RATIONALE: A number of tasks are used to assess working memory in rodents, but the odor span task (OST) is unique in studying performance as a function of the number of stimuli to remember. OBJECTIVES: The purpose of the present study was to better characterize the behavioral pharmacology of the OST by exploring the effects of several amnestic agents including an NMDA antagonist (dizocilpine), a positive GABA-A modulator (chlordiazepoxide), an anticholinergic compound (scopolamine), and as a negative control, an opiate receptor agonist (morphine). METHODS: Rats were trained to perform on the OST which is a non-match-to-sample procedure with an incrementing number of sample odors to remember as the session progresses. Trials with a simple odor discrimination task (SD) were interspersed to provide a control for effects unrelated to memory load. RESULTS: All four drugs disrupted performances on the OST task in a dose-dependent fashion, but only the NMDA antagonist dizocilpine produced impairments that were clearly dependent on the number of stimuli to remember. Dizocilpine impaired OST performance at a dose (0.1 mg/kg) that did not affect SD, and that impairment depended on memory load. Chlordiazepoxide (3.0 mg/kg) also produced amnestic effects that were manifest by shorter memory spans and runs of correct responding. In contrast, morphine and scopolamine impaired OST accuracy only at doses that also disrupted SD (18.0 and 0.3 mg/kg, respectively). CONCLUSIONS: These results provide evidence of NMDA and benzodiazepine modulation of working memory as assessed by the OST.
RATIONALE: A number of tasks are used to assess working memory in rodents, but the odor span task (OST) is unique in studying performance as a function of the number of stimuli to remember. OBJECTIVES: The purpose of the present study was to better characterize the behavioral pharmacology of the OST by exploring the effects of several amnestic agents including an NMDA antagonist (dizocilpine), a positive GABA-A modulator (chlordiazepoxide), an anticholinergic compound (scopolamine), and as a negative control, an opiate receptor agonist (morphine). METHODS:Rats were trained to perform on the OST which is a non-match-to-sample procedure with an incrementing number of sample odors to remember as the session progresses. Trials with a simple odor discrimination task (SD) were interspersed to provide a control for effects unrelated to memory load. RESULTS: All four drugs disrupted performances on the OST task in a dose-dependent fashion, but only the NMDA antagonist dizocilpine produced impairments that were clearly dependent on the number of stimuli to remember. Dizocilpine impaired OST performance at a dose (0.1 mg/kg) that did not affect SD, and that impairment depended on memory load. Chlordiazepoxide (3.0 mg/kg) also produced amnestic effects that were manifest by shorter memory spans and runs of correct responding. In contrast, morphine and scopolamine impaired OST accuracy only at doses that also disrupted SD (18.0 and 0.3 mg/kg, respectively). CONCLUSIONS: These results provide evidence of NMDA and benzodiazepine modulation of working memory as assessed by the OST.
Authors: Miriam Z Mintzer; Ryan K Lanier; Michelle R Lofwall; George E Bigelow; Eric C Strain Journal: Drug Alcohol Depend Date: 2010-06-09 Impact factor: 4.492
Authors: Sophie Dix; Gary Gilmour; Slavinka Potts; Janice W Smith; Mark Tricklebank Journal: Psychopharmacology (Berl) Date: 2010-07-31 Impact factor: 4.530
Authors: Gary Gilmour; Elsa Y Pioli; Sophie L Dix; Janice W Smith; Michael W Conway; Wendy T Jones; Sally Loomis; Rebecca Mason; Shahram Shahabi; Mark D Tricklebank Journal: Psychopharmacology (Berl) Date: 2009-05-07 Impact factor: 4.530
Authors: David Phenis; Sarah A Vunck; Valentina Valentini; Hugo Arias; Robert Schwarcz; John P Bruno Journal: Psychopharmacology (Berl) Date: 2020-03-11 Impact factor: 4.530