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Lods M, Mortessagne P, Pacary E, Terral G, Farrugia F, Mazier W, Masachs N, Charrier V, Cota D, Ferreira G, Abrous DN, Tronel S. Chemogenetic stimulation of adult neurogenesis, and not neonatal neurogenesis, is sufficient to improve long-term memory accuracy. Prog Neurobiol 2022; 219:102364. [DOI: 10.1016/j.pneurobio.2022.102364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 09/21/2022] [Accepted: 10/06/2022] [Indexed: 12/05/2022]
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Lods M, Pacary E, Mazier W, Farrugia F, Mortessagne P, Masachs N, Charrier V, Massa F, Cota D, Ferreira G, Abrous DN, Tronel S. Adult-born neurons immature during learning are necessary for remote memory reconsolidation in rats. Nat Commun 2021; 12:1778. [PMID: 33741954 PMCID: PMC7979763 DOI: 10.1038/s41467-021-22069-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 02/25/2021] [Indexed: 01/09/2023] Open
Abstract
Memory reconsolidation, the process by which memories are again stabilized after being reactivated, has strengthened the idea that memory stabilization is a highly plastic process. To date, the molecular and cellular bases of reconsolidation have been extensively investigated particularly within the hippocampus. However, the role of adult neurogenesis in memory reconsolidation is unclear. Here, we combined functional imaging, retroviral and chemogenetic approaches in rats to tag and manipulate different populations of rat adult-born neurons. We find that both mature and immature adult-born neurons are activated by remote memory retrieval. However, only specific silencing of the adult-born neurons immature during learning impairs remote memory retrieval-induced reconsolidation. Hence, our findings show that adult-born neurons immature during learning are required for the maintenance and update of remote memory reconsolidation.
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Affiliation(s)
- Marie Lods
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Emilie Pacary
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Wilfrid Mazier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Fanny Farrugia
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Pierre Mortessagne
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Nuria Masachs
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Vanessa Charrier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Federico Massa
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Daniela Cota
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Guillaume Ferreira
- INRA, Bordeaux INP, Nutrition and Integrative Neurobiology, UMR 1286, Bordeaux Cedex, France
| | - Djoher Nora Abrous
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France.
| | - Sophie Tronel
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France.
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Masachs N, Charrier V, Farrugia F, Lemaire V, Blin N, Mazier W, Tronel S, Montaron MF, Ge S, Marsicano G, Cota D, Deroche-Gamonet V, Herry C, Abrous DN. The temporal origin of dentate granule neurons dictates their role in spatial memory. Mol Psychiatry 2021; 26:7130-7140. [PMID: 34526669 PMCID: PMC8873024 DOI: 10.1038/s41380-021-01276-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 07/20/2021] [Indexed: 11/27/2022]
Abstract
The dentate gyrus is one of the only brain regions that continues its development after birth in rodents. Adolescence is a very sensitive period during which cognitive competences are programmed. We investigated the role of dentate granule neurons (DGNs) born during adolescence in spatial memory and compared them with those generated earlier in life (in embryos or neonates) or during adulthood by combining functional imaging, retroviral and optogenetic tools to tag and silence DGNs. By imaging DGNs expressing Zif268, a proxy for neuronal activity, we found that neurons generated in adolescent rats (and not embryos or neonates) are transiently involved in spatial memory processing. In contrast, adult-generated DGNs are recruited at a later time point when animals are older. A causal relationship between the temporal origin of DGNs and spatial memory was confirmed by silencing DGNs in behaving animals. Our results demonstrate that the emergence of spatial memory depends on neurons born during adolescence, a function later assumed by neurons generated during adulthood.
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Affiliation(s)
- Nuria Masachs
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Vanessa Charrier
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Fanny Farrugia
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Valerie Lemaire
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Nicolas Blin
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Wilfrid Mazier
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Energy Balance and Obesity Group, U1215, F-33000 Bordeaux, France
| | - Sophie Tronel
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Marie-Françoise Montaron
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Shaoyu Ge
- grid.36425.360000 0001 2216 9681Program in Neuroscience, SUNY at Stony Brook, Stony Brook, New York, NY USA
| | - Giovanni Marsicano
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Endocannabinoids and Neuroadaptation Group, U1215, F-33000 Bordeaux, France
| | - Daniela Cota
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Energy Balance and Obesity Group, U1215, F-33000 Bordeaux, France
| | - Véronique Deroche-Gamonet
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Psychobiology of Drug Addiction Group, U1215, F-33000 Bordeaux, France
| | - Cyril Herry
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neuronal Circuits of Associative Learning Group, U1215, F-33000 Bordeaux, France
| | - Djoher Nora Abrous
- Univ. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000, Bordeaux, France.
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Boitard C, Parkes SL, Cavaroc A, Tantot F, Castanon N, Layé S, Tronel S, Pacheco-Lopez G, Coutureau E, Ferreira G. Switching Adolescent High-Fat Diet to Adult Control Diet Restores Neurocognitive Alterations. Front Behav Neurosci 2016; 10:225. [PMID: 27917115 PMCID: PMC5116459 DOI: 10.3389/fnbeh.2016.00225] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 11/08/2016] [Indexed: 11/18/2022] Open
Abstract
In addition to metabolic and cardiovascular disorders, obesity is associated with adverse cognitive and emotional outcomes. Its growing prevalence in adolescents is particularly alarming since this is a period of ongoing maturation for brain structures (including the hippocampus and amygdala) and for the hypothalamic-pituitary-adrenal (HPA) stress axis, which is required for cognitive and emotional processing. We recently demonstrated that adolescent, but not adult, high-fat diet (HF) exposure leads to impaired hippocampal function and enhanced amygdala function through HPA axis alteration (Boitard et al., 2012, 2014, 2015). Here, we assessed whether the effects of adolescent HF consumption on brain function are permanent or reversible. After adolescent exposure to HF, switching to a standard control diet restored levels of hippocampal neurogenesis and normalized enhanced HPA axis reactivity, amygdala activity and avoidance memory. Therefore, while the adolescent period is highly vulnerable to the deleterious effects of diet-induced obesity, adult exposure to a standard diet appears sufficient to reverse alterations of brain function.
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Affiliation(s)
- Chloé Boitard
- Institut national de la Recherche Agronomique (INRA), Nutrition and Integrative Neurobiology, UMR 1286Bordeaux, France
- Université de BordeauxBordeaux, France
| | - Shauna L. Parkes
- Institut national de la Recherche Agronomique (INRA), Nutrition and Integrative Neurobiology, UMR 1286Bordeaux, France
- Université de BordeauxBordeaux, France
- Centre National de la Recherche Scientifique (CNRS), Institut de Neurosciences Cognitives et Intégratives d’Aquitaine, UMR 5287Bordeaux, France
| | - Amandine Cavaroc
- Institut national de la Recherche Agronomique (INRA), Nutrition and Integrative Neurobiology, UMR 1286Bordeaux, France
- Université de BordeauxBordeaux, France
| | - Frédéric Tantot
- Institut national de la Recherche Agronomique (INRA), Nutrition and Integrative Neurobiology, UMR 1286Bordeaux, France
- Université de BordeauxBordeaux, France
| | - Nathalie Castanon
- Institut national de la Recherche Agronomique (INRA), Nutrition and Integrative Neurobiology, UMR 1286Bordeaux, France
- Université de BordeauxBordeaux, France
| | - Sophie Layé
- Institut national de la Recherche Agronomique (INRA), Nutrition and Integrative Neurobiology, UMR 1286Bordeaux, France
- Université de BordeauxBordeaux, France
| | - Sophie Tronel
- Université de BordeauxBordeaux, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 Neuro Centre MagendieBordeaux, France
| | - Gustavo Pacheco-Lopez
- Biological and Health Sciences Division, Campus Lerma, Metropolitan Autonomous University (UAM)Lerma, Mexico
| | - Etienne Coutureau
- Université de BordeauxBordeaux, France
- Centre National de la Recherche Scientifique (CNRS), Institut de Neurosciences Cognitives et Intégratives d’Aquitaine, UMR 5287Bordeaux, France
| | - Guillaume Ferreira
- Institut national de la Recherche Agronomique (INRA), Nutrition and Integrative Neurobiology, UMR 1286Bordeaux, France
- Université de BordeauxBordeaux, France
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Tronel S, Charrier V, Sage C, Maitre M, Leste-Lasserre T, Abrous DN. Adult-born dentate neurons are recruited in both spatial memory encoding and retrieval. Hippocampus 2015; 25:1472-9. [PMID: 25913775 DOI: 10.1002/hipo.22468] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2015] [Indexed: 11/08/2022]
Abstract
Adult neurogenesis occurs in the dentate gyrus (DG) of the hippocampus, which is a key structure in learning and memory. Adult-generated granule cells have been shown to play a role in spatial memory processes such as acquisition or retrieval, in particular during an immature stage when they exhibit a period of increased plasticity. Here, we demonstrate that immature and mature neurons born in the DG of adult rats are similarly activated in spatial memory processes. By imaging the activation of these two different neuron generations in the same rat and by using the immediate early gene Zif268, we show that these neurons are involved in both spatial memory acquisition and retrieval. These results demonstrate that adult-generated granule cells are involved in memory beyond their immaturity stage.
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Affiliation(s)
- Sophie Tronel
- Neurocentre MagendiePhysiopathologie De La Plasticité NeuronaleUnité 862, Institut National De La Santé Et De La Recherche Médicale, Inserm U862, Bordeaux-F33077, Paris, France.,Université Bordeaux, Bordeaux-F33000, France
| | - Vanessa Charrier
- Neurocentre MagendiePhysiopathologie De La Plasticité NeuronaleUnité 862, Institut National De La Santé Et De La Recherche Médicale, Inserm U862, Bordeaux-F33077, Paris, France.,Université Bordeaux, Bordeaux-F33000, France
| | - Cyrille Sage
- Neurocentre MagendiePhysiopathologie De La Plasticité NeuronaleUnité 862, Institut National De La Santé Et De La Recherche Médicale, Inserm U862, Bordeaux-F33077, Paris, France.,Université Bordeaux, Bordeaux-F33000, France
| | - Marlene Maitre
- Neurocentre MagendiePhysiopathologie De La Plasticité NeuronaleUnité 862, Institut National De La Santé Et De La Recherche Médicale, Inserm U862, Bordeaux-F33077, Paris, France.,Université Bordeaux, Bordeaux-F33000, France
| | - Thierry Leste-Lasserre
- Neurocentre MagendiePhysiopathologie De La Plasticité NeuronaleUnité 862, Institut National De La Santé Et De La Recherche Médicale, Inserm U862, Bordeaux-F33077, Paris, France.,Université Bordeaux, Bordeaux-F33000, France
| | - Djoher N Abrous
- Neurocentre MagendiePhysiopathologie De La Plasticité NeuronaleUnité 862, Institut National De La Santé Et De La Recherche Médicale, Inserm U862, Bordeaux-F33077, Paris, France.,Université Bordeaux, Bordeaux-F33000, France
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Tronel S, Lemaire V, Charrier V, Montaron MF, Abrous DN. Influence of ontogenetic age on the role of dentate granule neurons. Brain Struct Funct 2014; 220:645-61. [PMID: 24510284 DOI: 10.1007/s00429-014-0715-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 01/24/2014] [Indexed: 12/20/2022]
Abstract
New neurons are continuously produced in the adult dentate gyrus of the hippocampus, a key structure in learning and memory. It has been shown that adult neurogenesis is crucial for normal memory processing. However, it is not known whether neurons born during the developmental period and during adulthood support the same functions. Here, we demonstrate that neurons born in neonates (first postnatal week) are activated in different memory processes when they are mature compared to neurons born in adults. By imaging the activation of these two different neuron generations in the same rat and using the IEG Zif268 and Fos, we show that these neurons are involved in discriminating dissimilar contexts and spatial problem solving, respectively. These findings demonstrate that the ontogenetic stage during which neurons are generated is crucial for their function within the memory network.
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Boitard C, Etchamendy N, Sauvant J, Aubert A, Tronel S, Marighetto A, Layé S, Ferreira G. Juvenile, but not adult exposure to high-fat diet impairs relational memory and hippocampal neurogenesis in mice. Hippocampus 2012; 22:2095-100. [DOI: 10.1002/hipo.22032] [Citation(s) in RCA: 186] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2012] [Indexed: 12/29/2022]
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Tronel S, Belnoue L, Grosjean N, Revest JM, Piazza PV, Koehl M, Abrous DN. Adult-born neurons are necessary for extended contextual discrimination. Hippocampus 2010; 22:292-8. [PMID: 21049483 DOI: 10.1002/hipo.20895] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2010] [Indexed: 12/25/2022]
Abstract
New neurons are continuously produced in the adult dentate gyrus of the hippocampus. It has been shown that one of the functions of adult neurogenesis is to support spatial pattern separation, a process that transforms similar memories into nonoverlapping representations. This prompted us to investigate whether adult-born neurons are required for discriminating two contexts, i.e., for identifying a familiar environment and detect any changes introduced in it. We show that depleting adult-born neurons impairs the animal's ability to disambiguate two contexts after extensive training. These data suggest that the continuous production of new dentate neurons plays a crucial role in extracting and separating efficiently contextual representation in order to discriminate features within events.
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Tronel S, Alberini CM. Persistent disruption of a traumatic memory by postretrieval inactivation of glucocorticoid receptors in the amygdala. Biol Psychiatry 2007; 62:33-9. [PMID: 17207472 PMCID: PMC1978220 DOI: 10.1016/j.biopsych.2006.09.009] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 08/24/2006] [Accepted: 09/02/2006] [Indexed: 11/30/2022]
Abstract
BACKGROUND Posttraumatic stress disorder (PTSD) is characterized by acute and chronic changes in the stress response, which include alterations in glucocorticoid secretion and critically involve the limbic system, in particular the amygdala. Important symptoms of PTSD manifest as a classical conditioning to fear, which recurs each time trauma-related cues remind the subject of the original insult. Traumatic memories based on fear conditioning can be disrupted if interfering events or pharmacological interventions are applied following their retrieval. METHODS AND RESULTS Using an animal model, here we show that a traumatic memory is persistently disrupted if immediately after its retrieval glucocorticoid receptors are inactivated in the amygdala. The disruption of the memory is long lasting and memory retention does not re-emerge following strong reminders of the conditioned fear. CONCLUSIONS We propose that a combinatorial approach of psychological and pharmacological intervention targeting the glucocorticoid system following memory retrieval may represent a novel direction for the treatment of PTSD.
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Affiliation(s)
- Sophie Tronel
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York 10029, USA.
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Abstract
Memories become stabilized through a time-dependent process that requires gene expression and is commonly known as consolidation. During this time, memories are labile and can be disrupted by a number of interfering events, including electroconvulsive shock, trauma and other learning or the transient effect of drugs such as protein synthesis inhibitors. Once consolidated, memories are insensitive to these disruptions. However, they can again become fragile if recalled or reactivated. Reactivation creates another time-dependent process, known as reconsolidation, during which the memory is restabilized. Here we discuss some of the questions currently debated in the field of memory consolidation and reconsolidation, the molecular and anatomical requirements for both processes and, finally, their functional relationship.
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Affiliation(s)
- C M Alberini
- Department of Neuroscience, Mount Sinai School of Medicine, Box 1065, New York, NY 10029, USA.
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Tronel S, Milekic MH, Alberini CM. Linking new information to a reactivated memory requires consolidation and not reconsolidation mechanisms. PLoS Biol 2005; 3:e293. [PMID: 16104829 PMCID: PMC1188238 DOI: 10.1371/journal.pbio.0030293] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2005] [Accepted: 06/21/2005] [Indexed: 11/19/2022] Open
Abstract
A new memory is initially labile and becomes stabilized through a process of consolidation, which depends on gene expression. Stable memories, however, can again become labile if reactivated by recall and require another phase of protein synthesis in order to be maintained. This process is known as reconsolidation. The functional significance of the labile phase of reconsolidation is unknown; one hypothesis proposes that it is required to link new information with reactivated memories. Reconsolidation is distinct from the initial consolidation, and one distinction is that the requirement for specific proteins or general protein synthesis during the two processes occurs in different brain areas. Here, we identified an anatomically distinctive molecular requirement that doubly dissociates consolidation from reconsolidation of an inhibitory avoidance memory. We then used this requirement to investigate whether reconsolidation and consolidation are involved in linking new information with reactivated memories. In contrast to what the hypothesis predicted, we found that reconsolidation does not contribute to the formation of an association between new and reactivated information. Instead, it recruits mechanisms similar to those underlying consolidation of a new memory. Thus, linking new information to a reactivated memory is mediated by consolidation and not reconsolidation mechanisms. The association of new information with an established memory is mediated through a consolidation mechanism, leaving the original memory intact.
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Affiliation(s)
- Sophie Tronel
- 1Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Maria H Milekic
- 1Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Cristina M Alberini
- 1Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
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Abstract
A rapidly learned odor discrimination task based on spontaneous foraging behavior of the rat was used to evaluate the role of N-methyl-D-aspartate (NMDA) receptors (NMDARs) in ongoing memory consolidation. Rats were trained in a single session to discriminate among three odors, one of which was associated with palatable food reward. Previous experiments showed that the NMDAR antagonist DL-APV induced amnesia for this task when injected immediately after training. In the present study, memory was reactivated 24 h after training by exposure to the rewarded odor within the experimental context after which rats received an intracerebroventricular injection of APV. Combined reactivation-drug treatment induced profound amnesia when tested 48 h later. Animals receiving drug alone, in absence of reactivation, showed perfect retention. It is concluded that NMDARs support a consolidation process taking place after memory reactivation.
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Affiliation(s)
- Meritxell Torras-Garcia
- Laboratory of Neuromodulation and Memory, CNRS UMR 7102, Université Pierre & Marie Curie, 75005 Paris, France
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Abstract
These experiments investigated the role of the noradrenergic system in the late stage of memory consolidation and in particular its action at beta receptors in the prelimbic region (PL) of the prefrontal cortex in the hours after training. Rats were trained in a rapidly acquired, appetitively motivated foraging task based on olfactory discrimination. They were injected with a beta adrenergic receptor antagonist into the PL 5 min or 2 h after training and tested 48 h later. Rats injected at 2 h showed amnesia, whereas those injected at 5 min had good retention, equivalent to saline-injected controls. Monitoring extracellular noradrenaline efflux in PL by in vivo microdialysis during the first hours after training revealed a significant increase shortly after training, with a rapid return to baseline, and then another increase around the 2-h posttraining time window. Pseudo-trained rats showed a smaller early efflux and did not show the second wave of efflux at 2 h. These results confirm earlier pharmacological and immunohistochemical studies suggesting a delayed role of noradrenaline in a late phase of long-term memory consolidation and the engagement of the PL during these consolidation processes.
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Affiliation(s)
- Sophie Tronel
- Neuromodulation and Memory Processes, Unité Mixte de Recherche 7102, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Paris 75005, France
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Tronel S, Sara SJ. Blockade of NMDA receptors in prelimbic cortex induces an enduring amnesia for odor-reward associative learning. J Neurosci 2003; 23:5472-6. [PMID: 12843246 PMCID: PMC6741223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2003] [Revised: 04/29/2003] [Accepted: 05/01/2003] [Indexed: 03/03/2023] Open
Abstract
The competitive antagonist 2-amino-5-phosphonoeptanoic acid (APV) was injected intracerebroventricularly to determine the involvement of NMDA receptors in different stages of memory consolidation. Subsequent experiments used local injections to determine possible sites of drug action. Rats were trained in a rapidly learned olfactory task to find palatable food in a hole in a sponge impregnated with the target odor in the presence of two other sponges with nonrewarded odors. APV injections were made intracerebroventricularly 5 min or 2 hr after the end of the training, and a retention test was given 48 hr later. The results showed that blockade of NMDA receptors immediately after training induces a profound and enduring amnesia with no effect when the treatment is delayed at 2 hr after training. To address the question of the effective sites of action of the intracerebroventricular treatment, APV injections into the hippocampus and into the prelimblic region of the frontal cortex (PLC) were made. Blockade of NMDA receptors into the PLC but not into the hippocampus impaired memory formation of the odor-reward association. The amnesia is not transient, because the retention tests were made 48 hr after training. These results underlie the role of NMDA receptors in the early stage of consolidation of a simple odor-reward associative memory and confirm the role of the PLC in the consolidation of long-term memory.
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Affiliation(s)
- Sophie Tronel
- Neuromodulation and Memory Processes, Unité Mixte de Recherche 7102, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, 75005 Paris, France
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15
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Tronel S, Sara SJ. Mapping of olfactory memory circuits: region-specific c-fos activation after odor-reward associative learning or after its retrieval. Learn Mem 2002; 9:105-11. [PMID: 12074998 PMCID: PMC182591 DOI: 10.1101/lm.47802] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2002] [Accepted: 04/30/2002] [Indexed: 11/24/2022]
Abstract
Although there is growing knowledge about intracellular mechanisms underlying neuronal plasticity and memory consolidation and reconsolidation after retrieval, information concerning the interaction among brain areas during formation and retrieval of memory is relatively sparse and fragmented. Addressing this question requires simultaneous monitoring of activity in multiple brain regions during learning, the post-acquisition consolidation period, and retrieval and subsequent reconsolidation. Immunoreaction to the immediate early gene c-fos is a powerful tool to mark neuronal activation of specific populations of neurons. Using this method, we are able to report, for the first time, post-training activation of a network of closely related brain regions, particularly in the frontal cortex and the basolateral amygdala (BLA), that is specific to the learning of an odor-reward association. On the other hand, retrieval of a well-established associative memory trace does not seem to differentially activate the same regions. The amygdala, in particular, is not engaged after retrieval, whereas the lateral habenula (LHab) shows strong activation that is restricted to animals having previously learned the association. Although intracellular mechanisms may be similar during consolidation and reconsolidation, this study indicates that different brain circuits are involved in the two processes, at least with respect to a rapidly learned olfactory task.
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Affiliation(s)
- Sophie Tronel
- Neurobiologie des Processus Adaptatifs Centre National de la Recherche Scientifique, Unite Mixte de Recherche 7102, Laboratoire de Neuromodulation et Processus Mnésiques, Université P & M Curie, 75005 Paris, France
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