Localization and anatomical identification of theta and complex spike cells in dorsal hippocampal formation of rats

doi:10.1016/0014-4886(75)90213-7

Experimental Neurology

Volume 49, Issue 1, October 1975, Pages 299-313

https://doi.org/10.1016/0014-4886(75)90213-7 Get rights and content

Abstract

Microelectrodes were passed through the dorsal hippocampal formation of unrestrained rats, recording for at least 5 min each 35.3 μm. At each site the amplitude and duration of action potential spikes, frequency of firing, relation to slow wave theta rhythm, and presence of complex spikes or theta cells was recorded. One thousand and fourteen neurons were recorded from. (When recording from many neurons simultaneously, the “number” of the neurons was “counted” in an arbitrary and approximate way.) Of 949 nontheta cells greater than 80 μV amplitude, only one was not in the hilus of fascia dentata or in a layer of cells which overlapped stratum pyramidale and stratum granulosum. These are the locations of the cell bodies of projection cells (pyramidal cells and granule cells). However, this layer is, up to 400 μm thicker than stratum pyramidale. Theta cells were seen in sites of cell bodies of projection cells and also in stratum oriens of CA1, suprapyramidal layers of CA3, and dorsal part of the hilus of fascia dentata. The frequency of occurrence in these locations corresponded to the distribution of cell bodies of interneurons. We conclude that the class of projection cells and the class of nontheta cells have a very large overlap, and that the class of interneurons and the class of theta cells have a very large overlap.

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¹: Current address for both authors is: Dept. of Physiology, Downstate Medical Center, State University of New York, Brooklyn, New York 11203. Sally Wu and Jacqueline Smith helped in some of the early stages of the work. The technical assistance of Ann Maxwell was important throughout. This work was supported by grants from the National Institute of Mental Health (MH 12979), The National Science Foundation (GB 26184), and the National Institute of Health (NS-10970).

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Localization and anatomical identification of theta and complex spike cells in dorsal hippocampal formation of rats

Abstract

Exp. Neurol.

Location of postsynaptic inhibitory synapses on hippocampal pyramids

J. Neurophysiol.

Pathway of postsynaptic inhibition in the hippocampus

J. Neurophysiol.

Participation of inhibitory and excitatory interneurons in the control of hippocampal cortical output

Penicillin-induced interictal discharges from the cat hippocampus. II. Mechanisms underlying origin and restriction

J. Neurophysiol.

Studies on the structure of the cerebral cortex. II. Continuation of the study of the Ammonic system

J. Psychol. Neurol.