The level of salts in the brain plays a critical
role in whether we are asleep or awake. This
discovery may be of great importance to research on
psychiatric diseases such as schizophrenia and
convulsive fits from lack of sleep as well as
post-anaesthetization confusion, according to
Professor Maiken Nedergaard.
Salts in our brain decide whether we are asleep or
awake. For the first time, researchers have shown
that the level of salts in our body and brain differ
depending on whether we are asleep or awake. A new
study from the University of Copenhagen reveals that
by influencing the level of salts, it is possible to
control a mouse’s sleep-wake cycle. The research has
just been published in the scientific journal,
SCIENCE.
“These salts play a much larger and much more
decisive role than hitherto imagined. The discovery
reveals a completely new layer of understanding of
how the brain functions. First and foremost, we
learn more about how sleep is controlled. It may,
however, also open up for a better future
understanding of why some people suffer convulsive
fits when staying awake all through the night,” says
Professor Maiken Nedergaard from the Center for
Basic and Translational Neuroscience at the
University of Copenhagen.
The researchers have used mice to test whether
injecting salt into the brain enables control of the
mouse’s sleep-wake cycle – independently of the
so-called neuromodulators. Neuromodulators are
compounds such as for example, adrenalin, which
plays a decisive role in our waking up every
morning.
The study shows that adrenalin and other
neuromodulators change the level of salts
surrounding the neurons and that the salt balance
then decides whether the neurons are sensitive to
stimulation in the shape of a touch.
When we are awake, the salt balance makes neurons
highly sensitive to stimulation, as opposed to the
salt balance in the brain during sleep, where the
level of salts makes it harder to activate the
neurons.
“It’s much simpler than previously believed in brain
research. The research conducted used to focus only
on the brain’s neural activity as a means of mapping
and analysing complicated processes such as being
asleep or awake. The study shows that the brain uses
something as simple as changing the level of salts
to control whether we are asleep or awake. This
discovery reveals that studying only neurons in
order to understand brain activity is not enough. We
must include all the supportive cells, especially
the so-called astrocytes, which regulate the level
of salts in the brain.
The brain is more than a group of neurons that
function like a computer. The fact that the brain
needs 7-8 hours of sleep to function well on a daily
basis reveals that there’s much more we need to
understand, aside from neurocomputation,” Professor
Maiken Nedergaard concludes.
For more information
Science
Changes in the composition of brain interstitial
ions control the sleep-wake cycle
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University of Copenhagen
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