Effectiveness of Isochronic Tones on Gamma-domain Brainwave Stimulation

Abstract

The surge of electric pulses and chemical reactions in human brain produce brain waves at five distinct frequency domains between 0.5 Hz and 100 Hz. These domains are associated with different brain activities and characterize different mental states. The cerebral brain cells, which produce the frequency patterns in accordance to the brain activity, can be synchronized to or resonated at a desired frequency by externally stimulating the cells using acoustical means including binaural beats (BB) and isochronic tones (IT). IT are single frequency tones that can be easily generated and perceived by the brain whereas BB are auditory brainstem responses originating from the decomposition of two tones. The states of alertness and focus can be traced to areas within the frontal lobes of the brain at gamma range of brainwave frequencies, i. e. circa 40 Hz and above. This paper presents the preliminary investigation on the effectiveness of IT over BB on stimulating the mental states of alertness and attention on human brain at the gamma domain. A maiden group of ten healthy male human subjects are chosen for this purpose. Electroencephalograph signals of the evoked potential due to resonance of the prefrontal cortex (PFC) with the induced aural stimuli are measured. It is observed that the root-mean-square values of the potentials recorded at the anterior front electrode locations namely, AF3 and AF4, after exposition to IT increased by an average of 15% over that measured post exposition to BB. Similar observation is made at the frontal right (F4) location, which has a greater influence of the mental states mentioned above. The results indicate that IT has an improved effect than BB on the potentials measured at the PFC locations and render a positive influence on the focus and attention mental states of the brain.