Dorsolateral Prefrontal Cortex and Task-Switching Performance: Effects of Anodal Transcranial Direct Current...

Task switching refers to the process by which an individual transfers focus from one cognitive task to another. In recent years, transcranial direct current stimulation (tDCS) technology had been used to investigate the causal relationship between the dorsolateral prefrontal cortex (DLPFC) and task-switching performance. However, the effects of anodal-tDCS (a-tDCS) on task switching remain unclear, and the relationship between DLPFC and various task predictabilities have not yet been studied. Therefore, this study mainly investigated the effects of left anode tDCS (LA) and right anode tDCS (RA) in predictable and unpredictable task-switching performance. Thirty-six participants were randomly assigned to three tDCS groups (including LA, RA, and sham) and were asked to complete both the predictable and unpredictable tasks. Compared with LA and sham tDCS, increasing the activity of the right DLPFC improved task-switching performance (switch cost) of unpredictable but not predictable tasks. The results suggested there is a causal association between DLPFC and unpredictable task switching and implied a task-specific effect in task switching. We concluded that the DLPFC is not essential for exogenous adjustment in predictable task switching.