Diurnal variations of EEG and mood

Abstract

The purpose of this study is to find the new periodic change in the α wave activities of EEG during day time. In addition, the psychological state, especially mood, was investigated in order to find the relationship between mood and α wave activities. EEG records were obtained from 6 young health students (aged 20-23). The analyzed results of the records were as follows:
(1) In diurnal rhythms of the α wave power, it was recognized that there were several kinds of Ultradian rhythms, whose periods were about 70sec. 23∼min. 1.5hr. 4-5hr, and 6-8hr.
(2) In the α wave amplitude during day time, we observed that there were some variations about ±30% in the α wave power.
(3) At about 2:00pm, it was recognized that the positive and negative mood showed the violent variation.
(4) There were the significant correlation between the α wave power and the Fatigue-Sleep and Vigor-Activity mood.