Elsevier

Brain Research

Volume 266, Issue 2, 5 May 1983, Pages 334-339
Brain Research

Phase relations of hippocampal projection cells and interneurons to theta activity in the anesthetized rat

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Abstract

The correlation between cell firing and hippocampal theta activity was studied with the spike-triggered averaging method in rats anesthetized with urethane. Projection cells in the CA1 region and the dentate gyrus fired with highest probability on the negative phase of the theta waves recorded from the corresponding regions. CA1 interneurons discharged mainly on the positive phase. In the dentate gyrus about half of the interneurons fired on the negative phase, while the remaining half discharged preferentially on the positive phase of the locally derived theta waves. It was suggested that septal theta ‘pacemaker’ cells directly excite hippocampal interneurons which in turn rhythmically inhibit a large number of projection cells.

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  • Cited by (0)

    **

    The authors wish to thank Drs. R. Fariello, B. H. Bland and C. H. Vanderwolf for their comments on the manuscript, Gail Walden and Joe Nystel for technical assistance, and Becky Ramirez and Lynne Mitchell for typing the manuscript. The manuscript was prepared, in part, at the Department of Psychology, University of Western Ontario, London, Ontario, Canada, where the senior author is currently a visiting scientist.

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