[Relationship between a state of sleep and wakefulness and transmission of an afferent signal through the posterior ventral nucleus of the thalamus].

Chronic experiments were carried out on nonanesthetized cats. A study was made of peculiarities attending the transmission of the afferent signals and the following inhibitory processes in the posterior ventral nucleus of the thalamus, depending on the state of sleep and wakefulness. Transmission of the signals decreases during the dreaming condition and the slow-wave sleep, and increases during the active states of alert cats. In paradoxical sleep the signal transmission is at the same level as such at resting wakeful condition. A marked transmission fluctuation is seen during the dreaming state and in the course of the first phase of sleep. The level of signal transmission is the most stable during the active states. The degree of the trance inhibitory process after the afferent signal transmission depends on the level of anesthesia, wakefulness and natural sleep. Processes following the afferent signal transmission in the posterior ventral nucleus of the thalamus show a radical difference in the barbituiate-anesthetized in comparison with nonanesthetized animals. The trace inhibition, so characteristic of anesthesia, was expressed in the dreaming state of the animal but insignificantly; in the wakeful condition it is not manifested at all.