Alpha-frequency feedback to early visual cortex orchestrates coherent natural vision

Abstract

During natural vision, the brain generates coherent percepts by integrating sensory inputs scattered across the visual field. Here, we asked whether this integration process is mediated by rhythmic cortical feedback. In EEG and fMRI experiments, we experimentally manipulated the demand for integration by changing the spatiotemporal coherence of natural videos presented across visual hemifields. Our EEG data revealed that information about incongruent videos is coded in feedforward-related gamma activity while information about congruent videos is coded in feedback-related alpha activity, indicating that integration is indeed mediated by rhythmic feedback. Our fMRI data identified scene-selective cortex as a likely source of this feedback. Analytically combining our EEG and fMRI data further revealed that feedback-related representations in the alpha band shape the earliest stages of visual processing in cortex. Together, our findings indicate that the construction of coherent visual experiences relies on rhythmic cortical feedback that fully traverses the visual hierarchy.