Around six years of his or her life is spent by the average person in clearing up the brain. Dreams help, according to the views of numerous researchers, in replaying event memories from the previous day. In doing this, the thinking organ deletes useless sections and archives the valuable ones. Researchers are however not yet agreed on the purpose of dreams, which also occur with higher level animals. Only too happily would researchers like to know, for example, how nightmares originate and how one can switch them off as soon as possible.
In most cases we are only passengers riding along with the storyline of the film. About half of the population has however on some occasion also experienced a different kind of cinema in their sleep – one in which the actual dreamer himself or herself defines the plot and decides where the journey is going, yet at the same time is aware that he or she is not awake. For a long time lucid dreams were considered to be fantasies. The possibility though of these dreams being used to both protect against stress as well as to help in dealing with the most complicated tasks in everyday life now makes them interesting to medicine and psychiatry.
The lucid dream program starts, as do involuntary dreams, mostly in the REM sleep (Rapid Eye Movement) phases, which define sleep especially during the second half of the night. Ursula Voss from the University of Frankfurt is occupied intensively with lucid dreaming in her work. She believes that lucid dreaming mainly has to do with the maturation of the brain: “Children and young people often have lucid dreams”. This finding is the result of an investigation made of more than 800 children and adolescents. With puberty the frequency of these dreams then decreases. Voss speculates that lucid dreaming is closely related to the cross-linking of the frontal lobe to the rest of the brain; this is a process that occurs relatively late in the development of the brain. The lucid dream then reflects network processing during sleep, she believes. Among adults lucid dreams would be relatively rare, because in them the connections are disabled in the frontal lobe during sleep.
40 Hertz amplifies gamma waves
It is already clearly known from previous studies that this kind of realistic dream is accompanied by an increased activity of gamma waves seen in EEG imaging, which shoot mainly through the frontal and temporal regions of the brain at a frequency of around 40 Hertz. The causal relationship between dreaming and this EEG pattern has, however, remained hidden until the Frankfurt group’s study brought forward its revelations. The scientists, using non-invasive technology, induced such brainwaves in 27 patients, none of whom had experienced lucid dreams. In addition, three minutes after the beginning of the REM sleep stage they applied electric fields by way of transcranial electrical stimulation in the range of 2 to 100 Hz. Shortly thereafter, the experimenter woke the patients and asked them specific questions about their dreams. In the instances where frequencies from 25 to 40 Hz were used the subjects reported having dream experiences typical of lucid dreams. The subject took over the role of director while also being the audience which watched the hero during his or her adventures. The typical gamma waves were especially elevated in instances of using 40 Hz. Among those people who had already experienced lucid dreaming, this effect appeared to be amplified.
40 Hz gamma waves barely occur during normal REM sleep to any noticeable extent and are associated with executive functions in the waking state. The authors of the article in Nature Neuroscience believe that certain interneurons generate these waves. These nerves connect, according to animal studies, cortical networks that are responsible for the processing of sensory impressions. It appears that such gamma waves can be induced via electric stimulation and are decisively involved in the production of lucid dreams.
Independent control of sleep phase and dream
People mostly dream during REM sleep. The control of dream and sleep phase occur largely independent of one another, as South African Mark Solms of the University of Cape Town discovered about fifteen years ago in experiments involving stroke patients. Although as a result of neurological damage the REM phase no longer occurred in the brain during their sleep, patients still kept on having dreams. In the frontal lobe, where “logical thinking” takes place in the waking state, during the REM phase when having “normal” dreams almost nothing occurs, says Martin Dresler of the Munich Max-Planck-Institute of Psychiatry. In the centres that process emotions – and also visual impressions – however, a large volume of operational activity dominates.
Just how dreams are very disconnected from reality is something shown by the respective results of Ursula Voss’s working group: people with a physical disability, for example the paralysed, but also the deaf-mute, dream just the same as do the able-bodied. Their handicaps are hardly present in their dreams. Perhaps there are in the relevant regions predetermined stimulus processing patterns already programmed in which during sleep at least are not influenced by physical disability.
Training in sleep
The fact that such stimulus processing patterns which take place during lucid dreaming can also however be used in life beyond sleep is something shown by Daniel Erlach’s studies at the universities of Heidelberg and Bern. He studied around 800 athletes. Almost one in ten of them uses lucid dreams to rehearse complex movement patterns in his or her sport. Here the brain blocks almost all muscles during sleep (except respiratory and eye muscles), but lets certain processes “train” which then work much better during the day. A swimmer, in not needing to pay attention to not swallow water, or an athlete, in not needing to concern oneself with the risks of freezing during winter, could during their sleeping and dreaming time benefit even more through the latest findings if these lucid dreams could be deliberately invoked via targeted stimulation.
This is also true for people with nightmares, or depressive patients for whom an unprocessed trauma always keeps appearing during sleep. After all, eight percent of the population report of occasional or even constant nightmares. The reprogramming from random to lucid dreaming could thus become an additional treatment option. It’s worth keeping in mind that the previous exercise programs employed against such mental stress during sleep have thus far not always been successful. If one could virtually put in front of the dreaming person the director’s seat at the press of a button while the person is dreaming, then the nightly dramas could be able to lead to a happy ending.