Explore the vast range of titles available.

Transcranial Direct Current Stimulation (tDCS) is a non-invasive technique used to modulate neural tissue. Neuromodulation apparently improves cognitive functions in several neurologic diseases treatment and sports performance. In this study, we present a comprehensive, integrative review of tDCS for motor rehabilitation and motor learning in healthy individuals, athletes and multiple neurologic and neuropsychiatric conditions. We also report on neuromodulation mechanisms, main applications, current knowledge including areas such as language, embodied cognition, functional and social aspects, and future directions. We present the use and perspectives of new developments in tDCS technology, namely high-definition tDCS (HD-tDCS) which promises to overcome one of the main tDCS limitation (i.e., low focality) and its application for neurological disease, pain relief, and motor learning/rehabilitation. Finally, we provided information regarding the Transcutaneous Spinal Direct Current Stimulation (tsDCS) in clinical applications, Cerebellar tDCS (ctDCS) and its influence on motor learning, and TMS combined with electroencephalography (EEG) as a tool to evaluate tDCS effects on brain function.

Abstract The cerebellum is involved in multiple closed-loops circuitry which connect the cerebellar modules with the motor cortex, prefrontal, temporal, and parietal cortical areas, and contribute to motor control, cognitive processes, emotional processing, and behavior. Among them, the cerebello-thalamo-cortical pathway represents the anatomical substratum of cerebellum-motor cortex inhibition (CBI). However, the cerebellum is also connected with basal ganglia by disynaptic pathways, and cerebellar involvement in disorders commonly associated with basal ganglia dysfunction (e.g., Parkinson’s disease and dystonia) has been suggested. Lately, cerebellar activity has been targeted by non-invasive brain stimulation (NIBS) techniques including transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) to indirectly affect and tune dysfunctional circuitry in the brain. Although the results are promising, several questions remain still unsolved. Here, a panel of experts from different specialties (neurophysiology, neurology, neurosurgery, neuropsychology) reviews the current results on cerebellar NIBS with the aim to derive the future steps and directions needed. We discuss the effects of TMS in the field of cerebellar neurophysiology, the potentials of cerebellar tDCS, the role of animal models in cerebellar NIBS applications, and the possible application of cerebellar NIBS in motor learning, stroke recovery, speech and language functions, neuropsychiatric and movement disorders.

Background Progressive cerebellar ataxia is a neurodegenerative disorder without effective treatment options that seriously hinders quality of life. Previously, transcranial direct current stimulation (tDCS) has been demonstrated to benefit cerebellar functions (including improved motor control, learning and emotional processing) in healthy individuals and patients with neurological disorders. While tDCS is an emerging therapy, multiple daily sessions are needed for optimal clinical benefit. This case study tests the symptomatic benefit of remotely supervised tDCS (RS-tDCS) for a patient with cerebellar ataxia. Methods We report a case of a 71-year-old female patient with progressive cerebellar ataxia, who presented with unsteady gait and balance impairment, treated with tDCS. tDCS was administered using our RS-tDCS protocol and was completed daily in the patient’s home (Monday – Friday) with the help of a trained study technician. tDCS was paired with 20 min of simultaneous cognitive training, followed by 20 min of physical exercises directed by a physical therapist. Stimulation consisted of 20 min of 2.5 mA direct current targeting the cerebellum via an anodal electrode and a cathodal electrode placed over the right shoulder. The patient completed baseline and treatment end visits with neurological, cognitive, and motor (Lafayette Grooved Pegboard Test, 25 ft walk test and Timed Up and Go Test) assessments. Results The patient successfully completed sixty tDCS sessions, 59 of which were administered remotely at the patient’s home with the use of real time supervision as enabled by video conferencing. Mild improvement was observed in the patient’s gait with a 7% improvement in walking speed, which she completed without a walking-aid at treatment end, which was in stark contrast to her baseline assessment. Improvements were also achieved in manual dexterity, with an increase in pegboard scores bilaterally compared to baseline. Conclusions Results from this case report suggest that consecutively administered tDCS treatments paired with cognitive and physical exercise hold promise for improving balance, gait, and manual dexterity in patients with progressive ataxia. Remotely supervised tDCS provides home access to enable the administration over an extended period. Further controlled study in a large group of those with cerebellar ataxia is needed to replicate these findings. Trial registration ClinicalTrials.gov Identifier: NCT03049969 . Registered 10 February 2017- Retrospectively registered.

[This corrects the article DOI: 10.3389/fnhum.2025.1629499.].[This corrects the article DOI: 10.3389/fnhum.2025.1629499.].

Introduction: Parkinson’s Disease is a progressive neurological disorder resulting from the death of dopamine-producing cells in the substantia nigra. People with Parkinson’s disease require effective rehabilitation therapies to control the motor symptoms that are commonly associated with this disease. Transcranial current direct stimulation is a promising tool to enhance sensorimotor functioning in people with Parkinson’s disease, and the combination of transcranial current direct stimulation with Virtual Reality tasks is being explored in motor functioning, however, there is still a lack of evidence.  Objective: compare the motor performance between an active or sham single session of transcranial direct current stimulation combined with a Virtual Reality task in individuals with Parkinson Disease. Methods: a triple-blinded randomized controlled trial protocol was performed. Fifty-four individuals with a Modified Hoehn & Yahr Scale rating from 1 to 4 were recruited. Individuals were randomly assigned to the following groups: active Transcranial Direct Current Stimulation (Transcranial Direct Current Stimulation + Virtual Reality task) or (sham Transcranial Direct Current Stimulation + Virtual Reality task). The protocol was performed in 18 minutes consisting of the following blocks: (5 minutes of initial rest stimuli, 4 minutes of the Transcranial Direct Current Stimulation + Virtual Reality task for Upper Limbs, 4 minutes of the Transcranial Direct Current Stimulation + Virtual Reality task for Lower Limbs, and 5 minutes of final rest stimuli). The active Transcranial Direct Current Stimulation protocol included low-frequency Transcranial Direct Current Stimulation with an intensity of 2 milliamperes (mA) over the primary cortex (M1) area of the dominant side of the brain.  Results: a significant effect for Groups and Blocks was found considering the measures of absolute and variable errors. Both active and sham Transcranial Direct Current Stimulation groups showed improvement in Upper Limb performance compared to Lower Limb performance.  Conclusion: active Transcranial Direct Current Stimulation could be an effective tool for enhancing motor performance during a Virtual Reality task. This may involve improved accuracy and precision of movement in both the Upper and Lower Limbs of individuals with Parkinson Disease. Positive effects in the active Transcranial Direct Current Stimulation were noticeable, even with a single session of Transcranial Direct Current Stimulation. In future research, investigation of the effect of a longer-term protocol is recommended, including follow-up measures. Introdução: a Doença de Parkinson é um distúrbio neurológico progressivo resultante da morte de células produtoras de dopamina na substância negra. Pessoas com Doença de Parkinson necessitam de terapias de reabilitação eficazes para controlar os sintomas motores comumente associados a essa condição. A estimulação transcraniana por corrente contínua (ETCC) é uma ferramenta promissora para aprimorar o funcionamento sensório-motor em pessoas com Parkinson, e a combinação dessa técnica com tarefas de Realidade Virtual (RV) vem sendo explorada no campo do desempenho motor. No entanto, ainda há escassez de evidências sobre essa associação. Objetivo: comparar o desempenho motor entre uma sessão única ativa ou simulada de estimulação transcraniana por corrente contínua combinada com uma tarefa em Realidade Virtual em indivíduos com Doença de Parkinson. Método: foi conduzido um protocolo de ensaio clínico randomizado, triplo-cego. Cinquenta e quatro indivíduos, com pontuação entre 1 e 4 na Escala Modificada de Hoehn & Yahr, foram recrutados. Os participantes foram aleatoriamente distribuídos nos seguintes grupos: ETCC ativa (ETCC + tarefa em RV) ou ETCC simulada (sham ETCC + tarefa em RV). O protocolo teve duração de 18 minutos, composto pelos seguintes blocos: 5 minutos de estímulo em repouso inicial, 4 minutos de ETCC + tarefa em RV para os membros superiores, 4 minutos de ETCC + tarefa em RV para os membros inferiores e 5 minutos de estímulo em repouso final. O protocolo ativo de ETCC utilizou baixa frequência, com intensidade de 2 miliamperes (mA), aplicada sobre o córtex motor primário (M1) do lado dominante do cérebro. Resultados: foi observado um efeito significativo entre Grupos e Blocos nas medidas de erro absoluto e erro variável. Ambos os grupos, ativo e simulado, apresentaram melhora no desempenho dos membros superiores em comparação com os membros inferiores. Conclusão: a ETCC ativa pode ser uma ferramenta eficaz para aprimorar o desempenho motor durante uma tarefa em Realidade Virtual. Isso pode envolver melhorias na precisão e na exatidão dos movimentos dos membros superiores e inferiores em indivíduos com Doença de Parkinson. Efeitos positivos foram observados no grupo ativo mesmo após uma única sessão de ETCC. Pesquisas futuras são recomendadas para investigar os efeitos de protocolos de longa duração, incluindo medidas de acompanhamento.

This article presents a case report of a 57-year-old patient with chronic (>20 years) schizophrenia and severe treatment-refractory coenaesthetic hallucinations located within the genital area. Due to the lack of therapeutic alternatives, a course of transcranial direct current stimulation targeting the somatosensory cortex that represents the genital area was performed. The severity of symptoms was assessed using the Clinical Global Impression (CGI, Severity and Improvement), Positive and Negative Syndrome Scale (PANSS) and three visual-analogue scales, separately for the three distinctive features of “general discomfort”, “ripping out”, and “pain”. After completing the three-week transcranial direct current stimulation course, there were no changes between the baseline and final clinical scores.

Transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) has been shown to induce changes in motor performance and learning. Recent studies indicate that tDCS is capable of modulating widespread neural network properties within the brain. However the temporal evolution of online- and after-effects of tDCS on functional connectivity (FC) within and across the stimulated motor cortices (M1) still remain elusive. In the present study, two different tDCS setups were investigated: (i) unilateral M1 tDCS (anode over right M1, cathode over the contralateral supraorbital region) and (ii) bilateral M1 tDCS (anode over right M1, cathode over left M1). In a randomized single-blinded cross-over design, 12 healthy subjects underwent functional magnetic resonance imaging at rest before, during and after 20 min of either bi-, unilateral, or sham M1 tDCS. Seed-based FC analysis was used to investigate tDCS-induced changes across and within M1. We found that bilateral M1 tDCS induced (a) a decrease in interhemispheric FC during stimulation and (b) an increase in intracortical FC within right M1 after termination of the intervention. While unilateral M1 tDCS also resulted in similar effects during stimulation, no such changes could be observed after termination of tDCS. Our results provide evidence that depending on the electrode montage, tDCS acts upon a modulation of either intracortical and/or interhemispheric processing of M1.

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that alters cortical excitability in a polarity specific manner and has been shown to influence learning and memory. tDCS may have both on-line and after-effects on learning and memory, and the latter are thought to be based upon tDCS-induced alterations in neurochemistry and synaptic function. We used ultra-high-field (7T) magnetic resonance spectroscopy (MRS), together with a robotic force adaptation and de-adaptation task, to investigate whether tDCS-induced alterations in GABA and Glutamate within motor cortex predict motor learning and memory. Note that adaptation to a robot-induced force field has long been considered to be a form of model-based learning that is closely associated with the computation and ‘supervised’ learning of internal ‘forward’ models within the cerebellum. Importantly, previous studies have shown that on-line tDCS to the cerebellum, but not to motor cortex, enhances model-based motor learning. Here we demonstrate that anodal tDCS delivered to the hand area of the left primary motor cortex induces a significant reduction in GABA concentration. This effect was specific to GABA, localised to the left motor cortex, and was polarity specific insofar as it was not observed following either cathodal or sham stimulation. Importantly, we show that the magnitude of tDCS-induced alterations in GABA concentration within motor cortex predicts individual differences in both motor learning and motor memory on the robotic force adaptation and de-adaptation task. •Ultra-high-field (7 T) magnetic resonance spectroscopy study of the effects of tDCS.•Anodal tDCS leads to a polarity and site specific reduction in MRS-GABA.•tDCS-induced changes in MRS-GABA in M1 predict model-based motor learning/memory.

Introduction Cheap, easy to apply, well-tolerable, with the potential of altering cortical excitability, and for testing causalities—these are attributes that have made transcranial direct current stimulation (tDCS) a highly popular research tool in cognitive neuroscience. Since its reintroduction over 15 years ago by Nitsche and Paulus (2000), the number of publications reporting tDCS results has risen exponentially (a Scopus® literature search indicates over 500 such journal articles published in 2015 alone). [...]Cason and Medina (2016) find average statistical power in tDCS studies to be below 50%. [...]one potential reason for the reported inconsistencies might be that sample size is usually very small in most tDCS studies (including those from our research group). [...]depending on which studies are included in systematic reviews and meta- analyses (i.e., findings published in peer-reviewed journals; unpublished nil-effects; nil-effects reported as an additional finding in papers with the actual focus on another, significant, effect, etc.), small sample size in tDCS research could lead to both under—and overestimation of tDCS efficacy. By doing so, they overcome the problem of under-powering, an issue that seems so fundamental in tDCS research. [...]to investigate the effect of sample size on tDCS efficacy and to contribute to increased research transparency we designed a simple, pre-registered study (https://osf.io/eb9c5/?view_only=2743a0c4600943c998c2c37fbfb25846) with a sufficiently large number of young, healthy volunteers estimated with a priori power analysis.