Visual Surround Suppression and Perceptual Expectation Under Psilocybin

The prospective 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.

Status Recruiting
Results Published
Start date 01 May 2021
End date 01 May 2024
Chance of happening 90%
Phase Phase I
Design Blinded
Type Interventional
Generation First
Participants 75
Sex All
Age 25- 65
Therapy No

Trial Details

The proposed 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.

NCT Number NCT04424225

Sponsors & Collaborators

University of Minnesota
Researchers at the Nielsen Lab at the University of Minnesota are diving into the world of psychedelics and drug policy reform.

Minneapolis Veterans Affairs Medical Center
This company doesn't have a full profile yet, it is linked to a clinical trial.

Papers

Enhanced visual contrast suppression during peak psilocybin effects: Psychophysical results from a pilot randomized controlled trial
This placebo-controlled study (n=6) investigates how psilocybin (25mg) affects visual surround suppression compared to placebo (100mg niacin). The study finds increased surround suppression effects under psilocybin, with stronger suppression correlating with more intense subjective visual effects.

Measures Used

Mystical Experience Questionnaire
The MEQ is a self-report measure that has been used to measure mystical-type experiences in laboratory studies of psychedelics. The scale was developed by Walter Pahnke in 1963 and covers the major dimensions of classic mystical experience: unity (internal and external), transcendence of time and space, noetic quality, sacredness, positive mood, and ineffability/paradoxicality. Variations of the MEQ exist; the MEQ-30 and the MEQ-43.

5-Dimensional Altered States of Consciousness Questionnaire
The 5D-ASC scale measures altered states of consciousness and contains 94 items (visual analog scales).

Data attribution

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