Kochubey S. The mechanisms of synchronous oscillations in the networks of hippocampus interneurons with shunting GABA-ergic synapses.

The thesis is devoted to the computer simulation research of the mechanisms providing the generation of stable synchronous electric oscillations in the range of gamma rhythm in the networks of hippocampus interneurons. The influence of extrasynaptic receptors on the frequence and synchronization of oscillations in the network, frequency and power of stochastic synaptic excitatory signal from the hippocampus pyramidal cells and the conductivity of tonic GABA-ergic current coming from the extrasynaptic receptors is revealed in the thesis. The simplified mathematical model of interneurons, shunt and excitatory synapses as well as external excitatory and shunt signals was used in the thesis. The ability of hippocampus interneuron network to work as a non-linear frequency modulator, transforming the wide frequency range coming from the pyramidal neurons into the synchronous gamma rhythm oscillations is demonstrated for the first time. It is investigated and proven that the bilateral effect of the GABAergic current is capable of increasing or decreasing the synchronization of oscillations in the network depending on the tonic conductivity. The ability of GABA to cause spontaneous oscillations in the interneuron network is demonstrated. Keywords: interneurons, neuronal networks, hippohampus, shunting synapses, pyramidal cells, synchronization, frequence of oscillations, extrasynaptic receptors, gamma-aminobutyric acid (GABA).