Temporal Dynamics and Representational Consequences of the Control of Processing Conflict between Visual Working Memory and Visual Perception

Visual working memory (WM) extensively interacts with visual perception. When information between the two processes is in conflict, cognitive control can be recruited to effectively mitigate the resultant interference. The current study investigated the neural bases of the control of conflict between visual WM and visual perception. We recorded the EEG from 25 human participants (13 male) performing a dual task combining visual WM and tilt discrimination, the latter occurring during the WM delay. The congruity in orientation between the memorandum and the discriminandum was manipulated. Behavioral data were fitted to a reinforcement-learning model of cognitive control to derive trial-wise estimates of demand for preparatory and reflexive control, which were then used for EEG analyses. The level of preparatory control was associated with sustained frontal-midline theta activity preceding trial onset, as well as with the strength of the neural representation of the memorandum. Subsequently, discriminandum onset triggered a control prediction error signal that was reflected in a left frontal positivity. On trials when an incongruent discriminandum was not expected, reflexive control that scaled with the prediction error acted to suppress the neural representation of the discriminandum, producing below-baseline decoding of the discriminandum that, in turn, exerted a repulsive serial bias on WM recall on the subsequent trial. These results illustrate the flexible recruitment of two modes of control and how their dynamic interplay acts to mitigate interference between simultaneously processed perceptual and mnemonic representations.