Salts in brain act as 'wake-up' switch

A team of researchers has claimed that salts in the brain play 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.

The University of Copenhagen study reveals that by influencing the level of salts, it is possible to control a mouse's sleep-wake cycle.

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.

Nedergaard concluded, "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 neurocomputations."

The research is published in the scientific journal, SCIENCE.