Recent studies show that subtle, chronic sleep problems are associated with such neurological disorders as Alzheimer's disease, Parkinson's disease, and schizophrenia, in addition to hormonal imbalance and high susceptibility to cardiac or metabolic disorders. Now, researchers from the University of Bern and Bern University Hospital (Germany) have used optogenetics to make a discovery that portends new strategies for medical treatment of sleep disorders—and even recovery of consciousness from vegetative states.1
|EEG recordings from a mouse brain controlled with optogenetics show emergence from anesthesia. (Image credit: Department of Clinical Research, University of Bern)|
The scientists identified a brain circuit in mice whose activation causes rapid wakefulness, and whose inhibition deepens sleep. They engineered neurons taken from the hypothalamus to be controllable with millisecond-timescale light pulses. Then, they showed that activating these neurons produced wakefulness: Transient activation during light sleep quickly induced awakenings, while chronic activation maintained prolonged wakefulness. In contrast, optogenetic silencing of this circuit was shown to stabilize light sleep and increase its intensity. Thus, the circuit is a potential a new therapeutic target.
1. C. Gutierrez Herrera et al., NatureNeurosci., doi:10.1038/nn.4209 (2015).