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Becker JE, Price JL, Leonard D, Suris A, Kandil E, Shaw M, Kroener S, Brown ES, Adinoff B. The Efficacy of Lidocaine in Disrupting Cocaine Cue-Induced Memory Reconsolidation. Drug Alcohol Depend 2020; 212:108062. [PMID: 32480252 DOI: 10.1016/j.drugalcdep.2020.108062] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 04/06/2020] [Accepted: 05/04/2020] [Indexed: 01/10/2023]
Abstract
RATIONAL Cue-induced craving memories, linked to drug-seeking behaviors, require key molecular processes for memory reconsolidation. Lidocaine, a sodium channel blocker, inhibits NMDA receptor activation and suppresses nitric oxide and ERK production. These processes are required for memory re-consolidation; inhibiting them may reduce cue-related craving memories in cocaine dependent subjects. OBJECTIVES To assess the efficacy of lidocaine in decreasing cue-induced cocaine craving and cocaine use. METHODS Treatment-seeking cocaine-dependent participants (n = 33, 25 men) were recruited. Personalized craving and relaxation scripts were developed. Participants were then randomly assigned in a double-blind design to either receive intravenous lidocaine immediately following a cocaine craving script (lidocaine/craving), saline following a craving script (saline/craving), or lidocaine following a relaxation script (lidocaine/relax). One week following the infusion, cue-induced craving was assessed in the same paradigm without an infusion. Cocaine use and craving were assessed for 4 weeks following infusion. RESULTS The administration of lidocaine during craving induction (lidocaine/craving) did not decrease cue-induced craving during craving reactivation one week later or craving and cocaine use over the 4-week follow-up period compared to the saline/craving group. There were no significant differences in craving and cocaine use between the lidocaine/relax and saline/craving groups. CONCLUSION Lidocaine administered following craving induction did not decrease subsequent cue-induced craving or cocaine use. Blocking the reconsolidation of craving-related memories with pharmacological agents remains an important area of investigation.
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Affiliation(s)
- Josh E Becker
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX USA; School of Behavior and Brain Sciences, UT Dallas, Dallas, TX USA
| | - Julianne L Price
- Department of Psychiatry, University of Florida, Gainesville, FL USA
| | - David Leonard
- David Leonard Statistical Consulting, Wichita Falls, TX USA
| | - Alina Suris
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX USA; VA North Texas Health Care System, Dallas, TX USA
| | - Enas Kandil
- Department of Psychiatry, University of Colorado School of Medicine, Aurora, CO USA; Department of Anesthesiology & Pain Management, UT Southwestern Medical Center, Dallas, TX USA; School of Behavior and Brain Sciences, UT Dallas, Dallas, TX USA
| | - Meredith Shaw
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX USA; VA North Texas Health Care System, Dallas, TX USA
| | - Sven Kroener
- School of Behavior and Brain Sciences, UT Dallas, Dallas, TX USA
| | - E Sherwood Brown
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX USA
| | - Bryon Adinoff
- Department of Psychiatry, University of Colorado School of Medicine, Aurora, CO USA
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Silva MB, Soares AB. Reconsolidation of human motor memory: From boundary conditions to behavioral interventions-How far are we from clinical applications? Behav Brain Res 2018; 353:83-90. [PMID: 29983391 DOI: 10.1016/j.bbr.2018.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 07/02/2018] [Accepted: 07/02/2018] [Indexed: 01/12/2023]
Abstract
The memory reconsolidation hypothesis states that a previously consolidated and stable memory can return to a temporary labile state after retrieved, requiring a new stabilization process. During the labile period, the memory trace is vulnerable to modification, which provides a potential therapeutic opportunity to weaken, updated or strengthen that memory. As such, reconsolidation has been the subject of numerous studies in different domains of human memory that seek strategies to treat post-traumatic disorders and erase or modify pathological memories. A few studies have also investigated the impairment effects of behavioral interferences on motor memory. However, very little has been researched and written about the possibility of using reconsolidation to enhance motor skill learning. Here, we present a critical review of the literature and trace possible applications for human motor memory reconsolidation. We discuss the boundary conditions and the mechanisms to trigger the reconsolidation process, as well as the effects of behavioral interventions in modifying the performance of motor skills.
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Affiliation(s)
- Maristella Borges Silva
- Biomedical Engineering Laboratory, Faculty of Electrical Engineering, Federal University of Uberlandia, Brazil
| | - Alcimar Barbosa Soares
- Biomedical Engineering Laboratory, Faculty of Electrical Engineering, Federal University of Uberlandia, Brazil.
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Gisquet-Verrier P, Riccio DC. Memory integration: An alternative to the consolidation/reconsolidation hypothesis. Prog Neurobiol 2018; 171:15-31. [PMID: 30343034 DOI: 10.1016/j.pneurobio.2018.10.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 09/11/2018] [Accepted: 10/13/2018] [Indexed: 10/28/2022]
Abstract
The original concept of consolidation considers that memory requires time to be fixed. Since 2000, a comparable protein-dependent re-stabilization phase, called reconsolidation, has been assumed to take place after memory retrieval. This consolidation/reconsolidation hypothesis, has dominated the literature for more than 50 years, despite compelling evidence that is inconsistent with it. In this review, we present an historical overview and explain how, despite serious criticisms, this hypothesis has persisted for decades and become accepted as a dogma. Based on both older and more recent evidence, we next propose the concept of memory integration which involves the linkage or embedding of new material into an already existing representation. We believe integration provides a viable explanation for retrograde amnesia in place of the consolidation/reconsolidation hypothesis. Integration can further be the basis for several major cases of memory alteration such as time dependent memory enhancement, interference, counter-conditioning, updating and other instances of memory malleability. In a final section we consider the implications this new concept may have for memory processes and its translational applications.
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Affiliation(s)
- Pascale Gisquet-Verrier
- Neuro-PSI, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Bât 446, Orsay, F-91405, France.
| | - David C Riccio
- Department of Psychological Sciences, Kent State University, Kent, OH, 44242, USA
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4
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Abstract
Research on the reconsolidation effect was greatly revitalized by the highly analytic demonstration of memory reconsolidation (Nader et al. Nature 406:722-726, 2000) in a well-defined behavioral protocol (auditory fear conditioning in the rat). Since this study, reconsolidation has been demonstrated in hundreds of studies over a range of species, tasks, and amnesic agents. Evidence for reconsolidation does not come solely from the behavioral level of analysis. Cellular and molecular correlates of reconsolidation have also been found. In this chapter, I will first define the evidence on which reconsolidation is concluded to exist. I will then discuss some of the conceptual issues facing the field in determining when reconsolidation does and does not occur. Lastly I will explain the clinical implications of this effect.
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Affiliation(s)
- Karim Nader
- Psychology Department, McGill University, 1205 Dr. Penfield Ave, Montreal, QC, Canada, H3A 1B1,
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5
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Abstract
Memory reconsolidation is the process in which reactivated long-term memory (LTM) becomes transiently sensitive to amnesic agents that are effective at consolidation. The phenomenon was first described more than 50 years ago but did not fit the dominant paradigm that posited that consolidation takes place only once per LTM item. Research on reconsolidation was revitalized only more than a decade ago with the demonstration of reconsolidation in a well-defined behavioral protocol (auditory fear conditioning in the rat) subserved by an identified brain circuit (basolateral amygdala). Since then, reconsolidation has been shown in many studies over a range of species, tasks, and amnesic agents, and cellular and molecular correlates of reconsolidation have also been identified. In this review, I will first define the evidence on which reconsolidation is based, and proceed to discuss some of the conceptual issues facing the field in determining when reconsolidation does and does not occur. Last, I will refer to the potential clinical implications of reconsolidation.
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Affiliation(s)
- Karim Nader
- Psychology Department, McGill University, Montréal, Quebec H3A 1B1, Canada
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6
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Delorenzi A, Maza FJ, Suárez LD, Barreiro K, Molina VA, Stehberg J. Memory beyond expression. ACTA ACUST UNITED AC 2014; 108:307-22. [PMID: 25102126 DOI: 10.1016/j.jphysparis.2014.07.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 07/16/2014] [Accepted: 07/17/2014] [Indexed: 01/05/2023]
Abstract
The idea that memories are not invariable after the consolidation process has led to new perspectives about several mnemonic processes. In this framework, we review our studies on the modulation of memory expression during reconsolidation. We propose that during both memory consolidation and reconsolidation, neuromodulators can determine the probability of the memory trace to guide behavior, i.e. they can either increase or decrease its behavioral expressibility without affecting the potential of persistent memories to be activated and become labile. Our hypothesis is based on the findings that positive modulation of memory expression during reconsolidation occurs even if memories are behaviorally unexpressed. This review discusses the original approach taken in the studies of the crab Neohelice (Chasmagnathus) granulata, which was then successfully applied to test the hypothesis in rodent fear memory. Data presented offers a new way of thinking about both weak trainings and experimental amnesia: memory retrieval can be dissociated from memory expression. Furthermore, the strategy presented here allowed us to show in human declarative memory that the periods in which long-term memory can be activated and become labile during reconsolidation exceeds the periods in which that memory is expressed, providing direct evidence that conscious access to memory is not needed for reconsolidation. Specific controls based on the constraints of reminders to trigger reconsolidation allow us to distinguish between obliterated and unexpressed but activated long-term memories after amnesic treatments, weak trainings and forgetting. In the hypothesis discussed, memory expressibility--the outcome of experience-dependent changes in the potential to behave--is considered as a flexible and modulable attribute of long-term memories. Expression seems to be just one of the possible fates of re-activated memories.
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Affiliation(s)
- A Delorenzi
- Laboratorio de Neurobiología de la Memoria, Departamento de Fisiología y Biología Molecular, IFIByNE-CONICET, Pabellón II, FCEyN, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), Argentina.
| | - F J Maza
- Laboratorio de Neurobiología de la Memoria, Departamento de Fisiología y Biología Molecular, IFIByNE-CONICET, Pabellón II, FCEyN, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), Argentina.
| | - L D Suárez
- Laboratorio de Neurobiología de la Memoria, Departamento de Fisiología y Biología Molecular, IFIByNE-CONICET, Pabellón II, FCEyN, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), Argentina.
| | - K Barreiro
- Laboratorio de Neurobiología de la Memoria, Departamento de Fisiología y Biología Molecular, IFIByNE-CONICET, Pabellón II, FCEyN, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), Argentina.
| | - V A Molina
- Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, IFEC-CONICET (X5000HUA), Argentina.
| | - J Stehberg
- Laboratorio de Neurobiología, Departamento de Ciencias Biológicas, Universidad Andrés Bello, Chile.
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7
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Tronson NC, Taylor JR. Addiction: a drug-induced disorder of memory reconsolidation. Curr Opin Neurobiol 2013; 23:573-80. [PMID: 23415831 PMCID: PMC3677957 DOI: 10.1016/j.conb.2013.01.022] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Revised: 01/15/2013] [Accepted: 01/16/2013] [Indexed: 12/15/2022]
Abstract
Persistent maladaptive memories that maintain drug seeking and are resistant to extinction are a hallmark of addiction. As such, disruption of memory reconsolidation after retrieval has received attention for its therapeutic potential. Unrestrained reconsolidation may have the opposite effect, leading to reiterative and cumulative strengthening of memory over long periods of time. Here we review the molecular mechanisms underlying reconsolidation of appetitive and drug-rewarded memories, and discuss how these findings contribute to our understanding of the nature of this process. Finally, we suggest that drug-induced alterations to signal transduction might lead to dysregulation of reconsolidation, causing enhancements of drug-related memory after retrieval, and significantly contribute to the compulsive drug seeking that is a core component of addiction.
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Affiliation(s)
- Natalie C Tronson
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109,
| | - Jane R. Taylor
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06508
- Department of Psychology, Yale University, New Haven, CT 06508,
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8
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The temporal dynamics of enhancing a human declarative memory during reconsolidation. Neuroscience 2013; 246:397-408. [DOI: 10.1016/j.neuroscience.2013.04.033] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 04/16/2013] [Accepted: 04/16/2013] [Indexed: 11/23/2022]
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9
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Besnard A, Caboche J, Laroche S. Reconsolidation of memory: A decade of debate. Prog Neurobiol 2012; 99:61-80. [PMID: 22877586 DOI: 10.1016/j.pneurobio.2012.07.002] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 06/13/2012] [Accepted: 07/08/2012] [Indexed: 10/28/2022]
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Ramirez DR, Bell GH, Lasseter HC, Xie X, Traina SA, Fuchs RA. Dorsal hippocampal regulation of memory reconsolidation processes that facilitate drug context-induced cocaine-seeking behavior in rats. Eur J Neurosci 2009; 30:901-12. [PMID: 19712098 DOI: 10.1111/j.1460-9568.2009.06889.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Exposure to a cocaine-paired context increases the propensity for relapse in cocaine users and prompts cocaine-seeking behavior in rats. According to the reconsolidation hypothesis, upon context re-exposure, established cocaine-related associations are retrieved and can become labile. These associations must undergo reconsolidation into long-term memory to effect enduring stimulus control. The dorsal hippocampus (DH), dorsolateral caudate-putamen and dorsomedial prefrontal cortex are critical for the expression of context-induced cocaine seeking, and these brain regions may also play a role in the reconsolidation of cocaine-related memories that promote this behavior. To test this hypothesis, rats were trained to press a lever for unsignaled cocaine infusions (0.2 mg/infusion, i.v.) in a distinct environmental context (cocaine-paired context), followed by extinction training in a different context (extinction context). Rats were then re-exposed to the cocaine-paired context for 15 min in order to reactivate cocaine-related memories or received comparable exposure to a novel unpaired context. Immediately thereafter, rats received bilateral microinfusions of the protein synthesis inhibitor anisomycin, the sodium channel blocker tetrodotoxin or vehicle into one of the above brain regions. After additional extinction training in the extinction context, reinstatement of cocaine-seeking behavior (i.e., non-reinforced lever presses) was assessed in the cocaine-paired context. Tetrodotoxin, but not anisomycin, administered into the DH inhibited drug context-induced cocaine-seeking behavior in a memory reactivation-dependent manner. Other manipulations failed to alter this behavior. These findings suggest that the DH facilitates the reconsolidation of associative memories that maintain context-induced cocaine-seeking behavior, but it is not the site of anisomycin-sensitive memory restabilization per se.
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Affiliation(s)
- Donna R Ramirez
- Department of Psychology, University of North Carolina, Chapel Hill, NC, USA
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11
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Abstract
The predominant view about memory formation states that a consolidation process stabilizes newly acquired traces until they are safely stored in the brain. However, during the last ten years evidence has accumulated to indicate that, upon retrieval, consolidated memories are rendered again vulnerable to the action of metabolic blockers, notably protein synthesis inhibitors. This has led to the hypothesis that memories are reconsolidated at the time of retrieval, and that this requires protein synthesis in different brain regions. Here we will address the consolidation-reconsolidation debate and discuss some controversial issues about the reconsolidation hypothesis, in particular the biological role of this process.
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12
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13
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Diergaarde L, Schoffelmeer ANM, De Vries TJ. Pharmacological manipulation of memory reconsolidation: towards a novel treatment of pathogenic memories. Eur J Pharmacol 2008; 585:453-7. [PMID: 18410917 DOI: 10.1016/j.ejphar.2008.03.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 02/27/2008] [Accepted: 03/04/2008] [Indexed: 11/18/2022]
Abstract
Well-consolidated memories, when retrieved, may return to a transiently fragile state, and need to be consolidated again in order to be maintained. This process has been referred to as memory reconsolidation and presumably serves to modify or strengthen memory traces. In recent years, our understanding of the neurobiological mechanisms underlying this phenomenon has increased rapidly. Here, we will briefly review some of the pharmacological evidence, stressing a crucial role for the brain's major neurotransmitter systems, such as glutamate and noradrenaline, in memory reconsolidation. Pharmacological intervention of reconsolidation processes may have clinical relevance, especially for the treatment of psychiatric disorders that are characterized by pathological memories, including post-traumatic stress disorder and addictive behaviour.
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Affiliation(s)
- Leontien Diergaarde
- Department of Anatomy and Neurosciences, Center for Neurogenomics and Cognitive Research, VU Medical Center, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
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15
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Rossato JI, Bevilaqua LRM, Medina JH, Izquierdo I, Cammarota M. Retrieval induces hippocampal-dependent reconsolidation of spatial memory. Learn Mem 2006; 13:431-40. [PMID: 16882860 PMCID: PMC1538920 DOI: 10.1101/lm.315206] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Nonreinforced retrieval can cause extinction and/or reconsolidation, two processes that affect subsequent retrieval in opposite ways. Using the Morris water maze task we show that, in the rat, repeated nonreinforced expression of spatial memory causes extinction, which is unaffected by inhibition of protein synthesis within the CA1 region of the dorsal hippocampus. However, if the number of nonreinforced retrieval trials is insufficient to induce long-lasting extinction, then a hippocampal protein synthesis-dependent reconsolidation process recovers the original memory. Inhibition of hippocampal protein synthesis after reversal learning sessions impairs retention of the reversed preference and blocks persistence of the original one, suggesting that reversal learning involves reconsolidation rather than extinction of the original memory. Our results suggest the existence of a hippocampal protein synthesis-dependent reconsolidation process that operates to recover or update retrieval-weakened memories from incomplete extinction.
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Affiliation(s)
- Janine I Rossato
- Centro de Memória, Instituto de Pesquisas Biomédicas, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil
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Frenkel L, Maldonado H, Delorenzi A. Memory strengthening by a real-life episode during reconsolidation: an outcome of water deprivation via brain angiotensin II. Eur J Neurosci 2005; 22:1757-66. [PMID: 16197516 DOI: 10.1111/j.1460-9568.2005.04373.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A considerable body of evidence reveals that consolidated memories, recalled by a reminder, enter into a new vulnerability phase during which they are susceptible to disruption again. Consistently, reconsolidation was shown by the amnesic effects induced by administration of consolidation blockers after memory labilization. To shed light on the functional value of reconsolidation, we explored whether an endogenous process activated during a concurrent real-life experience improved this memory phase. Reconsolidation of long-term contextual memory has been well documented in the crab Chasmagnathus. Previously we showed that angiotensin II facilitates memory consolidation. Moreover, water deprivation increases brain angiotensin and improves memory consolidation and retrieval through angiotensin II receptors. Here, we tested whether concurrent water deprivation improves reconsolidation via endogenous angiotensin and therefore strengthens memory. We show that memory reconsolidation, induced by training context re-exposure, is facilitated by a concurrent episode of water deprivation, which induces a raise in endogenous brain angiotensin II. Positive modulation is expressed by full memory retention, despite a weak training, 24 or 72 but not 4 h after memory reactivation. This is the first evidence that memory can be positively modulated during reconsolidation through an identified endogenous process triggered during a real-life episode. We propose that the functional value for reconsolidation would be to make possible a change in memory strength by the influence of a concurrent experience. Reconsolidation improvement would lead to memory re-evaluation, not by altering memory content but by modifying the behaviour as an outcome of changing the hierarchy of the memories that control it.
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Affiliation(s)
- Lia Frenkel
- Laboratorio de Neurobiología de la Memoria, Departamento de Fisiología y Biología Molecular y Celular, Universidad de Buenos Aires, IFIBYNE-CONICET, Argentina
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Abstract
The idea that new memories are initially 'labile' and sensitive to disruption before becoming permanently stored in the wiring of the brain has been dogma for >100 years. Recently, we have revisited the hypothesis that reactivation of a consolidated memory can return it to a labile, sensitive state - in which it can be modified, strengthened, changed or even erased! The data generated from some of the best-described paradigms in memory research, in conjunction with powerful neurobiological technologies, have provided striking support for a very dynamic neurobiological basis of memory, which is beginning to overturn the old dogma.
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Affiliation(s)
- Karim Nader
- Department of Psychology, McGill University, Montreal, Quebec, Canada H3A 1B1.
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Affiliation(s)
- S J Sara
- Neuromodulation and Cognitive Processes, Institut des Neurosciences, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 7624, 75005 Paris, France.
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Rodriguez WA, Horne CA, Padilla JL. Effects of glucose and fructose on recently reactivated and recently acquired memories. Prog Neuropsychopharmacol Biol Psychiatry 1999; 23:1285-317. [PMID: 10581649 DOI: 10.1016/s0278-5846(99)00063-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
1. The effects of glucose and fructose on memory reactivation were investigated. 2. Rats were trained originally on a brightness discrimination passive avoidance task. 3. Memory reactivation treatment consisted of re-exposing the rats 24 hr later to the footshock unconditioned stimulus in the experimental room. Glucose or fructose (32, 100, 320, 1000, or 2000 mg/kg) was administered immediately after reactivation. 4. Twenty-four hr after reactivation (48 hr after training) the rats were tested for their ability to acquire an active avoidance (reversal) task. 5. The dose-response functions for the effects of both glucose and fructose on the reactivated memory followed identical cubic trends. However, a combined dose of glucose and fructose was significantly less effective at modulating memory than was an equimolar dose of either sugar alone. 6. We compared analytically the effects of combined glucose and fructose treatment on new versus old memories. The dose-response functions for both types of memories follow cubic trends, suggesting that similar multiple interacting mechanisms operate when memories are originally stored and when they are later re-encoded.
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Affiliation(s)
- W A Rodriguez
- Department of Psychology, University of California, Berkeley, USA
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