The rhythmic slow activity recorded from entorhinal cortex in freely moving cats

Abstract

The relationships between the entorhinal cortex (EC) and the hippocampal formation (Hipp) field potentials were examined in the present study. The detailed analyses of the signal let us group the patterns of theta appearance into three categories: (1) Theta rhythm dominating in both recordings from the EC and from the Hipp (2) Theta rhythm dominating in the Hipp with irregular activity in the EC (3) Theta rhythm dominating in the EC with irregular activity in the Hipp. These findings provide the evidence for the intrinsic generator of theta rhythm to be localized in entorhinal cortex in cats.