A, Lesions to HC, PFC, or PER significantly impaired order memory compared to controls. B, No significant differences were found following HC, PFC, or PER lesions on item memory. C, Difference scores (order DI minus item DI) were significantly lower than chance (difference score = 0) following HC, PFC, or PER lesions. Controls were not different from chance. Note that each animal was tested three times on each task (using different sets of odors) and the mean score of each rat was used for data analysis. Data shows group means ± SEM.