Anodal transcranial direct current stimulation increases corticospinal excitability, while performance is unchanged

Anodal transcranial direct current stimulation (a-tDCS) has been shown to improve bicycle time to fatigue (TTF) tasks at 70–80% of VO2max and downregulate rate of perceived exertion (RPE). This study aimed to investigate the effect of a-tDCS on a RPE-clamp test, a 250-kJ time trial (TT) and motor evoked potentials (MEP). Twenty participants volunteered for three trials; control, sham stimulation and a-tDCS. Transcranial magnetic stimulation was used to determine the corticospinal excitability for 12 participants pre and post sham stimulation and a-tDCS. The a-tDCS protocol consisted of 13 minutes of stimulation (2 mA) with the anode placed above the Cz. The RPE-clamp test consisted of 5 minutes ergometer bicycling at an RPE of 13 on the Borg scale, and the TT consisted of a 250 kJ (∼10 km) long bicycle ergometer test. During each test, power output, heart rate and oxygen consumption was measured, while RPE was evaluated. MEPs increased significantly by 36% (±36%) post a-tDCS, with 8.8% (±31%) post sham stimulation (p = 0.037). No significant changes were found for any parameter at the RPE-clamp or TT. The lack of improvement may be due to RPE being more controlled by afferent feedback during TT tests than during TTF tests. Based on the results of the present study, it is concluded that a-tDCS applied over Cz, does not enhance self-paced cycling performance.

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Acute Changes in Motor Cortical Excitability During Slow Oscillatory and Constant Anodal Transcranial Direct Current Stimulation

Journal of Neurophysiology ◽

10.1152/jn.00437.2009 ◽

2009 ◽

Vol 102 (4) ◽

pp. 2303-2311 ◽

Cited By ~ 35

Author(s):

Til Ole Bergmann ◽

Sergiu Groppa ◽

Markus Seeger ◽

Matthias Mölle ◽

Lisa Marshall ◽

...

Keyword(s):

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Cortical Excitability ◽

Motor Evoked Potentials ◽

Corticospinal Excitability ◽

Slow Oscillation ◽

Facilitatory Effect ◽

Endogenous Rhythms ◽

Direct Current Stimulation ◽

On Line

Transcranial oscillatory current stimulation has recently emerged as a noninvasive technique that can interact with ongoing endogenous rhythms of the human brain. Yet, there is still little knowledge on how time-varied exogenous currents acutely modulate cortical excitability. In ten healthy individuals we used on-line single-pulse transcranial magnetic stimulation (TMS) to search for systematic shifts in corticospinal excitability during anodal sleeplike 0.8-Hz slow oscillatory transcranial direct current stimulation (so-tDCS). In separate sessions, we repeatedly applied 30-s trials (two blocks at 20 min) of either anodal so-tDCS or constant tDCS (c-tDCS) to the primary motor hand area during quiet wakefulness. Simultaneously and time-locked to different phase angles of the slow oscillation, motor-evoked potentials (MEPs) as an index of corticospinal excitability were obtained in the contralateral hand muscles 10, 20, and 30 s after the onset of tDCS. MEPs were also measured off-line before, between, and after both stimulation blocks to detect any lasting excitability shifts. Both tDCS modes increased MEP amplitudes during stimulation with an attenuation of the facilitatory effect toward the end of a 30-s tDCS trial. No phase-locking of corticospinal excitability to the exogenous oscillation was observed during so-tDCS. Off-line TMS revealed that both c-tDCS and so-tDCS resulted in a lasting excitability increase. The individual magnitude of MEP facilitation during the first tDCS trials predicted the lasting MEP facilitation found after tDCS. We conclude that sleep slow oscillation-like excitability changes cannot be actively imposed on the awake cortex with so-tDCS, but phase-independent on-line as well as off-line facilitation can reliably be induced.

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Preconditioning cathodal transcranial direct current stimulation facilitates the neuroplastic effect of subsequent anodal transcranial direct current stimulation applied during cycling in young adults

10.1101/653634 ◽

2019 ◽

Author(s):

Maryam Pourmajidian ◽

Benedikt Lauber ◽

Simranjit K Sidhu

Keyword(s):

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Motor Evoked Potentials ◽

Corticospinal Excitability ◽

Anodal Tdcs ◽

Double Blind ◽

Cycling Exercise ◽

Direct Current Stimulation ◽

Post Test ◽

Double Blind Design

AbstractThe study aimed to examine the effect of a priming cathodal transcranial direct current stimulation (ctDCS) before subsequent anodal-tDCS (atDCS) was applied during low workload cycling exercise on the corticospinal responses in young healthy individuals. Eleven young subjects participated in two sessions receiving either priming ctDCS or sham stimulation, followed by atDCS while cycling (i.e. ctDCS-atDCS, sham-atDCS) at 1.2 times their body weight (84 ± 20 W) in a counterbalanced double-blind design. Corticospinal excitability was measured with motor evoked potentials (MEPs) elicited via transcranial magnetic stimulation with the intensity set to produce an MEP amplitude of 1 mV in a resting hand muscle at baseline (PRE), following priming tDCS (POST-PRIMING) and post atDCS combined with cycling exercise (POST-TEST). There was a significant interaction between time and intervention (P < 0.01) on MEPs. MEPs increased from PRE (1.0 ± 0.06 mV) to POST-TEST (1.3 ± 0.06 mV) during ctDCS-atDCS (P < 0.001) but did not change across time during sham-atDCS (1.0 ± 0.06 mV, P > 0.7). Furthermore, MEPs were higher in ctDCS-atDCS compared to sham-atDCS (P < 0.01) at both POST-PRIMING (ctDCS-atDCS: 1.1 ± 0.06, sham-atDCS: 1.0 ± 0.06) and POST-TEST (ctDCS-atDCS: 1.3 ± 0.06, sham-atDCS: 1.0 ± 0.06). These outcomes demonstrate that cathodal tDCS priming can enhance corticospinal excitability following anodal tDCS applied in combination with cycling exercise. The findings have implications for the application of tDCS in combination with cycling exercise in rehabilitation and sporting contexts.

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Bilateral Transcranial Direct Current Stimulation Modulates Activation-Induced Regional Blood Flow Changes during Voluntary Movement

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2011.72 ◽

2011 ◽

Vol 31 (10) ◽

pp. 2086-2095 ◽

Cited By ~ 34

Author(s):

Caroline Paquette ◽

Michael Sidel ◽

Basia A Radinska ◽

Jean-Paul Soucy ◽

Alexander Thiel

Keyword(s):

Blood Flow ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Primary Motor Cortex ◽

Cortical Excitability ◽

Motor Evoked Potentials ◽

Regional Blood Flow ◽

Active Movement ◽

Sham Stimulation ◽

Direct Current Stimulation

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that induces changes in cortical excitability: anodal stimulation increases while cathodal stimulation reduces excitability. Imaging studies performed after unilateral stimulation have shown conflicting results regarding the effects of tDCS on surrogate markers of neuronal activity. The aim of this study was to directly measure these effects on activation-induced changes in regional cerebral blood flow (⊿rBF) using positron emission tomography (PET) during bilateral tDCS. Nine healthy subjects underwent repeated rCBF measurements with 15O-water and PET during a simple motor task while receiving tDCS or sham stimulation over the primary motor cortex (M1). Motor evoked potentials (MEPs) were also assessed before and after real and sham stimulation. During tDCS with active movement, ⊿rBF in M1 was significantly lower on the cathodal than the anodal side when compared with sham stimulation. This decrease in ⊿rBF was accompanied by a decrease in MEP amplitude on the cathodal side. No effect was observed on resting or activated rCBF relative to sham stimulation. We thus conclude that it is the interaction of cathodal tDCS with activation-induced ⊿rBF rather than the effect on resting or activated rCBF itself which constitutes the physiological imaging correlate of tDCS.

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Visual Cortex Transcranial Direct Current Stimulation for Proliferative Diabetic Retinopathy Patients: A Double-Blinded Randomized Exploratory Trial

Brain Sciences ◽

10.3390/brainsci11020270 ◽

2021 ◽

Vol 11 (2) ◽

pp. 270

Author(s):

Angelito Braulio F. de Venecia ◽

Shane M. Fresnoza

Keyword(s):

Diabetic Retinopathy ◽

Visual Cortex ◽

Proliferative Diabetic Retinopathy ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Vision Loss ◽

Sham Stimulation ◽

Direct Current Stimulation ◽

Residual Vision ◽

Cathodal Tdcs

Proliferative diabetic retinopathy (PDR) is a severe complication of diabetes. PDR-related retinal hemorrhages often lead to severe vision loss. The main goals of management are to prevent visual impairment progression and improve residual vision. We explored the potential of transcranial direct current stimulation (tDCS) to enhance residual vision. tDCS applied to the primary visual cortex (V1) may improve visual input processing from PDR patients’ retinas. Eleven PDR patients received cathodal tDCS stimulation of V1 (1 mA for 10 min), and another eleven patients received sham stimulation (1 mA for 30 s). Visual acuity (logarithm of the minimum angle of resolution (LogMAR) scores) and number acuity (reaction times (RTs) and accuracy rates (ARs)) were measured before and immediately after stimulation. The LogMAR scores and the RTs of patients who received cathodal tDCS decreased significantly after stimulation. Cathodal tDCS has no significant effect on ARs. There were no significant changes in the LogMAR scores, RTs, and ARs of PDR patients who received sham stimulation. The results are compatible with our proposal that neuronal noise aggravates impaired visual function in PDR. The therapeutic effect indicates the potential of tDCS as a safe and effective vision rehabilitation tool for PDR patients.

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Can Transcranial Direct Current Stimulation Enhance Functionality in Older Adults? A Systematic Review

Journal of Clinical Medicine ◽

10.3390/jcm10132981 ◽

2021 ◽

Vol 10 (13) ◽

pp. 2981

Author(s):

Andrés Pino-Esteban ◽

Álvaro Megía-García ◽

David Martín-Caro Álvarez ◽

Hector Beltran-Alacreu ◽

Juan Avendaño-Coy ◽

...

Keyword(s):

Systematic Review ◽

Older Adults ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Randomized Clinical Trials ◽

Scientific Evidence ◽

Healthy Older Adults ◽

Sham Stimulation ◽

Direct Current Stimulation ◽

Potential Benefits

Transcranial direct current stimulation (tDCS) is a non-invasive, easy to administer, well-tolerated, and safe technique capable of affecting brain excitability, both at the cortical and cerebellum levels. However, its effectiveness has not been sufficiently assessed in all population segments or clinical applications. This systematic review aimed at compiling and summarizing the currently available scientific evidence about the effect of tDCS on functionality in older adults over 60 years of age. A search of databases was conducted to find randomized clinical trials that applied tDCS versus sham stimulation in the above-mentioned population. No limits were established in terms of date of publication. A total of 237 trials were found, of which 24 met the inclusion criteria. Finally, nine studies were analyzed, including 260 healthy subjects with average age between 61.0 and 85.8 years. Seven of the nine included studies reported superior improvements in functionality variables following the application of tDCS compared to sham stimulation. Anodal tDCS applied over the motor cortex may be an effective technique for improving balance and posture control in healthy older adults. However, further high-quality randomized controlled trials are required to determine the most effective protocols and to clarify potential benefits for older adults.

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Transcranial direct current stimulation: Adverse effects and the efficacy of a commonly utilised sham protocol

European Psychiatry ◽

10.1016/j.eurpsy.2017.02.392 ◽

2017 ◽

Vol 41 (S1) ◽

pp. S374-S374 ◽

Cited By ~ 3

Author(s):

A. Kortteenniemi ◽

T. Ali-Sisto ◽

J. Wikgren ◽

S. Lehto

Keyword(s):

Adverse Effects ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Sham Group ◽

Control Procedure ◽

Current Standard ◽

Sham Stimulation ◽

Direct Current Stimulation ◽

Cohen’S D ◽

Cohen's D

IntroductionTranscranial direct current stimulation (tDCS) is a promising neuromodulation method that has, for example, been used to treat depression. Nevertheless, the adverse effects of tDCS and the validity of the current standard tDCS sham protocols have received limited attention.ObjectivesTo evaluate the extent and types of tDCS adverse effects and to assess the reliability of sham stimulation as a control procedure for tDCS in a double-blind setting.AimsTo compare adverse effects between tDCS and sham stimulation groups, and to determine how well the participants and the experimenter are able to distinguish tDCS from sham stimulation.MethodsA sample of healthy volunteers received a 20-minute session of either tDCS (n = 41; 2 mA) or sham stimulation (n = 41; ramp up 15 s, ramp down 15 s; no current in between). The anode was placed over F3 and cathode over F4. Both the participants and the experimenter reported immediate adverse effects and the perceived likelihood for the participant to receive tDCS. Analyses were conducted using the Mann–Whitney U-test.ResultsThe tDCS group reported more erythema compared with the sham group (P = 0.016, Cohen's D = 0.444). No other significant differences in adverse effects were observed. In the tDCS group, both the participants (P = 0.034, Cohen's D = 0.612) and the experimenter (P = 0.006, Cohen's D = 0.674) reported a higher perceived likelihood of the participant receiving tDCS than in the sham group.ConclusionstDCS has only modest adverse effects. Nevertheless, the current standard sham protocol appears insufficient.Disclosure of interestThe authors have not supplied their declaration of competing interest.

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Comparison of repeated transcranial stimulation and transcranial direct-current stimulation on primary motor cortex excitability and inhibition: A pilot study

Movement & Sport Sciences - Science & Motricité ◽

10.1051/sm/2018001 ◽

2018 ◽

pp. 59-67 ◽

Cited By ~ 1

Author(s):

Vincent Cabibel ◽

Makii Muthalib ◽

Jérôme Froger ◽

Stéphane Perrey

Keyword(s):

Pilot Study ◽

Motor Cortex ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Primary Motor Cortex ◽

Motor Evoked Potentials ◽

High Definition ◽

Direct Current Stimulation ◽

Motor Cortex Excitability ◽

The Right

Repeated transcranial magnetic stimulation (rTMS) is a well-known clinical neuromodulation technique, but transcranial direct-current stimulation (tDCS) is rapidly growing interest for neurorehabilitation applications. Both methods (contralesional hemisphere inhibitory low-frequency: LF-rTMS or lesional hemisphere excitatory anodal: a-tDCS) have been employed to modify the interhemispheric imbalance following stroke. The aim of this pilot study was to compare aHD-tDCS (anodal high-definition tDCS) of the left M1 (2 mA, 20 min) and LF-rTMS of the right M1 (1 Hz, 20 min) to enhance excitability and reduce inhibition of the left primary motor cortex (M1) in five healthy subjects. Single-pulse TMS was used to elicit resting and active (low level muscle contraction, 5% of maximal electromyographic signal) motor-evoked potentials (MEPs) and cortical silent periods (CSPs) from the right and left extensor carpi radialis muscles at Baseline, immediately and 20 min (Post-Stim-20) after the end of each stimulation protocol. LF-rTMS or aHD-tDCS significantly increased right M1 resting and active MEP amplitude at Post-Stim-20 without any CSP modulation and with no difference between methods. In conclusion, this pilot study reported unexpected M1 excitability changes, which most likely stems from variability, which is a major concern in the field to consider.

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The effects of transcranial direct current stimulation on objective and subjective indexes of exercise performance: a systematic review and meta-analysis.

10.31236/osf.io/e2buc ◽

2018 ◽

Author(s):

Darias Holgado ◽

Miguel A. Vadillo ◽

Daniel Sanabria

Keyword(s):

Systematic Review ◽

Direct Current ◽

Exercise Performance ◽

Transcranial Direct Current Stimulation ◽

Perceived Exertion ◽

Effect Sizes ◽

Electrode Placement ◽

Current Evidence ◽

Time To Exhaustion ◽

Direct Current Stimulation

Objective: To examine the effectss of transcranial direct current stimulation (tDCS) on objective and subjective indexes of exercise performance.Design: Systematic review and meta-analysis.Data Sources: A systematic literature search of electronic databases (PubMed, Web of Science, Scopus, Google Scholar) and reference lists of included articles up to June 2018.Eligibility Criteria: Published articles in journals or in repositories with raw data available, randomized sham-controlled trial comparing anodal stimulation with a sham condition providing data on objective (e.g. time to exhaustion or time-trial performance) or subjective (e.g. rate of perceived exertion) indexes of exercise performance.Results: The initial search provided 420 articles of which 31 were assessed for eligibility. Finally, the analysis of effect sizes comprised 24 studies with 386 participants. The analysis indicated that anodal tDCS had a small but positive effect on performance g = 0.34, 95% CI [0.12, 0.52], z = 3.24, p = 0.0012. Effects were not significantly moderated by type of outcome, electrode placement, muscles involved, number of sessions, or intensity and duration of the stimulation. Importantly, the funnel plot showed that, overall, effect sizes tended to be larger in studies with lower sample size and high standard error. Summary: The results suggest that tDCS may have a positive impact on exercise performance. However, the effect is probably small and most likely biased by low quality studies and the selective publication of significant results. Therefore, the current evidence does not provide strong support to the conclusion that tDCS is an effective means to improve exercise performance.

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