Washington: Cannot remember what you exactly saw in your dream last night? Well, you could soon be able to do that, as scientists have developed a new technique which they say could accurately read what people are dreaming about.
Using brain imaging, a team at the Max Planck Institute of Psychiatry in Germany said they were able to compare the brain activity of "lucid dreamers" as they entertained the same thoughts awake and asleep.
The brain activity was similar, if weaker during sleep, the researchers reported in the journal Current Biology.
Lucid dreamers are sleepers who are aware that they are dreaming and can deliberately control their dream actions, and it's a learned skill which is very useful to scientists trying to understand the secrets of dreams, the researchers said.
"The main obstacle in studying specific dream content is that spontaneous dream activity cannot be experimentally controlled, as subjects typically cannot perform pre-decided mental actions during sleep," study researcher Michael Czisch said. "Employing the skill of lucid dreaming can help to overcome these obstacles."
For their study, the researchers recruited six practiced lucid dreamers, who slumbered in a functional magnetic resonance imaging (fMRI) machine which measures blood flow to regions of the brain. An increase in blood flow suggests that particular region of the brain is active and working.
Meanwhile, the participants were asked to make a series of hand-clenching movements and eye movements (beneath closed eyelids) when they entered into a lucid dream-state.
The sensory and motor areas activated by those movements in wakefulness also lit up the brain scans during the movements in lucid dreams. The scans of their brains showed identical brain activity when they clenched a real hand, and when they clenched a dream hand. The discovery paves the way to use recently demonstrated "reconstruction" technology to build images of people's dreams, the researchers said.
So far, the German scientists have reconstructed just two dreams. The number of scans and the difficulty of controlling dreams meant that the experiment was extremely difficult.
"The participants have to fall asleep in a scanner, reach REM sleep and enter a stable lucid dream state," said Czisch.    

But he is optimistic about the technology. "This is a proof-of concept study and provides the first evidence that it may be possible to use brain imaging to read the contents of a person's dream," Czisch said.
Earlier this year, researchers from the University of California, Berkeley, managed to decipher brain activity by measuring blood flow through the brain's visual cortex, and used this information to construct images of what they were "thinking".