[Influence of CA1 hippocampal field on theta-activity in rats under urethane anesthesia]

The influence of CA1 hippocampal field on the theta-activity production depending on the efficiency of CA1 synaptic inputs was studied in urethanized rats. The long-term posttetanic potentiation (LTP) of Shaffer collaterals resulted in an increase in the theta-power in hippocampal EEG without change in its frequency. A high correlation was shown between the increase in the theta-power and the amplitude of the local potentials induced by LTP. The mechanisms and the functional role of the observed relations between the LTP and theta activity are discussed.