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MODELLING WORKING AND REFERENCE MEMORY IN RATS: EFFECTS OF SCOPOLAMINE ON DELAYED MATCHING-TO-POSITION
Citation:
Bushnell, P. MODELLING WORKING AND REFERENCE MEMORY IN RATS: EFFECTS OF SCOPOLAMINE ON DELAYED MATCHING-TO-POSITION. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-90/350 (NTIS PB91163642), 1990.
Description:
A model of working and reference memory in rats is described, based on a discrete-trial operant procedure with concurrent spatial matching and nonspatial discrimination components. orking memory was assessed by delivery food to rats for pressing one of two retractable levers after a delay if that lever had been presented in the prior sample phase of the trial. eference memory was assessed on other trials by delivering food for pressing the lever illuminated by a cue light after the delay interval. he model was tested with scopolamine (0.10 to 0.56 mg/kg, ip), which reduced matching accuracy in a dose-related manner. inear slope and intercept estimates of retention gradients showed that intercepts declined and slopes remained unchanged with increasing scopolamine dose, suggesting that cholinergic blockade disrupts encoding processes while sparing retention. n contrast, scopolamine had no effect on nonspatial discrimination accuracy, suggesting insensitivity of reference memory to cholinergic blockade. o compare the effects of scopolamine on spatial and nonspatial discriminations, a second group of rats was trained to discriminate between the spatial locations of two levers. copolamine at the same doses caused a small, consistent decrease in spatial discrimination accuracy, suggesting that spatial discrimination was more sensitive than nonspatial discrimination to disruption by scopolamine. he combined delayed matching-to-position/nonspatial discrimination procedure appears to provide a useful technique for characterizing mnemonic effects of drugs and toxicants in rats.