Explainer · 2 min read
Can we send a signal from inside a dream?
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How can we know what is happening in a dream while it is unfolding? Researchers usually wait until the person wakes up. The account then depends on what they remember.
Lucid dreaming offers another possibility. In this state, the sleeper knows they are dreaming. Some people can follow instructions agreed before falling asleep and produce bodily signals that recording equipment can recognise.
Karen Konkoly and colleagues used this method with 13 lucid dreamers. They asked them to open and close their eyes within the dream, then signal their actions, notably through sequences of sniffs recorded with a nasal sensor.
Closing these “dream eyes” could darken the scene or make it disappear. However, the researchers did not find a reproducible increase in brain activity called alpha, which is usually observed when people close their actual eyes while awake.
An action experienced in a dream can therefore change the experience without exactly reproducing the brain’s response to the waking action. Above all, these signals provide time markers: they allow researchers to relate a dream event to brain activity recorded at the same moment.
Further reading: Bulletin of 6 September 2026 (in French).
Source: Konkoly et al. (2026), “Using Real-time Reporting to Investigate Visual Experiences in Dreams”, Journal of Cognitive Neuroscience. Full text.