Homogeneity of variance and group normality were validated using the Levene and Kolmogorov-Smirnov statistics, respectively. A separate two-way (Rearing × Handling) independent analysis of variance was performed for each behavior and each structure for LC/MS and densitometry measures. Tukey post hocs were performed to identify the source of significant interactions. Endocannabinoid levels and elevated plus maze behavior (% open arm time as a function of total maze time) were additionally analyzed using planned comparisons (two-tailed, independent samples t-tests) between rearing conditions, performed separately in non-handled and handled rats. Planned comparisons were performed because handling has been reported to alter anxiolytic-like effects of the fatty-acid amide hydrolase (FAAH) inhibitor URB597 in the elevated plus maze (Haller et al., 2009). Thus, planned comparisons offered statistical sensitivity (decreased likelihood of making a type II error) for examination of the effects of rearing by removing variance due to handling, which could otherwise mask detection of endocannabinoid-dependent effects in a 2 × 2 ANOVA.
