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.

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 Effects of Transcranial Direct Current Stimulation on effort during a working-memory task

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
David Framorando ◽  
Tianlan Cai ◽  
Yi Wang ◽  
Alan J. Pegna
Keyword(s):  
Working Memory ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Memory Task ◽  
Time Interval ◽  
Direct Current Stimulation ◽  
Anodal Stimulation ◽  
Dorsolateral Prefrontal ◽  
Systolic Time ◽  
Task Mastery

AbstractTranscranial Direct Current Stimulation (tDCS) has shown that stimulation of Dorsolateral Prefrontal Cortex (DLPFC) facilitates task performance in working-memory tasks. However, little is known about its potential effects on effort. This study examined whether tDCS affects effort during a working-memory task. Participants received anodal, cathodal and sham stimulation over DLPFC across three sessions before carrying out a 2-back task. During the task, effort-related cardiovascular measures were recorded—especially the Initial Systolic Time Interval (ISTI). Results showed that anodal stimulation produced a shorter ISTI, indicating a greater effort compared to cathodal and sham conditions, where effort was lower. These findings demonstrate that anodal stimulation helps participants to maintain engagement in a highly demanding task (by increasing task mastery), without which they would otherwise disengage. This study is the first to show that tDCS impacts the extent of effort engaged by individuals during a difficult task.

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