The scientific method of stimulation
Scientists have figured out how lucid dreaming arise, and were able to cause them artificially.
Many people sometimes experience a state when you know that you are asleep, you can wake up if you want, and if you don’t, you can continue to watch a movie and control its script.
Such states are called lucid dreams.
Neuroscientists from the Goethe University in Frankfurt, in collaboration with specialists from Harvard Medical School in Boston, have succeeded in shedding light on the mechanism of this condition. They published the results in Nature Neuroscience. They found out the features of the electrical activity of the brain, necessary for the emergence of lucid dreams. Moreover, they could even cause them in the subjects with the help of electrical stimulation of the brain.
Dreaming we contemplate during a certain stage of sleep, it is called the phase of fast, or paradoxical sleep.
Its paradox is that Electroencephalography (EEG), recorded during this time, shows high-frequency (fast) and low-amplitude waves characteristic of wakefulness.
At the same time, the muscles of the body during this stage are completely relaxed and it arises against the background of deep sleep. Another sign – the rapid movement of the eyeballs under the eyelids, for this reason, fast sleep is also called REM sleep, from the phrase rapid eye movements (rapid eye movements).
Despite the fact that scientists have been actively researching sleep for a long time, the nature of dreams is not yet completely clear to them. According to the doctor of biological sciences Vladimir Kovalzona, now most experts consider visual images that appear in a dream, simply as a by-product of brain activity. Nevertheless, scientists are trying to understand dreams, learn to read a person’s dreams, and perhaps even program them.
Differences between lucid dreaming and ordinary
As the authors of the article write, during ordinary dreams the brain is in the primary state of consciousness: what is happening directly here and now is perceived, and the memory of the past and the planning of the future are inaccessible. When a person wakes up, cognitive functions of a secondary, higher order are instantly turned on: a person is aware of himself in time and space, uses past experience, anticipates future events, manifests free will and is capable of reflection.
During lucid dreams, there are elements of a secondary consciousness of a higher order; therefore, a person behaves not as a passive but as an active subject of what is happening.
He knows that he is asleep, that he can wake up, he can take control of what is happening in a dream, for example, drive away some nightmare or continue “an exciting adventure”.
The electrical waves that the brain generates are divided into several frequency ranges — delta (0.5–3 Hz), theta (4–8 Hz), alpha (8–13 Hz), beta (14–40 Hz), and gamma (40 Hz and above).
When registering an EEG during sleep, experts found that lucid dreams are accompanied by synchronization of activity in different areas of the brain and the appearance of rhythms of very high frequency (about 40 Hz) in the gamma range in the frontal and temporal regions.
Scientists previously associated such high-frequency gamma rhythms only with the state of active wakefulness, intense intellectual activity. It was unexpected to find them in a state of sleep.
The 27 volunteers who participated in the study, said, that they did not have any experience of lucid dreams during the previous few nights.
Scientists wanted to answer the question of what comes first: gamma activity leads to lucid dreaming or vice versa. They stimulated the brain of the subjects during sleep with weak electric current of different frequencies (from 2 to 100 Hz), that is, in all frequency ranges at which the brain itself operates. The electrodes were applied to the frontal and temporal regions. According to the researchers, this method of stimulation was not felt at all by volunteers and did not interfere with their sleep.
It turned out that stimulation with a frequency of 40 Hz does not violate the usual signs of REM sleep, but leads to the fact that the brain itself begins to generate high-frequency waves of the gamma range (37–43 Hz).
Scientists believe that in such conditions, neurons begin to emit synchronously electrical pulses with a given frequency. To a lesser extent, it was caused by stimulation with a frequency of 25 Hz.
Stimulation at low and higher frequencies had no effect on the brain’s own activity at all.
A few seconds after the end of the current supply, the subjects were woken up and asked them about dreams. It turned out that stimulation at frequencies of 40 and 25 Hz caused conscious dreams in volunteers that they could control.
Thus, scientists have found a key electrophysiological feature of lucid dreams and learned how to induce them artificially. In addition to the fact that this opens up the possibility of external intervention in dreams, which in itself is interesting, there are also clinical applications.
By giving a person the ability to control dreams, you can save him from nightmares and obsessive states.
So, perhaps, the method of electrical stimulation during sleep will find application in the clinic.