Learning impairment by Δ(9)-tetrahydrocannabinol in adolescence is attributable to deficits in chunking

• Published in: Behavioural pharmacology Vol. 22; no. 8; p. 837
• Main Authors: Steel, Ryan W J, Miller, John H, Sim, Dalice A, Day, Darren John
• Format: Journal Article
• Language: English
• Published: England 01.12.2011
• Subjects: Animals; Behavior, Animal - drug effects; Dronabinol - pharmacology; Male; Maze Learning - drug effects; Memory - drug effects; Rats; Rats, Sprague-Dawley; Spatial Behavior - drug effects
• ISSN: 1473-5849
• DOI: 10.1097/FBP.0b013e32834dbbb1

Cannabis is the most popular illicit drug used by adolescents. Yet, there are only a few studies that have examined the effects of cannabis use on learning and memory during this sensitive and important neurodevelopmental stage. Male adolescent Sprague-Dawley rats were treated with Δ(9)-tetrahydrocannabinol (THC, 6 mg/kg) daily for 27 days and concurrently trained in a spatial learning and memory task. The chronic effects of cannabis use were specifically examined by assessing animal behaviour during the 'postacute' period (17 h after drug exposure), when minimal acute drug burden is expected to be present. The postacute period is a good model for cannabis use patterns in human adolescents. In addition, we investigated whether the hierarchical organization of working memory (chunking) was impaired by THC-treatment. We show that THC exposure impairs adolescent learning when tested in the postacute period, and that THC impairs the ability of animals to use a chunking strategy.