Effects of varied doses of psilocybin on time interval reproduction in human subjects

• Published in: Neuroscience letters Vol. 435; no. 1; pp. 51 - 55
• Main Authors: Wackermann, Jiří, Wittmann, Marc, Hasler, Felix, Vollenweider, Franz X.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 11.04.2008; Elsevier
• Subjects: Adult; Altered states of consciousness; Biological and medical sciences; Brain - drug effects; Brain - physiology; Cognition - drug effects; Cognition - physiology; Consciousness Disorders - chemically induced; Dose-Response Relationship, Drug; Dual klepsydra model; Female; Fundamental and applied biological sciences. Psychology; Hallucinogens - administration & dosage; Humans; Judgment - drug effects; Judgment - physiology; Male; Mental Processes - drug effects; Mental Processes - physiology; Psilocybin; Psilocybin - administration & dosage; Subjective duration; Time experience; Time Factors; Time Perception - drug effects; Time Perception - physiology; Time reproduction; Vertebrates: nervous system and sense organs; Dual klepsydra model; Altered states of consciousness; Psilocybin; Subjective duration; Time experience; Time reproduction; Human; Reproduction; Duration; Models
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2008.02.006

Action of a hallucinogenic substance, psilocybin, on internal time representation was investigated in two double-blind, placebo-controlled studies: Experiment 1 with 12 subjects and graded doses, and Experiment 2 with 9 subjects and a very low dose. The task consisted in repeated reproductions of time intervals in the range from 1.5 to 5 s. The effects were assessed by parameter κ of the ‘dual klepsydra’ model of internal time representation, fitted to individual response data and intra-individually normalized with respect to initial values. The estimates κ ˆ were in the same order of magnitude as in earlier studies. In both experiments, κ was significantly increased by psilocybin at 90 min from the drug intake, indicating a higher loss rate of the internal duration representation. These findings are tentatively linked to qualitative alterations of subjective time in altered states of consciousness.