Evaluating the Effects of Online tDCS with Emotional n-back Training on Working Memory and Associated Cognitive Abilities

Working memory (WM) is a core cognitive ability important for everyday functioning. A burgeoning area of research suggests that WM can be improved via working memory training (WMT) paradigms. Additionally, recent research has shown that WM may be enhanced through noninvasive neuromodulation such as transcranial direct current stimulation (tDCS). In this study, we evaluated how a single-session, brief-but-concentrated combination of tDCS over the left dorsolateral prefrontal cortex (dlPFC; F3 region), paired with a WMT paradigm utilizing emotional stimuli (emotional n-back) could produce gains in WM and associated, untrained cognitive abilities. Healthy undergraduate participants were randomized to receive either active tDCS and WMT, or sham-tDCS and WMT. Cognitive abilities (WM, attention control, and cognitive inhibition) were measured before and after the intervention. No significant differences were found in WM performance or associated abilities between those who received active or sham tDCS. Individuals in both groups evidenced a faster reaction time on an Operation Span task, and an Emotional Stroop Task, following the WMT session. These findings add to the mixed picture of the effectiveness of single-session WMT protocols and highlight the importance of the dose-response relationship in training core cognitive processes such as WM.