title: Dentate gyrus-selective colchicine lesion and performance in temporal and spatial tasks.
abstract: The effects of multiple-site, intradentate, colchicine injections on the performance of a temporal, 'differential reinforcement of low rates of responding' (DRL-20s) task and a spatial, 'delayed non-matching-to-place' (DNMTP) task in a plus-maze were investigated in rats trained in both tasks prior to the lesion. Quantitative analysis revealed a greater than 86% reduction in the dentate gyrus (DG) of the colchicine-injected rats compared to the sham-operated controls. Dentate gyrus damage rendered rats less efficient than sham-operated controls in the performance of the DRL-20s task. The DRL inter-response time (IRT) distribution for the DG-lesioned rats and the sham-operated controls was similar; however, while the distribution peak for the control rats was 20s, it was 16s for the DG-lesioned rats, indicating that the latter rats underestimated time. Performance of the DG-lesioned rats was also disrupted in the DNMTP task. However, DG-lesioned rats recovered control levels of performance during repeated training with an intertrial interval equal to 3s. An increase in intertrial interval in lesioned and sham-operated controls disrupted performance in both groups; however, while DG-lesioned rats performed at chance levels when the intertrial interval was increased to 4min or longer, the sham-operated controls performed at chance levels only when the intertrial interval was increased to 16min. These results seem most parsimoniously interpreted following the cognitive map theory of hippocampal function.
authors.affiliation: Setor de Psicobiologia, Departamento de Psicologia e Educação da Faculdade Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. dos Bandeirantes, Brazil. costaval@terra.com.br
authors.forename: Valéria Catelli Infantozzi
authors.initials: VC
authors.lastname: Costa
authors.forename: José Lino Oliveira
authors.initials: JL
authors.lastname: Bueno
authors.forename: Gilberto Fernando
authors.initials: GF
authors.lastname: Xavier
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001927:Brain Diseases / Q000503:physiopathology; D003078:Colchicine / Q000633:toxicity*; D003714:Denervation; D018891:Dentate Gyrus / Q000293:injuries / Q000473:pathology / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects; D012054:Reinforcement, Psychology; D013028:Space Perception / Q000187:drug effects*; D013037:Spatial Behavior / Q000187:drug effects*; D013997:Time Factors
chemical_list: D003078:Colchicine