Hippocampal lesions enhance configural learning by reducing proactive interference
- 1 January 1998
- journal article
- research article
- Published by Wiley in Hippocampus
- Vol. 8 (2) , 138-146
- https://doi.org/10.1002/(sici)1098-1063(1998)8:2<138::aid-hipo6>3.0.co;2-h
Abstract
Rats were trained on an operant conditional discrimination in which an ambiguous stimulus (X) indicated both the occasions on which responding in the presence of a second cue (A) would be reinforced and the occasions on which responding in the presence of a third cue (B) would not be reinforced (X → A+, A−, X → B−, B+). Both rats with neurotoxic lesions of the hippocampus and control rats learned this discrimination more rapidly when the training trials were widely spaced (mean intertrial interval of 8 min) than when they were massed (mean intertrial interval of 1 min). With spaced practice, lesioned and control rats learned this discrimination equally well. But when the training trials were massed, lesioned rats learned more rapidly than controls. At the end of training, performance of all rats was tested at three different intertrial intervals, 0.5 min, 1 min, and 8 min. The control rats trained with 8-min intertrial intervals showed deficits in discrimination performance when the test intertrial interval was 0.5 min or 1 min. An analysis of sequential effects indicated that a major source of this performance deficit was the control rats' failure to withhold responding on nonreinforced trials when those trials were immediately preceded by reinforced trials within 0.5 min or 1 min. In contrast, performance of lesioned rats was not affected by either the test intertrial interval or by the nature of preceding trials. Thus, with short intertrial intervals, hippocampal lesions may have improved learning or performance on a given trial by reducing proactive interference from the previous trial. Hippocampus 1998;8:138–146.Keywords
This publication has 17 references indexed in Scilit:
- The Effects of Intertrial and Feature–Target Intervals on Operant Serial Feature Negative Discrimination LearningLearning and Motivation, 1996
- The effects of intertrial and feature-target intervals on operant serial feature-positive discrimination learningLearning & Behavior, 1995
- Preserved configural learning and spatial learning impairment in rats with hippocampal damageHippocampus, 1992
- A neural network approach to hippocampal function in classical conditioning.Behavioral Neuroscience, 1991
- Associations across time: The hippocampus as a temporary memory storeBehavioral and Brain Sciences, 1985
- Effects of proactive interference on rats’ continuous nonmatching-to-sample performanceLearning & Behavior, 1983
- Place navigation impaired in rats with hippocampal lesionsNature, 1982
- Hippocampus, space, and memoryBehavioral and Brain Sciences, 1979
- Proactive effects of stimuli, delays, and response position during delayed matching from sampleLearning & Behavior, 1976
- Latent inhibition and stimulus generalization of the classically conditioned nictitating membrane response in rabbits (Oryctolagus cuniculus) following hippocampal ablation.Journal of Comparative and Physiological Psychology, 1975