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Hypofunction of the dorsal hippocampal NMDA receptors impairs retrieval of memory to partially presented foreground context in a single-trial fear conditioning in rats.
Eur Neuropsychopharmacol. 2006 May; 16(4):241-7.EN

Abstract

In the present study, the effects of N-methyl-D-aspartate (NMDA) receptor antagonist, D,L-2-amino-5-phosphonopentanoic acid (AP5) bilaterally infused into the dorsal hippocampus (2.0 microl /5 microg), on the retrieval of fear memory to partial and whole foreground cues were evaluated by using a step-through passive avoidance and Pavlovian fear conditioning. In the both conditioning tasks, following a 30-s preshock exposure period to the shock-associated context, rats received a single shock in a foreground manner for fear memory exhibition by freezing. Rats with AP5 infusion 5 min before the retrieval tests showed profound freezing deficits either immediately or 48 h after the shock in the testing section of the passive avoidance chamber where foreground cues was partially presented. In the Pavlovian conditioning chamber where fear conditioning was tested in the whole of the context that was explicitly paired with the shock, AP5 rats in all infusion schedules exhibited robust freezing responses. These results showed that hypofunction of the hippocampal NMDA receptors impaired the retrieval of fear memory to partial, and not whole, foreground cues. This suggests that NMDA receptors of the hippocampus are involved in the formation of background context representations about foreground events when there is a deficit in perceiving certain sensory properties of the foreground retrieval cues.

Authors+Show Affiliations

Department of Physiology, Division of Neurophysiology, Medical Faculty, University of Cukurova, 01330-Balcali, Adana, Turkey. emelik@cu.edu.trNo 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

16176870

Citation

Melik, Enver, et al. "Hypofunction of the Dorsal Hippocampal NMDA Receptors Impairs Retrieval of Memory to Partially Presented Foreground Context in a Single-trial Fear Conditioning in Rats." European Neuropsychopharmacology : the Journal of the European College of Neuropsychopharmacology, vol. 16, no. 4, 2006, pp. 241-7.
Melik E, Babar E, Ozen E, et al. Hypofunction of the dorsal hippocampal NMDA receptors impairs retrieval of memory to partially presented foreground context in a single-trial fear conditioning in rats. Eur Neuropsychopharmacol. 2006;16(4):241-7.
Melik, E., Babar, E., Ozen, E., & Ozgunen, T. (2006). Hypofunction of the dorsal hippocampal NMDA receptors impairs retrieval of memory to partially presented foreground context in a single-trial fear conditioning in rats. European Neuropsychopharmacology : the Journal of the European College of Neuropsychopharmacology, 16(4), 241-7.
Melik E, et al. Hypofunction of the Dorsal Hippocampal NMDA Receptors Impairs Retrieval of Memory to Partially Presented Foreground Context in a Single-trial Fear Conditioning in Rats. Eur Neuropsychopharmacol. 2006;16(4):241-7. PubMed PMID: 16176870.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Hypofunction of the dorsal hippocampal NMDA receptors impairs retrieval of memory to partially presented foreground context in a single-trial fear conditioning in rats. AU - Melik,Enver, AU - Babar,Emine, AU - Ozen,Elif, AU - Ozgunen,Tuncay, Y1 - 2005/09/19/ PY - 2005/04/13/received PY - 2005/07/05/revised PY - 2005/07/11/accepted PY - 2005/9/24/pubmed PY - 2006/8/5/medline PY - 2005/9/24/entrez SP - 241 EP - 7 JF - European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology JO - Eur Neuropsychopharmacol VL - 16 IS - 4 N2 - In the present study, the effects of N-methyl-D-aspartate (NMDA) receptor antagonist, D,L-2-amino-5-phosphonopentanoic acid (AP5) bilaterally infused into the dorsal hippocampus (2.0 microl /5 microg), on the retrieval of fear memory to partial and whole foreground cues were evaluated by using a step-through passive avoidance and Pavlovian fear conditioning. In the both conditioning tasks, following a 30-s preshock exposure period to the shock-associated context, rats received a single shock in a foreground manner for fear memory exhibition by freezing. Rats with AP5 infusion 5 min before the retrieval tests showed profound freezing deficits either immediately or 48 h after the shock in the testing section of the passive avoidance chamber where foreground cues was partially presented. In the Pavlovian conditioning chamber where fear conditioning was tested in the whole of the context that was explicitly paired with the shock, AP5 rats in all infusion schedules exhibited robust freezing responses. These results showed that hypofunction of the hippocampal NMDA receptors impaired the retrieval of fear memory to partial, and not whole, foreground cues. This suggests that NMDA receptors of the hippocampus are involved in the formation of background context representations about foreground events when there is a deficit in perceiving certain sensory properties of the foreground retrieval cues. SN - 0924-977X UR - https://www.unboundmedicine.com/medline/citation/16176870/Hypofunction_of_the_dorsal_hippocampal_NMDA_receptors_impairs_retrieval_of_memory_to_partially_presented_foreground_context_in_a_single_trial_fear_conditioning_in_rats_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0924-977X(05)00114-8 DB - PRIME DP - Unbound Medicine ER -