Effects of ayahuasca on binocular rivalry with dichoptic stimulus alternation

Frecska, Ede; White, Keith D.; Luna, Luís Eduardo

doi:10.1007/s00213-003-1701-x

Cited by 25 publications

(28 citation statements)

References 61 publications

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“…When continually viewing this stimulus, observers 306 Nichols experience repeated switches between visual awareness of the two images. Frecska et al (2004) examined the effects of the hallucinogenic brew ayahuasca on binocular rivalry in 10 subjects. As noted earlier, ayahuasca is a decoction made from two Amazonian plants, containing DMT as the active psychedelic component, and b-carboline alkaloids that inhibit the liver MAO that normally breaks down orally ingested DMT.…”

Section: Effects On Visual Perceptionmentioning

confidence: 99%

Psychedelics

2016

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Section: Effects On Visual Perceptionmentioning

confidence: 99%

Psychedelics

2016

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“…Further strengthening this link between deviations in perceptual rivalry rhythm and fluctuations in conscious state was the incidental observation that the rhythmicity of perceptual alternations during binocular rivalry was greatly increased 10 h after the reported consumption of LSD (Carter and Pettigrew, 2003). This subject showed a rhythmic, multimodal pattern of harmonic and forbidden intervals, with perceptual switches occurring only after a duration of around 0.9, 1.8, 2.8, or 3.7 s, while few switches were reported after 0.5, 1.5, or 2.5 s. In line with this observation, there was a recent study showing that ayahuasca, a dimethyltryptamine-containing hallucinogenic brew made from psychoactive plants from the Amazon, significantly alters the rate of perceptual switches (Frecska et al, 2004).…”

Section: Introductionmentioning

confidence: 55%

Modulating the Rate and Rhythmicity of Perceptual Rivalry Alternations with the Mixed 5-HT2A and 5-HT1A Agonist Psilocybin

Carter

Pettigrew

Hasler

et al. 2005

Neuropsychopharmacol

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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-HT 2A 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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“…However, there is increasing evidence that binocular rivalry may also reflect brain processes involved in determining more global aspects of conscious state. Changes in perceptual switch rate are now associated with clinical psychosis (Leonard et al 2001;Miller et al 2003;Pettigrew and Miller 1998), drug-induced altered states of consciousness (Carter et al 2005b;Frecska et al 2004), and meditation (Carter et al 2005c). Previous rivalry studies have used functional imaging (Lee et al 2005;Lumer et al 1998;Tong and Engel 2001) and electrophysiological recording techniques (Leopold and Logothetis 1996;Sheinberg and Logothetis 1997) to identify neuronal activity that correlates with perceptual awareness.…”

Section: Introductionmentioning

confidence: 99%

Psilocybin links binocular rivalry switch rate to attention and subjective arousal levels in humans

et al. 2007

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Rationale Binocular rivalry occurs when different images are simultaneously presented to each eye. During continual viewing of this stimulus, the observer will experience repeated switches between visual awareness of the two images. Previous studies have suggested that a slow rate of perceptual switching may be associated with clinical and drug-induced psychosis.Objectives The objective of the study was to explore the proposed relationship between binocular rivalry switch rate and subjective changes in psychological state associated with 5-HT 2A receptor activation. Materials and methods This study used psilocybin, the hallucinogen found naturally in Psilocybe mushrooms that had previously been found to induce psychosis-like symptoms via the 5-HT 2A receptor. The effects of psilocybin (215 μg/kg) were considered alone and after pretreatment with the selective 5-HT 2A antagonist ketanserin (50 mg) in ten healthy human subjects. Results Psilocybin significantly reduced the rate of binocular rivalry switching and increased the proportion of transitional/mixed percept experience. Pretreatment with ketanserin blocked the majority of psilocybin's "positive" psychosis-like hallucinogenic symptoms. However, ketanserin had no influence on either the psilocybin-induced slowing of binocular rivalry or the drug's "negative-type symptoms" associated with reduced arousal and vigilance. Conclusions Together, these findings link changes in binocular rivalry switching rate to subjective levels of arousal and attention. In addition, it suggests that psilocybin's effect on binocular rivalry is unlikely to be mediated by the 5-HT 2A receptor.

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Effects of ayahuasca on binocular rivalry with dichoptic stimulus alternation

Abstract: It is discussed that ayahuasca-induced survival of binocular rivalry at high DSA rates may be related to slow visual processing and increased mean dominance periods may result from hallucinogen-induced alteration of gamma oscillations in the visual pathways.

Cited by 25 publications

References 61 publications

Psychedelics

Psychedelics

Modulating the Rate and Rhythmicity of Perceptual Rivalry Alternations with the Mixed 5-HT2A and 5-HT1A Agonist Psilocybin

Psilocybin links binocular rivalry switch rate to attention and subjective arousal levels in humans

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