[The possible mechanisms of the plastic reorganizations of neuronal activity under different regimens of...

Effects of rhythmical, random and associative intracellular stimulation were studied in identified single neurons of isolated CNS of the Lymnaea stagnalis snail under the conditions of computer controlled experiment. By means of cluster, correlation, and factor methods of analysis were evaluated and compared changes of the character of spontaneous discharge activity induced by above mentioned modes of stimulation. Connections of the basic frequency and temporary characteristics of the endogenous activity of neurons with parameters of external influences were shown to be revealed only during stimulation associated with certain components of endogenous rhythmicity. These connections were practically absent during rhythmical and random stimulation. Three factors were separated which determine the formation of the structure of spike impulsation at application of suprathreshold stimuli. By their variables' composition the factors may be interpreted as: 1) factor of intensity of spontaneous activity; 2) factor of variability of interspike intervals; 3) reinforcing factor. Possible cellular mechanisms of adaptive reorganization of spontaneous activity under the conditions of associative influences are discussed.