Figure 4

Schematic of lesions of the hippocampus. Black shading indicates the extent of neuronal loss common to all subjects (and also the third and lateral ventricles); grey indicates the area lesioned in at least one subject. Coronal sections are (from top to bottom) -1.8, -2.8, -3.8, -4.8, -5.8, and -6.8 mm relative to bregma. Diagrams are modified from ref. [114]. Panels a-c show schematics for Experiment 1 (acquisition of a free-operant instrumental response with delayed reinforcement; 0 s, 10 s, and 20 s groups, respectively) while d shows schematics for Experiment 2 (choice between small, immediate and large, delayed reinforcement).