title: Cannabinoid modulation of sensitivity to time.
abstract: The present studies used a psychophysical approach to examine the effect of cannabinoids on temporal processing. Rats trained to discriminate 2- and 8-s (Experiment 1, n=72) and 4- and 16-s (Experiment 2, n=60) intervals were tested with intermediate durations. Psychophysical functions for time, relating the probability of judging a duration as "long" as a function of the actual stimulus durations, were characterized by measures of central tendency (point of subjective equality, PSE) and variability (Weber fraction, WF). The potent cannabinoid agonist, WIN55,212-2 (1-3 mg/kg), produced a dose-related decrease in sensitivity to time (i.e. increase in WF) without systematically affecting PSE (Experiments 1 and 2). The central cannabinoid CB1 antagonist, SR141716A (1-3 mg/kg), did not alter either the WF or PSE (Experiments 1 and 2). Coadministration of SR141716A with WIN55,212-2 blocked the effect of the agonist on WF (Experiment 2), suggesting that the WF effect is mediated by actions at cannabinoid CB1 receptors. Computational modeling with an information processing theory of timing suggests that the reduction in sensitivity to time can be attributed to a disorder of attention.
authors.affiliation: Department of Psychology, University of Georgia, Athens, GA 30602-3013, USA. jcrystal@uga.edu
authors.forename: Jonathon D
authors.initials: JD
authors.lastname: Crystal
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Maxwell
authors.forename: Andrea G
authors.initials: AG
authors.lastname: Hohmann
mesh_terms: D000700:Analgesics / Q000008:administration & dosage; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D048588:Benzoxazines; D002186:Cannabinoids / Q000819:agonists / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D003216:Conditioning, Operant; D004193:Discrimination Learning / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D008297:Male; D009025:Morpholines / Q000008:administration & dosage; D009281:Naphthalenes / Q000008:administration & dosage; D010880:Piperidines / Q000008:administration & dosage; D011720:Pyrazoles / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077285:Rimonabant; D012680:Sensitivity and Specificity; D013995:Time; D013998:Time Perception / Q000187:drug effects*
chemical_list: D000700:Analgesics; D048588:Benzoxazines; D002186:Cannabinoids; D009025:Morpholines; D009281:Naphthalenes; D010880:Piperidines; D011720:Pyrazoles; C070417:(3R)-((2,3-dihydro-5-methyl-3-((4-morpholinyl)methyl)pyrrolo-(1,2,3-de)-1,4-benzoxazin-6-yl)(1-naphthalenyl))methanone; D000077285:Rimonabant