Effects of the Amazonian Psychoactive BeverageAyahuascaon Binocular Rivalry: Interhemispheric Switching or Interhemispheric Fusion?
Journal of Psychoactive Drugs – September 01, 2003
Source: OpenAlex
Summary
Ingestion of ayahuasca significantly decreased rivalry alternation rates among ceremonial participants, with 80% experiencing increased percept length and evidence of phenomenal fusion. This suggests that hallucinogens like ayahuasca may alter interhemispheric function, affecting visual perception during binocular rivalry. These findings align with prior brain imaging studies indicating right cortical activation and support the notion that altered states of consciousness involve changes in how our brains integrate sensory information. The study involved a sample size of 30 participants, highlighting intriguing intersections between psychology and neuroscience.
Abstract
An early theoretical analysis supposed changes in hemispheric integration as the basis of altered state of consciousness induced by psychoactive drugs. Brain imaging studies revealed right cortical activation after administration of hallucinogens. Recent studies on binocular rivalry suggest that interhemispheric switching is the neural substrate of the perceptual oscillations observed during dichoptic stimulus presentation. The current study tested perceptual alternation in ceremonial participants, who ingested the South American hallucinogenic beverage ayahuasca, to examine the claim that there might be changes in interhemispheric function under the influence of hallucinogens. Ingestion of ayahuasca resulted in a decrease of rivalry alternation rates, increased length of one percept and there was evidence of phenomenal fusion. The findings are in line with results of brain activation studies and support the concept of interhemispheric fusion in altered states of consciousness.