A group of researchers in Japan has found they can decode the visual content of dreams to discover what people are dreaming about while they sleep.
Researchers from the ATR Computational Neuroscience Laboratories in Kyoto, Japan, used functional neuro-imaging to scan the brains of people as they slept and also recorded their brain waves using electroencephalography (EEG) at the same time. The researchers found that they were able to partially decode some of the visual content of subjects' dreams and discover some clues as to what they were dreaming about while they slept.
In the unusual experiment, the researchers woke the sleeping participants as soon as they detected the pattern of brain waves associated with the onset of sleep and then asked them what they had just dreamed about before directing them to go back to sleep. The studies were performed in three-hour blocks of time, and repeated from seven to ten times a night for each sleeping participant. During each block of time, the participants were awakened an average of ten times per hour. This resulted in each sleeping volunteer reporting having visual dreams that they could remember about six or seven times every hour, a process that gave the researchers hundreds of different dream reports to analyze.
Although most of the dream reports centered on unremarkable everyday experiences, some contained definite unusual content that allowed the researchers to extract key words from the reports and create 20 different categories for the words that appeared most frequently in the reports. The research team then selected photographs that represented each category and showed them to the participants as they scanned their brains in order to compare those waking scans with the brain activity patterns that were recorded just before the participants were again woken up.
The researchers analyzed the activity in the areas of the brain which are involved in the earliest stages of visual processing while also looking at other regions of the brain that are associated with higher order visual functions like object recognition. In this manner, the researchers found that the activities in the higher order brain regions were able to accurately reflect some of the content of the participants’ dreams. Analyzing the brain activities during the nine seconds immediately before the subjects were awakened allowed the researchers to predict whether a subject was actually in the dreaming state with an accuracy of nearly 80%. The unusual findings indicate that dreaming and visual perception share similar neural representations in the higher order areas of the brain involved in visual imagery.
It also suggests that a human’s ability to remember their dreams is likely associated with short-term memory because the researcher’s dream decoding attempts were the most accurate in the ten seconds just before the subjects were awakened. This recent Japanese experiment could lead to more groundbreaking new insights about human dreaming and unlock how the content of dreams relates to brain activity overall in the near future.