Psilocybin alters visual contextual computations
Aqil, M., de Hollander, G., Dumoulin, S. O., Knapen, T., Vreugdenhil, N.
This pre-print, multimodal study (n=18) investigates psilocybin’s (5mg and 10mg) effects on perception and brain dynamics using psychophysics, ultra-high field fMRI, and computational modelling. It finds that psilocybin alters contextual perception in the Ebbinghaus illusion, modifies cortical responses to visual stimuli, and proposes a computational model linking these changes, suggesting altered contextual computations as a potential general mechanism of psychedelic action.
Abstract
Psilocybin alters perception and brain dynamics. Contextual computations are ubiquitous in the brain. Here, we investigate the effects of psilocybin using psychophysics, ultra-high field functional MRI, and computational modeling. We find that 1) psilocybin alters contextual perception in the Ebbinghaus illusion, 2) psilocybin alters contextual modulation in cortical responses to visual stimuli, and 3) we propose a computational model capable of capturing and linking these changes. Leveraging vision as a beachhead, our findings highlight the alteration of contextual computations as a potential general mechanism underlying psychedelic action.