Proactive visual and motor prioritization differentially scale with cue reliability

Environmental cues enable the brain to anticipate and prepare for upcoming behavior, such as by selectively prioritizing relevant visual representations and associated action plans in working memory in service of an imminent task. While it has been demonstrated that neural dynamics of visual and motor prioritization each scale with cue reliability, studies to date tracked either visual or motor prioritization in isolation. It therefore remains unknown whether visual and motor prioritization scale similarly or differently with cue reliability. To fill this gap, we manipulated cue reliability (100%, 80%, 60%) in a visual-motor working-memory task that uniquely enabled us to isolate the neural dynamics associated with visual and motor prioritization in anticipation of an imminent working-memory task. EEG measurements in male and female human volunteers revealed how cue reliability differentially drives visual and motor prioritization. While the strength and timing of visual prioritization were largely invariant to cue reliability, motor prioritization profoundly scaled with cue reliability and developed more gradually with lower certainty. These findings show that visual and motor prioritization in working memory are differentially susceptible to the certainty conveyed by environmental cues, and suggest that motor prioritization may be more cautious in nature. Significance StatementTo cope with the ever-changing world, the human brain continuously leverages environmental cues to anticipate upcoming behavior, such as by prioritizing relevant visual representations and action plans in mind. Yet, in a volatile world, environment cues typically vary in the certainty they provide. Building on prior work studying visual or action prioritization in isolation, we uniquely studied how cue certainty shapes both visual and motor prioritization within the same task. We unveil how cue certainty distinctly drives visual and action prioritization, with action prioritization requiring more certainty before deployment, whilst also being deployed more gradually at lower certainty. Thus, prioritization of potential actions is distinct from--and more cautious than-- prioritization of the visual representations that guide these actions.