title: Marihuana extract in chimpanzees: absence of long-term effects on operant behavior.
mesh_terms: D000818:Animals; D002188:Cannabis / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects*; D005108:Extinction, Psychological; D002679:Pan troglodytes; D011930:Reaction Time / Q000187:drug effects; D012054:Reinforcement, Psychology