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 Verbal Fluency in Mild Alzheimer’s Disease: Transcranial Direct Current Stimulation over the Dorsolateral Prefrontal Cortex

2021 ◽  
pp. 1-11
Author(s):  
Daniela Smirni ◽  
Massimiliano Oliveri ◽  
Eliana Misuraca ◽  
Angela Catania ◽  
Laura Vernuccio ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Verbal Fluency ◽  
Dorsolateral Prefrontal Cortex ◽  
Control Group ◽  
Direct Current Stimulation ◽  
Cathodal Tdcs ◽  
Dorsolateral Prefrontal ◽  
The Right

Background: Recent studies showed that in healthy controls and in aphasic patients, inhibitory trains of repetitive transcranial magnetic stimulation (rTMS) over the right prefrontal cortex can improve phonemic fluency performance, while anodal transcranial direct current stimulation (tDCS) over the left prefrontal cortex can improve performance in naming and semantic fluency tasks. Objective: This study aimed at investigating the effects of cathodal tDCS over the left or the right dorsolateral prefrontal cortex (DLPFC) on verbal fluency tasks (VFT) in patients with mild Alzheimer’s disease (AD). Methods: Forty mild AD patients participated in the study (mean age 73.17±5.61 years). All participants underwent cognitive baseline tasks and a VFT twice. Twenty patients randomly received cathodal tDCS to the left or the right DLPFC, and twenty patients were assigned to a control group in which only the two measures of VFT were taken, without the administration of the tDCS. Results: A significant improvement of performance on the VFT in AD patients was present after tDCS over the right DLPFC (p = 0.001). Instead, no difference was detected between the two VFTs sessions after tDCS over the left DLPFC (p = 0.42). Furthermore, these results cannot be related to task learning effects, since no significant difference was found between the two VFT sessions in the control group (p = 0.73). Conclusion: These data suggest that tDCS over DLPFC can improve VFT performance in AD patients. A hypothesis is that tDCS enhances adaptive patterns of brain activity between functionally connected areas.

scholarly journals Effects of Transcranial Direct Current Stimulation over Left Dorsolateral pFC on the Attentional Blink Depend on Individual Baseline Performance

2015 ◽  
Vol 27 (12) ◽  
pp. 2382-2393 ◽  
Author(s):  
Raquel E. London ◽  
Heleen A. Slagter
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Attentional Blink ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Critical Role ◽  
Anodal Tdcs ◽  
Direct Current Stimulation ◽  
Cathodal Tdcs ◽  
Left Dlpfc

Selection mechanisms that dynamically gate only relevant perceptual information for further processing and sustained representation in working memory are critical for goal-directed behavior. We examined whether this gating process can be modulated by anodal transcranial direct current stimulation (tDCS) over left dorsolateral pFC (DLPFC)—a region known to play a key role in working memory and conscious access. Specifically, we examined the effects of tDCS on the magnitude of the so-called “attentional blink” (AB), a deficit in identifying the second of two targets presented in rapid succession. Thirty-four participants performed a standard AB task before (baseline), during, and after 20 min of 1-mA anodal and cathodal tDCS in two separate sessions. On the basis of previous reports linking individual differences in AB magnitude to individual differences in DLPFC activity and on suggestions that effects of tDCS depend on baseline brain activity levels, we hypothesized that anodal tDCS over left DLPFC would modulate the magnitude of the AB as a function of individual baseline AB magnitude. Indeed, individual differences analyses revealed that anodal tDCS decreased the AB in participants with a large baseline AB but increased the AB in participants with a small baseline AB. This effect was only observed during (but not after) stimulation, was not found for cathodal tDCS, and could not be explained by regression to the mean. Notably, the effects of tDCS were not apparent at the group level, highlighting the importance of taking individual variability in performance into account when evaluating the effectiveness of tDCS. These findings support the idea that left DLPFC plays a critical role in the AB and in conscious access more generally. They are also in line with the notion that there is an optimal level of prefrontal activity for cognitive function, with both too little and too much activity hurting performance.

Enhancing Working Memory Training with Transcranial Direct Current Stimulation

2016 ◽  
Vol 28 (9) ◽  
pp. 1419-1432 ◽  
Author(s):  
Jacky Au ◽  
Benjamin Katz ◽  
Martin Buschkuehl ◽  
Kimberly Bunarjo ◽  
Thea Senger ◽  
...  
Keyword(s):  
Working Memory ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Cortical Excitability ◽  
Brain Plasticity ◽  
Memory Training ◽  
Direct Current Stimulation ◽  
Training Interventions ◽  
Learning Tasks ◽  
The Right

Working memory (WM) is a fundamental cognitive ability that supports complex thought but is limited in capacity. Thus, WM training interventions have become very popular as a means of potentially improving WM-related skills. Another promising intervention that has gained increasing traction in recent years is transcranial direct current stimulation (tDCS), a noninvasive form of brain stimulation that can modulate cortical excitability and temporarily increase brain plasticity. As such, it has the potential to boost learning and enhance performance on cognitive tasks. This study assessed the efficacy of tDCS to supplement WM training. Sixty-two participants were randomized to receive either right prefrontal, left prefrontal, or sham stimulation with concurrent visuospatial WM training over the course of seven training sessions. Results showed that tDCS enhanced training performance, which was strikingly preserved several months after training completion. Furthermore, we observed stronger effects when tDCS was spaced over a weekend break relative to consecutive daily training, and we also demonstrated selective transfer in the right prefrontal group to nontrained tasks of visual and spatial WM. These findings shed light on how tDCS may be leveraged as a tool to enhance performance on WM-intensive learning tasks.

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.

scholarly journals High-Definition Transcranial Direct Current Stimulation Over the Right Lateral Prefrontal Cortex Increases Maximization Tendencies

2021 ◽  
Vol 15 ◽  
Author(s):  
Haixia Wang ◽  
Hanqi Zhang
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Memory Task ◽  
High Definition ◽  
Direct Current Stimulation ◽  
Dorsolateral Prefrontal ◽  
The Right ◽  
Motivational Changes

People seek the best in every aspect of life. However, little is known about the neurobiological mechanisms supporting this process of maximization. In this study, maximization tendencies were increased by using high-definition transcranial direct current stimulation (HD-tDCS) over the right dorsolateral prefrontal cortex (DLPFC). Participants (n = 64) received 2 mA anodal 4 × 1 HD-tDCS or sham stimulation over the right DLPFC in two sessions and subsequently completed an N-back working memory task and a maximization scale (MS). We observed that maximization tendency scores increased during anodal stimulation. Furthermore, the results indicate that this increase in maximization tendency was driven by motivational changes. On the MS, alternative search subscale scores were significantly increased, demonstrating an increase in motivation to evaluate more alternatives; however, the results did not indicate that the increase in maximization tendencies was due to working memory improvement. These results demonstrated that maximization tendencies can be strengthened through noninvasive interventions and that the right DLPFC has a causal relationship with maximization tendencies.

scholarly journals A selective working memory impairment after transcranial direct current stimulation to the right parietal lobe

2010 ◽  
Vol 479 (3) ◽  
pp. 312-316 ◽  
Author(s):  
Marian E. Berryhill ◽  
Elaine B. Wencil ◽  
H. Branch Coslett ◽  
Ingrid R. Olson
Keyword(s):  
Working Memory ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Memory Impairment ◽  
Parietal Lobe ◽  
Direct Current Stimulation ◽  
The Right ◽  
Selective Working

scholarly journals Enhancement of Visuospatial Working Memory by Transcranial Direct Current Stimulation (tDCS) on Prefrontal and Parietal Cortices

2021 ◽  
pp. 1-15
Author(s):  
Yousef Moghadas Tabrizi ◽  
◽  
Meysam Yavari Kateb ◽  
Shahnaz Shahrbanian ◽  
◽  
...  
Keyword(s):  
Working Memory ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Spatial Working Memory ◽  
Direct Current Stimulation ◽  
Frontoparietal Network ◽  
Dorsolateral Prefrontal ◽  
Posterior Parietal ◽  
The Right ◽  
Parietal Cortices

Objective: Previous studies have reported dorsolateral prefrontal cortex (DLPFC) and posterior parietal (PPC) activation during the performance of spatial working memory (SWM), so we decided to investigate the comparison of Transcranial Direct current stimulation (tDCS) effect between these two areas. Methods: Fifty-four healthy right-handed students (27 female, 27 male; age= 24.3±.2 years) were randomly assigned to anodal (N=27) and sham group (N= 27), each of these groups was further divided into F4 (representing right DLPFC) or P4 (representing right PPC) subgroups, respectively. A Computerized Corsi Block Tapping task has then used to measure spatial working memory. The t-DCS intervention consisted of five daily sessions with a direct current of 1.5 mA for 15 minutes over the F4 or P4 area of the brain at 24-hour intervals. Results: Significant enhancement of the SWM span as well as a faster response were seen after anodal tDCS in both the forward and backward direction. Moreover, the right DLPFC stimulation induced a faster reaction time compared to the right PPC. Conclusions: Both DLPFC and PP cortices stimulation, as an element of the frontoparietal network, showed SWM enhancement, with the DLPFC being more effected. Our finding provides new evidence for the comparison of the effect of stimulation on the two main activated cortical areas during visuospatial WM.

Cerebellar Transcranial Direct Current Stimulation Impairs the Practice-dependent Proficiency Increase in Working Memory

2008 ◽  
Vol 20 (9) ◽  
pp. 1687-1697 ◽  
Author(s):  
R. Ferrucci ◽  
S. Marceglia ◽  
M. Vergari ◽  
F. Cogiamanian ◽  
S. Mrakic-Sposta ◽  
...  
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Reaction Times ◽  
After Effects ◽  
Direct Current Stimulation ◽  
Cathodal Tdcs ◽  
Cerebellar Tdcs ◽  
Sternberg Task

How the cerebellum is involved in the practice and proficiency of non-motor functions is still unclear. We tested whether transcranial direct current stimulation (tDCS) over the cerebellum (cerebellar tDCS) induces after-effects on the practice-dependent increase in the proficiency of a working memory (WM) task (Sternberg test) in 13 healthy subjects. We also assessed the effects of cerebellar tDCS on visual evoked potentials (VEPs) in four subjects and compared the effects of cerebellar tDCS on the Sternberg test with those elicited by tDCS delivered over the prefrontal cortex in five subjects. Our experiments showed that anodal or cathodal tDCS over the cerebellum impaired the practice-dependent improvement in the reaction times in a WM task. Because tDCS delivered over the prefrontal cortex induced an immediate change in the WM task but left the practice-dependent proficiency unchanged, the effects of cerebellar tDCS are structure-specific. Cerebellar tDCS left VEPs unaffected, its effect on the Sternberg task therefore seems unlikely to arise from visual system involvement. In conclusion, tDCS over the cerebellum specifically impairs the practice-dependent proficiency increase in verbal WM.

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