How brain triggers deep sleep

In a discovery that may go a long way in addressing the growing problem of insomnia and poor sleep, scientists have found that switching on one area of the brain chemically can trigger deep sleep.

"Although we know that certain sedatives are effective, there are lots of gaps in scientists' knowledge in terms of precisely what sedatives are doing in the brain," said Nick Franks of Imperial College London.

"We looked at the class of sedative drugs commonly used for patients undergoing investigative procedures or minor operations, to try and identify the circuitry in the brain that they are affecting," he added.

They 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 deep recovery sleep. The researchers found that the process that is triggered by the sedatives is very similar.

"There are many different sleeping pills available but none of them provide rest that is as restorative as natural sleep. We hope that our new research will ultimately lead to new ways of addressing this problem," said study co-author professor Bill Wisden of Imperial College.

Lack of sleep is a really serious problem for many people, such as those suffering from stress or people working in irregular shifts, and it affects their physical and mental health, said Wisden.

The findings were published in Nature Neuroscience.