Hypnagogic Imagery Shows Objects in Dreams, Visual Decoder Learns Algorithms

Researchers can now see your dreams too using "hypnagogic  imagery," the dream-like state that people fall into during sleep. A new study by neuroscientist Yukiyasu Kamitani and colleagues at the Advanced Telecommunications Research Institute International in Kyoto, Japan monitored three men falling asleep inside an fMRI scanner while the machine monitored their brain activity. They also monitored each volunteer's brain activity with EEG electrodes, and when they saw an EEG signature indicative of dreaming, they woke him up to ask what he'd been dreaming about.

Each participant was woken up 200 times over the course of several days to build up information on dreams, according to Wired.

The second part of the experiment involved developing a visual imagery decoder based on machine learning algorithms. The decoder was trained to classify patterns of brain activity recorded from the same three men while they were awake and watching a video montage of hundreds of images from online databases. After the decoder for each person had been trained, the researchers used input for a pattern of brain activity and had the decoder predict which image was most likely to have produced that pattern of brain activity.

Using these developments, researchers were able to decode specific information that could be used to determine objects that the men dreamed about.

This enabled them to correctly identify objects the men had seen in their dreams, according to an article publishe in the journal Science. However, researchers note that, "Our dream decoding is still very primitive," Kamitani said, explaining that they still cannot tell the color or activity of objects seen in dreams.