Investigation of the influence of emotions on working memory capacity using ERP and ERSP

Recent studies have reported that there are individual differences in working memory (WM), and that WM may be affected by emotions. To date, it remains controversial whether emotions impair or facilitate WM and whether there are individual differences in their effect on WM. In this study, three emotions (negative, neutral, and positive) were induced by a video database that was established according to the emotional stimuli habit of Chinese people. A change detection paradigm was used to examine the effect of emotions on the visual WM. Participants were divided into high- and low-capacity groups according to their WM capacity. The behavioral results revealed that both negative and positive emotions may enhance WM capacity in the high-capacity group compared with the neutral emotion. In contrast, an opposite effect was observed in the low-capacity group. Analysis of the contralateral delay activity and P300 components demonstrated significantly higher amplitudes in the high-capacity group following positive and negative emotions; the effects were opposite in the low-capacity group. The event-related spectral perturbation results demonstrated a more powerful event-related synchronization in the alpha-band (300-400ms) in the low-capacity group in positive and negative emotions; opposite results were observed in the high-capacity group. The consistence of the behavioral and electrophysiological results suggests interindividual differences in the impact of emotions on the WM capacity. Moreover, both positive and negative emotions can facilitate WM capacity in the high-capacity group, while they impair WM capacity in the low-capacity group.