[Effect of inhibitory-inhibitory connections and the form of postsynaptic potentials on the formation of rhythmic processes in the cerebral cortex: analysis of the approximate equation of the electroencephalogram].

The integral equation, describing the electroencephalogram and taking into account the steepness of PSP fronts, delays of action potential spread, and neural Inhibito-inhibitory connections, is derived and analysed. The damping decrements and frequencies of the equation solutions in the continuum of parameters, associated with total numbers excitatory and inhibitory neurons in the cerebral cortex, density of synapses, and average level of excitation of cortical neurons are considered. The steepness of PSP fronts does not qualitatively change the solution's structure with the influences of EPSP and IPSP fronts being opposite. The inhibito-inhibitory connections expand the damped solutions regions. The delays of action potential spread between excitatory neurons enlarge the damped solutions region, and the delays in ones between inhibitory and excitatory neurons decrease it, especially for higher frequencies.