The role of dopamine in switching between sleep and wakefulness

The breakthrough was made possible by the development of a new neural microsystem created jointly by the teams of the Chinese Academy of Sciences and Zhejiang University. They have designed a new-generation multielectrode probe capable of simultaneously detecting the electrical activity of neurons and changes in dopamine levels directly in the brains of living, freely moving animals.

Unlike previous technologies, the new system does not require external support electrodes and ensures high signal stability in long-term experiments. This way, tissue damage was avoided and more accurate data was obtained without interference between different types of measurements.

Experiments on mice have shown that dopamine levels vary markedly depending on the sleep phase. The maximum values were recorded during wakefulness, the minimum values were recorded during slow—wave sleep, and the sharpest spike was observed at the moment of transition from REM sleep to awakening. The data indicate an active role of dopamine in triggering awakening.

At the same time, the researchers identified several types of neurons whose activity is strictly synchronized with dopamine fluctuations. A particularly close relationship was observed between dopamine releases and neurons active during the phases of wakefulness and REM sleep. This was a direct proof that dopamine not only accompanies the change of states, but is involved in their neural control.

The new technology opens up broad prospects for studying the deep structures of the brain. In the future, it can be adapted to track other neurotransmitters, such as serotonin or glutamate, which will make it possible to more accurately decode the work of neural networks.

The results obtained are important not only for fundamental neuroscience, but also for clinical applications: from the development of brain–computer interfaces to evaluating the effectiveness of neuromodulation and the treatment of sleep disorders.