title: Dexamphetamine enhances explicit new word learning for novel objects.
abstract: Past research suggests that dexamphetamine (Dex) can facilitate learning and memory in healthy individuals and after a neurological lesion. This study investigated the effects of Dex on the learning of names for new objects in young healthy adults (n=37) within an explicit learning paradigm by using a double-blind, placebo-controlled between- subjects design. Participants received 10 mg Dex or a placebo each morning over five consecutive days before viewing 100 novel objects with non-word names plus matched fillers. Compared to the placebo, Dex enhanced both the rate of learning and the retention of the words 1 wk and 1 month later. The improved word learning correlated with baseline attention and memory scores for participants in the Dex group only. No correlations were observed between word-learning success and sustained attention, mood or cardiovascular arousal. It was concluded that the improved explicit word learning may have reflected dexamphetamine-induced changes in short-term memory and/or memory consolidation.
authors.affiliation: Division of Speech Pathology, The University of Queensland, St Lucia, Queensland, Australia.
authors.forename: Emma
authors.initials: E
authors.lastname: Whiting
authors.forename: Helen
authors.initials: H
authors.lastname: Chenery
authors.forename: Jonathan
authors.initials: J
authors.lastname: Chalk
authors.forename: Ross
authors.initials: R
authors.lastname: Darnell
authors.forename: David
authors.initials: D
authors.lastname: Copland
mesh_terms: D000293:Adolescent; D000328:Adult; D000339:Affect / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003913:Dextroamphetamine / Q000494:pharmacology*; D004298:Dopamine / Q000502:physiology; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects; D011939:Mental Recall / Q000187:drug effects; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D021641:Recognition, Psychology / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000502:physiology; D014706:Verbal Learning / Q000187:drug effects*
chemical_list: D000697:Central Nervous System Stimulants; D003913:Dextroamphetamine; D004298:Dopamine