Activation of serotonin 2A receptors underlies the psilocybin-induced effects on α oscillations, N170 visual-evoked potentials, and visual hallucinations.
Level 2 - randomized trial
Randomized controlled pharmacological trial in healthy humans
PubMed 23785166 · doi:10.1523/JNEUROSCI.3007-12.2013
What was done
Healthy human subjects received psilocybin (215 μg/kg vs. placebo) to evaluate its effects on α oscillations (which regulate cortical excitability) and early visual-evoked potentials (P1 and N170). To evaluate the role of 5-HT2A receptors, participants were additionally pretreated with the preferential 5-HT2A receptor antagonist ketanserin (50 mg vs. placebo).
What was found
The abstract reports directional outcomes without exact numerical values. Psilocybin strongly decreased prestimulus parieto-occipital α power, preventing subsequent stimulus-induced α power decreases. Psilocybin also strongly decreased N170 potentials, which was associated with visual perceptual alterations and visual hallucinations. Pretreatment with ketanserin blocked all of these neurophysiological and perceptual effects.
Why it matters
The study directly links psilocybin-induced visual hallucinations and early visual processing disruption (N170 attenuation and α oscillation modulation) to 5-HT2A receptor activation in humans.
Limits
The abstract does not report the sample size (n), participant demographics, or numerical data (such as effect sizes, variances, or p-values). Findings from healthy volunteers under acute drug challenge may not directly translate to chronic hallucinatory pathophysiology in schizophrenia or Parkinson's disease.
Cited by
- supports Psilocybin and classic hallucinogens bind to serotonin 5-HT2A and 5-HT2C receptors, with primary behavioral effects mediated through the 5-HT2A receptor.