Figure 7

Effect of hippocampal lesions on acquisition of free-operant responding with delayed reinforcement. Data plotted to show the effects of hippocampal lesions (same data as in the previous figure). There was a delay-dependent impairment in H-lesioned rats (significant lesion × delay interaction, see text), who learned less well than shams only when reinforcement was not delayed. (a) With a delay of 0 s, H-lesioned rats responded less on the active lever than shams did. (b) With a 10 s delay, H-lesioned rats responded the same as shams. (c) With a 20 s delay, H-lesioned rats responded more than shams on the active lever, though this difference was not statistically significant on its own.