Does cross‐frequency phase coupling of oscillatory brain activity contribute to a better understanding of visual working memory?

Nesting of fast rhythmical brain activity (gamma) into slower brain waves (theta) has frequently been suggested as a core mechanism of multi‐item working memory (WM) retention. It provides a better understanding of WM capacity limitations, and, as we discuss in this review article, it can lead to applications for modulating memory capacity. However, could cross‐frequency coupling of brain oscillations also constructively contribute to a better understanding of the neuronal signatures of working memory compatible with theoretical approaches that assume flexible capacity limits? Could a theta‐gamma code also be considered as a neural mechanism of flexible sharing of cognitive resources between memory representations in multi‐item WM? Here, we propose potential variants of theta‐gamma coupling that could explain WM retention beyond a fixed memory capacity limit of a few visual items. Moreover, we suggest how to empirically test these predictions in the future.