The duration of nicotine-induced attentional enhancement in the five-choice serial reaction time task: lack of long-lasting cognitive improvement

Abstract

There is evidence that nicotine-induced enhancements of cognition may persist for days or even weeks after the drug has been cleared, but the generality of this effect is not known. The objective was to determine the time course of nicotine's effects on performance of the five-choice serial reaction time task (5-CSRTT) when the drug is given acutely and chronically. In the 5-CSRTT, rats were trained to obtain food reinforcers by detecting light stimuli and then received daily postsession injections of nicotine (0.4 mg/kg) or saline. The dose-related effects of presession injections of various acutely administered doses of nicotine were then determined at three different times after injection, whereas controls received saline only (n=12). Finally, performance of all animals was tracked for 8 days after the end of all dosing with nicotine. Daily postsession administration of nicotine for 16 days had no effect on performance the next day. Acute presession administration of nicotine positively influenced several response indices, confirming previous results. Daily administration of nicotine over a total period of 50 days weakened the effect of nicotine on response accuracy, perhaps because of an elevation of the baseline, but had no effect on other measures of performance. The effects of presession nicotine were very clear in tests carried out at 10 or 25 min after injection, and were less consistent at 75 min. There were no persisting differences between the performance of rats as a function of previous histories of exposure to nicotine everyday for 50 days, either under baseline conditions or when task demands were increased. The data suggest that there are no effects of nicotine on attentional performance in the 5-CSRTT that persist after exposure to the drug has ended.