Generators of theta and alpha waves in the development of human: EEGs included persons with mental retardation

Abstract

The research I have undertaken in the physiological psychology of mentally retarded children has been based on an analysis of their basic EEG rhythms. In the days when I began my research, the characteristics of the EEGs of mentally retarded children were identified as follows; (a) slowing of α wave (b) distinctive emergence of θ wave (c) emergence of irregular and unstable waves (d) noticeable individual differencesI studied normal and mentally retarded children's EEGs utilizing both cross-sectional studies and longitudinal studies, and suggested a schema of EEG development, which I presented both in Japan and abroad. While α waves frequency continuously increases as children grow up, this schema shows that there is a change in particular components and each of them has a generator which produces these particular components. Therefore I especially tried to clarify the differences of characteristics between θ and α waves. I suggested that the θ wave's generator is located much deeper in from the scalp than α wave's, because of the alternation of the EEG power. I also clarified the difference of both particular components in terms of the temporal correlation of their emergence, response to optical stimulus and the relation between their physical locations. I would suggest that all characteristics of mentally retarded children's EEGs are connected to the development of the EEG. In conclusion, I assume that α wave component has an inhibitive function in relation to components of low-frequency. (Japanese Journal of Physiological Psychology and Psychophysiology, 30(1) : 25-38, 2012.)