Electrophysiological, histological, and behavioral studies in a cat with acute compression of the spinal cord

We made an animal model of cervical spinal cord injury in a cat and performed electrophysiological, histological, and bechavioral studies. The cervical spinal cord injury model was made by inserting a screw through the fourth cervical vertebral body of the cat. After the injury, muscle tonus of the limbs and trunk diminished. The cat was able to walk and to perform target reaching after the injury, although the trunk was unstable and the movement of the forelimb was ataxic. Atrophy of the back muscle remained. The cat was unable to stand bipedally. These behavioral disturbances suggested dysfunction of the ventral funiculus. After behavioral analysis for 3 months, an electrophysiological study was performed. Action potentials of the ventral funiculus evoked by stimulation of the lateral vestibular nucleus or the medial longitudinal fasciculus were recorded at several levels of the cervical cord. They were diminished at levels caudal to the compression site. After the recording, the cervical cord was studied histologically. There was demyelination and gliosis in the ventral funiculus and in part of the ventrolateral funiculus at or near the injured site. Electrophysiological and histological findings were in good agreement with the behavioral ones. Behavioral studies seem useful for evaluating the function of the spinal cord, especially for assessing the injured system in the spinal cord.