Behavioral characterization of a transection of dorsal CA3 subcortical efferents: comparison with scopolamine and physostigmine infusions into dorsal CA3.

Full Abstract

Cholinergic projections from the medial septum and diagonal band of Broca into the hippocampus have long been implicated in learning and memory. Projections from CA3 to neurons in the medial septum and the diagonal band of Broca have been anatomically characterized. The present experiments were designed to evaluate interactions between the dorsal CA3 subcortical efferents and the cholinergic efferents from the medial septum and diagonal band of Broca for spatial and nonspatial (visual object) novelty detection in the rat. In Experiment 1, physostigmine and scopolamine (both 0.4 microL at 30 microM) were infused into dorsal CA3 and animals were tested on a spatial and nonspatial (visual object) novelty detection paradigm. Scopolamine infusions into dorsal CA3 caused deficits for both spatial and nonspatial (visual object) novelty detection. Physostigmine infusions into dorsal CA3 enhanced both spatial and nonspatial (visual object) novelty detection. These data support models proposing that acetylcholine may control the dynamics for encoding, consolidation, and retrieval in the hippocampus. In Experiment 2, a selective transection of dorsal CA3 efferents in the fimbria resulted in deficits for spatial and nonspatial (visual object) novelty detection. These deficits were similar to the deficits caused by scopolamine infusions into dorsal CA3. These data demonstrate that dorsal CA3 and the medial septum/diagonal band of Broca interact, and that dorsal CA3 influences cholinergic inputs into the hippocampus to facilitate encoding.

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Author information

Author/s: Hunsaker, Michael R (MR); Rogers, Jason L (JL); Kesner, Raymond P (RP);

Affiliation: University of Utah, Department of Psychology, Salt Lake City, UT 84112, USA.

Grants: R01 MH065314-04 (Agency:NIMH NIH HHS) ; R01MH065314 (Agency:NIMH NIH HHS)

Journal and publication information

Publication Type: Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.

Journal: Neurobiology of learning and memory (Neurobiol Learn Mem), published in United States. (Language: eng)

Reference: 2007-Jul; vol 88 (issue 1) : pp 127-36

Dates: Created 2007/05/30; Completed 2007/08/31; Revised 2008/11/20;

PMID: 17350296, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Animals
Cholinergic Fibers - drug effects; metabolism
Cholinesterase Inhibitors - pharmacology
Diagonal Band of Broca - drug effects; metabolism
Discrimination (Psychology) - drug effects; physiology
Exploratory Behavior - drug effects; physiology
Hippocampus - drug effects; metabolism
Male

Male
Muscarinic Antagonists - pharmacology
Neural Pathways - drug effects; metabolism
Pattern Recognition, Visual - drug effects; physiology
Physostigmine - pharmacology
Rats
Scopolamine - pharmacology
Septal Nuclei - drug effects; metabolism

Associated Chemicals: Cholinesterase Inhibitors (0) ; Muscarinic Antagonists (0) ; Scopolamine (51-34-3) ; Physostigmine (57-47-6)

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