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fMRI and EEG Dream Catchers

1 May, 2013 | EEG, MRI

Native American dream catcher

Native American dream catcher

In a recent research conducted at the ATR Computational Neuroscience Laboratories in Kyoto, Japan, functional magnetic resonance imaging (fMRI) and Electroencephalography (EEG) systems were used to decipher dream images during the hypnagogic sleep stage; the stage experienced during the transition to and from sleep.

The experiment focused on three subjects who were asked to fall asleep in an MRI for three hour sessions, over a period of ten days. The brain activity was monitored using an fMRI and the subjects were awoken every time the EEG detected the presence of a hallucination. Each subject was awoken at least 200 times and was asked each time to describe what he had visually seen before awakening. The subjects were awoken approximately every 6 to 7 minutes and a visual image was described for over 75% of the times they awoke.

The visual images that were verbally reported were transferred to WordNet –a lexical database for English that groups “nouns, verbs, adjectives and adverbs… into sets of cognitive synonyms” referred to as synsets, “each expressing a distinct concept.” Words that appeared at least ten times for a specific subject were grouped and about twenty general categories were created for each subject.

Subsequently, designated software designed for the experiment was “taught” to associate the category with the brain pattern, and images that correspond to the categories were downloaded from the internet. After this ‘teaching’ process, a second dreaming round was conducted, and this time using the fMRI the computer tried to predict what the person was dreaming, while the person was asleep. The results showed a 60% correlation between what the person reported and the image that the computer displayed.

Robert Stickgold, a neuroscientist at Harvard Medical School, said that “this is probably the first real demonstration of the brain basis of dream content.”

The images during the hypnagogic stage are actually “hypnagogic hallucinations” rather than the classic dreams in REM sleep, they have “a different underlying physiology,” said  Allan Hobson, a psychiatrist at Harvard Medical School.

This experiment provides a robust basis to understanding that what we see in dreams is real, in the sense that we do not make them up. It is the first objective step into a world that hitherto had been the most private domain of the human being – our thoughts.