Methamphetamine's effect on repeated acquisitions with serial discrimination reversals

Rats were trained through a series of discrimination reversals until they developed a stable, repeated acquisition baseline. Methamphetamine (0.5 mg/kg) accelerated acquisition measured from this baseline. The drug effect was demonstrated with successive cumulative records and with a graphic method using a distribution of error scores to develop a baseline. Generally, with low doses(0.25–0.50), methamphetamine reduced errors without affecting rewarded responding. This effect is dose dependent, although at 1.0 mg/kg the drug may disrupt operant behavior.Experiments I and II were conducted while the author was an NSF Science Faculty Fellow at Indiana University. Facilities were provided by the Psychopharmacology Laboratory supported by USPHS Grant MH-14658 to Dr. G. A. Heise. Experiment III was conducted at the University of Tennessee.