Recovery of Locomotion After Ventral and Ventrolateral Spinal Lesions in the Cat. I. Deficits and Adaptive Mechanisms

• Published in: Journal of neurophysiology 1998-09, Vol.80 (3), p.1245-1267
• Main Authors: Brustein, Edna, Rossignol, Serge
• Format: Article
• Language: English
• Subjects: Animals; Cats; Conditioning (Psychology) - physiology; Denervation; Electromyography; Forelimb - innervation; Forelimb - physiology; Gait - physiology; Hindlimb - innervation; Hindlimb - physiology; Locomotion - physiology; Motor Neurons - physiology; Spinal Cord - cytology; Spinal Cord - physiology; Spinal Cord - surgery
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.1998.80.3.1245

Edna Brustein and Serge Rossignol Centre de recherche en Sciences Neurologiques, Faculté de Médecine, Université de Montréal, Montreal, Quebec H3C 3J7, Canada Brustein, Edna and Serge Rossignol. Recovery of locomotion after ventral and ventrolateral spinal lesions in the cat. I. Deficits and adaptive mechanisms. J. Neurophysiol. 80: 1245-1267, 1998. The recovery of treadmill locomotion of eight adult cats, subjected to chronic ventral and ventrolateral spinal lesions at low thoracic levels (T 11 or T 13 ), preserving at least one dorsolateral funiculus and the dorsal columns, was documented daily using electromyographic (EMG) and kinematic methods. The data show that all cats eventually recovered quadrupedal voluntary locomotion despite extensive damage to important pathways (such as the reticulospinal and the vestibulospinal) as verified by injection of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) caudal to the site of lesion. Initially (in the early period after the spinal lesion), all the cats suffered from pronounced locomotor and postural deficits, and they could not support their hindquarters or walk with their hindlimbs. Gradually, during the recovery period, they regained quadrupedal walking, although their locomotion was wobbly and inconsistent, and they suffered from poor lateral stability. EMG and kinematic data analyses showed a tendency for an increase in the variability of the step cycle duration but no major changes in the step cycle structure or in the intralimb coupling of the joints. However, the homolateral fore- and hindlimb coupling was highly perturbed in cats with the largest lesions. Although the general alternating pattern of extensor and flexors was maintained, there were various changes in the duration and amplitude of the EMG bursts as well as a lack of amplitude modulation during walking uphill or downhill on the treadmill. In cats with larger lesions, the forelimbs also seem to take a greater propulsive role than usual as revealed by a consistent increase of the activity of the triceps. In cats with smaller lesions, these deficits were transient, but, for the most extensively lesioned cats, they were pronounced and lasted long term postlesion even after reaching a more or less stable locomotor behavior (plateau period). It is concluded that recovery of quadrupedal locomotion is possible even after a massive lesion to ventral and ventrolateral quadrants, severing the vestibulospinal pathway and causing severe, althoug