Modulating the rate and rhythmicity of perceptual rivalry alternations with the mixed 5-HT2A and 5-HT1A agonist psilocybin

Carter, Olivia L. and Pettigrew, John D. and Hasler, Felix and Wallis, Guy M. and Liu, Guang B. and Hell, Daniel and Vollenweider, Franz X. (2005) Modulating the rate and rhythmicity of perceptual rivalry alternations with the mixed 5-HT2A and 5-HT1A agonist psilocybin. Neuropsychopharmacology, 30 (6). pp. 1154-1162. ISSN 0893-133X

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Abstract

Binocular rivalry occurs when different images are presented simultaneously to corresponding points within the left and right eyes. Under these conditions, the observer’s perception will alternate between the two perceptual alternatives. Motivated by the reported link between the rate of perceptual alternations, symptoms of psychosis and an incidental observation that the rhythmicity of perceptual alternations during binocular rivalry was greatly increased 10 h after the consumption of LSD, this study aimed to investigate the pharmacology underlying binocular rivalry and to explore the connection between the timing of perceptual switching and psychosis. Psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine, PY) was chosen for the study because, like LSD, it is known to act as an agonist at serotonin (5-HT)1A and 5-HT2A receptors and to produce an altered state sometimes marked by psychosis-like symptoms. A total of 12 healthy human volunteers were tested under placebo, low-dose (115 mg/kg) and high-dose (250 mg/kg) PY conditions. In line with predictions, under both low- and high-dose conditions, the results show that at 90 min postadministration (the peak of drug action), rate and rhythmicity of perceptual alternations were significantly reduced from placebo levels. Following the 90 min testing period, the perceptual switch rate successively increased, with some individuals showing increases well beyond pretest levels at the final testing, 360 min postadministration. However, as some subjects had still not returned to pretest levels by this time, the mean phase duration at 360 min was not found to differ significantly from placebo. Reflecting the drug-induced changes in rivalry phase durations, subjects showed clear changes in psychological state as indexed by the 5D-ASC (altered states of consciousness) rating scales. This study suggests the involvement of serotonergic pathways in binocular rivalry and supports the previously proposed role of a brainstem oscillator in perceptual rivalry alternations and symptoms of psychosis.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published version deposited in accordance with the copyright policy of the publisher.
Depositing User: Dr Guang Liu
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 27 Jan 2008 22:54
Last Modified: 02 Jul 2013 22:50
Uncontrolled Keywords: binocular rivalry
Fields of Research (FOR2008): 11 Medical and Health Sciences > 1115 Pharmacology and Pharmaceutical Sciences > 111502 Clinical Pharmacology and Therapeutics
11 Medical and Health Sciences > 1117 Public Health and Health Services > 111714 Mental Health
Identification Number or DOI: doi: 10.1038/sj.npp.1300621
URI: http://eprints.usq.edu.au/id/eprint/3267

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