The influence of the potential dependence of the amplitude of postsynaptic potentials on rhythmic processes of bioelectric activity of the cerebral cortex

The dependence of the postsynaptic potential amplitude on the membrane potential was entered into the earlier derived integral equations describing the interactions between excitatory and inhibitory populations of neocortical neurons. The influence of the potential dependence on steady states and the stable region of oscillations of the mean membrane potential of neurons were investigated. Encephalograms of humans and animals in different functional states were numerically simulated. The real form of a power spectrum of electroencephalogram was obtained. The occurrence of the nonregular spindle-shaped activity was revealed, which expands the frequency of basic oscillations and widens the spectral peak. In the unsteady region, the existence of a limiting cycle and the possibility of arising of the pathological activity observed upon abnormal brain functioning were shown with the help of the numerical nonlinear analysis.