For the first time in the history of the study of dreams, Japanese researchers claimed to have managed to predict with some accuracy the content of dreams that three volunteers had seen.
The study reveals the involvement of eyesight in dreams and seems to confirm that our nighttime adventures rarely stay in memory when we wake up.
The impressive study was led by Yukiyasu Kamitani, a neuroscientist at the ATR Computational Neuroscience Laboratories in Kyoto, who claims to have managed to guess what the volunteers had seen in their sleep.
How the content of dreams was decoded
To do this, the volunteers first gave detailed reports of their dreams, so the researchers knew in advance the “repertoire” they were to analyze.
The results were presented at the conference of the Society for Neuroscience in New Orleans.
The researchers asked three people to sleep in the laboratory while their brain activity was being examined with electroencephalography EEG and functional magnetic resonance (fMRI).
Every time the EEG signals showed that the volunteer was dreaming, the researchers would wake them and ask them about the dream. About ten days later, they collected data for about 200 dreams.
The researchers analyzed reports and chose 20 categories of dreams which corresponded to keywords like “car“, “computer”, “man” and “woman.”
In the next phase, the volunteers underwent fMRI while looking at pictures of these corresponding categories – cars, computers, etc. The recorded signals then became the key to the analysis of the content of dreams.
Specifically, the researchers looked for these signals in the records gathered during the volunteers’ sleep. Indeed, the analysis showed that the signals did appear while the volunteers were dreaming.
According to the researchers, the results confirm that dreams and visual perception share common representations in the brain, ie dreams are something that our visual system literally ‘sees’.
Furthermore, the study shows that our dreams are fleeting since the accuracy of guessing was highest in the last seconds before the volunteers were woken, which means that dreams are stored in short-term memory and usually vanish within a few seconds.
However, the study does not provide answers to the biggest questions of concern to neuroscientists: why we sleep and why we dream.
Who knows? Maybe in the future, brain imaging techniques will reveal details about the brain functioning during sleep that we still are not aware of.
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