The Role of Beta Oscillations in the (Re)Activation of Working Memory

Wiehe, Melanie

The Role of Beta Oscillations in the (Re)Activation of Working Memory

Files

s1042590_Wiehe,M_MSc_thesis_2021.pdf (10.8 MB)

Authors

Wiehe, Melanie

Issue Date

2021-08-16

Language

en

URI

https://theses.ubn.ru.nl/handle/123456789/14729

Abstract

Beta oscillations (15 to 35 Hz) have traditionally been associated with sensorimotor functions in the parietal cortex. However, more and more research investigates their role in top-down processing and long-range information processing throughout the brain. With this in mind, many studies have investigated their role in working memory. Seemingly contradictory results, and the role of beta oscillations remain debated. Some of these studies found a beta power decrease during working memory maintenance, leading to the assumption that beta oscillations ful l a similar mechanism as alpha by inhibiting the processing of irrelevant information and thus protecting working memory from interference. In contrast, other studies found an increase in beta power during memory delay and showed that beta oscillations carry information about memory content and predict decision outcomes. Our paradigm was designed to test the proposal that content-speci c beta oscillations serve to reactivate latent memory representations to bring them back into the focus of attention. In this study, 33 participants performed a novel working memory paradigm that resembled real-life navigation situations while their brain activity was recorded using magnetoencephalography (MEG). We modulated working memory load and decision-making by the presentation of distractors and a navigation rule which indicated whether participants had to maintain or change direction. We found that a decrease in parietal beta power predicted faster responses and higher working memory load during distractor presentation. Further, we found that di erent beta patterns predicted decision outcome, i.e. whether participants maintained or changed direction. Finally, we showed that beta oscillations predicted whether a left or right direction cue was retained in memory. In summary, we provide evidence that beta oscillations carry information about the memory content and predict the participant's decisions which is line with the proposed framework. However, our ndings that beta power decreases with better performance and increased memory load also support a possible second role for beta in line with the hypothesis that beta serves an inhibitory gating role similar to alpha.