REM sleep tunes eating behaviour

Using a technique called optogenetics, the activity of cells in the brain can be specifically suppressed with light pulses. Pascal Gugler / Insel Gruppe - Despite our broad understanding of the different brain regions activated during rapid-eye-movement sleep, little is known about what this activity serves for. Researchers at the University of Bern and the Inselspital have now discovered that the activation of neurons in the hypothalamus during REM sleep regulates eating behaviour: suppressing this activity in mice decreases appetite. While we are asleep, we transition between different phases of sleep each of which may contribute differently to us feeling rested. During (rapid eye movement) REM sleep, a peculiar sleep stage also called paradoxical sleep during which most dreaming occurs, specific brain circuits show very high electrical activity, yet the function of this sleep-specific activity remains unclear. Among the brain regions that show strong activation during REM sleep are areas that regulate memory functions or emotion, for instance. The lateral hypothalamus, a tiny, evolutionarily well conserved brain structure in all mammals also shows high activity during REM sleep.