Effects of Stimulation of the Inferior Colliculi in Krushinskii–Molodkina Rats

Abstract

The effects of chemical and electrical stimulation of the central nucleus of the inferior colliculus on the generation and formation of convulsive manifestations and on the organization of sleep were studied in Krushinskii–Molodkina rats with an inherited predisposition to audiogenic convulsions. Microinjection of quinolinic acid (10 μg in 1 μl of distilled water) or electrical stimulation at a frequency of 70 Hz generated paroxysmal manifestations in the form of intense rotatory movement acts, similar to “wild running” of animals in the initial convulsion-free stage of audiogenic seizures. This provides grounds for suggesting that in Krushinskii–Molodkina rats the inferior colliculi are part of the neural network responsible for the generation and execution of the running stage during the formation of convulsive responses to sound stimuli. Application of these stimuli was also followed by a decrease in the total duration of fast-wave sleep during the poststimulus period. Conversely, electrical stimulation of the inferior colliculi at a frequency of 7 Hz on the background of deep slow-wave sleep induced episodes of fast-wave sleep in the rats; after 3–4 sessions of this stimulation producing this effect, there was an almost two-fold increase in the total duration of fastwave sleep during the post-stimulus period due to an increase in the number but not the duration of these episodes. These results provide evidence that the inferior colliculi in rats may have a modulatory effect on the functioning of the fast-wave sleep triggering system.