Toggle improves both sleep and memory

Swiss scientists have discovered why rocking a baby helps to put him to sleep. According to a study by researchers in Western Switzerland, the movement synchronizes neuronal activity in an area of ​​the brain responsible for both sleep and memory retention.

The findings could be used to treat sleep and memory disorders, say the Universities of Geneva and Lausanne and the University Hospital of Geneva (HUG), who conducted the research.

During a controlled test, 18 healthy young adults spent two nights at the HUG Sleep Medicine Center, once on a rocking bed and the other on a fixed bed.

Polysomnographic recordings revealed that they had longer, deeper sleep when they were cradled and that they fell asleep more quickly. The study showed that continuous tipping helped the brain to synchronize neuronal activity in thalamocortico-cortical networks.

As this region of the brain is also connected to memory, scientists have also performed memory tests. After a swinging night, test subjects were better able to remember the words they had been given before falling asleep.

Tests on mice also showed a connection to the vestibular system, located in the inner ear, which manages balance and spatial orientation. The study found that mice whose sensory receptors did not work in the inner ear did not sleep as well.

"The oscillatory vestibular sensory stimulation therefore acts on the networks of neurons responsible for the specific oscillations of the brain during sleep," the scientists said in a statement.

To better identify subcortical structures and specific neural networks affected by sleep switchover, researchers will now use other techniques, such as optogenetics, to observe and control specific neurons.

"Mapping the communication network between the two systems would develop new approaches to treating patients with insomnia and mood disorders, as well as older people often suffering from sleep disorders and memory, "said the team in a statement.