| Abstract: | ![]()
The dynamics of neuronal activity in the posterior hypothalamus in different phases of the sleep-wake cycle were investigated during experiments on free-ranging cats. The highest frequency discharges were found to occur in 89.3% of neurons belonging to this region during the stages of active wakefulness and emotionally influenced paradoxical sleep. These neurons become less active during restful wakefulness and the unemotional stage of paradoxical sleep; this reduced activity can be most clearly observed in the context of slow-wave sleep. It was found that 7.1% of test neurons discharged at the highest rate during the stage of active wakefulness. They did not achieve an activity level characteristic of active wakefulness during the period of paradoxical sleep, although activity level was higher than during other states. Only 3.6% of neurons followed the opposite pattern, with discharges succeeding more frequently in slow-wave sleep and activity reduced to an equal degree during wakefulness and paradoxical sleep. The neurophysiological mechanisms governing the sleep-wake cycle and how the posterior hypothalamus contributes to these mechanisms are discussed.I. S. Beritashvili Institute of Physiology, Academy of Sciences of Georgian SSR, Tbilisi. Translated from Neirofiziologiya, Vol. 20, No. 2, pp. 160–167, March–April, 1988. |
