"I'll See You in My Dreams" is an old song that's much loved. Now scientists have managed to "see" dreams using sophisticated scanner technology.
Scanning the brains of three sleeping people with functional neuroimaging technology, a team of Japanese scientists at the ATR Computational Neuroscience Laboratories in Kyoto, Japan were able to "see" what the subjects were dreaming.
According to their study, "Visual Image Reconstruction from Human Brain Activity using a Combination of Multiscale Local Image Decoders" published in the journal Neuron, the when the researchers observed brain wave activity linked to REM sleep and dreaming they woke the participant and questioned the subject about the dream. The participant was then permitted to return to sleeping.
Reportedly, this pattern was repeated as much as seven to 10 times on various days and each session was broken into segments lasting three hours. The blocks of time were further segmented into ten wake-ups each hour.
The approach enabled the dream research team to "harvest" about 200 dreams in total.
Lead author of the study, Yukiyasu Kamitani, and his colleagues claim a breakthrough in their study because they achieved their objective that is stated in their abstract: "The results suggest that our approach provides an effective means to read out complex perceptual states from brain activity while discovering information representation in multivoxel patterns."
As for the specific information gathered about dreams associated with brain wave activity, Nature writes that, "…some contained unusual content, such as talking to a famous actor. The researchers extracted key words from the participants’ verbal reports, and picked 20 categories—such as 'car', 'male', 'female', and 'computer'—that appeared most frequently in their dream reports."
The protocols for the study included selecting from an array of photographs depicting each category they identified from the dreams and then selectively re-scanning the participant's brain to compare the brain wave activity to that which was recorded just prior to the subject being awakened.
By analyzing certain key regions of the brain that account for the basic processing of visual encoding and images they were able to "see" the dreams represented by the scanning data. Other analysis of higher order visual centers of the brain that process recognition of objects and people were included.
“We built a model to predict whether each category of content was present in the dreams,” Kamitani explained to Nature. “By analyzing the brain activity during the nine seconds before we woke the subjects, we could predict whether a man is in the dream or not, for instance, with an accuracy of 75–80 percent.”
The study reveals that dreaming and the higher order of visual processing in the brain are linked and the discovery's created excitement among neuroscientists.
“This is an interesting and exciting piece of work,” neuroscientist Jack Gallant from UC Berkeley, told Nature. “It suggests that dreaming involves some of the same higher level visual brain areas that are involved in visual imagery. It also seems to suggest that our recall of dreams is based on short-term memory, because dream decoding was most accurate in the tens of seconds before waking.”
The next study Kamitani's team plans is researching the direct link between REM sleep and dreaming. “This is more challenging because we have to wait at least one hour before sleeping subjects reach that stage."
The research has potential applications for understanding the nature of sleep dysfunctions, some types of mental illness or impairment, and a greater understanding of how the higher visual processing regions of the brain create, store and interpret imaging data.
Such knowledge may also be used in the future for artificial intelligence and robotic software.