The Effects of Lesions of The Fornix on The Punishment of Runway Behavior in The Rat

Abstract

<p>Inhibition theories of hippocampal function had been proposed that animals with hippocampal lesions should show a deficit in passive avoidance. On the other hand, recently, O'Keefe and Dostovsky (1971) formulated the alternative theory. They argue that animals solve problems using the two strategies; (1) a cue strategy, (2) a spatial strategy, and that animals with hippocampal lesion should show no deficits on tasks requiring cue strategies but should show deficits on tasks requiring spatial strategies.</p> <p>The purpose of the present thesis was to evaluate this hypothesis by using tasks requiring spatial strategies.</p> <p>Three experiments were carried out. Experiment 1 replicated previous runaway punishment experiment. Fornicotomized rats and control rats were trained in a runaway apparatus with start box and goal box. After reinforcement, animals were shocked at the food cup on two trials. In Experiment 2, fornicotomized and control animals were shocked at the food cup or in the runaway. In Experiment 3, animals were assigned to 8 groups with 3 factors-lesion (fornicotomized and control), shock location (in the runway and at the food cup) and goal box color (white and black).</p> <p>Animals with fornical lesions inhibited responding in the goal box when they were shocked in the goal box; also, they inhibited responding in the runaway when they were shocked in the runaway. Furthermore, lesioned animals shocked in the goal box inhibited responding in the runway less than in the goal box, and lesioned animals shocked in the runway inhibited responding in the goal box less than in the runaway. In addition, normal subjects inhibited responding in locations other than those in which they had been shocked. The results were, in general, in accord with the spatial hypothesis.</p>