Selective entrainment of theta oscillations in the dorsal stream causally enhances auditory working memory performance

The implication of the dorsal stream in manipulating auditory information in working<br>memory has been recently established. However, the oscillatory dynamics within this<br>network and its causal relationship with behavior remain undefined. Using<br>simultaneous MEG/EEG, we show that theta oscillations in the dorsal stream predict<br>participants' manipulation abilities during memory retention in a task requiring the<br>comparison of two patterns differing in temporal order. We investigated the causal<br>relationship between brain oscillations and behavior by applying theta rhythmic-TMS<br>combined with EEG, over the MEG-identified target (left Intraparietal Sulcus) during the<br>silent interval between the two stimuli. Rhythmic-TMS entrained theta oscillation and<br>boosted participants' accuracy. TMS-induced oscillatory entrainment scaled with<br>behavioral enhancement, and both gains varied with participants' baseline abilities.<br>These effects were not seen for a melody-comparison control task, and were not<br>observed for arrhythmic-TMS. These data establish theta activity in the dorsal stream<br>as causally related to memory manipulation.<br><br>