Tracking electrophysiological dynamics of prior exploitation in visual motion perception

Motion perception relies on predictive mechanisms to facilitate optimal interaction with moving objects by integrating prior knowledge about motion dynamics and perceptual input. Evidence of these predictive processes can be found in the Representational Momentum (RM) effect, in which the perceived position of a moving object is displaced forward in the direction of motion. This is an ideal framework to assess whether modulations of event-related potentials (ERPs) observed for task-related “contextual” priors extend to deeply ingrained “structural” priors, acquired by experience or connected to intrinsic features of the sensory system. In this study, we examined ERP correlates of predictive processing of structural priors using a RM task where participants had to detect discrepancies in the orientation of a rotating bar's endpoint, relative to a subsequent firm bar (the probe). Our findings reveal the modulation of the perceptual prior (rotation speed) from earlier stages of visual processing, as reflected in the probe-evoked parieto-occipital P1. Parieto-occipital N2 and centro-frontal P3a exhibited modulations consistent with the use of both perceptual and expectation-based priors, given that they were also modulated by the direction of displacement. Differently, the centro-parietal slow wave (SW) component may reflect later model updating processes. At the individual level, the difference in both P3a and SW amplitudes between detected and undetected discrepancies correlated with the behavioural RM effect. These results describe a timeline of ERP activity underlying predictive processing in motion perception, providing insights into how the brain integrates prior intrinsic “structural” knowledge of the environment to optimize perceptual decisions.