Neural system for controlling the contents of object working memory in humans

Working memory (WM), the active maintenance of currently relevant information, is a flexible system allowing for fast and frequent goal-directed changes of rehearsed information. Successful WM maintenance prevents interference from distracting stimuli while allowing new task-relevant information to update the contents of WM. We used functional magnetic resonance imaging to show that when WM contents were updated, regardless of stimulus type (faces or houses), a frontoparietal network showed transient increases in activation. Some of these regions are highly similar to those identified in studies of shifting attention, supporting the idea that updating WM involves a change in the attentional priority afforded to the current perceptual input. A region within the mid-ventrolateral prefrontal cortex, near the junction of the inferior frontal sulcus and precentral sulcus (inferior frontal junction), that has previously been implicated in cognitive control, demonstrated transient increases in activity during updating as well as sustained maintenance activity. A more anterior prefrontal region, middle frontal gyrus, previously implicated in protecting the contents of WM from interfering stimuli during maintenance, demonstrated transient increases in activity during updating. The current study suggests that updating WM results from a combination of increased attention to the visual stimulus and a change in the system's interference protection state.