Timing of Sleep and Wakefulness

The brain functions like a computer composed of subsystems which in- teract in a hierarchical manner. But it is not a single hierarchy, but a com- plex system of hierarchies each of which has its very own and unique fea- ture. One of these concerns the cyclic or rhythmic control of neuronal ac- tivities which, among others, give rise to alternating states of wakefulness and sleep. The phenomenon of sleep still remains a mystery. The present monograph does not give us any new insights into its meaning and significance. Yet sleep research may not be the same after the appearance of this book be- cause it gives us a comprehensive mathematical theory which opens our eyes to new insights into the mechanism of the rhythm generation that under- lies the 'wake-sleep' cycle. No one who has worked his way through this book can again look at ex- perimental data without recognizing features which the 'models' developed in its various chapters so strikingly reveal.