[Dynamics of the neuronal activity of the posterior hypothalamus during a phase shift of the wakefulness-sleep cycle].

Dynamics of neuronal activity of the posterior hypothalamus in the sleep-wakefulness cycle was studied in free moving cats using mobile metal microelectrodes. Computer analysis and statistical treatment of the data have shown that the majority of neurons (89.3%) in the above-mentioned area discharge with high frequency during active wakefulness and emotional stage of paradoxical sleep; the frequency of discharges decreases during passive wakefulness and nonemotional stage of paradoxical sleep and is the lowest in the slow wave sleep though it has been higher than at the other states. Comparatively small number of neurons (3.6%) show opposite dynamics of the activity. They fire more intensely during slow wave sleep and the frequency of discharges decreases during active wakefulness and paradoxical sleep. In posterior hypothalamus some neurons (7.1%) are found which fire intensely during active wakefulness as compared with slow wave sleep and paradoxical sleep. The neurophysiological mechanisms for regulation of the sleep-wakefulness cycle and the involvement of posterior hypothalamus in this process are discussed.