Abstract
Transcranial 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.
Highlights
To determine stable cardiovascular baseline values and check for any significant differences at baseline, we ran repeated-measures ANOVAs of the 8 1-min scores of Initial Systolic Time Interval (ISTI), heart rate (HR), SBP, and diastolic blood pressure (DBP) with the three stimulation conditions included as a factor
Anodal stimulation of the Dorsolateral Prefrontal Cortex (DLPFC) is associated with shorter ISTI, which is interpreted as the result of higher effort
We decided to opt for Initial Systolic Time Interval (ISTI) as a measure of effort because it is less prone to errors, relying on salient waveform points that are and reliably identifiable
Summary
To determine stable cardiovascular baseline values and check for any significant differences at baseline, we ran repeated-measures ANOVAs of the 8 1-min scores of ISTI, HR, SBP, and DBP with the three stimulation conditions included as a factor. Given the absence of significant difference of the baseline measures for ISTI, HR and DBP across time and conditions and the absence of significant difference for the last seven minutes of the SBP, unique scores by indices were created using the last 7 measures of the baselines. The a priori contrasts for the task difficulty, success importance, feeling of ability and perceived performance (mean and standard error are depicted in Table 3) during the task were non-significant, Fs(1, 16) > 4.09, ps > 0.06, η2 < 0.20. The overall rating of the task demand was of 4.93 on a 7 Likert scale
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
