scholarly journals Investigating the effects of cerebellar transcranial direct current stimulation on saccadic adaptation and cortisol response

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Delia A. Gheorghe ◽  
Muriel T. N. Panouillères ◽  
Nicholas D. Walsh
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Stress Reactivity ◽  
Brain Regions ◽  
Direct Current Stimulation ◽  
Saccadic Adaptation ◽  
Stress Processing ◽  
Cerebellar Tdcs ◽  
Cortisol Levels ◽  
Associated Function

Abstract Background Transcranial Direct Current Stimulation (tDCS) over the prefrontal cortex has been shown to modulate subjective, neuronal and neuroendocrine responses, particularly in the context of stress processing. However, it is currently unknown whether tDCS stimulation over other brain regions, such as the cerebellum, can similarly affect the stress response. Despite increasing evidence linking the cerebellum to stress-related processing, no studies have investigated the hormonal and behavioural effects of cerebellar tDCS. Methods This study tested the hypothesis of a cerebellar tDCS effect on mood, behaviour and cortisol. To do this we employed a single-blind, sham-controlled design to measure performance on a cerebellar-dependent saccadic adaptation task, together with changes in cortisol output and mood, during online anodal and cathodal stimulation. Forty-five participants were included in the analysis. Stimulation groups were matched on demographic variables, potential confounding factors known to affect cortisol levels, mood and a number of personality characteristics. Results Results showed that tDCS polarity did not affect cortisol levels or subjective mood, but did affect behaviour. Participants receiving anodal stimulation showed an 8.4% increase in saccadic adaptation, which was significantly larger compared to the cathodal group (1.6%). Conclusion The stimulation effect on saccadic adaptation contributes to the current body of literature examining the mechanisms of cerebellar stimulation on associated function. We conclude that further studies are needed to understand whether and how cerebellar tDCS may module stress reactivity under challenge conditions.

scholarly journals Cerebellar Transcranial Direct Current Stimulation Effects on Saccade Adaptation

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Eric Avila ◽  
Jos N. van der Geest ◽  
Sandra Kengne Kamga ◽  
M. Claire Verhage ◽  
Opher Donchin ◽  
...  
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Neuronal Excitability ◽  
Oculomotor System ◽  
Brain Regions ◽  
Direct Current Stimulation ◽  
Cerebellar Tdcs ◽  
Adaptation Experiment ◽  
Saccade Adaptation ◽  
Contact Electrode

Saccade adaptation is a cerebellar-mediated type of motor learning in which the oculomotor system is exposed to repetitive errors. Different types of saccade adaptations are thought to involve distinct underlying cerebellar mechanisms. Transcranial direct current stimulation (tDCS) induces changes in neuronal excitability in a polarity-specific manner and offers a modulatory, noninvasive, functional insight into the learning aspects of different brain regions. We aimed to modulate the cerebellar influence on saccade gains during adaptation using tDCS. Subjects performed an inward (n=10) or outward (n=10) saccade adaptation experiment (25% intrasaccadic target step) while receiving 1.5 mA of anodal cerebellar tDCS delivered by a small contact electrode. Compared to sham stimulation, tDCS increased learning of saccadic inward adaptation but did not affect learning of outward adaptation. This may imply that plasticity mechanisms in the cerebellum are different between inward and outward adaptation. TDCS could have influenced specific cerebellar areas that contribute to inward but not outward adaptation. We conclude that tDCS can be used as a neuromodulatory technique to alter cerebellar oculomotor output, arguably by engaging wider cerebellar areas and increasing the available resources for learning.

scholarly journals Transcranial direct current stimulation of cerebellum alters spiking precision in cerebellar cortex: A modeling study of cellular responses

2021 ◽  
Vol 17 (12) ◽  
pp. e1009609
Author(s):  
Xu Zhang ◽  
Roeland Hancock ◽  
Sabato Santaniello
Keyword(s):  
Purkinje Cells ◽  
Cerebellar Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Cellular Response ◽  
Cerebellar Neurons ◽  
Direct Current Stimulation ◽  
Repolarization Phase ◽  
Cerebellar Tdcs ◽  
Complex Spikes

Transcranial direct current stimulation (tDCS) of the cerebellum has rapidly raised interest but the effects of tDCS on cerebellar neurons remain unclear. Assessing the cellular response to tDCS is challenging because of the uneven, highly stratified cytoarchitecture of the cerebellum, within which cellular morphologies, physiological properties, and function vary largely across several types of neurons. In this study, we combine MRI-based segmentation of the cerebellum and a finite element model of the tDCS-induced electric field (EF) inside the cerebellum to determine the field imposed on the cerebellar neurons throughout the region. We then pair the EF with multicompartment models of the Purkinje cell (PC), deep cerebellar neuron (DCN), and granule cell (GrC) and quantify the acute response of these neurons under various orientations, physiological conditions, and sequences of presynaptic stimuli. We show that cerebellar tDCS significantly modulates the postsynaptic spiking precision of the PC, which is expressed as a change in the spike count and timing in response to presynaptic stimuli. tDCS has modest effects, instead, on the PC tonic firing at rest and on the postsynaptic activity of DCN and GrC. In Purkinje cells, anodal tDCS shortens the repolarization phase following complex spikes (-14.7 ± 6.5% of baseline value, mean ± S.D.; max: -22.7%) and promotes burstiness with longer bursts compared to resting conditions. Cathodal tDCS, instead, promotes irregular spiking by enhancing somatic excitability and significantly prolongs the repolarization after complex spikes compared to baseline (+37.0 ± 28.9%, mean ± S.D.; max: +84.3%). tDCS-induced changes to the repolarization phase and firing pattern exceed 10% of the baseline values in Purkinje cells covering up to 20% of the cerebellar cortex, with the effects being distributed along the EF direction and concentrated in the area under the electrode over the cerebellum. Altogether, the acute effects of tDCS on cerebellum mainly focus on Purkinje cells and modulate the precision of the response to synaptic stimuli, thus having the largest impact when the cerebellar cortex is active. Since the spatiotemporal precision of the PC spiking is critical to learning and coordination, our results suggest cerebellar tDCS as a viable therapeutic option for disorders involving cerebellar hyperactivity such as ataxia.

scholarly journals The Effect of Transcranial Direct Current Stimulation and Core Stability Training on the Balance and Disability of Patients With Multiple Sclerosis

2021 ◽  
Vol 11 (3) ◽  
pp. 189-198
Author(s):  
Soudabeh Raeisi ◽  
◽  
Seyed Kazem Mousavi Sadati ◽  
Mojtaba Azimian ◽  
◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Postural Control ◽  
Direct Current ◽  
Vestibular System ◽  
Transcranial Direct Current Stimulation ◽  
Core Stability ◽  
Direct Current Stimulation ◽  
Cerebellar Tdcs ◽  
Stability Training ◽  
Sensory Condition

Purpose: Physicians report balance disorders and fatigue as the symptoms of Multiple Sclerosis (MS) disease. The present study compares the effect of transcranial Direct Current Stimulation (tDCS) and core stability training on the balance and disability of patients with MS. Methods: This is a pre-test, post-test experiment study. The statistical population included all patients with MS who reffered to Rofaydeh Rehabilitation Hospital in Tehran City, Iran, in the winter of 2019. A total of 30 male and female patients aged 27-70 years were selected through available and purposive sampling methods and then randomly divided into experimental and control groups (each group 15 persons). The initial measurements of the participants’ kinetic variables of postural control were carried out by the posturography device, and afterward, Kurtzke Expanded Disability Status Scale (EDSS) was employed to measure disability. The participants’ training included core stability training for 8 weeks (30-40 min, 3 sessions per week) with 20 min online cerebellar transcranial direct current stimulation, 2 sessions per week (The first and third sessions). Then, the research variables were measured again. Results: The results demonstrated the significant influence of cerebellar tDCS on the variables of postural control equilibrium in the second sensory condition (P<0.001), third sensory condition (P<0.001), fourth sensory condition (P<0.001), fifth sensory condition (P=0.034), and combine equilibrium (P<0.001). Besides, the cerebellar current stimulation enhanced the sensory performance of the experimental group in using the vestibular system input data (P<0.001) and vision (P<0.001), but it had no significant effect on the ability to use somatosensory input (P=0.203) and vision preference (P=0.343). This research also revealed that the cerebellar current stimulation decreased EDSS in MS patients (P=0.026). Conclusion: The cerebellar tDCS has a beneficial effect on balance, EDSS, and modified fatigue impact scale in MS patients. The study findings also indicate that the cerebellum, vestibular system, and visual system are related, and they have an impact on balance, and cerebellar stimulation can facilitate learning motor skills.

Power spectral parameter variations after transcranial direct current stimulation in a bimanual coordination task

2019 ◽  
pp. 105971231987997 ◽  
Author(s):  
Atefeh Azarpaikan ◽  
HamidReza Taherii Torbati ◽  
Mehdi Sohrabi ◽  
Reza Boostani ◽  
Majid Ghoshuni
Keyword(s):  
Parietal Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Bimanual Coordination ◽  
Neuronal Membrane ◽  
Membrane Excitability ◽  
Direct Current Stimulation ◽  
Cerebellar Tdcs ◽  
Alpha Beta ◽  
The Brain

Transcranial direct current stimulation (tDCS) can shift neuronal membrane excitability by applying a weak slow electric current to the brain through the scalp. Attendant electroencephalography (EEG) can provide valuable information about the tDCS mechanisms. This study investigated the effects of anodal tDCS on parietal cortex and cerebellum activity to reveal possible modulation of spontaneous oscillatory brain activity. Timing of the tDCS priming protocol in relation to the intervention especially with respect to bimanual coordination task was also studied. EEG activity was measured in 120 healthy participants before and after sessions of anodal stimulation of the parietal cortex and cerebellum to detect the tDCS-induced alterations. Variations of the delta, theta, alpha, beta, and sensorimotor rhythm (SMR) power bands were analyzed using a MATLAB program. The results showed that anodal parietal and cerebellar tDCS cause changes in brain wave frequencies. They also showed an increase in alpha, beta, and SMR power bands during stimulation sessions for during stimulation parietal group ( p ≤ .01). Also, theta, alpha, beta, and SMR power bands were increased in during stimulation cerebellum group in stimulation sessions and 48 h later ( p ≤ .01). Moreover, the results revealed that the tDCS intervention led to a variety of activations in some areas of the brain. Altogether, the cerebellar tDCS during motor task had a significant improvement in off-line learning.

scholarly journals Cerebellar Transcranial Direct Current Stimulation in People with Parkinson’s Disease: A Pilot Study

2020 ◽  
Vol 10 (2) ◽  
pp. 96 ◽  
Author(s):  
Craig D. Workman ◽  
Alexandra C. Fietsam ◽  
Ergun Y. Uc ◽  
Thorsten Rudroff
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Berg Balance Scale ◽  
Preliminary Evidence ◽  
Balance Performance ◽  
Direct Current Stimulation ◽  
Limited Effectiveness ◽  
Cerebellar Tdcs

People with Parkinson’s disease (PwPD) often experience gait and balance problems that substantially impact their quality of life. Pharmacological, surgical, and rehabilitative treatments have limited effectiveness and many PwPD continue to experience gait and balance impairment. Transcranial direct current stimulation (tDCS) may represent a viable therapeutic adjunct. The effects of lower intensity tDCS (2 mA) over frontal brain areas, in unilateral and bilateral montages, has previously been explored; however, the effects of lower and higher intensity cerebellar tDCS (2 mA and 4 mA, respectively) on gait and balance has not been investigated. Seven PwPD underwent five cerebellar tDCS conditions (sham, unilateral 2 mA, bilateral 2 mA, unilateral 4 mA, and bilateral 4 mA) for 20 min. After a 10 min rest, gait and balance were tested. The results indicated that the bilateral 4 mA cerebellar tDCS condition had a significantly higher Berg Balance Scale score compared to sham. This study provides preliminary evidence that a single session of tDCS over the cerebellum, using a bilateral configuration at a higher intensity (4 mA), significantly improved balance performance. This intensity and cerebellar configuration warrants future investigation in larger samples and over repeated sessions.

scholarly journals Transcranial direct current stimulation over the right DLPFC selectively modulates subprocesses in working memory

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4906 ◽  
Author(s):  
Jiarui Wang ◽  
Jinhua Tian ◽  
Renning Hao ◽  
Lili Tian ◽  
Qiang Liu
Keyword(s):  
Working Memory ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Working Memory Capacity ◽  
Brain Regions ◽  
Cortical Activation ◽  
Direct Current Stimulation ◽  
Difficult Condition ◽  
Cathodal Tdcs ◽  
The Right

Background Working memory, as a complex system, consists of two independent components: manipulation and maintenance process, which are defined as executive control and storage process. Previous studies mainly focused on the overall effect of transcranial direct current stimulation (tDCS) on working memory. However, little has been known about the segregative effects of tDCS on the sub-processes within working memory. Method Transcranial direct current stimulation, as one of the non-invasive brain stimulation techniques, is being widely used to modulate the cortical activation of local brain areas. This study modified a spatial n-back experiment with anodal and cathodal tDCS exertion on the right dorsolateral prefrontal cortex (DLPFC), aiming to investigate the effects of tDCS on the two sub-processes of working memory: manipulation (updating) and maintenance. Meanwhile, considering the separability of tDCS effects, we further reconfirmed the causal relationship between the right DLPFC and the sub-processes of working memory with different tDCS conditions. Results The present study showed that cathodal tDCS on the right DLPFC selectively improved the performance of the modified 2-back task in the difficult condition, whereas anodal tDCS significantly reduced the performance of subjects and showed an speeding-up tendency of response time. More precisely, the results of discriminability index and criterion showed that only cathodal tDCS enhanced the performance of maintenance in the difficult condition. Neither of the two tDCS conditions affected the performance of manipulation (updating). Conclusion These findings provide evidence that cathodal tDCS of the right DLPFC selectively affects maintenance capacity. Besides, cathodal tDCS also serves as an interference suppressor to reduce the irrelevant interference, thereby indirectly improving the working memory capacity. Moreover, the right DLPFC is not the unique brain regions for working memory manipulation (updating).

scholarly journals Safety of transcranial direct current stimulation in a patient with deep brain stimulation electrodes

2019 ◽  
Vol 77 (3) ◽  
pp. 174-178
Author(s):  
Aline Iannone ◽  
Nasser Allam ◽  
Joaquim P. Brasil-Neto
Keyword(s):  
Deep Brain Stimulation ◽  
Direct Current ◽  
Brain Stimulation ◽  
Movement Disorders ◽  
Transcranial Direct Current Stimulation ◽  
Direct Current Stimulation ◽  
Cerebellar Tdcs ◽  
Stn Dbs ◽  
Deep Brain ◽  
Cerebellar Stimulation

ABSTRACT Background: Transcranial direct current stimulation (tDCS) has been investigated in movement disorders, making it a therapeutic alternative in clinical settings. However, there is still no consensus on the most appropriate treatment protocols in most cases, and the presence of deep brain stimulation (DBS) electrodes has been regarded as a contraindication to the procedure. We recently studied the effects of cerebellar tDCS on a female patient already undergoing subthalamic nucleus deep brain stimulation (STN-DBS) for generalized dystonia. She also presented with chronic pain and depression. With STN-DBS, there was improvement of dystonia, and botulinum toxin significantly reduced pain. However, depressive symptoms were worse after STN-DBS surgery. Methods: Neuromodulation with 2 mA anodal cerebellar tDCS was initiated, targeting both hemispheres in each daily 30 minute session: 15 minutes of left cerebellar stimulation followed by 15 minutes of right cerebellar stimulation. The DBS electrodes were in place and functional, but the current was turned off during tDCS. Results: Although our goal was to improve dystonic movements, after 10 tDCS sessions there was also improvement in mood with normalization of Beck Depression Inventory scores. There were no complications in spite of the implanted STN-DBS leads. Conclusion: Our results indicate that tDCS is safe in patients with DBS electrodes and may be an effective add-on neuromodulatory tool in the treatment of potential DBS partial efficacy in patients with movement disorders.

scholarly journals Optimizing transcranial direct current stimulation (tDCS) electrode position, size, and distance doubles the on-target cortical electric field: Evidence from 3000 Human Connectome Project models

2021 ◽  
Author(s):  
Kevin A. Caulfield ◽  
Mark S. George
Keyword(s):  
Electric Field ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Brain Regions ◽  
Cortical Activation ◽  
Electrode Position ◽  
Stimulation Intensity ◽  
Direct Current Stimulation ◽  
Field Evidence ◽  
Human Connectome Project

Transcranial direct current stimulation (tDCS) is a widely used noninvasive brain stimulation technique with mixed results and no FDA-approved therapeutic indication to date. So far, thousands of published tDCS studies have placed large scalp electrodes directly over the intended brain target and delivered the same stimulation intensity to each person. Inconsistent therapeutic results may be due to insufficient cortical activation in some individuals and the inability to determine an optimal dose. Here, we computed 3000 MRI-based electric field models in 200 Human Connectome Project (HCP) participants, finding that the largely unexamined variables of electrode position, size, and between-electrode distance significantly impact the delivered cortical electric field magnitude. At the same scalp stimulation intensity, smaller electrodes surrounding the neural target deliver more than double the on-target cortical electric field while stimulating only a fraction of the off-target brain regions. This new optimized tDCS method can ensure sufficient cortical activation in each person and could produce larger and more consistent behavioral effects in every prospective research and transdiagnostic clinical application of tDCS.

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