A Lucid dream (LD) is in which you are aware of, and possess the knowledge that it is a dream and not a reality. Hence, a lucid dreaming ability lies in letting his body sleep while keeping his mind wakeful and focused.
In short it's any dream in which you realize you're dreaming and/or are able to control elements of the dream. LD is scientifically verifiable in the lab and the effects can be replicated over and over.
In fact, not only are there MRI brain scan studies from the last decade that prove the existence of consciousness in dreams, but as you'll see below, lucid dreamers actively participate in scientific experiments to further develop our understanding of consciousness.
The first scientific evidence of LD came out of Hull University in the UK in 1975, when Dr Keith Hearne recorded the pre-determined eye movements of his lucid dreaming subject.
His subject, Alan Worsley, was wired to a sensitive multi-channel chart recorder and monitored through the night. Finally, at 8am, came a sequence of large zig-zag movements on the Electro-oculograph (EOG)
"On waking, the subject described how he suddenly realised he was dreaming, and consciously made the signals before continuing the LD experience. They were the first ever signals communicated from within a LD," explained Dr Hearne.
"It was an amazing, mind-boggling, situation. I was looking at a communication from a person in another room who was asleep, 'unconscious', dreaming, yet in his own vivid world in which he was perfectly conscious and interacting with others. It was his reality - I was in my reality. A channel of communication had been established between those two realities."
This remarkable proof of LD is now on permanent display in the London Science Museum.
In more recent years, scientists have made use of functional Magnetic Resonance Imaging (FMRI) techniques to study the brains of active lucid dreamers.
This study conducted at the Neurological Laboratory in Frankfurt in 2009 detected brainwaves in the range of 40 Hz (Gamma range) during LDs.
To put that in context, typical dreams take place in the Theta range (4-7 Hz), while waking consciousness averages in the Beta range (16-31 Hz).
That's massive. LD allow us to tap into even higher states of consciousness than waking reality.
And this all took place in the claustrophobic, thumping tube of an MRI machine. In total, six lucid dreamers were used to generate the data, over five nights each.
The study, led by Dr Ursula Voss, also found heightened activity in the frontal and frontolateral areas of the brain. These are home to linguistic thought as well as other higher mental functions associated with self-awareness.
The modern scientific study of LD is giving us heaps to get excited about.
This may start to sound like science fiction, but MRI has also brought about the chance record our dreams while they occur. As in -- video playback.
The technology is not exactly polished just yet. But in this study from the Max Planck Institute got lucid dreamers to perform a specific action in their dream. First, they signaled their lucidity with eye movements, then they lucidly clenched their right fist for 10 seconds in the dream.
At the same time, the MRI produced a live view of bloodflow in their brains.
The result? The very same areas of the brain were activated whether they clenched their fists in their LDs - or while awake.
The applied usefulness of this data is we can build a library of physical and dream actions detected by fMRI and translate them in real time.
And there's more.
"With this combination of sleep EEGs, imaging methods and lucid dreamers, we can measure not only simple movements during sleep but also the activity patterns in the brain during visual dream perceptions," explains Martin Dresler, a researcher at the Max Planck Institute for Psychiatry.
That's right - when this technology is developed, we'll be able to live stream and record our dreams visually.
In fact, these Japanese researchers at the ATR Computational Neuroscience Laboratories in Kyoto are already on the case.
Their study involved waking volunteers while dreaming inside an fMRI machine and asking what they were dreaming about.
This time, they weren't using lucid dreamers. So they had to wake them hundreds of times and glean the dream experiences retrospectively.
Their dream decoding software then pieced together these images, attempting to recreate the dream from the bloodflow data.