Tuning out emotional distractors by tuning in theta rhythm: improving visual working memory using TMS

Abstract

The relation between attentional control and visual working memory (vWM) has previously been studied with transcranial magnetic stimulation (TMS). For example, it has been shown that rhythmic TMS (rhTMS) can enhance attentional control and, consequently, vWM performance, by boosting prefrontal theta rhythm power. However, it remains unclear if the rhTMS protocol used to improve attentional control for neutral valence distractors can do the same for emotional distractors. Moreover, attentional control can be applied in different ways, either by amplifying relevant stimuli representation or by inhibiting distractor processing. In this study, we used rhTMS to increase theta power over the left dorsolateral prefrontal cortex in 19 healthy participants during a visual change-detection task. Auditory distractors with neutral and angry prosodies were heard during the task. Electroencephalography was used to measure theta power, contralateral delay activity, which indexes visual item maintenance, and the auditory P2, which indexes distractor processing. rhTMS boosted theta power and improved vWM accuracy compared to the sham condition. Theta boost was associated with lower emotional distractor processing, but not better maintenance. Our results indicate that the mechanism for attentional control of emotional auditory distractors in the vWM context is based on inhibition rather than amplification of relevant items.