A comparative statistical study of hippocampal neuronal spontaneous spike activity in situ and in vitro.

The statistical characteristics of the spontaneous spike activity of rat hippocampal neurons in fields CA1-2 were compared in situ and in tissue culture. Statistical analyses have shown strong similarities in estimators of basic numerical characteristics of interspike interval (SIS) distributions. These similarities may serve as evidence of maintenance of normal functional properties and an "organotypic arrangement" of neurons in tissue culture, and they are also indicative of an intrahippocampal origin of the spontaneous impulse activity in the hippocampus. On the other hand, some differences are noted in the tests of firing patterns. Interpretation of these results leads to some assumptions about mechanisms of the phenomenon under study.