Visual Surround Suppression and Perceptual Expectation Under Psilocybin

The prospective pilot study will address the critical need for more precise characterizations of the acute visual effects of the drug psilocybin by measuring the impact of acute psilocybin intoxication on a perceptual task known as visual surround suppression, compared to an active placebo control. The proposed pilot study will address the critical need for more precise characterizations of the acute visual effects of the drug psilocybin by measuring the impact of acute psilocybin intoxication on a perceptual task known as visual surround suppression, compared to an active placebo control. The data collected in the proposed experiment will make important contributions to knowledge of how psilocybin impacts contextual processing in the brain. Moreover, this will in turn inform the neurobiology of visual surround suppression in general, providing the first investigation of links between surround suppression and serotonergic pathways in humans. Furthermore, the impact of psilocybin on surround suppression will complement recent discoveries of differences in surround suppression present in certain clinical populations. Taken together, these points suggest that this relatively simple and straightforward study could have significant payoff in its contribution to knowledge, not only of the effects of psilocybin but also of key brain processes underpinning human vision and context processing more broadly.