[Multiparametric analysis of the effect of ethanol in various doses on EEG in rats].

Multiparametric EEG analysis (840 parameters) was performed for 24 points over the entire dorsal cerebral cortex in outbred rats intraperitoneally injected with ethanol in low (0.75 g/kg), medium (2.0 g/kg), and high subnarcotic (4.5 g/kg) doses. Acute intoxication with low ethanol doses led to an increase in the spectral power and coherence in the frequency band of the dominating theta-rhythm peak (5.75-7.25 Hz), which was indicative of activation of the septo-hippocampal system (with improvement of the related functions such as attention, memory, and exploratory activity). The coherence was also increased in several high-frequency bands of the EEG alpha- and beta-rhythm. Ethanol administered in medium and high doses produced a shift of the dominating theta-rhythm peak to lower frequencies (4.50-5.75 Hz), which was evidence of reduced activity of the septo-hippocampal system and the related CNS functions. These doses of ethanol significantly decreased the spectral power and coherence in most of the high-frequency bands of the EEG alpha- and beta-rhythm, which can be explained by reduced energy and synaptic activity of the cortex leading to impaired high brain functions and the development of somnolent and narcotic effects. Using special sets of reliably modified parameters and a special algorithm, it is possible to solve the inverse problem of identifying experiments (EEG fragments) corresponding to low, medium, and high doses of ethanol.