Stimulus

January 6, 2010, 12:55 pm • Tags: , ,

icon_08Brainwave synchronization is a practice that aims to cause brainwave frequency to synchronize with a frequency corresponding to the intended brain state. The technique has been used to induce sleep or to treat numerous psychological and physiological conditions.

It is usually performed with the use of specialized medical software. It depends upon a “frequency following” response, a naturally occurring phenomenon where the human brain has a tendency to change its dominant EEG frequency to the frequency of a dominant external stimulus. Such a stimulus may be aural, as in the case of binaural or monaural beats and isochronic tones, or visual, as with a dreamachine, a combination of the two with a mind machine, or even electromagnetic radiation.

Brainwave synchronization has been used in one form or another for centuries, from shamanistic societies’ use of drum beats to Ptolemy noting in 200 A.D. the effects of flickering sunlight generated by a spinning wheel. In the 1930s and ’40s, with then-new EEG equipment and strobe lights, W. Gray Walter performed some of the first scientific research on the subject. Later, in the 1960s and ’70s, interest in altered states led many artists to become interested in the subject, most notably Brion Gysin who, along with a Cambridge math student, invented the Dreammachine.

From the 1970s to date there have been numerous studies and various machines built that combine light and sound. These efforts were aided by continued development of micro circuitry and other electronic breakthroughs allowing for ever more sophisticated equipment for measuring and inducing brainwave synchronization. One of the most important breakthroughs was the discovery of binaural beats, first published in Scientific American in 1973 by Gerald Oster. With the development of isochronic tones by Arturo Manns, combined with more sophisticated equipment, these discoveries led to many attempts to use brainwave synchronization in the treatment of numerous diseases and disorders.