Figure 2.

Avoidance acquisition and extinction following hippocampal and entorhinal cortex lesion and in WKY rats. Hippocampal and entorhinal cortex lesions did not alter avoidance acquisition (A). Rats with hippocampal lesions were impaired in extinction learning compared to sham controls (A). Acquisition of avoidance in WKY rats did not differ from SD rats (B). WKY rats exhibited a trend toward impaired extinction of avoidant responding (B). Although all six groups were statistically analyzed together, lesion (A) and unoperated (B) groups are displayed separately for clarity.