Material and Methods

Abstract

This study is based upon experiments carried out in 56 adult cats. In 25, small unilateral lesions were made in known functional or architectonic fields of the cerebral cortex by removing a small portion of the pia mater, thus devascularizing the underlying cortex. Other, larger lesions were made in 5 cats with a suction aspirator and were regionally located only. In 16 cats, electrolytic lesions were made stereotaxically in the thalamus, using an electrode introduced horizontally from behind and entering the thalamus through the superior colliculus or the midbrain in order to avoid damage to the overlying cerebral cortex. In some cases, to avoid the corpus callosum, tentorium cerebelli or visual cortex, the electrode was given a slight upwards and/or lateral inclination. In 10 of this latter group of cats, the thalamic lesions were bilateral since the thalamo-cortical pathways involved are unilateral (Heath and Jones, 1971).