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Bao L, Rao J, Yu D, Zheng B, Yin B. Decoding the language of fear: Unveiling objective and subjective indicators in rodent models through a systematic review and meta-analysis. Neurosci Biobehav Rev 2024; 157:105537. [PMID: 38215801 DOI: 10.1016/j.neubiorev.2024.105537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/23/2023] [Accepted: 01/05/2024] [Indexed: 01/14/2024]
Abstract
While rodent models are vital for studying mental disorders, the underestimation of construct validity of fear indicators has led to limitations in translating to effective clinical treatments. Addressing this gap, we systematically reviewed 5054 articles from the 1960 s, understanding underlying theoretical advancement, and selected 68 articles with at least two fear indicators for a three-level meta-analysis. We hypothesized correlations between different indicators would elucidate similar functions, while magnitude differences could reveal distinct neural or behavioral mechanisms. Our findings reveal a shift towards using freezing behavior as the primary fear indicator in rodent models, and strong, moderate, and weak correlations between freezing and conditioned suppression ratios, 22-kHz ultrasonic vocalizations, and autonomic nervous system responses, respectively. Using freezing as a reference, moderator analysis shows treatment types and fear stages significantly influenced differences in magnitudes between two indicators. Our analysis supports a two-system model of fear in rodents, where objective and subjective fears could operate on a threshold-based mechanism.
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Affiliation(s)
- Lili Bao
- School of Psychology, Fujian Normal University, China; Key Laboratory for Learning and Behavioral Sciences, Fujian Normal University, China
| | - Jiaojiao Rao
- School of Psychology, Fujian Normal University, China; Key Laboratory for Learning and Behavioral Sciences, Fujian Normal University, China
| | - Delin Yu
- School of Psychology, Fujian Normal University, China; Key Laboratory for Learning and Behavioral Sciences, Fujian Normal University, China
| | - Benhuiyuan Zheng
- School of Psychology, Fujian Normal University, China; Key Laboratory for Learning and Behavioral Sciences, Fujian Normal University, China
| | - Bin Yin
- School of Psychology, Fujian Normal University, China; Key Laboratory for Learning and Behavioral Sciences, Fujian Normal University, China.
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2
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Milton AL. Drug memory reconsolidation: from molecular mechanisms to the clinical context. Transl Psychiatry 2023; 13:370. [PMID: 38040677 PMCID: PMC10692359 DOI: 10.1038/s41398-023-02666-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 11/07/2023] [Accepted: 11/13/2023] [Indexed: 12/03/2023] Open
Abstract
Since its rediscovery at the beginning of the 21st Century, memory reconsolidation has been proposed to be a therapeutic target for reducing the impact of emotional memories that can go awry in mental health disorders such as drug addiction (substance use disorder, SUD). Addiction can be conceptualised as a disorder of learning and memory, in which both pavlovian and instrumental learning systems become hijacked into supporting drug-seeking and drug-taking behaviours. The past two decades of research have characterised the details of the molecular pathways supporting the reconsolidation of pavlovian cue-drug memories, with more recent work indicating that the reconsolidation of instrumental drug-seeking memories also relies upon similar mechanisms. This narrative review considers what is known about the mechanisms underlying the reconsolidation of pavlovian and instrumental memories associated with drug use, how these approaches have translated to experimental medicine studies, and the challenges and opportunities for the clinical use of reconsolidation-based therapies.
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Affiliation(s)
- Amy L Milton
- Department of Psychology, University of Cambridge, Cambridge, UK.
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3
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Francis T, Wolter M, Leri F. The effects of passive and active administration of heroin, and associated conditioned stimuli, on consolidation of object memory. Sci Rep 2022; 12:20351. [PMID: 36437288 PMCID: PMC9701675 DOI: 10.1038/s41598-022-24585-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 11/17/2022] [Indexed: 11/28/2022] Open
Abstract
Mode of administration (i.e., active vs passive) could influence the modulatory action that drugs of abuse exert on memory consolidation. Similarly, drug conditioned stimuli modulate memory consolidation and, therefore, acquisition and extinction of this conditioned response could also be influenced by mode of drug administration. Exploring these questions in male Sprague-Dawley rats, Study 1 assessed memory modulation by post-training 0, 0.3 and 1 mg/kg heroin injected subcutaneously in operant chambers (i.e., drug conditioned context). Study 2 asked a similar question but in rats trained to self-administer 0.05 mg/kg/infusion heroin intravenously, as well as in rats that received identical amounts of intravenous heroin but passively, using a yoked design. The period of heroin exposure was followed by repeated drug-free confinement in the conditioned context, and by sessions during which responses on the active lever had no scheduled consequences. Study 2 also included a cue-induced reinstatement session during which lever responses reactivated a light cue previously paired with intravenous heroin infusions. The post-training effects of injected/self-administered/yoked heroin, extinction and reinstatement sessions on memory consolidation were tested using the object location memory task. It was found that post-sample heroin enhanced memory in injected and yoked, but not self-administering, rats. However, post-sample exposure to the heroin cues (i.e., context or/and light cue) modulated memory equally in all groups. Taken together, these data support the conclusion that mode of administration impacts the cognitive consequences of exposure to drugs but not of environmental stimuli linked to their reinforcing effects.
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Affiliation(s)
- Travis Francis
- grid.34429.380000 0004 1936 8198Department of Psychology and Neuroscience Specialization, University of Guelph, 50 Stone Road East, Guelph, ON N1G 1Y4 Canada
| | - Michael Wolter
- grid.34429.380000 0004 1936 8198Department of Psychology and Neuroscience Specialization, University of Guelph, 50 Stone Road East, Guelph, ON N1G 1Y4 Canada
| | - Francesco Leri
- grid.34429.380000 0004 1936 8198Department of Psychology and Neuroscience Specialization, University of Guelph, 50 Stone Road East, Guelph, ON N1G 1Y4 Canada
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4
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Quantifying the instrumental and noninstrumental underpinnings of Pavlovian responding with the Price equation. Psychon Bull Rev 2021; 29:1295-1306. [PMID: 34918283 DOI: 10.3758/s13423-021-02047-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2021] [Indexed: 11/08/2022]
Abstract
The Price equation is a mathematical expression of selectionist and non-selectionist pressures on biological, cultural, and behavioral change. We use it here to specify instrumental and noninstrumental behaviors as they arise within the context of the Pavlovian autoshaping procedure, for rats trained under reward certainty and reward uncertainty. The point of departure for this endeavor is that some portion of autoshaped behavior referred to as goal-tracking appears instrumental-a function of resource attainment (the individual approaches the location where the unconditioned stimulus is to be delivered). By contrast, some other portion of autoshaped behavior referred to as sign-tracking is noninstrumental-irrelevant to making contact with the to-be-delivered unconditioned stimulus. A Price equation model is proposed that unifies our understanding of Pavlovian autoshaping behavior by isolating operant and respondent influences on goal-tracking (instrumental) and sign-tracking (noninstrumental) behavior.
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Baidoo N, Wolter M, Holahan MR, Teale T, Winters B, Leri F. The effects of morphine withdrawal and conditioned withdrawal on memory consolidation and c-Fos expression in the central amygdala. Addict Biol 2021; 26:e12909. [PMID: 32418296 DOI: 10.1111/adb.12909] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/31/2020] [Accepted: 04/05/2020] [Indexed: 12/24/2022]
Abstract
The current study tested the hypothesis that drug withdrawal contributes to the addiction cycle in part because of an action on memory consolidation. Hence, four experiments in male Sprague-Dawley rats compared the effects of precipitated morphine withdrawal and conditioned morphine withdrawal on the consolidation of object memory and on activation of c-Fos in the central nucleus of the amygdala (CeA). It was found that immediate, but not 6 h delayed, post sample administration of 3 mg/kg of naltrexone significantly enhanced object memory in rats maintained, or previously maintained, on 10 mg/kg/day of morphine via osmotic minipumps. To establish whether conditioned withdrawal could also alter object memory, a contextual conditioning procedure was employed whereby morphine-maintained (10 mg/kg/day) animals received naltrexone (3 mg/kg) in a distinctive context (CS+) and vehicle in a separate context (CS-) for 10 days. During conditioning in the CS+, naltrexone suppressed locomotor activity, caused a rapid body weight loss and increased frequency of wet dog shakes. Interestingly, confinement to this CS+ immediately, but not 6 h, after the sample phase, also enhanced object memory. Finally, posttraining naltrexone and exposure to the CS+ both induced significant expression of c-Fos in the CeA. Therefore, this study reports for the first time that both acute precipitated withdrawal and conditioned withdrawal can facilitate memory consolidation, possibly through a common neural pathway that involves the central amygdala.
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Affiliation(s)
- Nana Baidoo
- Department of Psychology & Neuroscience University of Guelph Guelph Canada
| | - Michael Wolter
- Department of Psychology & Neuroscience University of Guelph Guelph Canada
| | | | - Tanisse Teale
- Department of Neuroscience Carleton University Ottawa Canada
| | - Boyer Winters
- Department of Psychology & Neuroscience University of Guelph Guelph Canada
| | - Francesco Leri
- Department of Psychology & Neuroscience University of Guelph Guelph Canada
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Huang WL, Hsiung MH, Dai W, Hu SSJ. Rottlerin, BDNF, and the impairment of inhibitory avoidance memory. Psychopharmacology (Berl) 2021; 238:421-439. [PMID: 33146738 DOI: 10.1007/s00213-020-05690-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 10/23/2020] [Indexed: 02/07/2023]
Abstract
RATIONALE AND OBJECTIVE As a eukaryotic elongation factor 2 kinase (eEF2K) inhibitor and a mitochondrial uncoupler, oncologists have extensively studied rottlerin. Neuroscientists, however, have accumulated scarce data on the role of rottlerin in affective and cognitive functions. Only two prior studies have, respectively, documented its antidepressant-like effect and how it impairs psychostimulant-supported memory. Whether or not rottlerin would affect aversive memory remains unknown. Hence, we sought to investigate the effects of rottlerin on aversive memory in the inhibitory avoidance (IA) task in mice. MATERIALS AND METHODS Male C57BL/6J mice were trained to acquire the IA task. Rottlerin (5 mg/kg, i.p. or 3 μg bilaterally in the hippocampus) or the vehicle was administered before footshock training (acquisition), after footshock training (consolidation), after the memory reactivation (reconsolidation), and before the test (retrieval) in the IA task. RESULTS Systemic and intrahippocampal rottlerin impaired the acquisition, consolidation, and retrieval of IA memory, without affecting the reconsolidation process. Rottlerin (5 mg/kg, i.p.) induced a fast-onset and long-lasting increase in the brain-derived neurotrophic factor (BDNF) protein levels in the mouse hippocampus. Systemic injection of 7,8-dihydroxyflavone (7,8-DHF, 30 mg/kg), a BDNF tropomyosin receptor kinase B (TrkB) agonist impaired IA memory consolidation, and treatment with K252a (5 μg/kg), a Trk receptor antagonist, reversed the suppressing effect of rottlerin on IA memory consolidation. CONCLUSION Rottlerin impairs IA memory consolidation through the enhancement of BDNF signaling in the mouse hippocampus. Excessive brain BDNF levels can be detrimental to cognitive function. Rottlerin is likely to affect the original memory-associated neuroplasticity. Thus, it can be combined with exposure therapy to facilitate the forgetting of maladaptive aversive memory, such as post-traumatic stress disorder (PTSD).
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Affiliation(s)
- Wan-Ling Huang
- Cannabinoid Signaling Laboratory, Department of Psychology, National Cheng Kung University, 1 University Rd, Tainan, 70101, Taiwan
| | - Ming-Heng Hsiung
- Cannabinoid Signaling Laboratory, Department of Psychology, National Cheng Kung University, 1 University Rd, Tainan, 70101, Taiwan
| | - Wen Dai
- Cannabinoid Signaling Laboratory, Department of Psychology, National Cheng Kung University, 1 University Rd, Tainan, 70101, Taiwan
| | - Sherry Shu-Jung Hu
- Cannabinoid Signaling Laboratory, Department of Psychology, National Cheng Kung University, 1 University Rd, Tainan, 70101, Taiwan.
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Luyten L, Schnell AE, Schroyens N, Beckers T. Lack of drug-induced post-retrieval amnesia for auditory fear memories in rats. BMC Biol 2021; 19:17. [PMID: 33499865 PMCID: PMC7836479 DOI: 10.1186/s12915-021-00957-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 01/11/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Long-term memory formation is generally assumed to involve the permanent storage of recently acquired memories, making them relatively insensitive to disruption, a process referred to as memory consolidation. However, when retrieved under specific circumstances, consolidated fear memories are thought to return to a labile state, thereby opening a window for modification (e.g., attenuation) of the memory. Several interventions during a critical time frame after this destabilization seem to be able to alter the retrieved memory, for example by pharmacologically interfering with the restabilization process, either by direct protein synthesis inhibition or indirectly, using drugs that can be safely administered in patients (e.g., propranolol). Here, we find that, contrary to expectations, systemic pharmacological manipulations in auditory fear-conditioned rats do not lead to drug-induced post-retrieval amnesia. RESULTS In a series of well-powered auditory fear conditioning experiments (four with propranolol, 10 mg/kg, two with rapamycin, 20-40 mg/kg, one with anisomycin, 150 mg/kg and cycloheximide, 1.5 mg/kg), we found no evidence for reduced cued fear memory expression during a drug-free test in adult male Sprague-Dawley rats that had previously received a systemic drug injection upon retrieval of the tone fear memory. All experiments used standard fear conditioning and reactivation procedures with freezing as the behavioral read-out (conceptual or exact replications of published reports) and common pharmacological agents. Additional tests confirmed that the applied drug doses and administration routes were effective in inducing their conventional effects on expression of fear (propranolol, acutely), body weight (rapamycin, anisomycin, cycloheximide), and consolidation of extinction memories (cycloheximide). CONCLUSIONS In contrast with previously published studies, we did not find evidence for drug-induced post-retrieval amnesia, underlining that this effect, as well as its clinical applicability, may be considerably more constrained and less readily reproduced than what the current literature would suggest.
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Affiliation(s)
- Laura Luyten
- KU Leuven, Faculty of Psychology and Educational Sciences, Psychology of Learning and Experimental Psychopathology, Tiensestraat 102 PB 3712, 3000 Leuven, Belgium
- Leuven Brain Institute, Herestraat 49 PB 1021, 3000 Leuven, Belgium
| | - Anna Elisabeth Schnell
- KU Leuven, Faculty of Psychology and Educational Sciences, Psychology of Learning and Experimental Psychopathology, Tiensestraat 102 PB 3712, 3000 Leuven, Belgium
- Leuven Brain Institute, Herestraat 49 PB 1021, 3000 Leuven, Belgium
| | - Natalie Schroyens
- KU Leuven, Faculty of Psychology and Educational Sciences, Psychology of Learning and Experimental Psychopathology, Tiensestraat 102 PB 3712, 3000 Leuven, Belgium
- Leuven Brain Institute, Herestraat 49 PB 1021, 3000 Leuven, Belgium
| | - Tom Beckers
- KU Leuven, Faculty of Psychology and Educational Sciences, Psychology of Learning and Experimental Psychopathology, Tiensestraat 102 PB 3712, 3000 Leuven, Belgium
- Leuven Brain Institute, Herestraat 49 PB 1021, 3000 Leuven, Belgium
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8
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Baidoo N, Wolter M, Leri F. Opioid withdrawal and memory consolidation. Neurosci Biobehav Rev 2020; 114:16-24. [PMID: 32294487 DOI: 10.1016/j.neubiorev.2020.03.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 03/20/2020] [Accepted: 03/29/2020] [Indexed: 12/14/2022]
Abstract
It is well established that learning and memory are central to substance dependence. This paper specifically reviews the effect of opioid withdrawal on memory consolidation. Although there is evidence that opioid withdrawal can interfere with initial acquisition and retrieval of older memories, there are several reasons to postulate a facilitatory action on the consolidation of newly acquired memories. In fact, there is substantial evidence that memory consolidation is facilitated by the release of stress hormones, that it requires the activation of the amygdala, of central noradrenergic and cholinergic pathways, and that it involves long-term potentiation. This review highlights evidence that very similar neurobiological processes are involved in opioid withdrawal, and summarizes recent results indicating that naltrexone-precipitated withdrawal enhanced consolidation in rats. From this neurocognitive perspective, therefore, opioid use may escalate during the addiction cycle in part because memories of stimuli and actions experienced during withdrawal are strengthened.
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Affiliation(s)
- Nana Baidoo
- Department of Psychology & Neuroscience, Guelph, Ontario, Canada
| | - Michael Wolter
- Department of Psychology & Neuroscience, Guelph, Ontario, Canada
| | - Francesco Leri
- Department of Psychology & Neuroscience, Guelph, Ontario, Canada.
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Cogan ES, Shapses MA, Robinson TE, Tronson NC. Disrupting reconsolidation: memory erasure or blunting of emotional/motivational value? Neuropsychopharmacology 2019; 44:399-407. [PMID: 29786067 PMCID: PMC6300536 DOI: 10.1038/s41386-018-0082-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/23/2018] [Accepted: 04/24/2018] [Indexed: 11/09/2022]
Abstract
When memories are retrieved they become labile, and subject to alteration by a process known as reconsolidation. Disruption of memory reconsolidation decreases the performance of learned responses, which is often attributed to erasure of the memory; in the case of Pavlovian learning, to a loss of the association between a conditioned stimulus (CS) and unconditioned stimulus (US). However, an alternative interpretation is that disrupting reconsolidation does not erase memories, but blunts their emotional/motivational impact. It is difficult to parse the predictive vs. emotional/motivational value of CSs in non-human animals, but studies on variation in the form of conditioned responses (CRs) in a Pavlovian conditioned approach task suggest a way to do this. In this task a lever-CS paired with a food reward (US) acquires predictive value in all rats, but is attributed with emotional/motivational value to a greater extent in some rats (sign-trackers) than others (goal-trackers). We report that the post-retrieval administration of propranolol selectively attenuates a sign-tracking CR, and the associated neural activation of brain "motive circuits", while having no effect on conditioned orienting behavior in sign-trackers, or on goal-tracking CRs evoked by either a lever-CS or a tone-CS. We conclude that the disruption of reconsolidation by post-retrieval propranolol degrades the emotional/motivational impact of the CS, required for sign-tracking, but leaves the CS-US association intact. The possibility that post-retrieval interventions can reduce the emotional/motivational aspects of memories, without actually erasing them, has important implications for treating maladaptive memories that contribute to some psychiatric disorders.
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Affiliation(s)
- Elizabeth S. Cogan
- 0000000086837370grid.214458.eBiopsychology Program, Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI 48109 USA
| | - Mark A. Shapses
- 0000000086837370grid.214458.eBiopsychology Program, Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI 48109 USA
| | - Terry E. Robinson
- 0000000086837370grid.214458.eBiopsychology Program, Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI 48109 USA
| | - Natalie C. Tronson
- 0000000086837370grid.214458.eBiopsychology Program, Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI 48109 USA
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10
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Cocaine preexposure enhances sexual conditioning and increases resistance to extinction in male Japanese quail. Learn Behav 2018; 45:313-322. [PMID: 28488062 DOI: 10.3758/s13420-017-0274-1] [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] [Indexed: 01/17/2023]
Abstract
The incentive-sensitization theory posits that drug addiction results from altered learning and motivational processes that stem from drug-induced changes in the brain's reward circuitry. Although it is generally accepted that problematic drug use results from these neuroadaptations, less research has focused on how these neural changes affect the incentive-motivational properties of naturally rewarding stimuli such as sex. The present set of experiments was conducted to investigate (1) dose-dependent effects of preexposure to chronic cocaine on sexual conditioning and (2) how prior cocaine exposure affects the extinction of sexually conditioned behavior in male Japanese quail. In Experiment 1, male quail were exposed to saline or to cocaine (5, 10, or 20 mg/kg ip) for 10 days, and their locomotor activity was measured. After a washout period, ten sexual-conditioning trials were conducted in which a light (CS) was presented prior to the presentation of a female quail (US) and approach to the light was measured. The results showed that cocaine dose-dependently enhanced sexually conditioned approach behavior and copulation. Experiment 2 was procedurally similar to Experiment 1, except that the quail received either saline or 10 mg/kg cocaine (ip) and 24 extinction trials were conducted. During extinction, no female was presented after the CS. The results showed that preexposure to cocaine delayed extinction. Therefore, cocaine may dose-dependently increase the strength of sexual conditioning, and this may subsequently increase resistance to extinction. These findings and their possible mechanisms are explored.
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Schuweiler D, Athens J, Thompson J, Vazhayil S, Garris P. Effects of an acute therapeutic or rewarding dose of amphetamine on acquisition of Pavlovian autoshaping and ventral striatal dopamine signaling. Behav Brain Res 2018; 336:191-203. [DOI: 10.1016/j.bbr.2017.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/28/2017] [Accepted: 09/01/2017] [Indexed: 12/16/2022]
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Kutlu MG, Gould TJ. Effects of drugs of abuse on hippocampal plasticity and hippocampus-dependent learning and memory: contributions to development and maintenance of addiction. Learn Mem 2016; 23:515-33. [PMID: 27634143 PMCID: PMC5026208 DOI: 10.1101/lm.042192.116] [Citation(s) in RCA: 198] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/19/2016] [Indexed: 11/25/2022]
Abstract
It has long been hypothesized that conditioning mechanisms play major roles in addiction. Specifically, the associations between rewarding properties of drugs of abuse and the drug context can contribute to future use and facilitate the transition from initial drug use into drug dependency. On the other hand, the self-medication hypothesis of drug abuse suggests that negative consequences of drug withdrawal result in relapse to drug use as an attempt to alleviate the negative symptoms. In this review, we explored these hypotheses and the involvement of the hippocampus in the development and maintenance of addiction to widely abused drugs such as cocaine, amphetamine, nicotine, alcohol, opiates, and cannabis. Studies suggest that initial exposure to stimulants (i.e., cocaine, nicotine, and amphetamine) and alcohol may enhance hippocampal function and, therefore, the formation of augmented drug-context associations that contribute to the development of addiction. In line with the self-medication hypothesis, withdrawal from stimulants, ethanol, and cannabis results in hippocampus-dependent learning and memory deficits, which suggest that an attempt to alleviate these deficits may contribute to relapse to drug use and maintenance of addiction. Interestingly, opiate withdrawal leads to enhancement of hippocampus-dependent learning and memory. Given that a conditioned aversion to drug context develops during opiate withdrawal, the cognitive enhancement in this case may result in the formation of an augmented association between withdrawal-induced aversion and withdrawal context. Therefore, individuals with opiate addiction may return to opiate use to avoid aversive symptoms triggered by the withdrawal context. Overall, the systematic examination of the role of the hippocampus in drug addiction may help to formulate a better understanding of addiction and underlying neural substrates.
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Affiliation(s)
- Munir Gunes Kutlu
- Department of Biobehavioral Health, Penn State University, University Park, Pennsylvania 16802, USA
| | - Thomas J Gould
- Department of Biobehavioral Health, Penn State University, University Park, Pennsylvania 16802, USA
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Escosteguy-Neto JC, Varela P, Correa-Neto NF, Coelho LS, Onaivi ES, Santos-Junior JG. Reconsolidation and update of morphine-associated contextual memory in mice. Neurobiol Learn Mem 2016; 130:194-201. [PMID: 26948121 DOI: 10.1016/j.nlm.2016.02.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 01/19/2016] [Accepted: 02/20/2016] [Indexed: 11/24/2022]
Abstract
Drug addiction can be viewed as a pathological memory that is constantly retrieved and reconsolidated. Since drug abuse takes place in different contexts, it could be considered that reconsolidation plays a role in memory updating. There is consistent evidence supporting the role of reconsolidation in the strength and maintenance of contextual memories induced by drugs of abuse. However, this role is not well established in memory update. The purpose of the current study was to assess the reconsolidation process over memory update. C57BL6 mice were subjected to a morphine-induced, conditioned place preference (CPP) paradigm. Based on CPP results, animals were divided into distinct experimental groups, according to the contextual characteristics of the re-exposure and a second CPP Test. Re-exposure in the original context was important for memory maintenance and re-exposure under discrete contextual changes resulted in memory updating, although original memory was maintained. Interestingly, cycloheximide, an inhibitor of protein synthesis, had different outcomes in our protocol. When the re-exposure was done under discrete contextual changes, cycloheximide treatment just after re-exposure blocked memory updating, without changes in memory maintenance. When re-exposure was done under the original context, only two subsequent cycloheximide injections (3 and 6h) disrupted later CPP expression. Considering the temporal window of protein synthesis in consolidation and reconsolidation, these findings suggest that re-exposure, according to the contextual characteristics in our protocol, could trigger both phenomena. Furthermore, when new information is present on retrieval, reconsolidation plays a pivotal role in memory updating.
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Affiliation(s)
- Joao Carlos Escosteguy-Neto
- Laboratory of Neurobiology, Federal University of Sao Paulo, R. Pedro de Toledo, 669, 3rd floor, Sao Paulo, SP 04039-032, Brazil; Department of Biology, William Paterson University, 300 Pompton Rd, Wayne, NJ 07470, USA
| | - Patricia Varela
- Laboratory of Neurobiology, Federal University of Sao Paulo, R. Pedro de Toledo, 669, 3rd floor, Sao Paulo, SP 04039-032, Brazil
| | - Nelson Francisco Correa-Neto
- Department of Physiological Science, Faculty of Medical Sciences of Santa Casa of São Paulo, R. Cesário Motta Jr, 61, 12th floor, São Paulo, SP 01221-020, Brazil
| | - Laura Segismundo Coelho
- Department of Physiological Science, Faculty of Medical Sciences of Santa Casa of São Paulo, R. Cesário Motta Jr, 61, 12th floor, São Paulo, SP 01221-020, Brazil
| | - Emmanuel S Onaivi
- Department of Biology, William Paterson University, 300 Pompton Rd, Wayne, NJ 07470, USA
| | - Jair Guilherme Santos-Junior
- Department of Physiological Science, Faculty of Medical Sciences of Santa Casa of São Paulo, R. Cesário Motta Jr, 61, 12th floor, São Paulo, SP 01221-020, Brazil.
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Bruning JEA, Breitfeld T, Kahl E, Bergado-Acosta JR, Fendt M. Relief memory consolidation requires protein synthesis within the nucleus accumbens. Neuropharmacology 2016; 105:10-14. [PMID: 26792192 DOI: 10.1016/j.neuropharm.2016.01.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 01/07/2016] [Accepted: 01/09/2016] [Indexed: 02/08/2023]
Abstract
Relief learning refers to the association of a stimulus with the relief from an aversive event. The thus-learned relief stimulus then can induce, e.g., an attenuation of the startle response or approach behavior, indicating positive valence. Previous studies revealed that the nucleus accumbens is essential for the acquisition and retrieval of relief memory. Here, we ask whether the nucleus accumbens is also the brain site for consolidation of relief memory into a long-term form. In rats, we blocked local protein synthesis within the nucleus accumbens by local infusions of anisomycin at different time points during a relief conditioning experiment. Accumbal anisomycin injections immediately after the relief conditioning session, but not 4 h later, prevented the consolidation into long-term relief memory. The retention of already consolidated relief memory was not affected by anisomycin injections. This identifies a time window and site for relief memory consolidation. These findings should complement our understanding of the full range of effects of adverse experiences, including cases of their distortion in humans such as post-traumatic stress disorder and/or phobias.
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Affiliation(s)
- Johann E A Bruning
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany
| | - Tino Breitfeld
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany
| | - Evelyn Kahl
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany
| | - Jorge R Bergado-Acosta
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany; Center of Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany.
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15
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Rossato JI, Köhler CA, Radiske A, Bevilaqua LRM, Cammarota M. Inactivation of the dorsal hippocampus or the medial prefrontal cortex impairs retrieval but has differential effect on spatial memory reconsolidation. Neurobiol Learn Mem 2015; 125:146-51. [PMID: 26348793 DOI: 10.1016/j.nlm.2015.09.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 08/10/2015] [Accepted: 09/01/2015] [Indexed: 10/23/2022]
Abstract
Active memories can incorporate new information through reconsolidation. However, the notion that memory retrieval is necessary for reconsolidation has been recently challenged. Non-reinforced retrieval induces hippocampus and medial prefrontal cortex (mPFC)-dependent reconsolidation of spatial memory in the Morris water maze (MWM). We found that the effect of protein synthesis inhibition on this process is abolished when retrieval of the learned spatial preference is hindered through mPFC inactivation but not when it is blocked by deactivation of dorsal CA1. Our results do not fully agree with the hypothesis that retrieval is unneeded for reconsolidation. Instead, they support the idea that a hierarchic interaction between the hippocampus and the mPFC controls spatial memory in the MWM, and indicate that this cortex is sufficient to retrieve the information essential to reconsolidate the spatial memory trace, even when the hippocampus is inactivated.
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Affiliation(s)
- Janine I Rossato
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Av. Nascimento de Castro 2155, RN 59056-450, Natal, Brazil
| | - Cristiano A Köhler
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Av. Nascimento de Castro 2155, RN 59056-450, Natal, Brazil
| | - Andressa Radiske
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Av. Nascimento de Castro 2155, RN 59056-450, Natal, Brazil
| | - Lia R M Bevilaqua
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Av. Nascimento de Castro 2155, RN 59056-450, Natal, Brazil
| | - Martín Cammarota
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Av. Nascimento de Castro 2155, RN 59056-450, Natal, Brazil.
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16
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Heath FC, Jurkus R, Bast T, Pezze MA, Lee JLC, Voigt JP, Stevenson CW. Dopamine D1-like receptor signalling in the hippocampus and amygdala modulates the acquisition of contextual fear conditioning. Psychopharmacology (Berl) 2015; 232:2619-29. [PMID: 25743759 PMCID: PMC4480849 DOI: 10.1007/s00213-015-3897-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 02/16/2015] [Indexed: 12/11/2022]
Abstract
RATIONALE Dopamine D1-like receptor signalling is involved in contextual fear conditioning, but the brain regions involved and its role in other contextual fear memory processes remain unclear. OBJECTIVES The objective of this study was to investigate (1) the effects of SCH 23390, a dopamine D1/D5 receptor antagonist, on contextual fear memory encoding, retrieval and reconsolidation, and (2) if the effects of SCH 23390 on conditioning involve the dorsal hippocampus (DH) and/or basolateral amygdala (BLA). METHODS Rats were used to examine the effects of systemically administering SCH 23390 on the acquisition, consolidation, retrieval and reconsolidation of contextual fear memory, and on locomotor activity and shock sensitivity. We also determined the effects of MK-801, an NMDA receptor antagonist, on contextual fear memory reconsolidation. The effects of infusing SCH 23390 locally into DH or BLA on contextual fear conditioning and locomotor activity were also examined. RESULTS Systemic administration of SCH 23390 impaired contextual fear conditioning but had no effects on fear memory consolidation, retrieval or reconsolidation. MK-801 was found to impair reconsolidation, suggesting that the behavioural parameters used allowed for the pharmacological disruption of memory reconsolidation. The effects of SCH 23390 on conditioning were unlikely the result of any lasting drug effects on locomotor activity at memory test or any acute drug effects on shock sensitivity during conditioning. SCH 23390 infused into either DH or BLA impaired contextual fear conditioning and decreased locomotor activity. CONCLUSIONS These findings suggest that dopamine D1-like receptor signalling in DH and BLA contributes to the acquisition of contextual fear memory.
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Affiliation(s)
- Florence C. Heath
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD UK
| | - Regimantas Jurkus
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Tobias Bast
- School of Psychology and Neuroscience, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Marie A. Pezze
- School of Psychology and Neuroscience, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Jonathan L. C. Lee
- School of Psychology, University of Birmingham, Edgbaston, Birmingham, B15 2TT UK
| | - J. Peter Voigt
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD UK
| | - Carl W. Stevenson
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD UK
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Meyer PJ, Cogan ES, Robinson TE. The form of a conditioned stimulus can influence the degree to which it acquires incentive motivational properties. PLoS One 2014; 9:e98163. [PMID: 24905195 PMCID: PMC4048203 DOI: 10.1371/journal.pone.0098163] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/29/2014] [Indexed: 11/19/2022] Open
Abstract
There is considerable individual variation in the extent to which food- and drug-associated cues (conditioned stimuli, CSs) acquire incentive salience, as indicated by whether they elicit approach towards them, and/or act as conditioned reinforcers. Here we asked whether this variation is influenced by properties of the CS itself. In rats, we assessed both the attractiveness and conditioned reinforcing properties of two CSs: a manipulable lever CS versus an auditory (tone) CS. There was considerable individual variation in the extent to which a lever CS acquired incentive motivational properties, as indicated by whether it became attractive (evoked a sign-tracking or goal-tracking conditioned response) or acted as a conditioned reinforcer. However, with a tone CS all rats learned a goal-tracking response, and the tone CS was an equally effective conditioned reinforcer in sign-trackers and goal-trackers. Even when presented in compound (a lever-tone CS), the two elements of the compound differentially acquired motivational properties. In contrast, amphetamine and stress potentiated the conditioned reinforcing properties of both visual and auditory CSs similarly in rats that primarily sign-tracked or goal-tracked. We conclude that variation in the to the ability of CSs to acquire incentive salience, and thus their ability to act as incentive stimuli capable of motivating behavior, is determined in part by properties of the CS itself.
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Affiliation(s)
- Paul J. Meyer
- Department of Psychology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Elizabeth S. Cogan
- Department of Psychology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Terry E. Robinson
- Department of Psychology, University of Michigan, Ann Arbor, Michigan, United States of America
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Shiflett MW, Riccie M, DiMatteo R. The effects of amphetamine sensitization on conditioned inhibition during a Pavlovian-instrumental transfer task in rats. Psychopharmacology (Berl) 2013; 230:137-47. [PMID: 23715640 PMCID: PMC3797263 DOI: 10.1007/s00213-013-3144-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 05/06/2013] [Indexed: 10/26/2022]
Abstract
RATIONALE Psychostimulant sensitization heightens behavioral and motivational responses to reward-associated stimuli; however, its effects on stimuli associated with reward absence are less understood. OBJECTIVES We examined whether amphetamine sensitization alters performance during Pavlovian-instrumental transfer (PIT) to conditioned excitors and inhibitors. We further sought to characterize the effects of amphetamine sensitization on learning versus performance by exposing rats to amphetamine prior to Pavlovian training or between training and test. METHODS Adult male Long-Evans rats were given conditioned inhibition (A+/AX-) and Pavlovian (B+) training, followed by variable-interval instrumental conditioning. Rats were sensitized to D-amphetamine (2 mg/kg daily injections for 7 days) or served as non-exposed controls. Rats were given a PIT test, in which they were presented with stimulus B alone or in compound with the conditioned inhibitor (BX). RESULTS During the PIT test, control rats significantly reduced instrumental responding on BX trials (to approximately 50 % of responding to B). Amphetamine sensitization prior to Pavlovian conditioning increased lever pressing on BX trials and reduced lever pressing on B trials compared to controls. Amphetamine sensitization between training and test increased lever pressing on B and BX trials compared to controls. No effects of sensitization were observed on conditioned food cup approach. CONCLUSIONS Amphetamine sensitization increases instrumental responding during PIT to a conditioned inhibitor by enhancing the excitation of conditioned stimuli and reducing the inhibition of conditioned inhibitors.
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19
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Reichelt AC, Lee JLC. Memory reconsolidation in aversive and appetitive settings. Front Behav Neurosci 2013; 7:118. [PMID: 24058336 PMCID: PMC3766793 DOI: 10.3389/fnbeh.2013.00118] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 08/20/2013] [Indexed: 11/16/2022] Open
Abstract
Memory reconsolidation has been observed across species and in a number of behavioral paradigms. The majority of memory reconsolidation studies have been carried out in Pavlovian fear conditioning and other aversive memory settings, with potential implications for the treatment of post-traumatic stress disorder. However, there is a growing literature on memory reconsolidation in appetitive reward-related memory paradigms, including translational models of drug addiction. While there appears to be substantial similarity in the basic phenomenon and underlying mechanisms of memory reconsolidation across unconditioned stimulus valence, there are also notable discrepancies. These arise both when comparing aversive to appetitive paradigms and also across different paradigms within the same valence of memory. We review the demonstration of memory reconsolidation across different aversive and appetitive memory paradigms, the commonalities and differences in underlying mechanisms and the conditions under which each memory undergoes reconsolidation. We focus particularly on whether principles derived from the aversive literature are applicable to appetitive settings, and also whether the expanding literature in appetitive paradigms is informative for fear memory reconsolidation.
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Affiliation(s)
- Amy C Reichelt
- School of Psychology, University of Birmingham Birmingham, UK
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20
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Arsenault JT, Nelissen K, Jarraya B, Vanduffel W. Dopaminergic reward signals selectively decrease fMRI activity in primate visual cortex. Neuron 2013; 77:1174-86. [PMID: 23522051 DOI: 10.1016/j.neuron.2013.01.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2013] [Indexed: 10/27/2022]
Abstract
Stimulus-reward coupling without attention can induce highly specific perceptual learning effects, suggesting that reward triggers selective plasticity within visual cortex. Additionally, dopamine-releasing events-temporally surrounding stimulus-reward associations-selectively enhance memory. These forms of plasticity may be evoked by selective modulation of stimulus representations during dopamine-inducing events. However, it remains to be shown whether dopaminergic signals can selectively modulate visual cortical activity. We measured fMRI activity in monkey visual cortex during reward-only trials apart from intermixed cue-reward trials. Reward without visual stimulation selectively decreased fMRI activity within the cue representations that had been paired with reward during other trials. Behavioral tests indicated that these same uncued reward trials strengthened cue-reward associations. Furthermore, such spatially-specific activity modulations depended on prediction error, as shown by manipulations of reward magnitude, cue-reward probability, cue-reward familiarity, and dopamine signaling. This cue-selective negative reward signal offers a mechanism for selectively gating sensory cortical plasticity.
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Affiliation(s)
- John T Arsenault
- Laboratory of Neuro and Psychophysiology, KU Leuven Medical School, Campus Gasthuisberg, 3000 Leuven, Belgium
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21
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Kishioka A, Uemura T, Fukushima F, Mishina M. Consolidation of auditory fear memories formed by weak unconditioned stimuli requires NMDA receptor activation and de novo protein synthesis in the striatum. Mol Brain 2013; 6:17. [PMID: 23587405 PMCID: PMC3637160 DOI: 10.1186/1756-6606-6-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 04/11/2013] [Indexed: 11/13/2022] Open
Abstract
Background Fear is one of the most potent emotional experiences and is an adaptive component of response to potentially threatening stimuli. Cumulative evidence suggests that the amygdala plays a central role in the acquisition, storage and expression of fear memory. We previously showed that the selective ablation of striatal neurons in the adult brain impairs the long-term, but not short-term, memory for auditory fear conditioning with a lower-intensity footshock. This finding raises an intriguing possibility that long-term auditory fear memory may be consolidated in the striatum. Results There was a significant difference in the freezing responses between two groups of mice subjected to paired and unpaired conditioning, indicating that the auditory fear conditioning with a lower-intensity footshock is an associative learning. Post-conditioning infusion of NMDA receptor inhibitors into the striatum suppressed the consolidation of auditory fear memory when mice were conditioned with a low-intensity footshock. Furthermore, intra-striatum infusion of protein synthesis blocker anisomycin immediately or 1 h after the conditioning prevented the formation of auditory fear memory. On the other hand, the infusion of anisomycin 3 h after conditioning exerted little effect on the auditory fear conditioning, consistent with the presence of a critical time window of protein synthesis for memory consolidation. Conclusions These results suggest that NMDA receptors and de novo protein synthesis in the striatum are crucial for the consolidation of auditory fear memory formed with a low-intensity unconditioned stimulus.
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Affiliation(s)
- Ayumi Kishioka
- Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan
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Over-expectation generated in a complex appetitive goal-tracking task is capable of inducing memory reconsolidation. Psychopharmacology (Berl) 2013; 226:649-58. [PMID: 23239132 DOI: 10.1007/s00213-012-2934-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 11/19/2012] [Indexed: 10/27/2022]
Abstract
RATIONALE Discrepancies in an expected outcome have been demonstrated to result in modification of behaviour in both appetitive and aversive conditioning settings. OBJECTIVES In this study, we sought to establish whether overexpectation generated from compound conditioning with two previously rewarded stimuli was able to induce memory destabilisation and subsequent reconsolidation in a Pavlovian conditioned approach setting. RESULTS It was shown that 4 days, but not 1 day, of overexpectation training was required to induce memory reconsolidation, and this was disrupted by application of the NMDA subtype of glutamate receptor antagonist MK-801 prior to overexpectation training, but not by MK-801 application 6 h post-training. CONCLUSIONS These data provide evidence that the memories underlying Pavlovian conditioned approach do undergo reconsolidation and that such reconsolidation can be triggered by overexpectation. Therefore, the updating of appetitive conditioned stimulus and unconditioned stimulus associations underpinning conditioned responding in manners other than extinction training is likely achieved through memory reconsolidation.
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Leri F, Nahas E, Henderson K, Limebeer CL, Parker LA, White NM. Effects of post-training heroin and d-amphetamine on consolidation of win-stay learning and fear conditioning. J Psychopharmacol 2013; 27:292-301. [PMID: 23325371 DOI: 10.1177/0269881112472566] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
It has been proposed that the reinforcing properties of drugs of abuse are due, in part, to their ability to enhance memory consolidation. To test this hypothesis, heroin (0.03-3 mg/kg, SC) and d-amphetamine (0.5-2 mg/kg, SC) were administered to male Sprague-Dawley rats immediately or 4 h after training on win-stay and fear conditioning tasks. On the win-stay, immediate post-training administration of lower doses of heroin and d-amphetamine enhanced acquisition, and probe tests further revealed that these drugs enhanced different aspects of learning. Higher doses had no effect or impaired performance, particularly when administered repeatedly. On fear conditioning, the memory-enhancing effects of immediate post-training administration of lower heroin and d-amphetamine doses were revealed only when a single tone-shock pairing procedure was employed. Therefore, under appropriate experimental conditions, mildly stimulatory doses of heroin and d-amphetamine enhanced the acquisition of tasks thought to involve different types of learning. These results support the hypothesis that one of the ways in which drugs of abuse such as opiates and psychomotor stimulants reinforce behavior is by enhancing memory consolidation processes.
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Reichelt AC, Lee JLC. Appetitive Pavlovian goal-tracking memories reconsolidate only under specific conditions. Learn Mem 2012; 20:51-60. [PMID: 23263844 DOI: 10.1101/lm.027482.112] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Despite extensive evidence that appetitive memories undergo reconsolidation, two notable failures to observe reconsolidation have been reported: instrumental responding and goal-tracking. However, these studies do not provide conclusive evidence for a lack of memory reconsolidation due to the numerous boundary conditions that dictate whether a memory will undergo reconsolidation. In this study we sought to reexamine reconsolidation in an appetitive, Pavlovian conditioned approach procedure and the behavioral boundary conditions within which memories are destabilized and reconsolidated. This study demonstrated that a Pavlovian goal-tracking memory, previously thought to be resistant to destabilization, will undergo memory reconsolidation under discrete conditions that favor reconsolidation as opposed to extinction, and that this is dependent on the amount of training rats received. With restricted training, systemic administration of MK-801 impaired memory extinction. In contrast, with more extended training, MK-801 administration impaired memory reconsolidation. We also demonstrate that behavioral boundary conditions that exist for appetitive memory reconsolidation are much more complex than simple parametric calculations. Moreover, extinction per se is not a boundary on reconsolidation, in that MK-801 also has no behavioral effect under some conditions.
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Affiliation(s)
- Amy C Reichelt
- School of Psychology, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
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25
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Cao G, Zhu J, Zhong Q, Shi C, Dang Y, Han W, Liu X, Xu M, Chen T. Distinct roles of methamphetamine in modulating spatial memory consolidation, retrieval, reconsolidation and the accompanying changes of ERK and CREB activation in hippocampus and prefrontal cortex. Neuropharmacology 2012; 67:144-54. [PMID: 23159329 DOI: 10.1016/j.neuropharm.2012.10.020] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Revised: 10/23/2012] [Accepted: 10/31/2012] [Indexed: 10/27/2022]
Abstract
Drugs of abuse modulated learning and memory in humans yet the underlying mechanism remained unclear. The extracellular signal-regulated kinase (ERK) and the transcription factor cAMP response element-binding protein (CREB) were involved in neuroplastic changes associated with learning and memory. In the current study, we used a Morris water maze to examine the effect of methamphetamine (METH) on different processes of spatial memory in mice. We then investigated the status of ERK and CREB in the hippocampus and prefrontal cortex (PFC). We found that 1.0 mg/kg dose of METH facilitated spatial memory consolidation when it was injected immediately after the last learning trial. In contrast, the same dose of METH had no effect on spatial memory retrieval when it was injected 30 min before the test. Furthermore, 1.0 mg/kg dose of METH injected immediately after retrieval had no effect on spatial memory reconsolidation. Activation of both ERK and CREB in the hippocampus was found following memory consolidation but not after retrieval or reconsolidation in METH-treated mouse groups. In contrast, activation of both ERK and CREB in the PFC was found following memory retrieval but not other processes in METH-treated mouse groups. These results suggested that METH facilitated spatial memory consolidation but not retrieval or reconsolidation. Moreover, activation of the ERK and CREB signaling pathway in the hippocampus might be involved in METH-induced spatial memory changes.
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Affiliation(s)
- Guofen Cao
- Department of Forensic Medicine, Xi'an Jiaotong University, School of Medicine, Xi'an, Shaanxi 710061, PR China
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The effects of amphetamine exposure on outcome-selective Pavlovian-instrumental transfer in rats. Psychopharmacology (Berl) 2012; 223:361-70. [PMID: 22562522 PMCID: PMC3439560 DOI: 10.1007/s00213-012-2724-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 04/13/2012] [Indexed: 10/28/2022]
Abstract
RATIONALE Repeated exposure to psychostimulants alters behavioral responses to reward-related cues; however, the motivational underpinnings of this effect have not been fully characterized. OBJECTIVES The following study was designed to examine how amphetamine sensitization affects performance in rats on a series of Pavlovian and operant tasks that distinguish between general-incentive and outcome-selective forms of conditioned responses. METHODS Adult male rats underwent Pavlovian and instrumental training for food pellet rewards. Following training, rats were sensitized to D-amphetamine (2 mg/kg for 7 days). Rats were subsequently tested on an outcome-selective Pavlovian-instrumental transfer (PIT) task, an outcome-reinstatement task, and an outcome devaluation task. Additionally, in a separate experiment, PIT was assessed in amphetamine-sensitized and control rats using a Pavlovian backward-conditioned stimulus. RESULTS Repeated amphetamine exposure sensitized locomotor activity to acute amphetamine challenge. Amphetamine altered responses to CS presentations by increasing conditioned approach. During tests of PIT, amphetamine-treated rats showed no outcome-selectivity in their responding, responding to a CS whether or not it shared a common outcome with the instrumental response. No effect of amphetamine sensitization was observed on tests of outcome-selective reinstatement by outcome delivery or action selection based on outcome value. Amphetamine-sensitized rats showed impaired outcome-selective PIT to a backward CS but were unaltered in conditioned approach. CONCLUSIONS Amphetamine sensitization prevents outcome-selective responding during PIT, which is dissociable from amphetamine's effects on conditioned approach. These data suggest fundamental alterations in how stimuli motivate action in addiction.
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Sorg BA. Reconsolidation of drug memories. Neurosci Biobehav Rev 2012; 36:1400-17. [PMID: 22342780 PMCID: PMC3526670 DOI: 10.1016/j.neubiorev.2012.02.004] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 02/01/2012] [Accepted: 02/03/2012] [Indexed: 12/30/2022]
Abstract
Persistent, unwanted memories are believed to be key contributors to drug addiction and the chronic relapse problem over the lifetime of the addict. Contrary to the long-held idea that memories are static and fixed, new studies in the last decade have shown that memories are dynamic and changeable. However, they are changeable only under specific conditions. When a memory is retrieved (reactivated), it becomes labile for a period of minutes to hours and then is reconsolidated to maintain long-term memory. Recent findings indicate that even well-established long-term memories may be susceptible to disruption by interfering with reconsolidation through delivery of certain amnestic agents during memory retrieval. Here I review the growing literature on memory reconsolidation in animal models of addiction, including sensitization, conditioned place preference and self-administration. I also discuss (a) several issues that need to be considered in interpreting the findings from reconsolidation studies and (b) future challenges and directions for memory reconsolidation studies in the field of addiction. The findings indicate promise for using this approach as a therapy for disrupting the long-lasting memories that can trigger relapse.
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Affiliation(s)
- Barbara A Sorg
- Translational Addiction Research Center, Alcohol and Drug Abuse Research Program and Program in Neuroscience, Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, Washington State University, Pullman, WA 99164-6520, USA.
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Extinction of appetitive learning is disrupted by cycloheximide and propranolol in the sand maze in rats. Neurobiol Learn Mem 2011; 95:484-90. [PMID: 21371561 DOI: 10.1016/j.nlm.2011.02.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 02/11/2011] [Accepted: 02/22/2011] [Indexed: 11/23/2022]
Abstract
The present study investigated whether memory for extinction in an appetitive task (the sand maze) could be attenuated by administration of cycloheximide (protein synthesis inhibitor) or propranolol (β-adrenergic receptor antagonist). Ninety-day-old male Long-Evans rats were trained to retrieve a sweet cereal reinforcer from an open container in the sand maze. One day following this non-spatial training, rats received three extinction trials in which they were placed in the maze with the reinforcer present, but unattainable. Thirty minutes prior to the first extinction trial, rats received an intraperitoneal injection of cycloheximide (1mg/kg), propranolol (25mg/kg), or vehicle (1mg/kg distilled water). Twenty-four hours later, rats were tested in the sand maze with the reinforcer again available. Results from the test trial showed that both cycloheximide and propranolol groups found the reinforcer more quickly than controls. Two weeks later, rats were trained on a spatial version of the sand maze in which they had to search for a buried reinforcer using extramaze cues. Cycloheximide and propranolol groups learned this task significantly faster than the control group, demonstrating the long-lasting effect of cycloheximide and propranolol on the blocking of memory for extinction.
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Hall DA, Gulley JM. Disruptive effect of amphetamines on Pavlovian to instrumental transfer. Behav Brain Res 2010; 216:440-5. [PMID: 20817041 DOI: 10.1016/j.bbr.2010.08.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 07/29/2010] [Accepted: 08/25/2010] [Indexed: 11/19/2022]
Abstract
Reward-seeking behavior can be powerfully modulated by exposure to a conditioned stimulus (CS) that was previously associated with that reward. This can be demonstrated in a Pavlovian to instrumental transfer (PIT) task where presentation of a CS (e.g., tone and light) previously paired with a rewarding unconditioned stimulus (US; e.g., food) leads to increases in a behavioral response, such as a lever press, that was also paired with the same US. The transfer effect can be enhanced in rats by exposing them repeatedly to amphetamine after they have undergone Pavlovian conditioning and instrumental training. However, it is not clear if amphetamine injections given immediately after Pavlovian conditioning, which are predicted to enhance memory consolidation for the CS-US association, would also enhance the transfer effect. We tested this hypothesis by giving male, Sprague-Dawley rats i.p. injections of saline or drug (0.5, 1.0, or 3.0 mg/kg amphetamine or methamphetamine) immediately following Pavlovian conditioning sessions. We found that amphetamine, but not methamphetamine, enhanced Pavlovian approach behavior. During a subsequent PIT test done under extinction conditions, we found that rats given either drug, particularly at the highest dose, exhibited deficits in PIT relative to saline-treated controls. These results suggest that treatment with amphetamines after Pavlovian conditioning sessions, when memory consolidation of the CS-US association is hypothesized to occur, inhibits the ability of the CS to subsequently elicit reward-seeking behavior.
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Affiliation(s)
- Darien A Hall
- Neuroscience Program, University of Illinois, Urbana-Champaign, IL 61820, USA
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Kennedy CD, Houmes SW, Wyrick KL, Kammerzell SM, Lukowiak K, Sorg BA. Methamphetamine enhances memory of operantly conditioned respiratory behavior in the snail Lymnaea stagnalis. ACTA ACUST UNITED AC 2010; 213:2055-65. [PMID: 20511519 DOI: 10.1242/jeb.042820] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Amphetamines have been used as cognitive enhancers to promote learning and memory. Amphetamines are also drugs of abuse that may promote the initiation of strong memories that ultimately lead to addiction. To understand how methamphetamine (Meth) may be augmenting learning and memory, we chose a relatively simple system, the pond snail, Lymnaea stagnalis. We studied the effects of Meth exposure on the long-term memory (LTM), extinction and reinstatement of operantly conditioned aerial respiratory behavior in Lymnaea. We first determined doses of Meth that would acutely alter respiratory behavior. Next, we measured the impact of training snails in Meth solution or water (control group) using a training procedure that produces LTM (>6 h) in control conditions. Meth exposure impaired the expression of LTM 21 h after two training sessions, but this appeared to be a context-dependent effect only. However, snails exposed to 3.3 mumol l(-1) Meth during training had a decreased rate of extinction of the operantly conditioned memory. We then tested whether this decreased ability of snails to extinguish memory was due to enhanced LTM or impaired extinction of that memory. Snails were operantly conditioned in water and exposed to Meth 16 h after their last trial but 4-5 h prior to extinction. Meth produced an increase rather than a decrease in extinction rate. Thus, Meth impaired extinction only when snails were exposed to Meth during training. Last, we tested the effect of Meth on the ability to form LTM using a single training procedure that is suboptimal for LTM formation. Control snails did not demonstrate LTM, as expected, but pre-exposure of snails to 3.3 micromol l(-1) Meth 24 h prior to the single training session produced LTM 24 h later, indicating that Meth pre-exposure primed snails for LTM formation. Taken together, our studies suggest that LTM is strengthened by Meth such that extinction training is less effective. Lymnaea provides a simple and useful model system to dissect the cellular and/or molecular mechanisms of how Meth may initiate the formation of stronger memories.
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Affiliation(s)
- Colin D Kennedy
- Alcohol and Drug Abuse Research Program and Program in Neuroscience, Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164-6520, USA
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Jonkman S, Everitt BJ. Post-learning infusion of anisomycin into the anterior cingulate cortex impairs instrumental acquisition through an effect on reinforcer valuation. Learn Mem 2009; 16:706-13. [PMID: 19864297 PMCID: PMC2775517 DOI: 10.1101/lm.1497709] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Accepted: 09/11/2009] [Indexed: 01/03/2023]
Abstract
The integrity of the rodent anterior cingulate cortex (ACC) is essential for various aspects of instrumental behavior, but it is not clear if the ACC is important for the acquisition of a simple instrumental response. Here, it was demonstrated that post-session infusions of anisomycin into the rat ACC completely prevented the acquisition of instrumental responding. The experimental use of post-session intracranial infusions of plasticity inhibitors is assumed to affect local consolidation of plasticity, but not behavioral task performance. However, in associative appetitive conditioning, post-session intracranial infusion of pharmaco-active compounds could actually interfere with subsequent task performance indirectly through retrospective effects on the valuation of ingested rewards. Thus, it was subsequently demonstrated that the intracranial infusion of anisomycin into the ACC after sucrose pellet consumption significantly reduced subsequent pellet consumption, suggesting that the infusion of anisomycin into the ACC produced conditioned taste avoidance. In the third experiment, an innovative procedure was introduced that dissociated the effects of intracranial infusions after conditioning sessions on task-learning and unconditioned stimulus valuation. With this procedure, the infusion of anisomycin into the ACC after instrumental sessions did not affect instrumental reinforcer valuation or the acquisition of instrumental responding, suggesting that plasticity in the ACC is not necessary for the acquisition of instrumental behavior.
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Affiliation(s)
- Sietse Jonkman
- Behavioural and Clinical Neuroscience Institute, Department of Experimental Psychology, University of Cambridge, Cambridge, United Kingdom.
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Carmack SA, Wood SC, Anagnostaras SG. Amphetamine and extinction of cued fear. Neurosci Lett 2009; 468:18-22. [PMID: 19853020 DOI: 10.1016/j.neulet.2009.10.049] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 09/15/2009] [Accepted: 10/15/2009] [Indexed: 10/20/2022]
Abstract
Much research is focused on developing novel drugs to improve memory. In particular, psychostimulants have been shown to enhance memory and have a long history of safe use in humans. In prior work, we have shown that very low doses of amphetamine administered before training on a Pavlovian fear-conditioning task can dramatically facilitate the acquisition of cued fear. The current experiment sought to expand these findings to the extinction of cued fear, a well-known paradigm with therapeutic implications for learned phobias and post-traumatic stress disorder. If extinction reflects new learning, one might expect drugs that enhance the acquisition of cued fear to also enhance the extinction of cued fear. This experiment examined whether 0.005 or 0.05 mg/kg of D-amphetamine (therapeutic doses shown to enhance acquisition) also enhance the extinction of cued fear. Contrary to our hypothesis, amphetamine did not accelerate extinction. Thus, at doses that enhance acquisition of conditioned fear, amphetamine does not appear to enhance extinction.
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Affiliation(s)
- Stephanie A Carmack
- Molecular Cognition Laboratory, Department of Psychology, University of California, San Diego, CA 92093-0109, USA.
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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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Mueller D, Olivera-Figueroa LA, Pine DS, Quirk GJ. The effects of yohimbine and amphetamine on fear expression and extinction in rats. Psychopharmacology (Berl) 2009; 204:599-606. [PMID: 19242678 PMCID: PMC2692542 DOI: 10.1007/s00213-009-1491-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Accepted: 02/05/2009] [Indexed: 11/30/2022]
Abstract
RATIONALE Psychostimulants, such as yohimbine and amphetamine, can enhance learning and memory. Extinction of conditioned fear involves new learning, so we asked whether psychostimulants could enhance this learning. Previous work suggests that yohimbine facilitates extinction, using freezing as a fear measure. However, psychostimulant-induced alterations in locomotion can confound freezing measurements. Furthermore, the effects of amphetamine on fear extinction have never been examined. OBJECTIVE We evaluated the effectiveness of yohimbine and amphetamine in enhancing fear extinction. In addition to freezing, we measured bar-press suppression, which is less sensitive to changes in locomotion. We asked: Do psychostimulants reduce fear during extinction training when drug is present? Does learning extinction with psychostimulants result in better extinction retention? MATERIALS AND METHODS Rats received fear conditioning on day 1 followed by partial extinction training on days 2 and 3. Yohimbine (1.0, 2.0, or 5.0 mg/kg, i.p.), amphetamine (1.0 mg/kg, i.p.), or vehicle were injected prior to extinction on day 2. RESULTS Yohimbine dose-dependently reduced freezing during extinction training on day 2, whereas bar-press suppression was reduced at the highest dose only. When tested drug-free, yohimbine-treated rats showed equivalent levels of freezing and suppression to controls. Amphetamine also decreased freezing during extinction, but did not decrease suppression. During the drug-free test, there was no difference between amphetamine-treated rats and controls in either measure. CONCLUSIONS Although yohimbine and amphetamine are capable of decreasing freezing, neither drug strengthened retention of fear extinction. Based on these rodent findings, psychostimulants may not be suitable adjuncts to extinction-based therapies for the treatment of anxiety disorders.
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Affiliation(s)
- Devin Mueller
- Departments of Psychiatry and Anatomy & Neurobiology, University of Puerto Rico School of Medicine, P.O. Box 365067, San Juan, Puerto Rico 00936−5067
| | | | - Daniel S. Pine
- Section on Development and Affective Neuroscience, NIMH Intramural Research Program, Bethesda, MD, USA 20817−2670
| | - Gregory J. Quirk
- Departments of Psychiatry and Anatomy & Neurobiology, University of Puerto Rico School of Medicine, P.O. Box 365067, San Juan, Puerto Rico 00936−5067
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Blaiss CA, Janak PH. The nucleus accumbens core and shell are critical for the expression, but not the consolidation, of Pavlovian conditioned approach. Behav Brain Res 2008; 200:22-32. [PMID: 19159648 DOI: 10.1016/j.bbr.2008.12.024] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Revised: 12/09/2008] [Accepted: 12/19/2008] [Indexed: 11/26/2022]
Abstract
The nucleus accumbens (NAc) is important for the ability of motivationally significant stimuli to guide behavior. To further delineate its role in appetitive Pavlovian conditioning, we tested the hypothesis that the NAc contributes to memory consolidation and expression for a goal-tracking version of Pavlovian conditioned approach (PCA) in rats. We found that neither post-training reversible inactivation with the GABA receptor agonists muscimol and baclofen nor inhibition of protein synthesis with anisomycin (ANI) in either the core or shell regions of the NAc had an effect on approach to a reward port in response to a reward-predictive cue (conditioned stimulus, CS+). In contrast, pre-test reversible inactivation of both the core and shell decreased conditioned responding during the CS+. Unlike inactivation of the core, however, reversible inactivation of the shell also produced an increase in responding during the CS- and the inter-trial interval. This suggests that the NAc is not involved in the consolidation of goal-tracking PCA, but that once the memory is formed, the core is required for expression of the CS-unconditioned stimulus (US) association and the shell is required to inhibit conditioned approach behavior at times when the CS+ is not presented.
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Affiliation(s)
- Cory A Blaiss
- Ernest Gallo Clinic and Research Center, University of California at San Francisco, Emeryville, CA 94608, USA.
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Lee JLC, Everitt BJ. Reactivation-dependent amnesia in Pavlovian approach and instrumental transfer. Learn Mem 2008; 15:597-602. [PMID: 18685151 PMCID: PMC2583130 DOI: 10.1101/lm.1029808] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Accepted: 06/11/2008] [Indexed: 11/24/2022]
Abstract
The theory of memory reconsolidation relates to the hypothesized restabilisation process that occurs following the reactivation of a memory through retrieval. Thus the demonstration of reactivation-dependent amnesia for a previously acquired memory is a prerequisite for showing that such a memory undergoes reconsolidation. Here we show that the appetitive Pavlovian representations that underlie Pavlovian approach and Pavlovian-instrumental transfer are destabilized following their retrieval. This reactivation-dependent amnesia demonstrates that the general motivational or incentive properties of appetitive conditioned stimuli, as well as their conditioned reinforcing properties, can be reduced by blocking memory reconsolidation.
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Affiliation(s)
- Jonathan L C Lee
- Behavioural and Clinical Neuroscience Institute, Department of Experimental Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom.
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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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