sham-controlled clinical trial performed in an outpatient orthopedic physical therapy clinic. Participants participated in 5 sessions of active or sham tDCS followed by individualized PT intervention. Pain outcomes included the Numeric Pain Rating Scale, Movement-Evoked Pain, pressure pain thresholds (PPT), and the Central Sensitization Inventory. Functional outcomes included the 2-minute walk test, 5-time sit-to-stand test, quadriceps strength, knee range of motion, Patient Specific Functional Scale, and the Lower Extremity Functional Scale. RESULTS: Thirty participants with chronic knee pain completed the study. There were no significant differences observed for primary patient-centered pain and functional outcomes. For secondary outcomes, the active tDCS group had a significant effect (p < 0.05) on percent change in lateral joint line PPT and a significant multivariate effect of group on PPT change scores for 3-site and 5-site clusters (p < 0.05). Exploratory responder analyses demonstrated that the active tDCS group was 12.8 times more likely to achieve the minimum detectable change in quadriceps strength improvement compared with the sham tDCS group (p < 0.05). DISCUSSION: There were no significant between-group differences for primary pain and functional outcomes. However, the active tDCS group showed improvements in pain sensitivity, as measured by PPT, and quadriceps strength, which were superior to those seen in the sham tDCS group. These preliminary findings provide insight into possible mechanisms of tDCS in addressing pain as opposed to efficacy. Given that there were no clear between-group differences in patient-centered outcomes, there is insufficient evidence for routine tDCS use for chronic knee pain. TRIAL REGISTRATION: NCT06132412.

Humans↗

PubMed2006

A randomized, sham-controlled, proof of principle study of transcranial direct current stimulation for the treatment of pain in fibromyalgia.

OBJECTIVE: Recent evidence suggests that fibromyalgia is a disorder characterized by dysfunctional brain activity. Because transcranial direct current stimulation (tDCS) can modulate brain activity noninvasively and can decrease pain in patients with refractory central pain, we hypothesized that tDCS treatment would result in pain relief in patients with fibromyalgia. METHODS: Thirty-two patients were randomized to receive sham stimulation or real tDCS with the anode centered over the primary motor cortex (M1) or the dorsolateral prefrontal cortex (DLPFC) (2 mA for 20 minutes on 5 consecutive days). A blinded evaluator rated the patient's pain, using the visual analog scale for pain, the clinician's global impression, the patient's global assessment, and the number of tender points. Other symptoms of fibromyalgia were evaluated using the Fibromyalgia Impact Questionnaire and the Short Form 36 Health Survey. Safety was assessed with a battery of neuropsychological tests. To assess potential confounders, we measured mood and anxiety changes throughout the trial. RESULTS: Anodal tDCS of the primary motor cortex induced significantly greater pain improvement compared with sham stimulation and stimulation of the DLPFC (P < 0.0001). Although this effect decreased after treatment ended, it was still significant after 3 weeks of followup (P = 0.004). A small positive impact on quality of life was observed among patients who received anodal M1 stimulation. This treatment was associated with a few mild adverse events, but the frequency of these events in the active-treatment groups was similar to that in the sham group. Cognitive changes were similar in all 3 treatment groups. CONCLUSION: Our findings provide initial evidence of a beneficial effect of tDCS in fibromyalgia, thus encouraging further trials.

Chronic Disease↗

PubMed2004

Facilitation of probabilistic classification learning by transcranial direct current stimulation of the prefrontal cortex in the human.

The aim of our study was to test if the electrical stimulation of the prefrontal cortex (PFC) could modify probabilistic classification learning (PCL). Transcranial direct current stimulation (tDCS) was administered to the left prefrontal and to the primary visual cortex of 22 healthy subjects while they performed a PCL task. In this task subjects learned which of two outcomes would occur on each trial after presentation of a particular combination of cues. Ten minutes of anodal, but not cathodal, stimulation improved implicit learning only when the left PFC was stimulated. Our results show that implicit PLC can be modified by weak anodal tDCS, which probably increases neural excitability, as has been shown in the motor and visual cortices previously. Our results suggest that further studies on the facilitation of learning and memory processes by tDCS are warranted.

Adult↗

PubMed2026

A single session of high-definition transcranial direct current stimulation does not modulate effects of knee two-point discrimination training or sensorimotor function in healthy adults: Double-blind randomised controlled trial.

BACKGROUND: Benefits of sensory-training interventions on sensorimotor outcomes are inconsistent, and it is unclear whether transcranial direct current stimulation (tDCS) can enhance proprioception, which is fundamental to neuromuscular control. Existing evidence is dominated by upper-limb studies, so transferability to the knee is unclear. This study investigated whether a single session of anodal high-definition (HD)-tDCS, alone or combined with brief two-point discrimination (TPD) training, enhances knee sensorimotor function and performance in healthy adults. METHODS: In a double-blind randomised-controlled trial, 57 healthy participants received (1) 20-min, 1 mA anodal HD-tDCS over the knee primary somatosensory (S1) map or sham stimulation, and (2) 15-min knee TPD training or no training. Knee somatosensory, sensorimotor, and functional performance measures were assessed pre- and immediately post-intervention. Three-way mixed-design ANOVAs, equivalence testing (smallest effect size of interest η2 = 0.02), Bayes factors, and linear mixed-effects models quantified effects. RESULTS: HD-tDCS, TPD training, and their sequential combination had no effect on any outcome measure (p ≥ 0.05; η2 ≤ 0.015). Confidence intervals spanned equivalence bounds, and equivalence testing results were non-significant (p ≥ 0.05). Bayes factors (<0.33) showed moderate evidence for the null (no effect). Mixed-effects modelling attributed ≤8% of total variance to intervention fixed effects, with the remainder captured by participant-level random effects. CONCLUSION: A single 20-minute session of 1 mA HD-tDCS, with or without brief TPD training, does not acutely modify knee somatosensory, sensorimotor, or functional performance in healthy adults. Existing evidence at the hand may not translate to the lower limb. Future work should investigate higher-dose, multi-session, task-concurrent, or network-targeted strategies in clinical populations.

Humans↗

PubMed2004

Oscillatory brain activity and transcranial direct current stimulation in humans.

The aim of this study was to induce changes of the oscillatory activity in the visual cortex of healthy human subjects by modulation of neuronal excitability using weak transcranial direct current stimulation (tDCS). tDCS is a non-invasive stimulation method which induces prolonged, polarity-dependent increases or reductions in cortical excitability. An increase in high frequency oscillatory activity in the beta and gamma frequency ranges is closely related in time to the N70 peak of the primary visual evoked potential (VEP), which is an early sensory component of visual activation. Therefore this potential can be used to observe tDCS-induced changes related to oscillatory activity. VEPs were recorded using sinusoidal luminance gratings in an on/off mode before, immediately after and 10, 20, 30 min after the end of 10 min anodal or cathodal stimulation. Cathodal stimulation significantly decreased while anodal stimulation slightly increased the normalized beta and gamma frequency powers. We have shown here that tDCS transiently and reversibly changed the organized cortical activity elicited by visual stimulation. Since gamma activity is also related to a higher level of information processing, tDCS might be a suitable method to affect higher order cognitive processes.

Adult↗

PubMed2000

Diminution of training-induced transient motor cortex plasticity by weak transcranial direct current stimulation in the human.

Training of a thumb movement in the opposite direction of a twitch in response to transcranial magnetic stimulation (TMS) induces a transient directional change of post-training TMS-evoked movements towards the trained direction. Functional synaptic mechanisms seem to underlie this rapid training-induced plasticity. Transcranial direct current stimulation (tDCS) induces outlasting changes of cerebral excitability, thus presenting as promising tool for neuroplasticity research. We studied the influence of tDCS, applied over the motorcortex during training, on angular deviation of post-training to pre-training TMS-evoked thumb movements. With tDCS of anodal and cathodal polarity the training-induced directional change of thumb movements was significantly reduced during a 10 min post-training interval, indicating an interference of tDCS with mechanisms of rapid training-induced plasticity.

Adult↗