EEG activation response under different neurohumoral states

Abstract

In order to determine under which neurohumoral conditions the response to usual opening of the eyes stimulates the Berger effect, the electroencephalographic, electrocardiographic, and electromyographic responses to eyes opening have been recorded simultaneously with the psychometric indices of emotional tension and cognitive performance in 59 healthy women aged 18–27 years every two or three days during one or two menstrual cycles determined according the progesterone level in the morning. For excluding the influence of the Novelty factor, the monitoring began at the menstrual phase of the cycle in 29 women and at the luteal phase in the other 30 women. A single examination has been performed in a separate group of 30 women to study the relationship of these parameters with the current progesterone and cortisol levels in saliva. Two-factor ANOVA has shown that the magnitude of amplitude suppression and the bandwidth of the low-frequency α EEG range in the follicular phase of the menstrual cycle are greater than in the luteal one and depend on the Novelty factor. The indices of the Berger effect of the upper-frequency α range do not depend on the neurohumoral state or the Novelty factor. The amplitude suppression and the bandwidth of the lowfrequency α range alone are predictors of the activation in the response to eyes opening because the changes are unidirectional and are interrelated with the autonomic and hormonal characteristics of the activation. It has been demonstrated that eyes opening is a stimulus for the activation only in the neurohumoral state corresponding to the follicular phase of the menstrual cycle. This study has established the dependence of the central and autonomic activation on the individual α frequency EEG profile and the neurohumoral state.