Psilocybin impairs high-level but not low-level motion perception

The hallucinogenic drug psilocybin, which activates serotonin receptors, selectively impairs the ability to perceive coherent motion in random dot patterns, a task that relies on high-level global motion detectors, while leaving contrast sensitivity for drifting gratings, mediated by low-level detectors, unaffected. This pattern of visual processing deficits mirrors those seen in schizophrenia, suggesting psilocybin may serve as a pharmacological model for studying psychosis and the neural basis of visual perception.

Study at a glance

Abstract

The hallucinogenic serotonin(1A&2A) agonist psilocybin is known for its ability to induce illusions of motion in otherwise stationary objects or textured surfaces. This study investigated the effect of psilocybin on local and global motion processing in nine human volunteers. Using a forced choice direction of motion discrimination task we show that psilocybin selectively impairs coherence sensitivity for random dot patterns, likely mediated by high-level global motion detectors, but not contrast sensitivity for drifting gratings, believed to be mediated by low-level detectors. These results are in line with those observed within schizophrenic populations and are discussed in respect to the proposition that psilocybin may provide a model to investigate clinical psychosis and the pharmacological underpinnings of visual perception in normal populations.