title: Methamphetamine and time estimation.
abstract: Three experiments were conducted to determine the effect of methamphetamine on the performance of rats in two timing tasks. When food sometimes followed the first response after T sec of a signal, the response rate increased to a peak near T sec and then declined. Methamphetamine decreased the time of the peak (Experiments 1 and 2). When one response (called a "short response") was reinforced following a short signal and a different response (a "long response") was reinforced following a long signal (where the short and long signals were 1 and 4, 2 and 8, or 4 and 16 sec), the probability of a long response increased as a function of signal duration. The point of indifference (50% long response) occurred near the geometric mean of the extreme durations, and methamphetamine decreased the point of indifference by about 10%. These results suggest that methamphetamine increases the speed of an internal clock used by rats in time discrimination tasks.
mesh_terms: D000818:Animals; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D051381:Rats; D013997:Time Factors; D013998:Time Perception / Q000187:drug effects*
chemical_list: D008694:Methamphetamine