Effects of Caudate Nuclei Removal in Cats. Comparison with Effects of Frontal Cortex Ablation

Publisher Summary This chapter describes a method for performing one-stage ablation of the caudate nuclei through a midline approach in cats. It presents an experiment in which 10 bilateral acaudate cats, with an average of 84% of caudate tissue removed, have been studied for an average of over 6 months. In addition, 11 cats with unilateral caudectomy, with an average of 95% of the nucleus removed, 10 cats with bilateral removal of the frontal-cortical areas, and 4 shamoperated cats have also been studied. Most cats were implanted with recording electrodes in neocortical areas, the hippocampus, the pontine reticular formation, neck muscles, and orbits. The chapter also presents the results of the gross behavioral, neurological, and polygraphic observations, and explains that total ablation of the caudate nuclei in the cat produces a characteristic behavioral change that is basically manifested as an exaggerated, stereotyped, approaching behavior, the exact nature of which remains to be elucidated. The caudate nuclei do not appear to have an essential role in the control of basic metabolic processes, elementary sensory–motor functions, and elementary cognitive functions.