Fig. 2. Number of correct choices to first error. Data were grouped into 3-day blocks and analyzed with a repeated-measures ANOVA, with anesthesia group and age as between-subject factors and day of testing as the within-subject factor. There was a main effect of age (P ≤ 0.001), training trial (P ≤ 0.001), and anesthesia (P ≤ 0.05), demonstrating that aged rats performed worse than young rats, that there was a learning effect, and that previously anesthetized rats performed worse than control rats. Data expressed as mean ± SEM.