Hippocampal ablation prolongs immobility response in rabbits (Oryctolagus cuniculus)

The present study was performed to test the hypothesis that damage to the hippocampus reduces tonic immobility in rabbits. Two measures were used: the number of successful inductions of tonic immobility in a test session and the duration of each successful immobilization. Both of these measures were found to increase in rabbits with hippocampal lesions rather than to decrease as expected. It is suggested that the hippocampus may act to suppress any ongoing dominant or prepotent response, whether the response involves movement or cessation of movement.