The analysis of the impulse activity of 2 neurons monosynaptically excitable by a 3rd using cross-correlation histograms and Cox's method. The potential for detecting neuronal and synaptic plasticity

By a method of mathematical modelling exogenic stationary random single impulse activity was reproduced of two neurones (N1 and N2), monosynaptically excited by a third one (N3). Value P12, defined from cross-correlation histogram and Cox coefficient beta 12 were used to evaluate the degree of dependence of N1 and N2 impulse trains. Dynamics of P12, beta 12 and of values of P1*, P2* and P3* proportional to corresponding mean interimpulse intervals of N1, N2 and N3, was studied under changes of efficiency of interneuronal connections, neurones excitability and summate action on them of independent random afferent synaptic inflows. It has been shown that the increase (decrease) of P12 or beta 12 accompanied by decrease (increase) of P1* and P2* is a sign of plastic change or N3 discharges frequency, or a sign of plastic changes of the amplitude of excited postsynaptic potentials elicited by these discharges.