||Effects of Selection Delays on Radial Maze Performance: Acquisition and Effects of Scopolamine (Journal Version).
Peele, D. B. ;
Baron, S. P. ;
||Health Effects Research Lab., Research Triangle Park, NC. ;Northrop Services, Inc./Environmental Sciences, Research Triangle Park, NC.
Maze learning ;
Laboratory animals ;
Belladonna alkaloids ;
Cholinergic blocking agents ;
Reaction time ;
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The effects of post-selection confinement (delays) on both the acquisition of performance and the response to the muscarinic blocker scopolamine were examined in an automated version of the eight arm radial maze. Long-Evans rats exposed to post-selection delays of 0.5 sec (n=4) or 100 sec (n=4) during daily training trials did not differ in either the number of trials to acquire an accurate baseline of performance or in the amount of time required to obtain all eight food pellets. However, rats exposed to the 0.5 sec delay typically selected arms adjacent to arms from which they exited while rats in the 100 sec delay were more likely to enter arms 2 removed from the exit arm. In contrast, rats in the 100 sec delay group showed an enhanced sensitivity to the accuracy-decreasing effects of scopolamine (0.03 to 1.0 mg/kg) as well as an increase in the time to obtain all eight pellets. The differential effect of delay value on delta arm scores was also eliminated in a dosage dependent manner with scopolamine. The results indicate that the post-selection delay procedure is a sensitive and selective test for chemical-induced dysfunctioning of spatial memory in rats.