Study objective: 

Sleep is homeostatically regulated, which means that longer waking episodes lead to longer, deeper and more consolidated sleep. The cellular and molecular mechanisms, by which sleep need is coded in the brain, are largely unknown. As many aspects of sleep are evolutionary conserved the use of animal models has provided novel insights into sleep function. In this presentation we will review our recent findings in rodent and zebrafish models.

Methods: 

Rodents (rats and mice) were implanted with electroencephalography (EEG) electrodes to objectively record vigilance stages. In addition, in vivo microdialysis was used to simultaneously collect samples from the brain areas know to be involved in sleep regulation. Zebrafish behavior and vigilance stages were recorded using low (25 frames/s) and high (200 frames/s) resolution video recording. Sleep homeostasis was tested by sleep deprivation (SD). Rodents were kept awake by introducing novel objects into their cages, zebrafish by custom-made water flow recording system.

Summary of results: 

We found that active waking as apposed to quiet waking was associated with increased homeostatic sleep pressure and increased accumulation of metabolic- and synaptic markers of neuronal activity.

Conclusions: 

Our results indicate a bidirectional link between sleep need and brain energy metabolism as well as neuronal plasticity.