REM sleep tunes eating behavior

Date:
August 6, 2020
Source:
University of Bern
Summary:
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 have now discovered
that the activation of neurons in the hypothalamus during REM
sleep regulates eating behavior: suppressing this activity in mice
decreases appetite.



FULL STORY ========================================================================== 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. In the awake animals, neurons from this brain region orchestrate appetite and the consumption
of food and they are involved in the regulation of motivated behaviours
and addiction.

In a new study, researchers headed by Prof. Dr. Antoine Adamantidis
at the University of Bern set out to investigate the function of the
activity of hypothalamic neurons in mice during REM sleep. They aimed at
better understanding how neural activation during REM sleep influences
our day-to-day behaviour. They discovered that suppressing the activity
of these neurons decreases the amount of food the mice consume. "This
suggests that REM sleep is necessary to stabilize food intake," says Adamantidis. The results of this study have been published in the journal Proceedings of the National Academy of Sciences (PNAS).

Long-lasting effect on neuronal activity and feeding behavior The
researcher discovered that specific activity patterns of neurons in the
lateral hypothalamus that usually signal eating in the awake mouse are
also present when the animals were in the stage of REM sleep. To assess
the importance of these activity patterns during REM sleep the research
group used a technique called optogenetics, with which they used light
pulses to precisely shut down the activity of hypothalamic neurons during
REM sleep. As a result, the researchers found that the activity patterns
for eating were modified and that the animals consumed less food.

"We were surprised how strongly and persistently our intervention affected
the neural activity in the lateral hypothalamus and the behaviour of
the mice," says Lukas Oesch, the first author of the study. He adds:
"The modification in the activity patterns was still measurable after
four days of regular sleep." These findings suggest that electrical
activity in hypothalamic circuits during REM sleep are highly plastic
and essential to maintain a stable feeding behaviour in mammals.

It is a question of quality These findings point out that sleep
quantity alone is not solely required for our well-being, but that sleep quality plays a major role in particular to maintain appropriate eating behaviour. "This is of particular relevance in our society where not
only sleep quantity decreases but where sleep quality is dramatically
affected by shift work, late night screen exposure or social jet- lag
in adolescents," explains Adamantidis.

The discovered link between the activity of the neurons during REM sleep
and eating behaviour may help developing new therapeutical approaches
to treat eating disorders. It might also be relevant for motivation
and addiction.

"However, this relationship might depend on the precise circuitry,
the sleep stage and other factors yet to be uncovered," adds Adamantidis.


========================================================================== Story Source: Materials provided by University_of_Bern. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Lukas T. Oesch, Mary Gazea, Thomas C. Gent, Mojtaba Bandarabadi,
Carolina
Gutierrez Herrera, Antoine R. Adamantidis. REM sleep stabilizes
hypothalamic representation of feeding behavior. Proceedings of
the National Academy of Sciences, 2020; 201921909 DOI: 10.1073/
pnas.1921909117 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200806111820.htm

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