Awake
defended on Oct 28 2026 at the Paris Brain Institute. Read the full thesis (PDF)
fast, alpha waves
The mind is rarely empty.
Even as we fall asleep, it produces thoughts, images and stories.
I explored what crosses our minds as we drift off,
and how we can see it in the brain.
slower, theta waves
falls asleep
we report 17 distinct ways of falling asleep.
Reported nationalities: France, Mexico, USA, South Africa, Australia, Kenya, India, Italy...
Each person rated 32 experiences: how often they happen, when, and how strongly.
Mental life at sleep onset appears to be richer than previously assumed.
Most of the 32 experiences were familiar to most people. Strange imagery at sleep onset is part of an ordinary night.
Thinking comes first. Dream-like imagery comes later, and to fewer people.
In their own words, people described 17 recurring themes, from reviewing the day to solving problems, making up scenarios, and perceiving fragments of imagery (see below).
your mind?
20 minutes. At the end, your own sleep-onset profile.
Take the questionnairespindles, K-complex
while awakeProbe / what was going through your mind?
92 people napped in our lab while we recorded their brain activity. Like Edison, each held a bottle. When it fell, we asked what was on their mind.
They rated each experience, and an algorithm grouped them. It found 4 mental states.
I saw an image of my mom.
I was listening to street sounds.
I saw images of small aliens.
I was thinking about what I would do tomorrow.
All four mental states appeared whether people were awake, falling asleep, or in light sleep.
Each mental state also carries its own signature in brain activity, whatever the sleep stage.
Read the paper in Cell Reportsown words
Free reports from the online study: how people describe falling asleep, in their own words.
slow waves
Being awake or asleep does not fully decide what crosses your mind.
Nicolas Decat / Paris Brain Institute