Repeated measures (GLM 3 SPSS 16.0) analysis of variance (ANOVA) was used to analyze data from all experiments, since each animal received all treatments. OxoSQ effects were tested for interaction with time. Time was binned into 30 min during the first 2 hours for the food and locomotor groups and 3 hours for the cocaine group. Since not all animals continued to press during the entire session, data were too sparse during the last 2-4 time bins to run treatment by time interaction ANOVA. To deal with this issue, separate ANOVA's were performed for each time bin to look for main effects of treatments followed by mean pairwise comparisons using Bonferroni correction. Significance for main effects was adjusted with Huynh and Feldt correction when the sphericity assumption was violated, according to Mauchly's test of sphericity (p < 0.05).
