You know that thing where you’re lying down, still somewhat awake, and suddenly you’re having what can only be described as a strange fever dream? Apparently, that’s not a glitch. According to researchers, your brain was just doing its thing.

Researchers at the Paris Brain Institute put 92 people in chairs, let them drift toward sleep, and then woke them up mid-drift to ask what was happening in their heads. The setup was lifted straight from Thomas Edison’s playbook: hold a bottle, fall asleep, drop the bottle, get jolted awake, report back. A second session used auditory alarms. Between the two, they racked up 420 reports, and what those reports revealed has been giving sleep researchers a lot to argue about ever since.

Here’s where it gets weird. The reports were sorted into four categories, and three make total sense for someone on the edge of sleep: scattered thoughts, waking observations, and deliberate mental to-do lists. The fourth, which the researchers labeled bizarre, is what grabbed everyone’s attention. Strange, dream-like experiences that the EEG confirmed were happening during full wakefulness. One participant described very strange imagery while their brainwaves were doing everything a conscious brain is supposed to do. The data said awake. The experience said something totally different.

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The study, published in Cell Reports, found that none of the four mental states were exclusive to a single sleep stage. Rational, deliberate thinking turned up during verified deeper sleep. Dream-like weirdness turned up during wakefulness. The line between the two, it seems, is considerably blurrier than anyone formally acknowledged before now.

What actually determines the texture of your mental experience, the researchers concluded, is fine-grained brain activity that standard sleep monitoring doesn’t capture. That matters beyond the abstract: disrupted sleep-wake transitions are common in insomnia, narcolepsy, depression, and Parkinson’s disease, and standard monitoring often fails to explain what patients actually report experiencing. The researchers were careful to call the clinical connections speculative, and the findings apply to healthy adults on the edge of sleep, not anyone zoning out in a meeting.

But still. The next time someone catches you staring at nothing and asks where you went, “my brain entered its bizarre mental state” is now a scientifically defensible answer.