New Scientist – Michael Czisch and Martin Dresler at the Max Planck Institute of Psychiatry in Munich, Germany, and their colleagues turned an array of brain-monitoring technology on lucid dreamers.
“A lucid dream is simply a dream in which you realise you’re dreaming,” says Dresler. The rare ability to “wake up” while still in a dream and be in control of their actions – and their dreams – makes lucid dreamers a real asset to dream researchers: they are the only people who can reliably, and in real time, communicate what they are dreaming about – usually with eye movements.
After tracking down six individuals who claimed to be able to have lucid dreams almost nightly, the team used both functional MRI scanning and near-infrared spectroscopy to observe each person’s brain activity as they clenched a hand while awake. They then compared this with the activity associated with imagining clenching the same hand, and clenching the hand in a lucid dream.
* Eye signals can be used to access dream content with concurrent EEG and neuroimaging
* Dreamed hand movements correspond to activity in the contralateral sensorimotor cortex
Since the discovery of the close association between rapid eye movement (REM) sleep and dreaming, much effort has been devoted to link physiological signatures of REM sleep to the contents of associated dreams. Due to the impossibility of experimentally controlling spontaneous dream activity, however, a direct demonstration of dream contents by neuroimaging methods is lacking. By combining brain imaging with polysomnography and exploiting the state of “lucid dreaming,” we show here that a predefined motor task performed during dreaming elicits neuronal activation in the sensorimotor cortex. In lucid dreams, the subject is aware of the dreaming state and capable of performing predefined actions while all standard polysomnographic criteria of REM sleep are fulfilled. Using eye signals as temporal markers, neural activity measured by functional magnetic resonance imaging (fMRI) and near-infrared spectroscopy (NIRS) was related to dreamed hand movements during lucid REM sleep. Though preliminary, we provide first evidence that specific contents of REM-associated dreaming can be visualized by neuroimaging.
Science Now – “About half of people have had a lucid dream, Dresler says, but “very few have them on a regular basis.” Certain people can learn to dream lucidly more often. The training involves techniques such as writing down dreams and committing to remember that you’re dreaming when you see a certain theme, such as a flying cow, says neuroscientist Daniel Erlacher of the University of Bern, who was not involved in the current research.
Only two of the subjects were able to have lucid dreams in the noisy scanners. But in each of them, one in fMRI and one in NIRS, the researchers saw the area of the motor cortex that controls the left hand light up in the same way as in someone who was awake. The subjects were able to perform the task in two different dreams each, the researchers report online today in Current Biology. That suggests that “dreams are not just represented as a visual scene” like watching a movie, Dresler says, but involve the whole body.