Researchers from the University of Bern have uncovered the mechanism in the brain that is responsible for rapidly waking people up from sleep. These results offer new strategies for dealing with sleep disorders in the medical realm, as well as the recovery of consciousness for those stuck in vegetative states.
In those with insomnia, studies have shown that in addition to length of sleep, the disorder also affects the depth of sleep, which is equally important for proper sleep and daily cognitive functioning.
"The consequences of sleep perturbations on life quality go far beyond daytime sleepiness and mood alteration. Cognitive impairment, hormonal imbalance and high susceptibility to cardiac or metabolic disorders are amongst some of the negative impacts frequently associated with subtle chronic sleep problems," Antoine Adamantidis, who headed the research, said in a press release.
Sleep quality and quantity can be used to determine the presence of various neurological disorders, including Parkinson's disease, Alzheimer's disease and schizophrenia, but there are currently no personalized medicine strategies for the treatment of disorders that encompass these aspects of sleep.
In the current study, Adamantidis and colleagues discovered a new circuit in the mouse brain whose activation led to rapid wakefulness and inhibition led to deeper sleep. This new neural circuit is located between the hypothalamus and thalamus, two brain regions that have been linked to EEG (electroencephalogram) rhythms during sleep.
Using a novel technology called optogenetics, the researchers were able to control hypothalamus neurons with light pulses and show that transient activation during light sleep induced rapid awakenings, whereas chronic activation induced prolonged wakefulness. Conversely, the silencing of this circuit maintained light sleep and increased its intensity.
"This is exciting discovery since therapeutical approaches to recover from a vegetative or minimally conscious state are quite limited," Adamantidis said.
The findings can help neuroscientists shed light on the region of the brain responsible for arousal during sleep and vegetative states and help the medical field develop new therapeutic treatments from these problems.
The findings were published in the Dec. 21 issue of Nature Neuroscience.
