RESUMEN
Two factorial experiments (brain status x environment x drug) were designed to measure the effects of methamphetamine and enriched experience on recovery after bilateral cortical lesions. Fisher male rats were operated or sham operated when 30 days old and thereafter raised in either an enriched (EC) or impoverished (IC) condition while daily injected with either methampheteamine (2 mg/kg) or saline. In EC, 12 rats lived together in a large cage with stimulus objects that were changed daily. In IC, a rat was kept alone in a small cage. The animals' performance was measured on a standard series of problems in a Hebb-Williams maze. The animals' scores were impaired by removal of tissue from the occipital cortex. Enriched experience, on the contrary, helped significantly in overcoming, at least partially, the effects of brain damage on problem-solving behavior regardless of whether this experience was given, for 2 h per day over a 60-day period (Expt. 1), or for 2 h per day over only a 30-day period (EXPT. 2). No drug effect was found in any of these experiments.