Experimental Studies on Vestibular Mechanisms: II. Vestibular Disorders in Decorticated Cats

Abstract

The effect of the removal of the neocortex upon vestibular reflexes was observed in a series of ten cats. The behavior, postural reflexes and motor performances of these animals fitted the classical description of the decorticated cat. No spontaneous nystagmus was ever observed, but it was possible to provoke it by repetitive vestibular stimulation. Transitory positional nystagmus of both irregular and direction-changing types were seen for several days in a few cases. The responses of both normal and decorticated cats to caloric and rotatory stimulation exhibited qualitatively a remarkable similarity. Quantitatively, however, there were some differences between the two sets of responses. After total ablation of the neocortex, the passive optokinetic nystagmus was demonstrated in a few cases.