Effect of Injury of the Cortico- and Rubro-Spinal Pathways on Operant Food-Procuring Reflexes in Cats

In experiments on cats with injury of the cortico- and rubro-spinal pathways, we studied the dynamics of recovery of operant (instrumental) food-procuring reactions at different durations of presurgery learning of animals. Operant manipulatory food-procuring movements were realized under conditions of horizontal and vertical tests, which required training for and support of a strictly defined pose in the course of performance of such movements and determined a specific pattern and stability of the coordinated motor phenomenon. The severity of abnormalities of operant food-procuring activity after transection of the lateral funiculus of the spinal cord at the level of D5-D6 and the time interval necessary for compensation of disorders of the developed manipulatory reaction depended significantly on the duration of presurgery motor learning and decreased considerably with increase in this duration. Such increase determined transformation of the pattern of postural rearrangement, which demonstrated no dependence on the amplitude and trajectory of the forthcoming operant phasic movements and was observed under conditions of both horizontal and vertical motor tests. Our results indicate that the main factor providing successful compensation of disorders of the developed operant habit in cats after injury of the cortico- and rubro-spinal pathways is active involvement of the tecto-and reticulo-spinal systems in the process of formation of the reflex. This can be due to an increase in the duration and intensity of presurgery learning of animals.