COMPUTATIONAL MODEL OF CA2-DEPENDENT POS TSYNAPTIC PROCESSES IN HIPPOCAMPUS (INDUCTION OF LTP AND LTD)()

The computational model was put forward of calcium-dependent posttetan ic processes in the dendritic spine of CA(3) hippocampal pyramidal neu ron which received excitatory and inhibitory afferents. The system of differential equations enables description and evaluation of changes i n protein kinase and protein phosphatase activity induced by changes i n postsynaptic Ca2+ ion concentration (Ca-p(2+)). It was shown that th e synaptic efficacy is determined by the ratio between active protein kinases and active protein phosphatase 1. According to the proposed mo del, increase/decrease in Ca-p(2+) concentration relative to the Ca-p( 2+) rise, produced by prior stimulation, results in the increase/decre ase in the number of phosphorylated ionotropic receptors and in LTP/LT D synaptic efficacy, It follows form the model calculations that the s ame mechanisms underlie the LTP, LTD, and depotentiation, Some results of experimental study of the hippocampal and neocortical synaptic pla sticity are explained and systematized.