Neuronal Correlates of Changes in the Time Parameters of Motor Responses in Rabbits after Tonic Immobilization

Abstract

Series of threshold current impulses applied to the limb with 2-sec intervals led to the formation of a latent focus of excitation in the sensorimotor cortex. After repeated performance of a tonic immobilization procedure, 2-sec twitches of the limb in response to a test stimulus were accompanied by spontaneous twitches with intervals close to 3 and 4 sec. Analysis of the linked (interacting) activity of pairs of close-lying neurons in the sensorimotor cortex of three rabbits repeatedly subjected to the immobilization procedure showed that a) in situations in which the animal performed movements with intervals of 2 sec, the linked activity of cells was dominated by a 2-sec rhythm; b) during movements performed with 3-sec intervals, the linked activity of cells significantly more frequently showed a 3-sec rhythm; c) in situations in which the animal did not perform movements, the linked activity of close-lying neurons showed equal frequencies of predominance of 2-sec and 3-sec rhythms. The linked activity of distantly located neurons in all three situations mostly showed a 2-sec rhythm, i.e., the rhythms to which the animals were subjected during formation of the latent excitation focus.