Engagement of a parieto-cerebellar network in prism adaptation. A double-blind high-definition transcranial direct current stimulation study on healthy individuals

Cortex ◽  
2021 ◽  
Author(s):  
Francesco Panico ◽  
Laura Sagliano ◽  
Gaia Sorbino ◽  
Luigi Trojano
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Prism Adaptation ◽  
Healthy Individuals ◽  
High Definition ◽  
Double Blind ◽  
Direct Current Stimulation

scholarly journals Differences in high-definition transcranial direct current stimulation over the motor hotspot versus the premotor cortex on motor network excitability

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Stephanie Lefebvre ◽  
Kay Jann ◽  
Allie Schmiesing ◽  
Kaori Ito ◽  
Mayank Jog ◽  
...  
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
High Definition ◽  
Double Blind ◽  
Promising Alternative ◽  
Direct Current Stimulation ◽  
Motor Network ◽  
Motor Excitability

AbstractThe effectiveness of transcranial direct current stimulation (tDCS) placed over the motor hotspot (thought to represent the primary motor cortex (M1)) to modulate motor network excitability is highly variable. The premotor cortex—particularly the dorsal premotor cortex (PMd)—may be a promising alternative target to reliably modulate motor excitability, as it influences motor control across multiple pathways, one independent of M1 and one with direct connections to M1. This double-blind, placebo-controlled preliminary study aimed to differentially excite motor and premotor regions using high-definition tDCS (HD-tDCS) with concurrent functional magnetic resonance imaging (fMRI). HD-tDCS applied over either the motor hotspot or the premotor cortex demonstrated high inter-individual variability in changes on cortical motor excitability. However, HD-tDCS over the premotor cortex led to a higher number of responders and greater changes in local fMRI-based complexity than HD-tDCS over the motor hotspot. Furthermore, an analysis of individual motor hotspot anatomical locations revealed that, in more than half of the participants, the motor hotspot is not located over anatomical M1 boundaries, despite using a canonical definition of the motor hotspot. This heterogeneity in stimulation site may contribute to the variability of tDCS results. Altogether, these preliminary findings provide new considerations to enhance tDCS reliability.

scholarly journals Sequential dual-site High-Definition transcranial Direct Current Stimulation (HD-tDCS) treatment in chronic subjective tinnitus: study protocol of a double-blind, randomized, placebo-controlled trial

2019 ◽  
Author(s):  
Emilie Cardon ◽  
Vincent Van Rompaey ◽  
Laure Jacquemin ◽  
Griet Mertens ◽  
Hanne Vermeersch ◽  
...  
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Controlled Trial ◽  
Chronic Tinnitus ◽  
High Definition ◽  
Double Blind ◽  
Direct Current Stimulation ◽  
Tinnitus Severity ◽  
The Impact ◽  
Dual Site

Abstract Background: Chronic tinnitus is a highly prevalent symptom, with many patients reporting considerable effects of tinnitus on quality of life. No clear evidence-based treatment options are currently available. While counseling-based methods are valuable in some cases, they are not sufficiently effective for all tinnitus patients. Neuromodulation techniques such as high-definition transcranial direct current stimulation (HD-tDCS) are proposed to have positive effects on tinnitus severity but, to date, these effects have not been proven conclusively. The proposed trial will investigate the hypothesis that chronic tinnitus patients receiving HD-tDCS will report a positive effect on the impact of tinnitus on daily life, as compared to patients receiving sham stimulation. Methods: This study proposes a randomized, double-blind, placebo-controlled trial with parallel group design. A total of 100 chronic tinnitus patients will be randomly allocated to an experimental group or a sham group, with allocation stratified according to gender and tinnitus severity. Patient and researcher will be blinded to the patient’s allocation. Patients will undergo six sessions of sequential dual-site HD-tDCS of the left temporal area and the right dorsolateral prefrontal cortex. Evaluations will take place at baseline, immediately following treatment, and at three and six months after the start of the therapy. The primary outcome measure is the change in Tinnitus Functional Index (TFI) score. Secondary outcome measures include audiological measurements, cortical auditory evoked potentials, the Repeatable Battery for the Assessment of Neuropsychological Status adjusted to test Hearing impaired individuals (RBANS-H), and supplementary questionnaires probing tinnitus severity and additional symptoms. By use of a linear regression model, the effects of HD-tDCS compared to sham stimulation will be assessed. Discussion: The objective of this study is to evaluate whether HD-tDCS can reduce the impact of tinnitus on daily life in chronic tinnitus patients. To date, published trials on the effects of HD-tDCS on tinnitus suffer from a lack of standardization, and few randomized controlled trials exist. The proposed study will be the first adequately powered trial to investigate the effects of sequential dual-site HD-tDCS on tinnitus severity. Trial registration: The present study protocol (version 2) was registered on 22 November 2018 at ClinicalTrials.gov: NCT03754127. Keywords: Chronic tinnitus, Transcranial direct current stimulation, Neuromodulation, Randomized controlled trial

scholarly journals Transcranial direct current stimulation above the medial prefrontal cortex counteracts the effects of diminished outcome controllability during reinforcement learning

2020 ◽  
Author(s):  
Gábor Csifcsák ◽  
Jorunn Bjørkøy ◽  
Sarjo Kuyateh ◽  
Haakon Reithe ◽  
Matthias Mittner
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Direct Current ◽  
Learned Helplessness ◽  
Transcranial Direct Current Stimulation ◽  
Parameter Estimates ◽  
Double Blind Study ◽  
High Definition ◽  
Double Blind ◽  
Direct Current Stimulation

Background: The arbitration between decision-making strategies is shaped by the degree of controllability over environmental events. Under low control, individuals might rely more heavily on Pavlovian bias (PB), which facilitates and inhibits actions when facing appetitive and aversive cues, respectively. More recently, extreme PB was implicated in learned helplessness (LH), which is typically induced by uncontrollable punishment. On the neural level, the medial prefrontal cortex (mPFC) was pinpointed as a region underlying both cognitive control over PB, and the pathogenesis of LH.Objective/Hypothesis: To test if high-definition transcranial direct current stimulation (HD-tDCS) targeting the mPFC counteracts with the deleterious behavioral effects of low controllability over rewards/losses (“yoking”) during reinforcement learning.Methods: In a pre-registered, between-group, double-blind study (N = 103, healthy adults), we tested the interaction of low controllability and HD-tDCS on performance in a Go/NoGo task. Yoking was implemented by presenting random outcomes following responses, while matching reward/loss frequencies between control and yoked groups. HD-tDCS was delivered for 15 minutes at 2 mA using a 4x1 montage centered at position Fz.Results: HD-tDCS improved response accuracy by the end of the task only when applied simultaneously with yoking. The beneficial consequences of active stimulation in yoked participants were more pronounced in reward-predictive trials. Finally, computational modeling revealed that parameter estimates of learning rate and choice randomness were modulated by yoking and HD-tDCS in an interactive manner.Conclusions: These results highlight the potential of our HD-tDCS protocol for interfering with choice arbitration in volatile environments, resulting in more adaptive behavior.

Transcranial Direct Current Stimulation Improves Word Retrieval in Healthy and Nonfluent Aphasic Subjects

2011 ◽  
Vol 23 (9) ◽  
pp. 2309-2323 ◽  
Author(s):  
Valentina Fiori ◽  
Michela Coccia ◽  
Chiara V. Marinelli ◽  
Veronica Vecchi ◽  
Silvia Bonifazi ◽  
...  
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Picture Naming ◽  
Naming Task ◽  
Word Retrieval ◽  
Healthy Individuals ◽  
Double Blind ◽  
Direct Current Stimulation ◽  
Sham Condition ◽  
Wernicke’S Area

A number of studies have shown that modulating cortical activity by means of transcranial direct current stimulation (tDCS) affects performances of both healthy and brain-damaged subjects. In this study, we investigated the potential of tDCS to enhance associative verbal learning in 10 healthy individuals and to improve word retrieval deficits in three patients with stroke-induced aphasia. In healthy individuals, tDCS (20 min, 1 mA) was applied over Wernicke's area (position CP5 of the International 10–20 EEG System) while they learned 20 new “words” (legal nonwords arbitrarily assigned to 20 different pictures). The healthy subjects participated in a randomized counterbalanced double-blind procedure in which they were subjected to one session of anodic tDCS over left Wernicke's area, one sham session over this location and one session of anodic tDCS stimulating the right occipito-parietal area. Each experimental session was performed during a different week (over three consecutive weeks) with 6 days of intersession interval. Over 2 weeks, three aphasic subjects participated in a randomized double-blind experiment involving intensive language training for their anomic difficulties in two tDCS conditions. Each subject participated in five consecutive daily sessions of anodic tDCS (20 min, 1 mA) and sham stimulation over Wernicke's area while they performed a picture-naming task. By the end of each week, anodic tDCS had significantly improved their accuracy on the picture-naming task. Both normal subjects and aphasic patients also had shorter naming latencies during anodic tDCS than during sham condition. At two follow-ups (1 and 3 weeks after the end of treatment), performed only in two aphasic subjects, response accuracy and reaction times were still significantly better in the anodic than in the sham condition, suggesting a long-term effect on recovery of their anomic disturbances.

Cerebellar, but not Motor or Parietal, High-Density Anodal Transcranial Direct Current Stimulation Facilitates Motor Adaptation

2016 ◽  
Vol 22 (9) ◽  
pp. 928-936 ◽  
Author(s):  
Michael Doppelmayr ◽  
Nils Henrik Pixa ◽  
Fabian Steinberg
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Motor Adaptation ◽  
Double Blind Study ◽  
Single Session ◽  
High Definition ◽  
Double Blind ◽  
Direct Current Stimulation ◽  
Anodal Stimulation ◽  
The Right

AbstractObjectives: Although motor adaptation is a highly relevant process for both everyday life as well as rehabilitation many details of this process are still unresolved. To evaluate the contribution of primary motor (M1), parietal and cerebellar areas to motor adaptation processes transcranial direct current stimulation (tDCS) has been applied. We hypothesized that anodal stimulation of the cerebellum and the M1 improves the learning process in mirror drawing, a task involving fine grained and spatially well-organized hand movements. Methods: High definition tDCS (HD-tDCS) allows a focal stimulation to modulate brain processes. In a single-session double-blind study, we compared the effects of different anodal stimulation procedures. The groups received stimulation either at the cerebellum (CER), at right parietal (PAR), or at left M1, and a SHAM group was included. Participants (n=83) had to complete several mirror drawing tasks before, during, and after stimulation. They were instructed to re-trace a line in the shape of a pentagonal star as fast and accurate as possible. Tracing time (seconds) and accuracy (deviation in mm) have been evaluated. Results: The results indicated that cerebellar HD-tDCS can facilitate motor adaptation in a single session. The stimulation at M1 showed only a tendency to increase motor adaptation and these effects were visible only during the first part of the stimulation. Stimulating the right parietal area, relevant for visuospatial processing did not lead to increased performance. Conclusions: Our results suggest that motor adaptation relies to a great extent on cerebellar functions and HD-tDCS can speed up this process. (JINS, 2016, 22, 928–936)

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