[Density of theta as a new parameter characterizing field activity in hippocampal formation of cats]

Our experiments conducted in the last decade on freely moving cats, showed that commonly used theta parameters: frequency, amplitude and power are not sufficient for a precise characterization of theta field activity. It is specially seen in condition when the experimental protocol involves sensory or chemical stimulation in order to induce hippocampal theta. We described a novel theta parameter--"theta density", that allows more adequate quantitative evaluation of this EEG pattern in freely moving cats.