Weak DCS causes a relatively strong cumulative boost of synaptic plasticity with spaced learning

Sharma, Mahima; Farahani, Forouzan; Bikson, Marom; Parra, Lucas C.

doi:10.1016/j.brs.2021.10.552

Cited by 18 publications

(14 citation statements)

References 57 publications

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“…Preclinical model studies indicate that tDCS produces lasting changes in brain excitability (e.g., hemodynamic response, functional connectivity, and neuroplastic changes 31 32 33 34 ) that are cumulative over repeated sessions, which is consistent with clinical neurophysiology. 23 35 36 37 38 Further, multiple-session protocols induce larger effects in terms of behavioral changes than do single-session protocols.…”

Section: Clinical Potential Of Tdcs In Adsupporting

confidence: 53%

Potential of Transcranial Direct Current Stimulation in Alzheimer’s Disease: Optimizing Trials Toward Clinical Use

et al. 2022

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Transcranial direct current stimulation (tDCS) is a safe and well-tolerated noninvasive method for stimulating the brain that is rapidly developing into a treatment method for various neurological and psychiatric conditions. In particular, there is growing evidence of a therapeutic role for tDCS in ameliorating or delaying the cognitive decline in Alzheimer’s disease (AD). We provide a brief overview of the current development and application status of tDCS as a nonpharmacological therapeutic method for AD and mild cognitive impairment (MCI), summarize the levels of evidence, and identify the improvements needed for clinical applications. We also suggest future directions for large-scale controlled clinical trials of tDCS in AD and MCI, and emphasize the necessity of identifying the mechanistic targets to facilitate clinical applications.

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Section: Clinical Potential Of Tdcs In Adsupporting

confidence: 53%

Potential of Transcranial Direct Current Stimulation in Alzheimer’s Disease: Optimizing Trials Toward Clinical Use

et al. 2022

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“…Verum stimulation was applied for 20 min with a ramp up and ramp down of 30 s each. Sham stimulation consisted of a 30 s ramp up and a 30 s ramp down at the beginning and the end, respectively, with no current during the intervening time (Figure 2B), facilitating blinding by mimicking the sensations of verum tDCS without actual neurological changes (Di Rosa et al, 2019;Sharma et al, 2021). After stimulation, participants were asked whether they received verum or sham stimulation and how confident they were based on a scale from 0 (complete guess) to 10 (absolutely sure), Additionally, another 11-point scale was used to evaluate the intensity of any sensations (e.g., itching, tingling, metallic taste, or burning) they felt during the stimulation, with 0 = no sensation and 10 = strongest sensation imaginable (Hill et al, 2017).…”

Section: High-definition Transcranial Direct Current Stimulationmentioning

confidence: 99%

Multitarget high-definition transcranial direct current stimulation improves response inhibition more than single-target high-definition transcranial direct current stimulation in healthy participants

et al. 2022

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Prior studies have focused on single-target anodal transcranial direct current stimulation (tDCS) over the right inferior frontal gyrus (rIFG) or pre-supplementary motor area (pre-SMA) to improve response inhibition in healthy individuals. However, the results are contradictory and the effect of multitarget anodal stimulation over both brain regions has never been investigated. The present study aimed to investigate the behavioral and neurophysiological effects of different forms of anodal high-definition tDCS (HD-tDCS) on improving response inhibition, including HD-tDCS over the rIFG or pre-SMA and multitarget HD-tDCS over both areas. Ninety-two healthy participants were randomly assigned to receive single-session (20 min) anodal HD-tDCS over rIFG + pre-SMA, rIFG, pre-SMA, or sham stimulation. Before and immediately after tDCS intervention, participants completed a stop-signal task (SST) and a go/nogo task (GNG). Their cortical activity was recorded using functional near-infrared spectroscopy (fNIRS) during the go/nogo task. The results showed multitarget stimulation produced a significant reduction in stop-signal reaction time (SSRT) relative to baseline. The pre-to-post SSRT change was not significant for rIFG, pre-SMA, or sham stimulation. Further analyses revealed multitarget HD-tDCS significantly decreased SSRT in both the high-performance and low-performance subgroups compared with the rIFG condition which decreased SSRT only in the low-performance subgroup. Only the multitarget condition significantly improved neural efficiency as indexed by lower △oxy-Hb after stimulation. In conclusion, the present study provides important preliminary evidence that multitarget HD-tDCS is a promising avenue to improve stimulation efficacy, establishing a more effective montage to enhance response inhibition relative to the commonly used single-target stimulation.

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“…Electric fields induced on the cortical surface with conventional tDCS are less than 1V/m 19 . This is well below values used in vitro to demonstrate effects on plasticity 4,5,[20][21][22][23] . The objective of this study is to establish a go-to behavioral experiment to test the effects of tDCS on learning.…”

Section: Introductionmentioning

confidence: 72%

Robust enhancement of motor sequence learning with 4mA transcranial electric stimulation

Hsu

Shereen

Cohen³

et al. 2022

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Background and ObjectivesMotor learning experiments with transcranial direct current stimulation (tDCS) at 2mA have produced mixed results. We hypothesize that tDCS will boost motor learning provided sufficiently high field intensity on the motor cortex.MethodsIn a single-blinded, between-subject design, 72 healthy right-handed participants received either anodal or cathodal tDCS at 4mA while they learned to perform a sequence of key presses using their non-dominant hand for about 12 minutes. Cathodal stimulation served as an active control for sensation. A separate sham-stimulation group established baseline performance. Gains during practice and rest periods were analyzed (called micro-online and -offline learning). The target for stimulation was identified on the motor cortex using fMRI. After optimization with individual current flow models, we selected a single montage for all 108 participants with 4 frontal and 4 parietal electrodes each drawing 1mA.ResultsWe found significant gains in performance with anodal stimulation (Cohen’s d=0.7). The boost in performance persisted for at least one hour. Subsequent learning for a new sequence and the opposite hand also improved. Concurrent tDCS enhanced micro-offline learning, while subsequent learning relied on micro-online gains. Sensation ratings were comparable in the active groups and did not exceed moderate levels. The new electrode montage achieved a better tradeoff between stimulation intensity and sensations on the scalp as compared to alternative montages.ConclusionThe present paradigm shows reliable behavioral effects at 4mA and is well-tolerated. It may serve as a go-to experiment for future studies on motor learning and tDCS.HighlightstDCS resulted in a lasting boost of concurrent learning with effect size of Cohen’s d=0.7.Subsequent learning was also improved, indicating a form of meta-learning.Detailed analysis of behavior suggests an effect of tDCS on sequence consolidation.A novel electrode montage with 1mA through each of 4+4 electrodes was well-tolerated.

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Weak DCS causes a relatively strong cumulative boost of synaptic plasticity with spaced learning

Cited by 18 publications

References 57 publications

Potential of Transcranial Direct Current Stimulation in Alzheimer’s Disease: Optimizing Trials Toward Clinical Use

Potential of Transcranial Direct Current Stimulation in Alzheimer’s Disease: Optimizing Trials Toward Clinical Use

Multitarget high-definition transcranial direct current stimulation improves response inhibition more than single-target high-definition transcranial direct current stimulation in healthy participants

Robust enhancement of motor sequence learning with 4mA transcranial electric stimulation

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