Generalization in place learning across geometrically different environments is impaired by hippocampal lesions in rats.
A recent study (Tommasi & Thinus-Blanc, 2004) found that when rats trained to search for food hidden in the center of a square-shaped enclosure were tested in the absence of food, they searched precisely in the center of the enclosure. Transfer tests carried out in enclosures differing in shape or size (rectangular-, large square-, and equilateral triangle-shaped) showed that rats searched in the geometric center of the novel environments. In the present work, half of those rats were lesioned bilaterally to the hippocampus and were then re-trained and re-tested in the same task, to be compared to sham rats that received the same retraining/re-test protocol. Results show that lesioned rats, although unimpaired in relearning to localize the center of the square-shaped enclosure, performed considerably worse than sham rats in the transfer tests in the enclosures differing in shape, suggesting a relevant role of the hippocampus in geometry-driven place generalization.
Tommasi
Luca
L
Facoltà di Psicologia, Università di Chieti, Via dei Vestini, I-66013 Chieti, Italy. luca.tommasi@unich.it
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Etienne
E
D000818:Animals; D001070:Appetitive Behavior / Q000502:physiology; D004193:Discrimination Learning / Q000502:physiology*; D004777:Environment; D005793:Generalization, Psychological / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology; D008297:Male; D008568:Memory / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D013037:Spatial Behavior / Q000502:physiology*