Psilocybin shifts visual feature integration and attention, linking serotonin 2A receptor activity to altered perception in a controlled human psychophysics study

Psilocybin alters visual perception by changing how the brain integrates local visual features into coherent global forms and by modulating attentional selection. Controlled human psychophysics findings connect these perceptual shifts to serotonergic mechanisms that likely contribute to the characteristic changes in consciousness and sensory experience seen during psychedelic states. The study centers on experimentally measured effects in healthy participants under psilocybin, using visual tasks to test feature binding, global-local processing, and attention. The results indicate that serotonin 2A receptor agonism can disrupt ordinary perceptual organization while enhancing or biasing sensitivity to certain stimulus properties, offering a concrete account of how visual distortions emerge. These findings matter because they move beyond subjective reports and tie psychedelic experience to quantifiable changes in perception. They help explain how altered sensory processing may feed broader changes in self-world interpretation, and they provide a framework for comparing psychedelic states with other models of consciousness and cortical information processing.