During REM sleep, many different brain regions show increased activity. Why this is so has not yet been conclusively clarified. However, recent research has now shown that the activity of certain neurons during REM sleep influences eating behavior. When the activity was suppressed in the mouse model, appetite was impaired.
Sleep consists of several sleep stages, all of which contribute to feeling rested in the morning. In rapid-eye-movement (REM) sleep, a specific sleep phase during which intense dreaming occurs, various brain areas and neuronal circuits are highly active. It is associated with sensorimotor development and learning, memory consolidation, and dreaming. However, it is still unclear what this electrical activity is for.
Highly active brain regions include centers responsible for regulating memories and emotions. The so-called lateral hypothalamus, a small, evolutionarily conserved structure in the diencephalon of all mammals, also shows increased activity during REM sleep. When awake, neurons from this brain area orchestrate appetite and food intake, and they play an important role in motivation and addictive behavior. Studies have highlighted a crucial role of LH neurons in foraging, food intake, compulsive behavior or hunting, and induction of conditioned place preference in the absence of rewards.
Blockade changes eating behavior
Scientists have now studied the activation of neurons in the hypothalamus of mice during REM sleep. They discovered that suppressing the activity of these neurons causes the mice to eat less food.
LH neurons, which modulate circuits involved in attention, arousal, and reward , all of which are essential for elaboration of a feeding behavior, are highly active during feeding. It was shown that certain patterns of activity of cells in the lateral hypothalamus that signal food intake during wakefulness also appear during REM sleep.
Sleep quality crucial
Light pulses were used to specifically switch off the activity of the nerve cells. This silencing of signals caused the cells’ eating activity patterns to change in awake mice, and the animals ate less food. The change in activity patterns was still detectable after four days. These findings suggest that electrical activity in hypothalamic circuits can be altered and contribute to stable eating behavior. Accordingly, it seems that not only the amount of sleep is important to feel good, but also the quality of sleep.
Source: “REM sleep influences eating behavior”, 06.08.2020, University of Bern.
Further reading:
- Oesch LT, Gazea M, Gent TC, et al: Adamantidis: REM sleep stabilizes hypothalamic representation of feeding behavior, Proceedings of the National Academy of Sciences of the United States of America, 31 July 2020 https://doi.org/10.1073/pnas.1921909117
InFo NEUROLOGY & PSYCHIATRY 2020; 18(5): 21.
