Long-term effects of sleep deprivation on neuronal activity in four hypothalamic areas

- Sleep deprivation (SD) affects neuronal electrical activity of diverse hypothalamic regulatory areas.
- The alterations found outlast the changes in cortical slow wave activity which is the standard marker for sleep need.
- The effects of SD on the hypothalamus could underlie the association between sleep loss and several health issues.
- The impact of SD on the hypothalamic nuclei suggests that sleep is also essential for vital autonomic functions.

Lack of adequate sleep has become increasingly common in our 24/7 society. Unfortunately diminished sleep has significant health consequences including metabolic and cardiovascular disease and mental disorders including depression. The pathways by which reduced sleep adversely affects physiology and behavior are unknown. We found that 6 h of sleep deprivation in adult male rats induces changes in neuronal activity in the lateral hypothalamus, the paraventricular nucleus, the arcuate nucleus and the mammillary bodies. Surprisingly, these alterations last for up to 48 h. The data show that sleep loss has prolonged effects on the activity of multiple hypothalamic areas. Our data indicate also that measuring electroencephalographic slow wave activity underestimates the amount of time that the hypothalamus requires to recover from episodes of sleep deprivation. We propose that these hypothalamic changes underlie the well-established relationship between sleep loss and several diseases such as metabolic disorders, stress and depression and that sufficient sleep is vital for autonomic functions controlled by the hypothalamus.