Acute dose-effects of scopolamine on false recognition.
BACKGROUND
Recently, there has been increased research interest in the phenomenon of false recognition, in which participants claim to recognize words that had not been presented during an initial study phase but that are associatively related to presented words. Acute administration of the benzodiazepine hypnotic triazolam has been shown to decrease false recognition rates. However, no false recognition studies have examined the effects of scopolamine, an anticholinergic drug that might produce a different profile of memory-impairing effects than the benzodiazepines due to its distinct neurochemical profile.


OBJECTIVE
This study was designed to examine the acute dose-effects of scopolamine on false recognition.


METHODS
The effects of subcutaneously administered scopolamine (0.3 and 0.6 mg/70 kg) on performance in the Deese/Roediger-McDermott false recognition paradigm were examined in a repeated-measures placebo-controlled double-blind design in 18 healthy volunteers.


RESULTS
Scopolamine produced dose-related reductions in both true and false recognition rates, and induced a more conservative response bias relative to placebo for recollection-based ("remember") responses to studied words.


CONCLUSIONS
While scopolamine's effects on false recognition are similar to those observed previously with triazolam, its effects on response bias may differ from those of triazolam.
Department of Psychiatry and Behavioral Sciences, Behavioral Biology Research Center, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA. mmintzer@jhmi.edu
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D000328:Adult; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D018757:GABA Modulators / Q000494:pharmacology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018727:Muscarinic Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D011597:Psychomotor Performance / Q000187:drug effects; D021641:Recognition, Psychology / Q000187:drug effects*; D012601:Scopolamine / Q000008:administration & dosage / Q000494:pharmacology*; D014229:Triazolam / Q000494:pharmacology
D018757:GABA Modulators; D018727:Muscarinic Antagonists; D014229:Triazolam; D012601:Scopolamine