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Thalamic and hippocampal mechanisms in spatial navigation: a dissociation between brain mechanisms for learning how versus learning where to navigate.
Behav Brain Res. 2006 Jun 30; 170(2):241-56.BB

Abstract

Various studies of hippocampus and medial thalamus (MT) suggest that these brain areas play a crucial, marginal, or no essential role in spatial navigation. These divergent views were examined in experiments using electrolytic Lesions of fimbria-fornix (FF) or radiofrequency or neurotoxic Lesions of MT of rats subsequently trained to find a stable visible (experiment 1) or hidden platform (experiments 2 and 3) in a water maze (WM) pool. Rats with electrolytic Lesions of FF or radiofrequency Lesions of MT were impaired in swimming to a stable visible platform, particularly the MT Lesion Group, suggesting impairment of WM strategies acquisition. Additional Lesioned rats were then tested in a hidden platform version of the WM task. Some rats were given Morris's nonspatial pretraining prior to Lesioning to provide them with training in the required WM behavioral strategies. Nonspatially Pretrained rats with FF Lesions eventually were able to navigate to the hidden platform, but the accuracy of place responding was impaired. This impairment occurred without problems in the motoric control of swimming or the use of WM behavioral strategies, suggesting that these rats had a spatial mapping impairment. Radiofrequency MT Lesions blocked acquisition of WM behavioral strategies by Naive rats throughout 3 days of training, severely impairing performance on all aspects of the hidden platform task. Nonspatially Pretrained rats given the same MT Lesions readily learned the hidden platform location and were indistinguishable from controls throughout spatial training. Rats given neurotoxic Lesions of MT for removal of cells were only mildly impaired and improved considerably during training, suggesting an important role for fibers of passage in WM strategies learning. The results provide a clear dissociation between a role for MT in learning WM behavioral strategies and the hippocampal formation in spatial mapping and memory. This is the first identification of a brain area, MT, that is essential for learning behavioral strategies that by themselves do not constitute the solution to the task but are necessary for the successful use of an innate learning ability: place response learning using spatial mapping.

Authors+Show Affiliations

Department of Psychology, University of Western Ontario, London, Ont., Canada N6A 5C2. cain@uwo.caNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16569442

Citation

Cain, Donald P., et al. "Thalamic and Hippocampal Mechanisms in Spatial Navigation: a Dissociation Between Brain Mechanisms for Learning How Versus Learning Where to Navigate." Behavioural Brain Research, vol. 170, no. 2, 2006, pp. 241-56.
Cain DP, Boon F, Corcoran ME. Thalamic and hippocampal mechanisms in spatial navigation: a dissociation between brain mechanisms for learning how versus learning where to navigate. Behav Brain Res. 2006;170(2):241-56.
Cain, D. P., Boon, F., & Corcoran, M. E. (2006). Thalamic and hippocampal mechanisms in spatial navigation: a dissociation between brain mechanisms for learning how versus learning where to navigate. Behavioural Brain Research, 170(2), 241-56.
Cain DP, Boon F, Corcoran ME. Thalamic and Hippocampal Mechanisms in Spatial Navigation: a Dissociation Between Brain Mechanisms for Learning How Versus Learning Where to Navigate. Behav Brain Res. 2006 Jun 30;170(2):241-56. PubMed PMID: 16569442.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Thalamic and hippocampal mechanisms in spatial navigation: a dissociation between brain mechanisms for learning how versus learning where to navigate. AU - Cain,Donald P, AU - Boon,Francis, AU - Corcoran,Michael E, Y1 - 2006/03/29/ PY - 2005/09/23/received PY - 2006/02/20/accepted PY - 2006/3/30/pubmed PY - 2006/9/15/medline PY - 2006/3/30/entrez SP - 241 EP - 56 JF - Behavioural brain research JO - Behav Brain Res VL - 170 IS - 2 N2 - Various studies of hippocampus and medial thalamus (MT) suggest that these brain areas play a crucial, marginal, or no essential role in spatial navigation. These divergent views were examined in experiments using electrolytic Lesions of fimbria-fornix (FF) or radiofrequency or neurotoxic Lesions of MT of rats subsequently trained to find a stable visible (experiment 1) or hidden platform (experiments 2 and 3) in a water maze (WM) pool. Rats with electrolytic Lesions of FF or radiofrequency Lesions of MT were impaired in swimming to a stable visible platform, particularly the MT Lesion Group, suggesting impairment of WM strategies acquisition. Additional Lesioned rats were then tested in a hidden platform version of the WM task. Some rats were given Morris's nonspatial pretraining prior to Lesioning to provide them with training in the required WM behavioral strategies. Nonspatially Pretrained rats with FF Lesions eventually were able to navigate to the hidden platform, but the accuracy of place responding was impaired. This impairment occurred without problems in the motoric control of swimming or the use of WM behavioral strategies, suggesting that these rats had a spatial mapping impairment. Radiofrequency MT Lesions blocked acquisition of WM behavioral strategies by Naive rats throughout 3 days of training, severely impairing performance on all aspects of the hidden platform task. Nonspatially Pretrained rats given the same MT Lesions readily learned the hidden platform location and were indistinguishable from controls throughout spatial training. Rats given neurotoxic Lesions of MT for removal of cells were only mildly impaired and improved considerably during training, suggesting an important role for fibers of passage in WM strategies learning. The results provide a clear dissociation between a role for MT in learning WM behavioral strategies and the hippocampal formation in spatial mapping and memory. This is the first identification of a brain area, MT, that is essential for learning behavioral strategies that by themselves do not constitute the solution to the task but are necessary for the successful use of an innate learning ability: place response learning using spatial mapping. SN - 0166-4328 UR - https://www.unboundmedicine.com/medline/citation/16569442/Thalamic_and_hippocampal_mechanisms_in_spatial_navigation:_a_dissociation_between_brain_mechanisms_for_learning_how_versus_learning_where_to_navigate_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0166-4328(06)00134-3 DB - PRIME DP - Unbound Medicine ER -