The Effects of AMPA‐induced Lesions of the Septo‐hippocampal Cholinergic Projection on Aversive Conditioning to Explicit and Contextual Cues and Spatial Learning in the Water Maze
- 1 February 1995
- journal article
- Published by Wiley in European Journal of Neuroscience
- Vol. 7 (2) , 281-292
- https://doi.org/10.1111/j.1460-9568.1995.tb01064.x
Abstract
The environmental context of an animal both subsumes and is associated with the explicit cues that guide its behavioural responses. Recent work in this laboratory suggests that learning about the relationship between the cues which comprise a context depends on the hippocampus. In the present study the role of the cholinergic input to the hippocampus in contextual learning was assessed in rats using a conditioned stimulus/context conditioning paradigm and spatial learning in the Morris water maze. In the former, a place preference apparatus provided the context. The subject was confined in the black chamber and a ‘clicker’conditioned stimulus was presented five times in a 20 min period. A trace interval of 5 or 30 s, depending on the group, was interposed between the end of the clicker and a footshock. Theory predicts that animals in the 5 s condition will learn more about the clicker as a predictor of shock and become strongly conditioned, while those in the 30 s condition learn relatively more about the context. Conditioning to the clicker (conditioned stimulus) was measured in a separate lick suppression chamber—presentation of the clicker suppresses drinking, and contextual learning was determined by recording the time spent on the black side of the place preference apparatus when both the black and a familiar white chamber were accessible. Lesions of the medial septum/ diagonal band induced by RS-α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) enhanced contextual learning in this paradigm but disrupted conditioned stimulus conditioning in the 30 s condition. Acquisition of the Morris water maze was largely unimpaired. The results are suggested to reflect a shift towards the use of hippocampal-dependent contextual learning strategies in lesioned animals.Keywords
This publication has 59 references indexed in Scilit:
- Effects of intracranial infusions of chlordiazepoxide on spatial learning in the Morris water maze. II. Neuropharmacological specificityBehavioural Brain Research, 1993
- Modality-Specific Retrograde Amnesia of FearScience, 1992
- Differential contribution of amygdala and hippocampus to cued and contextual fear conditioning.Behavioral Neuroscience, 1992
- The basal forebrain-cortical cholinergic system: interpreting the functional consequences of excitotoxic lesionsTrends in Neurosciences, 1991
- Effects of post-training bicuculline and muscimol on retention: Lack of state dependencyBehavioral and Neural Biology, 1990
- Benzodiazepine receptor ligand influences on acquisition: Suggestion of an endogenous modulatory mechanism mediated by benzodiazepine receptorsBehavioral and Neural Biology, 1990
- Two-stage model of memory trace formation: A role for “noisy” brain statesNeuroscience, 1989
- Basal forebrain magnocellular neurons stain for nerve growth factor receptor: Correlation with cholinergic cell bodies and effects of axotomyJournal of Neuroscience Research, 1987
- Hippocampus and trace conditioning of the rabbit's classically conditioned nictitating membrane response.Behavioral Neuroscience, 1986
- Feed-forward inhibition in the hippocampal formationProgress in Neurobiology, 1984