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Author (up) Honey, G.D.; Honey, R.A.E.; Sharar, S.R.; Turner, D.C.; Pomarol-Clotet, E.; Kumaran, D.; Simons, J.S.; Hu, X.; Rugg, M.D.; Bullmore, E.T.; Fletcher, P.C. url  openurl
  Title Impairment of specific episodic memory processes by sub-psychotic doses of ketamine: The effects of levels of processing at encoding and of the subsequent retrieval task Type Journal Article
  Year 2005 Publication Psychopharmacology Abbreviated Journal  
  Volume 181 Issue 3 Pages 445-457  
  Keywords episodic memory process; ketamine doses; N methyl D aspartate antagonist; memory deficits; retrieval processes; encoding; Episodic Memory; Human Information Storage; Ketamine; N-Methyl-D-Aspartate; Cognitive Processes; Drug Dosages  
  Abstract Rationale: The precise nature of the impact of the N-methyl-D-aspartate antagonist, ketamine, upon human episodic memory, has yet to be elucidated fully. Objectives: This study sought to assess the effects of ketamine on the sub-processes facilitating memory encoding and retrieval. Methods: We evaluated the effects of the drug on a series of memory performance measures depending upon whether it was administered at the encoding or retrieval stage and on the nature of the encoding task used. Twelve healthy volunteers participated in a double-blind, placebo-controlled, randomized, within-subjects study. Intravenous infusions of placebo, 50 ng/ml ketamine or 100 ng/ml ketamine were administered. We investigated the effects of ketamine on three key aspects of episodic memory: encoding vs retrieval processes, source memory, and depth of processing. Data were analysed using both multinomial modelling and standard measures of item discrimination and response bias. Results: Deleterious effects of ketamine on episodic memory were primarily attributable to its effects on encoding, rather than retrieval processes. Recognition memory was impaired for items encoded at an intermediate level of processing, but preserved for shallowly and deeply encoded items. Increased source guessing bias was also observed when encoding took place under ketamine. Conclusions: The effects of ketamine upon episodic memory seem, therefore, to predominate at encoding. Furthermore, our results are also consistent with a specific impairment of encoding processes that result in subsequent recollective, as opposed to familiarity-based, retrieval. The observed effects are compatible with memory deficits seen in schizophrenia and thus provide some support for the ketamine model of the disease. (PsycINFO Database Record (c) 2007 APA, all rights reserved) (from the journal abstract)  
  Address  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Fletcher, Paul C., Department of Psychiatry, University of Cambridge, Addenbrooke's Hospital, Box 25 Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes 0033-31581432-2072Accession Number: 2005-13526-003. First Author & Affiliation: Honey, Garry D.; Department of Psychiatry, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom. Other Journal Title: Psychopharmacology. Release Date: 20060117. Publication Type: Journal (0100) Peer Reviewed Journal (0110). Media Covered: Print. Media Available: Electronic; Print. Document Type: Journal Article. Language: English. Major Descriptor: Episodic Memory; Human Information Storage; Ketamine; N-Methyl-D-Aspartate. Minor Descriptor: Cognitive Processes; Drug Dosages. Classification: Psychopharmacology (2580) . Population: Human (10) Male (30) Female (40) . Location: United Kingdom. Age Group: Adulthood (18 yrs & older) (300) Young Adulthood (18-29 yrs) (320) Thirties (30-39 yrs) (340) Middle Age (40-64 yrs) (360) . Tests & Measures: Present State Examination 9th edition; National Adult Reading Test; . Methodology: Empirical Study; Quantitative Study. References Available: Y. Approved no  
  Call Number refbase @ user @ Honey2005 Serial 5637  
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