[The role of sleep dynamics and delta homeostasis in cognitive functions]

The paper is aimed to introduce the neuronal network basis of dynamic sleep processes, including the micro-structure of sleep and the relationship of sleep dynamics with homeostatic regulation and plastic changes during sleep. Newer studies tend to show that beyond the wellknown long-term homeostatic and circadian regulation of NREM sleep, sleep is regulated by a stimulus and arousal dependent flexible defense system, the elements of which participate in sleep delta homeostasis. Within the EEG elements of sleep a more larger amount represents reactible type as it was thought previously. Both the events of wake state and sensory input during sleep are shaping the sleep EEG in a function- and localisation specific way and the next day cognitive functios are determined by these changes.