Frecska E, White K D, Luna L E
Wasiwaska Research Center, Florianopolis, SC, Brazil.
Psychopharmacology (Berl). 2004 Apr;173(1-2):79-87. doi: 10.1007/s00213-003-1701-x. Epub 2004 Jan 8.
During binocular rivalry, two incompatible images are presented to each eye and these monocular stimuli compete for perceptual dominance, with one pattern temporarily suppressed from awareness. One variant of stimulus presentation in binocular rivalry experiments is dichoptic stimulus alternation (DSA), when stimuli are applied to the eyes in rapid reversals. There is preliminary report that in contrast with healthy controls, schizophrenic patients can maintain binocular rivalry even at very high DSA rates.
The study was undertaken to investigate whether binocular rivalry survives high rates of DSA induced by the South American hallucinogenic beverage ayahuasca.
Ten individuals who were participating in ayahuasca ceremonials were requested to volunteer for binocular rivalry tests (DSA=0, 3.75, 7.5, 15 and 30 Hz) without and after drinking the brew.
Ingestion of ayahuasca increased mean dominance periods both in standard binocular rivalry conditions (no DSA) and tests with DSA. At higher DSA rates (15 and 30 Hz) the total length of dominance periods was longer on the brew.
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.
在双眼竞争期间，向每只眼睛呈现两个不相容的图像，这些单眼刺激竞争感知优势，其中一种模式会暂时从意识中被抑制。双眼竞争实验中刺激呈现的一种变体是双眼刺激交替（DSA），即刺激在快速反转中施加于双眼。有初步报告称，与健康对照组相比，精神分裂症患者即使在非常高的DSA速率下也能维持双眼竞争。
本研究旨在调查饮用南美洲致幻饮料死藤水所诱导的高DSA速率下双眼竞争是否依然存在。
邀请10名参与死藤水仪式的个体在饮用该饮料之前和之后自愿参加双眼竞争测试（DSA = 0、3.75、7.5、15和30赫兹）。
饮用死藤水增加了标准双眼竞争条件（无DSA）和DSA测试中的平均优势期。在较高的DSA速率（15和30赫兹）下，饮用饮料后优势期的总长度更长。
讨论了死藤水在高DSA速率下诱导的双眼竞争持续存在可能与视觉处理速度减慢有关，而平均优势期增加可能是由于致幻剂引起的视觉通路中γ振荡改变所致。
