Transcranial direct current stimulation over the right and left VLPFC leads to differential effects on working and episodic memory.

Previous research suggests that the left VLPFC is involved in working memory, whereas right VLPFC is involved with subsequent episodic memory. High-Definition Transcranial Direct Current Stimulation (HD-tDCS) was used to test whether excitation of the left or right VLPFC would show differential effects of negative and neutral stimuli on working memory and episodic memory tasks. While receiving HD-tDCS over the left or right VLPFC or sham stimulation, participants completed a working memory task with negative and neutral distractors followed by a surprise recognition test for the distractors. HD-tDCS over the left VLPFC led to improved working memory performance compared to sham for both negative and neutral distractors. However, for trials that were subsequently remembered, a greater proportion of working memory trials were correct for both the right and left VLPFC group compared to the sham group, for both negative and neutral distractors. Whereas the results from the left VLPFC group can be attributed to overall higher working memory performance, findings from the right VLPFC suggest a role of the right VLPFC in coping with distracting stimuli. Taken together, these results indicate causal roles for the left VLPFC in working memory and the right VLPFC in working memory and episodic memory.