Bispectral analysis of rat EEG during maturation

Bispectra were computed for EEGs obtained from frontal cortex and hippocampal formation in normally developed rats. Although the bispectrum serves many purposes, it is utilized here to detect the presence of and quantify (by computing the biocoherence function) the degree of quadratic phase coupling and provide a measure of the deviation from normality in the amplitude distribution of EEGs recorded from two different types of brain tissue during maturation. Preliminary findings indicate that significant quadratic phase coupling exists in the hippocampal EEG during REM sleep, when the hippocampal theta rhythm dominates the frequency distribution of the hippocampal EEG, and that the relative increase in the values of the frequencies involved in the phase coupling follow the maturation of the theta rhythm.<>