According to traditional belief, prolonged wakefulness during the day is followed by brain rest at night in the form of sleep. This passive theory of sleep was replaced by the active sleep genesis concept, mainly after the realization that brain activity is only slightly reduced during sleep. There is now growing evidence to suggest that sleep is auto-regulatory and that it is not necessary to attribute sleep genesis to either an active or a passive mechanism. Sleep is a global phenomenon in the sense that almost all the brain segments have an inherent tendency for sleep-wake oscillation. It is also global in the sense that sleep and vigilance in a normal intact animal seem to emerge from the dynamic interaction of neuronal network throughout the brain. The tendency for sleep-wake oscillation is derived from a collective response of the several hundreds of neurons with oscillating membrane potential. In an intact animal, the prior activity in the network determines the probability of its entering the sleep-like state or awake-like state. Normal alteration and expression of sleep-wakefulness is influenced by several factors including external input and internal feedback. Thus, sleep is neither the product of any active mechanism, nor the result of a passive process.
According to traditional belief, prolonged wakefulness during the day is followed by brain rest at night in the form of sleep. This passive theory of sleep was replaced by the active sleep genesis concept, mainly after the realization that brain activity is only slightly reduced during sleep. There is now growing evidence to suggest that sleep is auto-regulatory and that it is not necessary to attribute sleep genesis to either an active or a passive mechanism. Sleep is a global phenomenon in the sense that almost all the brain segments have an inherent tendency for sleep-wake oscillation. It is also global in the sense that sleep and vigilance in a normal intact animal seem to emerge from the dynamic interaction of neuronal network throughout the brain. The tendency for sleep-wake oscillation is derived from a collective response of the several hundreds of neurons with oscillating membrane potential. In an intact animal, the prior activity in the network determines the probability of its entering the sleep-like state or awake-like state. Normal alteration and expression of sleep-wakefulness is influenced by several factors including external input and internal feedback. Thus, sleep is neither the product of any active mechanism, nor the result of a passive process.