Abstract
The dominant frequencies in the human electroencephlogram (EEG) are 8–13 Hz (Alpha), 4–7 Hz (Theta), less than 4 Hz (Delta), and greater than 13 Hz (Beta). The conventional explanation of the mechanism for these dominant rhythms involves the effect of electrical activity i n the thalamus on the cortical synaptic potentials that are recorded in an EEG (1,2). Although electrical activity in the thalamus is of prime importance in determining what is recorded Ly the EEG, it is not known why the dominant rhythms recorded are of those specific frequencies. These dominant frequencies may be related through evolution to some aspect of the environment. This paper is devoted to a consideration of the possible relation between the brain's electrical activity and external electromagnetic fields.