Neural synchrony between prefrontal and visual cortex supports visual working memory

Abstract

Working memory appears to depend on neural mechanisms that are distributed across the brain. Specifically, neural activity persists in the prefrontal cortex while memories are maintained, and at the same time, the visual contents of memory can be precisely decoded from the patterns of activity in visual cortex. Contemporary models attempt to account for these findings by positing that higher-order areas, like prefrontal cortex, somehow control memory storage by recruiting encoding mechanisms in sensory cortices. Demonstrating how prefrontal cortex influences working memory representations in visual cortex is methodologically challenging and direct evidence remains scarce. Here, we leveraged the excellent temporal resolution of magnetoencephalography to test hypotheses about how synchronization of neural activity between prefrontal and visual cortex coordinates working memory representations. During a visuospatial working memory task in humans (both sexes), increased power in -band activity persisted throughout memory maintenance, and changes in its topography over visual cortex predicted both memorized locations and trialwise memory errors. Moreover, neural activity in the -band synchronized between the prefrontal and visual cortices during memory. Not only do these findings align with a large body of work demonstrating that working memories are widely distributed across the brain, but they also help explain how the prefrontal and sensory cortices communicate during memory. New & NoteworthyWhile canonical models emphasize prefrontal memory storage, recent theories propose distributed interactions between executive control and sensory areas. Using magnetoencephalography, we demonstrate that -band oscillations over visual cortex track specific memory content and synchronize with prefrontal cortex activity during maintenance. Crucially, this localized sensory activity directly predicts trial-by-trial human memory errors. These findings provide critical empirical evidence for sensory recruitment models, revealing a dynamic, oscillatory mechanism coordinating working memory.