scholarly journals The Temporal Change of Cortical Activation Induced by the Ongoing Effects of Transcranial Direct Current Stimulation

2011 ◽  
Vol 23 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Yong Hyun Kwon ◽  
Ki Seok Nam ◽  
Mi Young Lee ◽  
Ji Won Park ◽  
Sung Ho Jang
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Temporal Change ◽  
Cortical Activation ◽  
Direct Current Stimulation

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 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.

Task-dependent and polarity-specific effects of prefrontal transcranial direct current stimulation on cortical activation during word fluency

NeuroImage ◽  
2016 ◽  
Vol 140 ◽  
pp. 134-140 ◽  
Author(s):  
Ann-Christine Ehlis ◽  
Florian B. Haeussinger ◽  
Alex Gastel ◽  
Andreas J. Fallgatter ◽  
Christian Plewnia
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Cortical Activation ◽  
Word Fluency ◽  
Direct Current Stimulation ◽  
Specific Effects

scholarly journals Extended fMRI-Guided Anodal and Cathodal Transcranial Direct Current Stimulation Targeting Perilesional Areas in Post-Stroke Aphasia: A Pilot Randomized Clinical Trial

2021 ◽  
Vol 11 (3) ◽  
pp. 306
Author(s):  
Leora R. Cherney ◽  
Edna M. Babbitt ◽  
Xue Wang ◽  
Laura L. Pitts
Keyword(s):  
Left Hemisphere ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Pilot Trial ◽  
Cortical Activation ◽  
Functional Language ◽  
Serious Adverse Events ◽  
Direct Current Stimulation ◽  
Post Stroke ◽  
Left Hemisphere Stroke

Transcranial direct current stimulation (tDCS) may enhance speech and language treatment (SLT) for stroke survivors with aphasia; however, to date, there is no standard protocol for the application of tDCS in post-stroke aphasia. We explored the safety and efficacy of fMRI-guided tDCS on functional language and cortical activity when delivered to the lesioned left hemisphere concurrently with SLT across an extended, six-week treatment period. Twelve persons with chronic, nonfluent aphasia following a single left-hemisphere stroke participated in the three-arm (anodal vs. cathodal vs. sham) single-blind, parallel, pilot trial. No serious adverse events occurred during 30 treatment sessions or in the following six weeks. All groups demonstrated functional language gains following intensive treatment; however, active tDCS resulted in greater gains in standardized, probe, and caregiver-reported measures of functional language than sham. Evidence declaring one polarity as superior for inducing language recovery was mixed. However, cathodal stimulation to the lesioned left hemisphere, expected to have a down-regulating effect, resulted in increased areas of cortical activation across both hemispheres, and specifically perilesionally. Generalization of these preliminary findings is limited; however, results are nevertheless compelling that tDCS combined with SLT can be safely applied across extended durations, with the potential to enhance functional language and cortical activation for persons with aphasia.

scholarly journals Neuroimaging Guided Transcranial Electrical Stimulation in Enhancing Surgical Skill Acquisition. Comment on Hung et al. The Efficacy of Transcranial Direct Current Stimulation in Enhancing Surgical Skill Acquisition: A Preliminary Meta-Analysis of Randomized Controlled Trials. Brain Sci. 2021, 11, 707

2021 ◽  
Vol 11 (8) ◽  
pp. 1078
Author(s):  
Pushpinder Walia ◽  
Kavya Narendra Kumar ◽  
Anirban Dutta
Keyword(s):  
Electrical Stimulation ◽  
Skill Acquisition ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Meta Analysis ◽  
Cortical Activation ◽  
Transcranial Electrical Stimulation ◽  
Surgical Skill ◽  
Direct Current Stimulation ◽  
Motor Complexity

Surgical skill acquisition may be facilitated with a safe application of transcranial direct current stimulation (tDCS). A preliminary meta-analysis of randomized control trials showed that tDCS was associated with significantly better improvement in surgical performance than the sham control; however, meta-analysis does not address the mechanistic understanding. It is known from skill learning studies that the hierarchy of cognitive control shows a rostrocaudal axis in the frontal lobe where a shift from posterior to anterior is postulated to mediate progressively abstract, higher-order control. Therefore, optimizing the transcranial electrical stimulation to target surgical task-related brain activation at different stages of motor learning may provide the causal link to the learning behavior. This comment paper presents the computational approach for neuroimaging guided tDCS based on open-source software pipelines and an open-data of functional near-infrared spectroscopy (fNIRS) for complex motor tasks. We performed an fNIRS-based cortical activation analysis using AtlasViewer software that was used as the target for tDCS of the motor complexity-related brain regions using ROAST software. For future studies on surgical skill training, it is postulated that the higher complexity laparoscopic suturing with intracorporeal knot tying task may result in more robust activation of the motor complexity-related brain areas when compared to the lower complexity laparoscopic tasks.

Effects of Transcranial Direct Current Stimulation on Apraxia of Speech and Cortical Activation in Patients With Stroke: A Randomized Sham-Controlled Study

2019 ◽  
Vol 28 (4) ◽  
pp. 1625-1637 ◽  
Author(s):  
Jie Wang ◽  
Dongyu Wu ◽  
Yinan Cheng ◽  
Weiqun Song ◽  
Ying Yuan ◽  
...  
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Primary Motor Cortex ◽  
Approximate Entropy ◽  
Cortical Activation ◽  
Controlled Study ◽  
Broca’S Area ◽  
Apraxia Of Speech ◽  
Broca's Area ◽  
Direct Current Stimulation

Purpose The study aims to investigate, using anodal transcranial direct current stimulation (A-tDCS), over which site, the left lip region of primary motor cortex (M1) or the Broca's area, there would be better recovery from apraxia of speech (AoS) in patients with poststroke aphasia and to examine for altered activation in speech-related areas after tDCS with nonlinear electroencephalography (EEG). Method Fifty-two patients with AoS were randomized into A-tDCS over the left M1 (A-tDCS-M1), Broca's area, and sham tDCS groups who underwent 10 sessions of tDCS and speech treatment for 5 days. The EEG nonlinear index of approximate entropy was calculated for 6 subjects in each group before and after treatment. Results After treatment, the change in speech-language performance improved more significantly in the A-tDCS-M1 group than the other 2 groups ( p < .05). EEG approximate entropy indicated that both A-tDCS groups could activate the stimulated sites; the improvement in the A-tDCS-M1 group was correlated with high activation in the dorsal lateral prefrontal cortex and Broca's areas of the left hemisphere in addition to the stimulated site. Conclusion A-tDCS over the left M1 can improve the speech function in patients with poststroke aphasia and severe AoS and excite and recruit more areas in the motor speech network.

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