Does the night really bring advice?

The expression has been around since the dawn of time. It would be enough to turn off the light and close our eyes to find the answer to dilemmas, the direction to take, the idea of the century. Or simply to increase our creativity tenfold. Is it really that simple? Let's see what science has to say.

Sleep, an intense activity

And diverse. The term sleep refers to a number of states of consciousness during which our brain disconnects from our external environment. Our neurons process the information they receive in different ways, but they are always busy, just as intensely as they are when we are awake.

Behind our eyelids, they are activated in several ways during the night. It starts with a phase of slow wave sleepduring which the body slows down its rhythm, right down to eye movements. In English, this is called non-rapid eye movement sleep (NREM sleep). Then the REM sleep (or rapid eye movement sleepREM sleep) follows. Brain activity intensifies to mimic that of wakefulness, dreams occur and the eyes, although closed, are restless. These two phases follow one another, in 4 to 6 cycles of 90 minutes per night: a busy schedule.

Slow wave sleep and REM sleep are also distinguished by the nature of the cerebral activity taking place during these two phases.

The role of slow wave sleep

Sort. Sorting. Organize. To do this, our brain replayed the events we had experienced, reviewing the knowledge we had studied during the day. It mobilizes both the hippocampus, one of the crucial regions of the brain for the proper functioning of the memory, and the cortex where the information is consolidated and classified.

It is thanks to this revision work that it will be possible to recount what you have experienced, to recall a memory. Slow wave sleep thus allows us to build a solid data baseOur brain will be able to use it to give us advice, just after the second phase.

The role of REM sleep

If REM sleep is most often associated with creativity, it feeds on the work done during the slow wave sleep phase that preceded it. Indeed, the information organized by the brain is then exploited by the latter, during this second phase. Activity increases in the cortex, which becomes desynchronized from the hippocampus. It is no longer a question of putting information away but of constructing new stories with it. Dreams, new associations of ideas, analogies...

The effects of REM sleep on reasoning and creativity have been the subject of numerous studies, which have identified a link between the two. For example, in 2009, a team of researchers from the University of San Diego in California tested the creative performance of 3 groups of individuals: after a period of rest but no sleep, after a phase of slow wave sleep, or after a complete sleep cycle, which includes both slow wave sleep and REM sleep. The result: the individuals who received full sleep performed better on the remote association test, which is often used in studies on creativity.

In practice

The night is therefore beneficial in several ways. A full sleep cycle helps to consolidate memory and create new associations of ideas, both of which are essential to creativity. And all the more reason to not to stay up too late. The next time you find yourself stuck, you can :

• Put the problem off until tomorrow. Without feeling guilty. The solution may be waiting for us when we wake up. And if not, it will still be easier to find after a good night's sleep.
• Get enough sleep to enjoy quality slow wave and REM sleep cycles. Adopt a bedtime ritual to fall asleep at the right time.
• Ask yourself the question you're looking for an answer to before you fall asleep. You can even write it down in a notebook and keep it near your bed. And as soon as you wake up, before you have completely regained contact with the outside world, you can write down your first thoughts, the memories of your last dream. The answer may be there!
• Take a nap, even a short one. We will not have time to reach the REM sleep phase, but slow wave sleep will be beneficial. By organizing the accumulated information, it gives the brain an overview of the problem at hand.

For the record

Many scientific advances are the result of years of research and... a dream. This is the case of Dmitri Mendeleev's periodic table of elements, which he reproduced on a piece of paper when he woke up. Or the atomic structure, discovered by Niels Bohr in a dream, by analogy with the structure of the solar system. As for the double helix shape of DNA, it would have been dreamed by James Watson before being verified.

Artists would also have put their nights at the service of their works. Surrealist painters, like Salvador Dalí, used dreams as a source of inspiration. Paul McCartney would have composed Yesterday from a melody heard in a dream. And the cult notes of I Can't Get No Satisfaction would have been recorded by Keith Richards during his sleep.