This randomized, crossover, placebo-controlled study (n=17) investigated the role of 5-HT2A/1A receptor in the hallucinogenic effects of psilocybin (8.75mg/70kg and 17.5mg/70kg). The authors found that 5-HT2A/1A plays a central role in the psilocybin-induced modulation of visual processing.
Abstract
“Background: Recent findings suggest that the serotonergic system and particularly the 5-HT2A/1A receptors are implicated in visual processing and possibly the pathophysiology of visual disturbances including hallucinations in schizophrenia and Parkinson’s disease.
Methods: To investigate the role of 5-HT2A/1A receptors in visual processing the effect of the hallucinogenic 5-HT2A/1A agonist psilocybin (125 and 250 μg/kg vs. placebo) on the spatiotemporal dynamics of modal object completion was assessed in normal volunteers (n = 17) using visual evoked potential recordings in conjunction with topographic-mapping and source analysis. These effects were then considered in relation to the subjective intensity of psilocybin-induced visual hallucinations quantified by psychometric measurement.
Results: Psilocybin dose-dependently decreased the N170 and, in contrast, slightly enhanced the P1 component selectively over occipital electrode sites. The decrease of the N170 was most apparent during the processing of incomplete object figures. Moreover, during the time period of the N170, the overall reduction of the activation in the right extrastriate and posterior parietal areas correlated positively with the intensity of visual hallucinations.
Conclusions: These results suggest a central role of the 5-HT2A/1A-receptors in the modulation of visual processing. Specifically, a reduced N170 component was identified as potentially reflecting a key process of 5-HT2A/1A receptor–mediated visual hallucinations and aberrant modal object completion potential.”
Authors: Michael Kometer, B. Rael Cahn, David Andel, Olivia L. Carter & Franz X. Vollenweider
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https://doi.org/10.1016/j.biopsych.2010.10.002
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Franz VollenweiderFranz X. Vollenweider is one of the pioneering psychedelics researchers, currently at the University of Zurich. He is also the director of the Heffter (sponsored) Research Center Zürich for Consciousness Studies (HRC-ZH).
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University of ZurichWithin the Department of Psychiatry, Psychotherapy and Psychosomatics at the University of Zurich, Dr Mialn Scheidegger is leading team conducting psychedelic research and therapy development.