The current human mind is bound to the body and thus to the nerves of the brain. Brainwaves - or better scalp-waves - represent an important regulator of the human psyche.
Even if neurosciences and behavioral psychology work together, they do not throw enough light on the subjective experience, since both disciplines are predominantly based on the objective perspective of the third person.
The human brain produces waves of different frequencies in the various sleep phases. The neurologist and psychiatrist Hans Berger (1873-1941) is the discoverer of the electromagnetic "brain signals". The EEG (electroencephalogram) known from medicine is traced back to him.
Modern medicine therefore differentiates several waves of the 'brain'(scalp):
Delta waves are in the frequency range from 1 to 4 Hertz and occur in deep sleep, which is irreplaceable for the regeneration of the body, the immune system and the cells as well as for the mental balance.
Theta waves from the range of 4 to 8 Hertz occur in a state of deepest relaxation or in certain meditations. Daydreams - in dangerous form also known as short "mental absence" during motorway trips - are eg. unwanted phases of theta wave. Their use and / or production can improve the memory and concentration capacity or the learning ability in the long term.
Alpha waves are in the range of 8 to 13 Hertz. They play an active role in neural network coordination and communication. Alpha waves occur mainly with the eyes closed and are replaced with the opening of the eyes by beta waves (Berger effect). The same effect can be achieved with closed eyes, if one begins to solve a simple math problem in the head.
Beta waves from the range from 13 to 30 Hertz represent the brain waves of the normal wake state or of excited situations. Slight stress and anxiety situations can also lead to beta waves.
They exists in the range over 25 and 100 Hz, while 40 Hz is typical. They occur during strong concentration, during learning processes and meditation. Experiments on tibetan monks have shown a correlation between transcendental mental states and gamma waves. Such gamma waves were e.g. detected in advanced monks during Vipassana meditation with amplitudes increased more than 30 times.
Even esoteric exercises can lead to a change in the brain waves. Professor Stephan Palos describes in his book "Breath and Meditation" changes in brainwave activity during the test of Chinese breath exercises.
After a research team around Dr. Ursula Voss of the Goethe University in 'Frankfurt am Main' and the Vitos Waldkrankenhaus Köppern and Walter Paulus of the University Hospital Göttingen who are currently reported in the journal "Nature Neuroscience" (DOI: 10.1038 / nn.3719), our normal dreams are so uncontrollable, because in the dream state the mind is turned off as a controlling filter. In this regard, gamma waves have been successfully transmitted to the brain via external electrodes through the cranial bone. The minimal electrical impulses in different frequencies between 2 and 100 Hertz led to clear dreams with frequencies of 25 and 40 Hertz in several trial subjects.
Biofeedback : The biofeedback was modern for a time and allows controlled deep relaxation .
Also a stimulation by electro-acupuncture can be successful.
Muskelstimulatoren : Per Reizstrommuster werden Muskeln entspannt. Diese Geräte erzeugen je nach Hersteller kurzfristige Impulse hoher Spannung und sind evtl. auf lange Zeit nicht ganz unbedenklich.
Tens devices (0-120Hz / 0-130 mA / one-sided pulses): Their effect is supposedly based on a nerve stimulation. Due to the high impulse currents, they are also not entirely harmless (depending on the design).
Bloodzapper (3.92 Hz / Ik = 3mA / alternating rectangle). It was built by a Mr. Beck, distributed free of charge and has been rebuilt in a different forms. In the US, the device has also been clinically tested.
In principle, it is a simple low-current square wave generator with current limiting to a few milliampers, which stimulates muscles and weakens bacteria and viruses (US patent) and works very gently because of the small currents and the low frequency. The original device provides alternating rectangles and had hand electrodes. Possibly, it also has an effect in the direction of electroacupuncture.