J. Allan Hobson, a dream researcher at Harvard Medical School in Boston, Massachusetts, has suggested that during a lucid dream, the dreamer is experiencing both the waking state and the dreaming state at the same time in different areas of the brain.
Hobson, who is known for developing the Activation Synthesis Theory of Dreams along with Robert W. McCarley, published his findings in a 2009 article in the International Journal of Dream Research.
Recently, Hobson developed a theory that dreaming is an alternate state of consciousness.
Hobson says that state dissociations – in which one person experiences two different brain states at the same time – are quite common.
Examples of state dissociations may include sleepwalking, night terrors, sleep paralysis and REM sleep behavior disorder.
When someone sleepwalks, for example, their cerebral cortex – the part of the brain that is involved with consciousness – is experiencing slow wave NREM sleep (Stage N3) while the parts of their brainstem that regulate walking and navigation behave as they would when the sleepwalker was completely awake.
In his work, Hobson provides examples of studies that show that during a lucid dream, some parts of the dreamer’s brain are awake while other parts are asleep.
One such study was performed by Ursula Voss at the University of Frankfurt, Germany.
Voss took EEG readings of lucid dreamers.
She found that when people have lucid dreams, they have more 40 Hertz (Hz) brainwaves in the frontal regions of the brain than when they have “normal” REM dreams, but less than when they are awake.
In addition, Michael Czisch of Munich, Germany’s Max Planck Institute of Psychiatry has been studying MRI scans of lucid dreamers.
These scans show that during a lucid dream, the frontal areas of the brain, as well as the temporal lobes and the occipital lobes, are more active than they are during a typical REM dream.
The areas of the brain that become active when the dreamer becomes lucid are the areas of the brain that distinguish human beings from macaque monkeys.
EEG studies have shown that activity in these parts of the human brain -as well as 40 Hz brainwaves – are associated with waking consciousness.
Hobson says that because during a lucid dream, the dreamer is neither fully asleep nor fully awake, it is very hard for the dreamer to remain in the lucid dream.
The brain wants to move completely to one state or the other.
Consequently, the lucid dreamer either awakens completely or switches to “normal” dreaming within a very short time.
Regions of the Brain Associated with Lucid Dreaming
In 2012, researchers at the Max Planck Institute of Psychiatry performed MRI scans on four lucid dreamers.
The dreamers were instructed to let the researchers know when they had begun dreaming lucidly by moving their eyes from side to side and clenching their hands in a predetermined manner.
One of them had two long, stable lucid dreams.
During these dreams, parts of the brain that are not normally activated during non-lucid REM sleep were activated.
These regions of the brain included:
- the precuneus, which is associated with thinking about yourself
- the bilateral frontopolar areas, which is associated with thinking about your own thoughts and feelings
- the dorsolateral prefrontal cortex, which is associated with metacognition (thinking about thinking) and with working memory
- the bilateral inferior and superior parietal lobules, which are also associated with working memory
- the bilateral cuneus and the occipitotemporal cortices, which are associated with conscious awareness during visual perception
Lucid dreaming is characterized by awareness of yourself and your state of mind (awareness that you are dreaming) and by the retention of memories from the waking state – the lucid dreamers in the study were able to remember the instructions to move their hands and clench their eyes. Lucid dreamers sometimes say that the scenery in lucid dreams is much more vivid than the scenery in non-lucid dreams; this could be explained by the activation of the bilateral cuneus and the occipitotemporal cortices.