Hierarchical brain dynamics supporting visual perceptual transitions

Summary

Transitions in conscious perception during a visual illusion involve two distinct mechanisms: boundary fading in the visual cortex, indicated by increased excitability and reduced alpha-band activity, and higher-order perceptual monitoring processes in the motor cortex, shown by decreased high-alpha and beta-band activity. Microsaccadic eye movements were found to reset both mechanisms. This supports a hierarchical model where visual and motor systems work together to influence conscious visual experience.

Study at a glance

Abstract

A longstanding debate in consciousness research concerns whether subjective perceptual experiences arise primarily from activity in sensory cortices or rely critically on inferences made in higher-order brain regions. We address this question using a compelling visual illusion (perceptual filling-in) that isolates neural processes underlying transitions from veridical to illusory conscious experience. Using whole-brain magnetoencephalographic imaging and rapid invisible frequency tagging, we tracked cortical dynamics during filling-in and assessed their modulation by microsaccadic eye movements, which are known to delay the illusion. We found that transitions in conscious perception involved two dissociable mechanisms: (i) boundary fading in visual cortex, reflected by increased excitability and reduced alpha-band activity, consistent with a shift in excitation-inhibition balance, and (ii) higher-order perceptual monitoring processes involving motor cortex, indexed by decreased high-alpha and beta-band activity. Microsaccades selectively reset both processes. These findings support a hierarchical framework in which visual and motor systems jointly shape transitions in conscious visual experience.

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