Emotion-Induced Transcranial Direct Current Stimulation for Working Memory Improvement

Abstract

Objective: To examine the effects of anodal transcranial direct current stimulation (tDCS) on working memory under different emotion-induced states. Method: A total of 180 healthy right-handed adults aged 18-35 years were assigned to a 3 (emotion: happy, neutral, sad) × 4 (stimulation: sham, 1.0 mA, 1.5 mA, 2.0 mA) between-subjects design. Emotions were induced by pictures or video clips and verified using the Positive and Negative Affect Schedule (PANAS). Participants completed a letter 2-back task before and after stimulation. Accuracy and correct-trial reaction time were analyzed. Results: Baseline accuracy did not differ across emotion conditions, whereas baseline reaction time showed a modest emotion effect. Active anodal tDCS generally increased accuracy and reduced reaction time compared with sham stimulation. Stimulation intensity showed significant main effects on both accuracy change and reaction-time change. Emotion showed a significant main effect on reaction-time change, whereas the emotion-by-intensity interaction was not significant. Conclusion: Anodal tDCS may improve working memory across different emotion-induced states. Stimulation intensity appears to be the dominant factor, while emotional state may influence baseline processing speed and the magnitude of behavioral response.