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Dorsal hippocampus is necessary for novel learning but sufficient for subsequent similar learning.
Hippocampus. 2012 Nov; 22(11):2157-70.H

Abstract

Our current understanding of brain mechanisms involved in learning and memory has been derived largely from studies using experimentally naïve animals. However, it is becoming increasingly clear that not all identified mechanisms may generalize to subsequent learning. For example, N-methyl-D-aspartate glutamate (NMDA) receptors in the dorsal hippocampus are required for contextual fear conditioning in naïve animals but not in animals previously trained in a similar task. Here we investigated how animals learn contextual fear conditioning for a second time-a response which is not due to habituation or generalization. We found that dorsal hippocampus infusions of voltage-dependent calcium channel blockers or the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) agonist impaired the first, not the second contextual learning. Only manipulations of the entire hippocampus led to an impairment in second learning. Specifically, inactivation of either the dorsal or ventral hippocampus caused the remaining portion of the hippocampus to acquire and consolidate the second learning. Thus, dorsal hippocampus seems necessary for initial contextual fear conditioning, but either the dorsal or ventral hippocampus is sufficient for subsequent conditioning in a different context. Together, these findings suggest that prior training experiences can change how the hippocampus processes subsequent similar learning.

Authors+Show Affiliations

Department of Psychology, McGill University, Montreal, Canada H3A 1B1. s.wang@ed.ac.ukNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

22593084

Citation

Wang, Szu-Han, et al. "Dorsal Hippocampus Is Necessary for Novel Learning but Sufficient for Subsequent Similar Learning." Hippocampus, vol. 22, no. 11, 2012, pp. 2157-70.
Wang SH, Finnie PS, Hardt O, et al. Dorsal hippocampus is necessary for novel learning but sufficient for subsequent similar learning. Hippocampus. 2012;22(11):2157-70.
Wang, S. H., Finnie, P. S., Hardt, O., & Nader, K. (2012). Dorsal hippocampus is necessary for novel learning but sufficient for subsequent similar learning. Hippocampus, 22(11), 2157-70. https://doi.org/10.1002/hipo.22036
Wang SH, et al. Dorsal Hippocampus Is Necessary for Novel Learning but Sufficient for Subsequent Similar Learning. Hippocampus. 2012;22(11):2157-70. PubMed PMID: 22593084.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Dorsal hippocampus is necessary for novel learning but sufficient for subsequent similar learning. AU - Wang,Szu-Han, AU - Finnie,Peter S B, AU - Hardt,Oliver, AU - Nader,Karim, Y1 - 2012/05/17/ PY - 2012/04/16/accepted PY - 2012/5/18/entrez PY - 2012/5/18/pubmed PY - 2013/4/12/medline SP - 2157 EP - 70 JF - Hippocampus JO - Hippocampus VL - 22 IS - 11 N2 - Our current understanding of brain mechanisms involved in learning and memory has been derived largely from studies using experimentally naïve animals. However, it is becoming increasingly clear that not all identified mechanisms may generalize to subsequent learning. For example, N-methyl-D-aspartate glutamate (NMDA) receptors in the dorsal hippocampus are required for contextual fear conditioning in naïve animals but not in animals previously trained in a similar task. Here we investigated how animals learn contextual fear conditioning for a second time-a response which is not due to habituation or generalization. We found that dorsal hippocampus infusions of voltage-dependent calcium channel blockers or the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) agonist impaired the first, not the second contextual learning. Only manipulations of the entire hippocampus led to an impairment in second learning. Specifically, inactivation of either the dorsal or ventral hippocampus caused the remaining portion of the hippocampus to acquire and consolidate the second learning. Thus, dorsal hippocampus seems necessary for initial contextual fear conditioning, but either the dorsal or ventral hippocampus is sufficient for subsequent conditioning in a different context. Together, these findings suggest that prior training experiences can change how the hippocampus processes subsequent similar learning. SN - 1098-1063 UR - https://www.unboundmedicine.com/medline/citation/22593084/Dorsal_hippocampus_is_necessary_for_novel_learning_but_sufficient_for_subsequent_similar_learning_ L2 - https://doi.org/10.1002/hipo.22036 DB - PRIME DP - Unbound Medicine ER -