Emotionality and the temporospatial organization of instantaneous EEG potentials

The characteristics of the temporospatial organization of cerebral cortical potentials at different levels of genetically determined emotionality were analyzed by constructing topograms of instantaneous EEG levels in the inbred rat strains MR and MNRA. Two parameters were calculated for each topogram: the total level and the similarity coefficient. Power spectra were calculated for the values and these were found to change in an oscillatory manner. Interstrain differences were found in the correlated changes in total levels and similarity coefficients, in the durations of changes in the total level, which were more marked than those of similarity coefficients, and the nature of interhemisphere asymmetry. In MR rats, the power spectra of both measures showed significant peaks with modes at 2.0, 6.5, and 9.0 Hz. In MNRA rats, peaks in the spectra of these measures both coincided (2.0 Hz) and differed (7.0 Hz in the spectrum of the total level and 3.0, 4.5, and 6.0 Hz in the spectrum of the similarity coefficient). These data suggest different types of functioning of the reticulothalamocortical and hippocampocortical systems in rats of these strains.