Selective excitotoxic lesions of the hippocampus and basolateral amygdala have dissociable effects on appetitive cue and place conditioning based on path integration in a novel Y-maze procedure.

Full Abstract

The hippocampus and amygdala are thought to be functionally distinct components of different learning and memory systems. This functional dissociation has been particularly apparent in pavlovian fear conditioning, where the integrity of the hippocampus is necessary for contextual conditioning, and of the amygdala for discrete cue conditioning. Their respective roles in appetitive conditioning, however, remain equivocal mainly due to the lack of agreement concerning the operational definition of a 'context'. The present study used a novel procedure to measure appetitive conditioning to spatial context or to a discrete cue. Following selective excitotoxic lesions of the hippocampus (HPC) or basolateral amygdala (BLA), rats were initially trained to acquire discrete CS-sucrose conditioning in a Y-maze apparatus with three topographically identical chambers, the chambers discriminated only on the basis of path integration. The same group of animals then underwent 'place/contextual conditioning' where the CS presented in a chamber assigned as the positive chamber was paired with sucrose, but the same CS presented in either of the other two chambers was not. Thus, spatial context was the only cue that the animal could use to retrieve the value of the CS. HPC lesions impaired the acquisition of conditioned place preference but facilitated the acquisition of cue conditioning, while BLA lesions had the opposite effect, retarding the acquisition of cue conditioning but leaving the acquisition of conditioned place preference intact. Here we provide strong support for the notion that the HPC and BLA subserve complementary and competing roles in appetitive cue and contextual conditioning.

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Author information

Author/s: Ito, Rutsuko (R); Robbins, Trevor W (TW); McNaughton, Bruce L (BL); Everitt, Barry J (BJ);

Affiliation: Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK. rutsuko.ito(-atsign-)psy.ox.ac.uk

Grants: 076244 (Agency:Wellcome Trust)

Journal and publication information

Publication Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't

Journal: The European journal of neuroscience (Eur J Neurosci), published in France. (Language: eng)

Reference: 2006-Jun; vol 23 (issue 11) : pp 3071-80

Dates: Created 2006/07/05; Completed 2006/09/28; Revised 2008/11/20;

PMID: 16819997, 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.

Amygdala - injuries; physiology
Animals
Appetitive Behavior - drug effects; physiology
Avoidance Learning - drug effects; physiology
Behavior, Animal
Conditioning, Classical - drug effects; physiology
Cues

Hippocampus - injuries; physiology
Ibotenic Acid - toxicity
Male
Maze Learning - drug effects; physiology
N-Methylaspartate - toxicity
Neurotoxins - toxicity
Rats

Associated Chemicals: Neurotoxins (0) ; Ibotenic Acid (2552-55-8) ; N-Methylaspartate (6384-92-5)

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