Smartphones uncover how the world sleeps

@ https://www.flickr.com/ licenses/by/2.0/ A pioneering study of worldwide sleep patterns combines math modelling, mobile apps and big data to parse the roles society and biology each play in setting sleep schedules. The study, led by University of Michigan mathematicians, used a free smartphone app that reduces jetlag to gather robust sleep data from thousands of people in 100 nations. The researchers examined how age, gender, amount of light and home country affect the amount of shut-eye people around the globe get, when they go to bed, and when they wake up. Among their findings is that cultural pressures can override natural circadian rhythms, with the effects showing up most markedly at bedtime. While morning responsibilities like work, kids and school play a role in wake-time, the researchers say they're not the only factor. Population-level trends agree with what they would expect from current knowledge of the circadian clock. "Across the board, it appears that society governs bedtime and one's internal clock governs wake time, and a later bedtime is linked to a loss of sleep," says Daniel Forger, who holds faculty positions in mathematics at the U-M College of Literature, Science, and the Arts, and in the U-M Medical School's Department of Computational Medicine and Bioinformatics. "At the same time, we found...

Read More........→May 29, 2016

Study shows how the brain can trigger a deep sleep

Scientists have discovered that switching on one area of the brain chemically can trigger a deep sleep. The new study, which explored how sedatives work in the brain's neural pathways, could lead to better remedies for insomnia and more effective anaesthetic drugs. Scientists from Imperial College London found that certain types of sedative drugs work by 'switching on' neurons in a particular area of the brain, called the preoptic hypothalamus. Their work, in mice, showed that it is these neurons that are responsible for shutting down the areas of the brain that are inactive during deep sleep. Following a period of sleep deprivation, the brain triggers a process that leads to a deep recovery sleep. The researchers found that the process that is triggered by the sedatives is very similar. In mice, when the researchers used a chemical to activate only specific neurons in the preoptic hypothalamus, this produced a recovery sleep in the animals. The new research is important because although scientists understand how sedatives bind to certain receptors to cause their desired effects, it had previously been assumed that they had a general effect throughout the brain. The knowledge that one distinct area of the brain triggers this kind of deep sleep paves the way for the development of better targeted sedative drugs and sleeping...

Read More........→March 11, 2015