Led by Dr. Micael Czisch, for the first time ever, researchers were able to compare brain activity of lucid dreamers as they consciously entertained the same thoughts while sleeping and while awake.
Lucid dreamers are those who, besides being actively aware of their dream state while sleeping, can also deliberately manipulate their dreams -- a learned skill that is very useful in dream research.
"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 according to LiveScience. "Employing the skill of lucid dreaming can help to overcome these obstacles."
For the study, six lucid dreamers were asked to sleep in a functional magnetic resonance imaging (fMRI) machine so blood flow to regions of their brain could be monitored. Once asleep, subjects were asked to confirm their lucid dream-state with a series of of eye movements. They were then asked to purposely "dream" that they were clenching their fists.
Researchers found that brain activity during the lucid dreaming of this task was similar to brain activity of the same task performed while subjects were awake. However, brain activity during sleep was weaker.
The team, which also included scientists from the Charite hospital in Berlin and the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, also found increased activity in parts of the brain that play a vital role in the planning of movements.
“Our dreams are therefore not a ‘sleep cinema’ in which we merely observe an event passively, but involve activity in the regions of the brain that are relevant to the dream content,” explained Czisch