How wakeful rest may boost brain power in a manner similar to sleep

Ask me what I had for breakfast and you will be met with a blank look. On other days, I can tell you the details of interviews I did, the plans I made, which snacks I packed my daughter for school and how much of each she ate. The difference between them doesn’t seem to correlate to how I slept.

In fact, only one factor seemed to matter: how much I rested. I have long thought that, on days when I am rushing around, I am just more stressed, which may affect memory formation. But there could be another reason: the role of rest itself.

We all know that a lack of restorative sleep impairs our cognitive abilities. When we are sleep-deprived, we can struggle to recall what we have learned, absorb new information and sustain focus. We may also be aware that resting while awake seems to partially restore our sleep-deprived minds.

Now, neuroscientist Giulio Tononi and his collaborators at the University of Wisconsin-Madison are revealing how certain housekeeping and cognitive tasks that happen during sleep can also occur, to some extent, while we are awake. This is “the last piece of the puzzle” that may answer why wakeful rest helps to fulfil some of the functions of sleep, says neuroscientist Thomas Andrillon at the Paris Brain Institute. Chronic inflammation messes with your mind.

Here’s how to calm it For decades, sleep was understood to be a global state that affects the whole brain at once. In deep sleep, the brain reverberates with slow brainwaves – in which neurons slowly cycle in sync between firing and silence – and mostly disconnects from the surrounding environment. But in recent years, research has complicated that perspective.

In 2011, a team of sleep researchers, including Tononi and his long-time collaborator Chiara Cirelli, also at the University of Wisconsin-Madison, published a paper describing an odd phenomenon. When rats were sleep-deprived yet awake, their brains showed sudden bursts of sleep-like slow waves – but only in clusters of neurons at a time. The team called it local sleep and considered it to be part of a broader phenomenon that exists in various forms across the animal kingdom (see “Sleeping with part of the brain”, at the end of this story).