201
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Yu XW, Curlik DM, Oh MM, Yin JC, Disterhoft JF. CREB overexpression in dorsal CA1 ameliorates long-term memory deficits in aged rats. eLife 2017; 6. [PMID: 28051768 PMCID: PMC5214885 DOI: 10.7554/elife.19358] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 12/15/2016] [Indexed: 11/20/2022] Open
Abstract
The molecular mechanisms underlying age-related cognitive deficits are not yet fully elucidated. In aged animals, a decrease in the intrinsic excitability of CA1 pyramidal neurons is believed to contribute to age-related cognitive impairments. Increasing activity of the transcription factor cAMP response element-binding protein (CREB) in young adult rodents facilitates cognition, and increases intrinsic excitability. However, it has yet to be tested if increasing CREB expression also ameliorates age-related behavioral and biophysical deficits. To test this hypothesis, we virally overexpressed CREB in CA1 of dorsal hippocampus. Rats received CREB or control virus, before undergoing water maze training. CREB overexpression in aged animals ameliorated the long-term memory deficits observed in control animals. Concurrently, cells overexpressing CREB in aged animals had reduced post-burst afterhyperpolarizations, indicative of increased intrinsic excitability. These results identify CREB modulation as a potential therapy to treat age-related cognitive decline. DOI:http://dx.doi.org/10.7554/eLife.19358.001
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Affiliation(s)
- Xiao-Wen Yu
- Department of Physiology, Northwestern University,Feinberg School of Medicine, Chicago, United States
| | - Daniel M Curlik
- Department of Physiology, Northwestern University,Feinberg School of Medicine, Chicago, United States.,Department of Behavioral Sciences, Psychology Program, York College of Pennsylvania, York, United States
| | - M Matthew Oh
- Department of Physiology, Northwestern University,Feinberg School of Medicine, Chicago, United States
| | - Jerry Cp Yin
- Departments of Genetics and Neurology, University of Wisconsin-Madison, Madison, United States
| | - John F Disterhoft
- Department of Physiology, Northwestern University,Feinberg School of Medicine, Chicago, United States
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202
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Mechanisms of Memory Consolidation and Transformation. COGNITIVE NEUROSCIENCE OF MEMORY CONSOLIDATION 2017. [DOI: 10.1007/978-3-319-45066-7_2] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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203
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Zhou M, Greenhill S, Huang S, Silva TK, Sano Y, Wu S, Cai Y, Nagaoka Y, Sehgal M, Cai DJ, Lee YS, Fox K, Silva AJ. CCR5 is a suppressor for cortical plasticity and hippocampal learning and memory. eLife 2016; 5. [PMID: 27996938 PMCID: PMC5213777 DOI: 10.7554/elife.20985] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 12/19/2016] [Indexed: 11/13/2022] Open
Abstract
Although the role of CCR5 in immunity and in HIV infection has been studied widely, its role in neuronal plasticity, learning and memory is not understood. Here, we report that decreasing the function of CCR5 increases MAPK/CREB signaling, long-term potentiation (LTP), and hippocampus-dependent memory in mice, while neuronal CCR5 overexpression caused memory deficits. Decreasing CCR5 function in mouse barrel cortex also resulted in enhanced spike timing dependent plasticity and consequently, dramatically accelerated experience-dependent plasticity. These results suggest that CCR5 is a powerful suppressor for plasticity and memory, and CCR5 over-activation by viral proteins may contribute to HIV-associated cognitive deficits. Consistent with this hypothesis, the HIV V3 peptide caused LTP, signaling and memory deficits that were prevented by Ccr5 knockout or knockdown. Overall, our results demonstrate that CCR5 plays an important role in neuroplasticity, learning and memory, and indicate that CCR5 has a role in the cognitive deficits caused by HIV.
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Affiliation(s)
- Miou Zhou
- Departments of Neurobiology, Psychology, Psychiatry, Integrative Center for Learning and Memory and Brain Research Institute, University of California, Los Angeles, Los Angeles, United States
| | - Stuart Greenhill
- Cardiff School of Biosciences, Cardiff University, Cardiff, United Kingdom.,School of Life and Health Sciences, Aston University, Birmingham, United Kingdom
| | - Shan Huang
- Departments of Neurobiology, Psychology, Psychiatry, Integrative Center for Learning and Memory and Brain Research Institute, University of California, Los Angeles, Los Angeles, United States
| | - Tawnie K Silva
- Departments of Neurobiology, Psychology, Psychiatry, Integrative Center for Learning and Memory and Brain Research Institute, University of California, Los Angeles, Los Angeles, United States
| | - Yoshitake Sano
- Departments of Neurobiology, Psychology, Psychiatry, Integrative Center for Learning and Memory and Brain Research Institute, University of California, Los Angeles, Los Angeles, United States.,Department of Applied Biological Science, Tokyo University of Science, Chiba, Japan
| | - Shumin Wu
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, United States
| | - Ying Cai
- Departments of Neurobiology, Psychology, Psychiatry, Integrative Center for Learning and Memory and Brain Research Institute, University of California, Los Angeles, Los Angeles, United States
| | - Yoshiko Nagaoka
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, United States
| | - Megha Sehgal
- Departments of Neurobiology, Psychology, Psychiatry, Integrative Center for Learning and Memory and Brain Research Institute, University of California, Los Angeles, Los Angeles, United States
| | - Denise J Cai
- Departments of Neurobiology, Psychology, Psychiatry, Integrative Center for Learning and Memory and Brain Research Institute, University of California, Los Angeles, Los Angeles, United States
| | - Yong-Seok Lee
- Departments of Neurobiology, Psychology, Psychiatry, Integrative Center for Learning and Memory and Brain Research Institute, University of California, Los Angeles, Los Angeles, United States.,Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Kevin Fox
- Cardiff School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Alcino J Silva
- Departments of Neurobiology, Psychology, Psychiatry, Integrative Center for Learning and Memory and Brain Research Institute, University of California, Los Angeles, Los Angeles, United States
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204
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Park S, Kramer EE, Mercaldo V, Rashid AJ, Insel N, Frankland PW, Josselyn SA. Neuronal Allocation to a Hippocampal Engram. Neuropsychopharmacology 2016; 41:2987-2993. [PMID: 27187069 PMCID: PMC5101572 DOI: 10.1038/npp.2016.73] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 04/26/2016] [Indexed: 12/17/2022]
Abstract
The dentate gyrus (DG) is important for encoding contextual memories, but little is known about how a population of DG neurons comes to encode and support a particular memory. One possibility is that recruitment into an engram depends on a neuron's excitability. Here, we manipulated excitability by overexpressing CREB in a random population of DG neurons and examined whether this biased their recruitment to an engram supporting a contextual fear memory. To directly assess whether neurons overexpressing CREB at the time of training became critical components of the engram, we examined memory expression while the activity of these neurons was silenced. Chemogenetically (hM4Di, an inhibitory DREADD receptor) or optogenetically (iC++, a light-activated chloride channel) silencing the small number of CREB-overexpressing DG neurons attenuated memory expression, whereas silencing a similar number of random neurons not overexpressing CREB at the time of training did not. As post-encoding reactivation of the activity patterns present during initial experience is thought to be important in memory consolidation, we investigated whether post-training silencing of neurons allocated to an engram disrupted subsequent memory expression. We found that silencing neurons 5 min (but not 24 h) following training disrupted memory expression. Together these results indicate that the rules of neuronal allocation to an engram originally described in the lateral amygdala are followed in different brain regions including DG, and moreover, that disrupting the post-training activity pattern of these neurons prevents memory consolidation.
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Affiliation(s)
- Sungmo Park
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada
| | - Emily E Kramer
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Valentina Mercaldo
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Asim J Rashid
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Nathan Insel
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Paul W Frankland
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada,Department of Psychology, University of Toronto, Toronto, ON, Canada
| | - Sheena A Josselyn
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada,Department of Physiology, University of Toronto, Toronto, ON, Canada,Department of Psychology, University of Toronto, Toronto, ON, Canada,Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada, Tel: +416 813 7654, Fax: +416 813 7717, E-mail:
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205
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Nair SS, Paré D, Vicentic A. Biologically based neural circuit modelling for the study of fear learning and extinction. NPJ SCIENCE OF LEARNING 2016; 1:16015. [PMID: 29541482 PMCID: PMC5846682 DOI: 10.1038/npjscilearn.2016.15] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/09/2016] [Accepted: 09/19/2016] [Indexed: 05/25/2023]
Abstract
The neuronal systems that promote protective defensive behaviours have been studied extensively using Pavlovian conditioning. In this paradigm, an initially neutral-conditioned stimulus is paired with an aversive unconditioned stimulus leading the subjects to display behavioural signs of fear. Decades of research into the neural bases of this simple behavioural paradigm uncovered that the amygdala, a complex structure comprised of several interconnected nuclei, is an essential part of the neural circuits required for the acquisition, consolidation and expression of fear memory. However, emerging evidence from the confluence of electrophysiological, tract tracing, imaging, molecular, optogenetic and chemogenetic methodologies, reveals that fear learning is mediated by multiple connections between several amygdala nuclei and their distributed targets, dynamical changes in plasticity in local circuit elements as well as neuromodulatory mechanisms that promote synaptic plasticity. To uncover these complex relations and analyse multi-modal data sets acquired from these studies, we argue that biologically realistic computational modelling, in conjunction with experiments, offers an opportunity to advance our understanding of the neural circuit mechanisms of fear learning and to address how their dysfunction may lead to maladaptive fear responses in mental disorders.
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Affiliation(s)
- Satish S Nair
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, MO, USA
| | - Denis Paré
- Center for Molecular and Behavioral Neuroscience, Rutgers University—Newark, Newark, NJ, USA
| | - Aleksandra Vicentic
- Division of Neuroscience and Basic Behavioral Science, National Institute of Mental Health, Rockville, MD, USA
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206
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Novaes LS, Dos Santos NB, Batalhote RFP, Malta MB, Camarini R, Scavone C, Munhoz CD. Environmental enrichment protects against stress-induced anxiety: Role of glucocorticoid receptor, ERK, and CREB signaling in the basolateral amygdala. Neuropharmacology 2016; 113:457-466. [PMID: 27815155 DOI: 10.1016/j.neuropharm.2016.10.026] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 10/23/2016] [Accepted: 10/24/2016] [Indexed: 11/17/2022]
Abstract
Environmental enrichment (EE) is an experimental animal model that enhances an animal's opportunity to interact with sensory, motor, and social stimuli, compared to standard laboratory conditions. A prominent benefit of EE is the reduction of stress-induced anxiety. The relationship between stress and the onset of anxiety-like behavior has been widely investigated in experimental research, showing a clear correlation with structural changes in the hippocampus and basolateral amygdala (BLA). However, the mechanisms by which EE exerts its protective roles in stress and anxiety remain unclear, and it is not known whether EE reduces the effects of acute stress on animal behavior shortly following the cessation of stress. We found that EE can prevent the emergence of anxiety-like symptoms in rats measured immediately after acute restraint stress (1 h) and this effect is not due to changes in systemic release of corticosterone. Rather, we found that stress promotes a rapid increase in the nuclear translocation of glucocorticoid receptor (GR) in the BLA, an effect prevented by previous EE exposure. Furthermore, we observed a reduction of ERK (a MAPK protein) and CREB activity in the BLA promoted by both EE and acute stress. Finally, we found that EE decreases the expression of the immediate-early gene EGR-1 in the BLA, indicating a possible reduction of neuronal activity in this region. Hyperactivity of BLA neurons has been reported to accompany anxiety-like behavior and changes in this process may be one of the mechanism by which EE exerts its protective effects against stress-induced anxiety.
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Affiliation(s)
- Leonardo S Novaes
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Nilton Barreto Dos Santos
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Rafaela F P Batalhote
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Marília Brinati Malta
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Rosana Camarini
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Cristoforo Scavone
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Carolina Demarchi Munhoz
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, 05508-000, Brazil.
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207
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Growth hormone biases amygdala network activation after fear learning. Transl Psychiatry 2016; 6:e960. [PMID: 27898076 PMCID: PMC5290350 DOI: 10.1038/tp.2016.203] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 07/07/2016] [Accepted: 07/18/2016] [Indexed: 01/27/2023] Open
Abstract
Prolonged stress exposure is a risk factor for developing posttraumatic stress disorder, a disorder characterized by the 'over-encoding' of a traumatic experience. A potential mechanism by which this occurs is through upregulation of growth hormone (GH) in the amygdala. Here we test the hypotheses that GH promotes the over-encoding of fearful memories by increasing the number of neurons activated during memory encoding and biasing the allocation of neuronal activation, one aspect of the process by which neurons compete to encode memories, to favor neurons that have stronger inputs. Viral overexpression of GH in the amygdala increased the number of amygdala cells activated by fear memory formation. GH-overexpressing cells were especially biased to express the immediate early gene c-Fos after fear conditioning, revealing strong autocrine actions of GH in the amygdala. In addition, we observed dramatically enhanced dendritic spine density in GH-overexpressing neurons. These data elucidate a previously unrecognized autocrine role for GH in the regulation of amygdala neuron function and identify specific mechanisms by which chronic stress, by enhancing GH in the amygdala, may predispose an individual to excessive fear memory formation.
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208
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Functional and structural underpinnings of neuronal assembly formation in learning. Nat Neurosci 2016; 19:1553-1562. [PMID: 27749830 DOI: 10.1038/nn.4418] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 09/14/2016] [Indexed: 02/07/2023]
Abstract
Learning and memory are associated with the formation and modification of neuronal assemblies: populations of neurons that encode what has been learned and mediate memory retrieval upon recall. Functional studies of neuronal assemblies have progressed dramatically thanks to recent technological advances. Here we discuss how a focus on assembly formation and consolidation has provided a powerful conceptual framework to relate mechanistic studies of synaptic and circuit plasticity to behaviorally relevant aspects of learning and memory. Neurons are likely recruited to particular learning-related assemblies as a function of their relative excitabilities and synaptic activation, followed by selective strengthening of pre-existing synapses, formation of new connections and elimination of outcompeted synapses to ensure memory formation. Mechanistically, these processes involve linking transcription to circuit modification. They include the expression of immediate early genes and specific molecular and cellular events, supported by network-wide activities that are shaped and modulated by local inhibitory microcircuits.
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209
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Guo L, Guo Z, Luo X, Liang R, Yang S, Ren H, Wang G, Zhen X. Phosphodiesterase 10A inhibition attenuates sleep deprivation-induced deficits in long-term fear memory. Neurosci Lett 2016; 635:44-50. [PMID: 27743798 DOI: 10.1016/j.neulet.2016.10.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 09/20/2016] [Accepted: 10/10/2016] [Indexed: 12/28/2022]
Abstract
Sleep, particularly rapid eye movement (REM) sleep, is implicated in the consolidation of emotional memories. In the present study, we investigated the protective effects of a phosphodiesterase 10A (PDE10A) inhibitor MP-10 on deficits in long-term fear memory induced by REM sleep deprivation (REM-SD). REM-SD caused deficits in long-term fear memory, however, MP-10 administration ameliorated the deleterious effects of REM-SD on long term fear memory. Brain-derived neurotropic factor (BDNF) and phosphorylated cAMP response element-binding protein (pCREB) were altered in specific brain regions associated with learning and memory in REM-SD rats. Accordingly, REM-SD caused a significant decrease of pCREB in hippocampus and striatum and a significant decrease of BDNF in the hippocampus, striatum and amygdala, however, MP-10 reversed the effects of REM-SD in a dose-dependent manner. Our findings suggest that REM-SD disrupts the consolidation of long-term fear memory and that administration of MP-10 protects the REM-SD-induced deficits in fear memory, which may be due to the MP-10-induced expression of BDNF in the hippocampus, striatum and amygdala, and phosphorylation of CREB in the hippocampus and striatum.
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Affiliation(s)
- Lengqiu Guo
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Disorders & Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu 215123, China; College of Pharmaceutical Sciences, Suzhou Health College, 28 Kehua Road, Suzhou, Jiangsu 215009, China
| | - Zhuangli Guo
- Department of Rehabilitation Medicine, The Affiliated Hospital of Qingdao University, 16 Jiangsu Road,Qingdao, Shandong 266003, China
| | - Xiaoqing Luo
- College of Pharmaceutical Sciences, Suzhou Health College, 28 Kehua Road, Suzhou, Jiangsu 215009, China
| | - Rui Liang
- College of Pharmaceutical Sciences, Suzhou Health College, 28 Kehua Road, Suzhou, Jiangsu 215009, China
| | - Shui Yang
- College of Pharmaceutical Sciences, Suzhou Health College, 28 Kehua Road, Suzhou, Jiangsu 215009, China
| | - Haigang Ren
- College of Pharmaceutical Sciences, Suzhou Health College, 28 Kehua Road, Suzhou, Jiangsu 215009, China
| | - Guanghui Wang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Disorders & Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu 215123, China.
| | - Xuechu Zhen
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Disorders & Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, 199 Ren'ai Road, Suzhou, Jiangsu 215123, China.
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210
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Shen HH. News Feature: To master memory, researchers pursue its roots. Proc Natl Acad Sci U S A 2016; 113:11376-11379. [PMID: 27729539 PMCID: PMC5068297 DOI: 10.1073/pnas.1615096113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023] Open
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211
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Choi KY, Kim YK. Plasticity-augmented psychotherapy for refractory depressive and anxiety disorders. Prog Neuropsychopharmacol Biol Psychiatry 2016; 70:134-47. [PMID: 27072378 DOI: 10.1016/j.pnpbp.2016.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 04/07/2016] [Accepted: 04/08/2016] [Indexed: 12/28/2022]
Abstract
Psychotherapy and pharmacotherapy have been the mainstays of treatment for depression and anxiety disorders during the last century. However, treatment response has not improved in the last few decades, with only half of all patients responding satisfactorily to typical antidepressants. To fulfill the needs of the remaining patients, new treatments with better efficacy are in demand. The addition of psychotherapy to antidepressant treatment has been shown to be superior to pharmacotherapy alone. However, the time costs of psychotherapy limit its use for clinicians and patients. Advancements in neuroscience have contributed to an improved understanding of the pathogenesis of depressive and anxiety disorders. In particular, recent advances in the field of fear conditioning have provided valuable insight into the treatment of refractory depressive and anxiety disorders. In this review, we studied the reconsolidation-updating paradigm and the concept of epigenetic modification, which has been shown to permanently attenuate remote fear memory. This has implications for drug-augmented, e.g. antidepressant and valproic acid, psychotherapy. Future research on more sophisticated psychotherapy techniques will increase the desirability of this treatment modality for both clinicians and patients.
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Affiliation(s)
- Kwang-Yeon Choi
- Department of Psychiatry, Korea University College of Medicine, Seoul, Republic of Korea
| | - Yong-Ku Kim
- Department of Psychiatry, Korea University College of Medicine, Seoul, Republic of Korea.
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212
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Jammal L, Whalley B, Ghosh S, Lamrecht R, Barkai E. Physiological expression of olfactory discrimination rule learning balances whole-population modulation and circuit stability in the piriform cortex network. Physiol Rep 2016; 4:4/14/e12830. [PMID: 27449811 PMCID: PMC4962067 DOI: 10.14814/phy2.12830] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 05/13/2016] [Indexed: 01/10/2023] Open
Abstract
Once trained, rats are able to execute particularly difficult olfactory discrimination tasks with exceptional accuracy. Such skill acquisition, termed "rule learning", is accompanied by a series of long-lasting modifications to three cellular properties which modulate pyramidal neuron activity in piriform cortex; intrinsic excitability, synaptic excitation, and synaptic inhibition. Here, we explore how these changes, which are seemingly contradictory at the single-cell level in terms of their effect on neuronal excitation, are manifested within the piriform cortical neuronal network to store the memory of the rule, while maintaining network stability. To this end, we monitored network activity via multisite extracellular recordings of field postsynaptic potentials (fPSPS) and with single-cell recordings of miniature inhibitory and excitatory synaptic events in piriform cortex slices. We show that although 5 days after rule learning the cortical network maintains its basic activity patterns, synaptic connectivity is strengthened specifically between spatially proximal cells. Moreover, while the enhancement of inhibitory and excitatory synaptic connectivity is nearly identical, strengthening of synaptic inhibition is equally distributed between neurons while synaptic excitation is particularly strengthened within a specific subgroup of cells. We suggest that memory for the acquired rule is stored mainly by strengthening excitatory synaptic connection between close pyramidal neurons and runaway synaptic activity arising from this change is prevented by a nonspecific enhancement of synaptic inhibition.
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Affiliation(s)
- Luna Jammal
- Sagol department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Ben Whalley
- School of Chemistry, Food & Nutritional Sciences and Pharmacy, The University of Reading, Reading, UK
| | - Sourav Ghosh
- Sagol department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Raphael Lamrecht
- Sagol department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Edi Barkai
- Sagol department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
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213
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Optogenetic Inhibitor of the Transcription Factor CREB. ACTA ACUST UNITED AC 2016; 22:1531-1539. [PMID: 26590638 DOI: 10.1016/j.chembiol.2015.09.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 09/11/2015] [Accepted: 09/24/2015] [Indexed: 01/28/2023]
Abstract
Current approaches for optogenetic control of transcription do not mimic the activity of endogenous transcription factors, which act at numerous sites in the genome in a complex interplay with other factors. Optogenetic control of dominant negative versions of endogenous transcription factors provides a mechanism for mimicking the natural regulation of gene expression. Here we describe opto-DN-CREB, a blue-light-controlled inhibitor of the transcription factor CREB created by fusing the dominant negative inhibitor A-CREB to photoactive yellow protein (PYP). A light-driven conformational change in PYP prevents coiled-coil formation between A-CREB and CREB, thereby activating CREB. Optogenetic control of CREB function was characterized in vitro, in HEK293T cells, and in neurons where blue light enabled control of expression of the CREB targets NR4A2 and c-Fos. Dominant negative inhibitors exist for numerous transcription factors; linking these to optogenetic domains offers a general approach for spatiotemporal control of native transcriptional events.
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214
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Rogerson T, Jayaprakash B, Cai DJ, Sano Y, Lee YS, Zhou Y, Bekal P, Deisseroth K, Silva AJ. Molecular and Cellular Mechanisms for Trapping and Activating Emotional Memories. PLoS One 2016; 11:e0161655. [PMID: 27579481 PMCID: PMC5007047 DOI: 10.1371/journal.pone.0161655] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/09/2016] [Indexed: 11/18/2022] Open
Abstract
Recent findings suggest that memory allocation to specific neurons (i.e., neuronal allocation) in the amygdala is not random, but rather the transcription factor cAMP-response element binding protein (CREB) modulates this process, perhaps by regulating the transcription of channels that control neuronal excitability. Here, optogenetic studies in the mouse lateral amygdala (LA) were used to demonstrate that CREB and neuronal excitability regulate which neurons encode an emotional memory. To test the role of CREB in memory allocation, we overexpressed CREB in the lateral amygdala to recruit the encoding of an auditory-fear conditioning (AFC) memory to a subset of neurons. Then, post-training activation of these neurons with Channelrhodopsin-2 was sufficient to trigger recall of the memory for AFC, suggesting that CREB regulates memory allocation. To test the role of neuronal excitability in memory allocation, we used a step function opsin (SFO) to transiently increase neuronal excitability in a subset of LA neurons during AFC. Post-training activation of these neurons with Volvox Channelrhodopsin-1 was able to trigger recall of that memory. Importantly, our studies show that activation of the SFO did not affect AFC by either increasing anxiety or by strengthening the unconditioned stimulus. Our findings strongly support the hypothesis that CREB regulates memory allocation by modulating neuronal excitability.
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Affiliation(s)
- Thomas Rogerson
- Integrative Center for Learning and Memory, Departments of Neurobiology, Psychology, and Psychiatry & Biobehavioral Sciences, and Brain Research Institute, Los Angeles, California, United States of America
| | - Balaji Jayaprakash
- Integrative Center for Learning and Memory, Departments of Neurobiology, Psychology, and Psychiatry & Biobehavioral Sciences, and Brain Research Institute, Los Angeles, California, United States of America
| | - Denise J. Cai
- Integrative Center for Learning and Memory, Departments of Neurobiology, Psychology, and Psychiatry & Biobehavioral Sciences, and Brain Research Institute, Los Angeles, California, United States of America
| | - Yoshitake Sano
- Integrative Center for Learning and Memory, Departments of Neurobiology, Psychology, and Psychiatry & Biobehavioral Sciences, and Brain Research Institute, Los Angeles, California, United States of America
| | - Yong-Seok Lee
- Integrative Center for Learning and Memory, Departments of Neurobiology, Psychology, and Psychiatry & Biobehavioral Sciences, and Brain Research Institute, Los Angeles, California, United States of America
| | - Yu Zhou
- Integrative Center for Learning and Memory, Departments of Neurobiology, Psychology, and Psychiatry & Biobehavioral Sciences, and Brain Research Institute, Los Angeles, California, United States of America
| | - Pallavi Bekal
- Integrative Center for Learning and Memory, Departments of Neurobiology, Psychology, and Psychiatry & Biobehavioral Sciences, and Brain Research Institute, Los Angeles, California, United States of America
| | - Karl Deisseroth
- Department of Bioengineering, Psychiatry and Behavioral Sciences, Neurosciences Program, CNC Program, Howard Hughes Medical Institute, Stanford University, Stanford, California, United States of America
| | - Alcino J. Silva
- Integrative Center for Learning and Memory, Departments of Neurobiology, Psychology, and Psychiatry & Biobehavioral Sciences, and Brain Research Institute, Los Angeles, California, United States of America
- * E-mail:
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215
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Guan JS, Jiang J, Xie H, Liu KY. How Does the Sparse Memory "Engram" Neurons Encode the Memory of a Spatial-Temporal Event? Front Neural Circuits 2016; 10:61. [PMID: 27601979 PMCID: PMC4993949 DOI: 10.3389/fncir.2016.00061] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 07/29/2016] [Indexed: 12/02/2022] Open
Abstract
Episodic memory in human brain is not a fixed 2-D picture but a highly dynamic movie serial, integrating information at both the temporal and the spatial domains. Recent studies in neuroscience reveal that memory storage and recall are closely related to the activities in discrete memory engram (trace) neurons within the dentate gyrus region of hippocampus and the layer 2/3 of neocortex. More strikingly, optogenetic reactivation of those memory trace neurons is able to trigger the recall of naturally encoded memory. It is still unknown how the discrete memory traces encode and reactivate the memory. Considering a particular memory normally represents a natural event, which consists of information at both the temporal and spatial domains, it is unknown how the discrete trace neurons could reconstitute such enriched information in the brain. Furthermore, as the optogenetic-stimuli induced recall of memory did not depend on firing pattern of the memory traces, it is most likely that the spatial activation pattern, but not the temporal activation pattern of the discrete memory trace neurons encodes the memory in the brain. How does the neural circuit convert the activities in the spatial domain into the temporal domain to reconstitute memory of a natural event? By reviewing the literature, here we present how the memory engram (trace) neurons are selected and consolidated in the brain. Then, we will discuss the main challenges in the memory trace theory. In the end, we will provide a plausible model of memory trace cell network, underlying the conversion of neural activities between the spatial domain and the temporal domain. We will also discuss on how the activation of sparse memory trace neurons might trigger the replay of neural activities in specific temporal patterns.
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Affiliation(s)
- Ji-Song Guan
- Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua UniversityBeijing, China; IDG/McGovern Institute for Brain Research at Tsinghua University, School of Life Sciences, Tsinghua UniversityBeijing, China; Center for Brain inspired Computing, Tsinghua UniversityBeijing, China
| | - Jun Jiang
- Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua UniversityBeijing, China; IDG/McGovern Institute for Brain Research at Tsinghua University, School of Life Sciences, Tsinghua UniversityBeijing, China; Center for Brain inspired Computing, Tsinghua UniversityBeijing, China
| | - Hong Xie
- Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua UniversityBeijing, China; IDG/McGovern Institute for Brain Research at Tsinghua University, School of Life Sciences, Tsinghua UniversityBeijing, China; Center for Brain inspired Computing, Tsinghua UniversityBeijing, China
| | - Kai-Yuan Liu
- Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua UniversityBeijing, China; IDG/McGovern Institute for Brain Research at Tsinghua University, School of Life Sciences, Tsinghua UniversityBeijing, China; Center for Brain inspired Computing, Tsinghua UniversityBeijing, China
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216
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Rashid AJ, Yan C, Mercaldo V, Hsiang HLL, Park S, Cole CJ, De Cristofaro A, Yu J, Ramakrishnan C, Lee SY, Deisseroth K, Frankland PW, Josselyn SA. Competition between engrams influences fear memory formation and recall. Science 2016; 353:383-7. [PMID: 27463673 DOI: 10.1126/science.aaf0594] [Citation(s) in RCA: 217] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 06/17/2016] [Indexed: 12/20/2022]
Abstract
Collections of cells called engrams are thought to represent memories. Although there has been progress in identifying and manipulating single engrams, little is known about how multiple engrams interact to influence memory. In lateral amygdala (LA), neurons with increased excitability during training outcompete their neighbors for allocation to an engram. We examined whether competition based on neuronal excitability also governs the interaction between engrams. Mice received two distinct fear conditioning events separated by different intervals. LA neuron excitability was optogenetically manipulated and revealed a transient competitive process that integrates memories for events occurring closely in time (coallocating overlapping populations of neurons to both engrams) and separates memories for events occurring at distal times (disallocating nonoverlapping populations to each engram).
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Affiliation(s)
- Asim J Rashid
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada. Department of Psychology, University of Toronto, Toronto, ON M5G 3G3, Canada. Institute of Medical Sciences, University of Toronto, Toronto, ON M5S 1A8, Canada. Department of Physiology, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Chen Yan
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada. Department of Psychology, University of Toronto, Toronto, ON M5G 3G3, Canada. Institute of Medical Sciences, University of Toronto, Toronto, ON M5S 1A8, Canada. Department of Physiology, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Valentina Mercaldo
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada. Department of Psychology, University of Toronto, Toronto, ON M5G 3G3, Canada. Institute of Medical Sciences, University of Toronto, Toronto, ON M5S 1A8, Canada. Department of Physiology, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Hwa-Lin Liz Hsiang
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada. Department of Psychology, University of Toronto, Toronto, ON M5G 3G3, Canada. Institute of Medical Sciences, University of Toronto, Toronto, ON M5S 1A8, Canada. Department of Physiology, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Sungmo Park
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada. Department of Psychology, University of Toronto, Toronto, ON M5G 3G3, Canada. Institute of Medical Sciences, University of Toronto, Toronto, ON M5S 1A8, Canada. Department of Physiology, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Christina J Cole
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada. Department of Psychology, University of Toronto, Toronto, ON M5G 3G3, Canada. Institute of Medical Sciences, University of Toronto, Toronto, ON M5S 1A8, Canada. Department of Physiology, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Antonietta De Cristofaro
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada
| | - Julia Yu
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada
| | - Charu Ramakrishnan
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA
| | - Soo Yeun Lee
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA
| | - Karl Deisseroth
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA
| | - Paul W Frankland
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada. Department of Psychology, University of Toronto, Toronto, ON M5G 3G3, Canada. Institute of Medical Sciences, University of Toronto, Toronto, ON M5S 1A8, Canada. Department of Physiology, University of Toronto, Toronto, ON M5G 1X8, Canada.
| | - Sheena A Josselyn
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada. Department of Psychology, University of Toronto, Toronto, ON M5G 3G3, Canada. Institute of Medical Sciences, University of Toronto, Toronto, ON M5S 1A8, Canada. Department of Physiology, University of Toronto, Toronto, ON M5G 1X8, Canada.
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217
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Surface expression of hippocampal NMDA GluN2B receptors regulated by fear conditioning determines its contribution to memory consolidation in adult rats. Sci Rep 2016; 6:30743. [PMID: 27487820 PMCID: PMC4973269 DOI: 10.1038/srep30743] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 07/07/2016] [Indexed: 11/16/2022] Open
Abstract
The number and subtype composition of N-methyl-d-aspartate receptor (NMDAR) at synapses determines their functional properties and role in learning and memory. Genetically increased or decreased amount of GluN2B affects hippocampus-dependent memory in the adult brain. But in some experimental conditions (e.g., memory elicited by a single conditioning trial (1 CS-US)), GluN2B is not a necessary factor, which indicates that the precise role of GluN2B in memory formation requires further exploration. Here, we examined the role of GluN2B in the consolidation of fear memory using two training paradigms. We found that GluN2B was only required for the consolidation of memory elicited by five conditioning trials (5 CS-US), not by 1 CS-US. Strikingly, the expression of membrane GluN2B in CA1was training-strength-dependently increased after conditioning, and that the amount of membrane GluN2B determined its involvement in memory consolidation. Additionally, we demonstrated the increases in the activities of cAMP, ERK, and CREB in the CA1 after conditioning, as well as the enhanced intrinsic excitability and synaptic efficacy in CA1 neurons. Up-regulation of membrane GluN2B contributed to these enhancements. These studies uncover a novel mechanism for the involvement of GluN2B in memory consolidation by its accumulation at the cell surface in response to behavioral training.
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218
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Cellular tagging as a neural network mechanism for behavioural tagging. Nat Commun 2016; 7:12319. [PMID: 27477539 PMCID: PMC4974651 DOI: 10.1038/ncomms12319] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 06/21/2016] [Indexed: 12/16/2022] Open
Abstract
Behavioural tagging is the transformation of a short-term memory, induced by a weak experience, into a long-term memory (LTM) due to the temporal association with a novel experience. The mechanism by which neuronal ensembles, each carrying a memory engram of one of the experiences, interact to achieve behavioural tagging is unknown. Here we show that retrieval of a LTM formed by behavioural tagging of a weak experience depends on the degree of overlap with the neuronal ensemble corresponding to a novel experience. The numbers of neurons activated by weak training in a novel object recognition (NOR) task and by a novel context exploration (NCE) task, denoted as overlapping neurons, increases in the hippocampal CA1 when behavioural tagging is successfully achieved. Optical silencing of an NCE-related ensemble suppresses NOR–LTM retrieval. Thus, a population of cells recruited by NOR is tagged and then preferentially incorporated into the memory trace for NCE to achieve behavioural tagging. Short-term memories (STM) can become long-term memories when occurring alongside novel experiences. Here, the authors investigate the neural mechanisms behind such 'behavioural tagging' and find STM neural populations are preferentially incorporated into the ensembles encoding novel experiences.
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219
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Exposure pattern influences the degree of drug-seeking behaviour after withdrawal. Acta Neuropsychiatr 2016; 28:199-205. [PMID: 26767799 DOI: 10.1017/neu.2015.62] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVES The occurrence of a relapse during abstinence is an important issue that must be addressed during treatment for drug addiction. We investigated the influence of drug exposure pattern on morphine-seeking behaviour following withdrawal. We also studied the role of the hippocampus in this process to confirm its involvement in drug relapse. METHODS Male Sprague-Dawley rats that were trained to self-administer morphine (1.0 mg/kg) using 2, 4, 6, 8, or 10 h daily sessions underwent withdrawal in their home cages and were re-exposed to the operant chamber to evaluate morphine-seeking behaviour. During the relapse session, rats were intravenously injected with morphine (0.25 mg/kg) or saline before re-exposure to the chamber. In the second experiment, rats were administered a microinjection of saline or cobalt chloride (CoCl2, 1 mM), a synaptic blocker, into the CA1 of the hippocampus prior to the relapse test. RESULTS In the first experiment, more morphine-seeking behaviour was observed in the 2 h group (animals trained to self-administer morphine during a 2 h daily session spread over 21 days) during the relapse session, despite all groups being exposed to similar amounts of morphine during the training period before withdrawal. In the second experiment, pretreatment with CoCl2 markedly reduced morphine-seeking behaviour in the 2 h group. CONCLUSIONS The present findings suggest that the exposure pattern influences the degree of relapse and that control of memorisation is important for prevention of relapse.
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220
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Yu XW, Oh MM, Disterhoft JF. CREB, cellular excitability, and cognition: Implications for aging. Behav Brain Res 2016; 322:206-211. [PMID: 27478142 DOI: 10.1016/j.bbr.2016.07.042] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 07/11/2016] [Accepted: 07/27/2016] [Indexed: 10/21/2022]
Abstract
Humans and laboratory animals display cognitive deficits as they age. However, there are currently no effective therapies available to treat these deficits, as the underlying mechanisms are poorly understood. Studies using pharmacological compounds have found a link between cognitive performance and the intrinsic cellular excitability of CA1 hippocampal neurons. Therefore, it is of great interest to identify molecular regulators that may be influencing both cognition and neuronal excitability, which could be changed with age. One possible regulator is the transcription factor cAMP response element binding-protein (CREB). In young adult animals, manipulation of CREB activity has resulted in modulation of both cognitive performance on behavioral tasks, and neuronal excitability. While evidence is sparse, studies also point to a dysfunction in CREB signaling with aging. We propose that CREB may be a viable therapeutic target for the treatment of age-related cognitive deficits, along with potential experiments to test this hypothesis.
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Affiliation(s)
- Xiao-Wen Yu
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Avenue, Chicago, IL 60611, USA.
| | - M Matthew Oh
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Avenue, Chicago, IL 60611, USA.
| | - John F Disterhoft
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E Chicago Avenue, Chicago, IL 60611, USA.
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221
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Lucas EK, Jegarl AM, Morishita H, Clem RL. Multimodal and Site-Specific Plasticity of Amygdala Parvalbumin Interneurons after Fear Learning. Neuron 2016; 91:629-43. [PMID: 27427462 DOI: 10.1016/j.neuron.2016.06.032] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 05/12/2016] [Accepted: 06/15/2016] [Indexed: 01/02/2023]
Abstract
Stimulus processing in fear conditioning is constrained by parvalbumin interneurons (PV-INs) through inhibition of principal excitatory neurons. However, the contributions of PV-IN microcircuits to input gating and long-term plasticity in the fear system remain unknown. Here we interrogate synaptic connections between afferent pathways, PV-INs, and principal excitatory neurons in the basolateral amygdala. We find that subnuclei of this region are populated two functionally distinct PV-IN networks. PV-INs in the lateral (LA), but not the basal (BA), amygdala possess complex dendritic arborizations, receive potent excitatory drive, and mediate feedforward inhibition onto principal neurons. After fear conditioning, PV-INs exhibit nucleus- and target-selective plasticity, resulting in persistent reduction of their excitatory input and inhibitory output in LA but not BA. These data reveal previously overlooked specializations of amygdala PV-INs and indicate specific circuit mechanisms for inhibitory plasticity during the encoding of associative fear memories.
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Affiliation(s)
- Elizabeth K Lucas
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Anita M Jegarl
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Hirofumi Morishita
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Psychiatry and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Roger L Clem
- Fishberg Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Psychiatry and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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222
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Morrison DJ, Rashid AJ, Yiu AP, Yan C, Frankland PW, Josselyn SA. Parvalbumin interneurons constrain the size of the lateral amygdala engram. Neurobiol Learn Mem 2016; 135:91-99. [PMID: 27422019 DOI: 10.1016/j.nlm.2016.07.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/07/2016] [Accepted: 07/09/2016] [Indexed: 11/19/2022]
Abstract
Memories are thought to be represented by discrete physiological changes in the brain, collectively referred to as an engram, that allow patterns of activity present during learning to be reactivated in the future. During the formation of a conditioned fear memory, a subset of principal (excitatory) neurons in the lateral amygdala (LA) are allocated to a neuronal ensemble that encodes an association between an initially neutral stimulus and a threatening aversive stimulus. Previous experimental and computational work suggests that this subset consists of only a small proportion of all LA neurons, and that this proportion remains constant across different memories. Here we examine the mechanisms that contribute to the stability of the size of the LA component of an engram supporting a fear memory. Visualizing expression of the activity-dependent gene Arc following memory retrieval to identify neurons allocated to an engram, we first show that the overall size of the LA engram remains constant across conditions of different memory strength. That is, the strength of a memory was not correlated with the number of LA neurons allocated to the engram supporting that memory. We then examine potential mechanisms constraining the size of the LA engram by expressing inhibitory DREADDS (designer receptors exclusively activated by designer drugs) in parvalbumin-positive (PV+) interneurons of the amygdala. We find that silencing PV+ neurons during conditioning increases the size of the engram, especially in the dorsal subnucleus of the LA. These results confirm predictions from modeling studies regarding the role of inhibition in shaping the size of neuronal memory ensembles and provide additional support for the idea that neurons in the LA are sparsely allocated to the engram based on relative neuronal excitability.
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Affiliation(s)
- Dano J Morrison
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Dept. Physiology, University of Toronto, Toronto, ON, Canada
| | - Asim J Rashid
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Adelaide P Yiu
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Dept. Physiology, University of Toronto, Toronto, ON, Canada
| | - Chen Yan
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Dept. Physiology, University of Toronto, Toronto, ON, Canada
| | - Paul W Frankland
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Dept. Physiology, University of Toronto, Toronto, ON, Canada; Dept. Psychology, University of Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Sheena A Josselyn
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Dept. Physiology, University of Toronto, Toronto, ON, Canada; Dept. Psychology, University of Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
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223
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Cai DJ, Aharoni D, Shuman T, Shobe J, Biane J, Song W, Wei B, Veshkini M, La-Vu M, Lou J, Flores S, Kim I, Sano Y, Zhou M, Baumgaertel K, Lavi A, Kamata M, Tuszynski M, Mayford M, Golshani P, Silva AJ. A shared neural ensemble links distinct contextual memories encoded close in time. Nature 2016; 534:115-8. [PMID: 27251287 PMCID: PMC5063500 DOI: 10.1038/nature17955] [Citation(s) in RCA: 542] [Impact Index Per Article: 67.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/24/2016] [Indexed: 12/18/2022]
Abstract
Recent studies suggest that a shared neural ensemble may link distinct memories encoded close in time. According to the memory allocation hypothesis, learning triggers a temporary increase in neuronal excitability that biases the representation of a subsequent memory to the neuronal ensemble encoding the first memory, such that recall of one memory increases the likelihood of recalling the other memory. Here we show in mice that the overlap between the hippocampal CA1 ensembles activated by two distinct contexts acquired within a day is higher than when they are separated by a week. Several findings indicate that this overlap of neuronal ensembles links two contextual memories. First, fear paired with one context is transferred to a neutral context when the two contexts are acquired within a day but not across a week. Second, the first memory strengthens the second memory within a day but not across a week. Older mice, known to have lower CA1 excitability, do not show the overlap between ensembles, the transfer of fear between contexts, or the strengthening of the second memory. Finally, in aged mice, increasing cellular excitability and activating a common ensemble of CA1 neurons during two distinct context exposures rescued the deficit in linking memories. Taken together, these findings demonstrate that contextual memories encoded close in time are linked by directing storage into overlapping ensembles. Alteration of these processes by ageing could affect the temporal structure of memories, thus impairing efficient recall of related information.
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Affiliation(s)
- Denise J. Cai
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095, USA
| | - Daniel Aharoni
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095, USA
- Departments of Neurology and Psychiatry & Biobehavioral Sciences, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095 and West Los Angeles VA Medical Center, 11301 Wilshire Blvd, Los Angeles, California 90073, USA
| | - Tristan Shuman
- Departments of Neurology and Psychiatry & Biobehavioral Sciences, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095 and West Los Angeles VA Medical Center, 11301 Wilshire Blvd, Los Angeles, California 90073, USA
| | - Justin Shobe
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095, USA
| | - Jeremy Biane
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093 and Veterans Affairs Medical Center, San Diego, California 92161, USA
| | - Weilin Song
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095, USA
| | - Brandon Wei
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095, USA
| | - Michael Veshkini
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095, USA
| | - Mimi La-Vu
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095, USA
| | - Jerry Lou
- Departments of Neurology and Psychiatry & Biobehavioral Sciences, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095 and West Los Angeles VA Medical Center, 11301 Wilshire Blvd, Los Angeles, California 90073, USA
| | - Sergio Flores
- Departments of Neurology and Psychiatry & Biobehavioral Sciences, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095 and West Los Angeles VA Medical Center, 11301 Wilshire Blvd, Los Angeles, California 90073, USA
| | - Isaac Kim
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095, USA
| | - Yoshitake Sano
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095, USA
| | - Miou Zhou
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095, USA
| | - Karsten Baumgaertel
- Departments of Cell Biology and Neurosciences, Institute for Childhood and Neglected Diseases, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Ayal Lavi
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095, USA
| | - Masakazu Kamata
- Division of Hematology/Oncology, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
| | - Mark Tuszynski
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093 and Veterans Affairs Medical Center, San Diego, California 92161, USA
| | - Mark Mayford
- Departments of Cell Biology and Neurosciences, Institute for Childhood and Neglected Diseases, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Peyman Golshani
- Departments of Neurology and Psychiatry & Biobehavioral Sciences, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095 and West Los Angeles VA Medical Center, 11301 Wilshire Blvd, Los Angeles, California 90073, USA
| | - Alcino J. Silva
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, California 90095, USA
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224
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Xie S, Jin N, Gu J, Shi J, Sun J, Chu D, Zhang L, Dai C, Gu J, Gong C, Iqbal K, Liu F. O-GlcNAcylation of protein kinase A catalytic subunits enhances its activity: a mechanism linked to learning and memory deficits in Alzheimer's disease. Aging Cell 2016; 15:455-64. [PMID: 26840030 PMCID: PMC4854926 DOI: 10.1111/acel.12449] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2016] [Indexed: 02/03/2023] Open
Abstract
Alzheimer's disease (AD) is characterized clinically by memory loss and cognitive decline. Protein kinase A (PKA)‐CREB signaling plays a critical role in learning and memory. It is known that glucose uptake and O‐GlcNAcylation are reduced in AD brain. In this study, we found that PKA catalytic subunits (PKAcs) were posttranslationally modified by O‐linked N‐acetylglucosamine (O‐GlcNAc). O‐GlcNAcylation regulated the subcellular location of PKAcα and PKAcβ and enhanced their kinase activity. Upregulation of O‐GlcNAcylation in metabolically active rat brain slices by O‐(2‐acetamido‐2‐deoxy‐d‐glucopyranosylidenamino) N‐phenylcarbamate (PUGNAc), an inhibitor of N‐acetylglucosaminidase, increased the phosphorylation of tau at the PKA site, Ser214, but not at the non‐PKA site, Thr205. In contrast, in rat and mouse brains, downregulation of O‐GlcNAcylation caused decreases in the phosphorylation of CREB at Ser133 and of tau at Ser214, but not at Thr205. Reduction in O‐GlcNAcylation through intracerebroventricular injection of 6‐diazo‐5‐oxo‐l‐norleucine (DON), the inhibitor of glutamine fructose‐6‐phosphate amidotransferase, suppressed PKA‐CREB signaling and impaired learning and memory in mice. These results indicate that in addition to cAMP and phosphorylation, O‐GlcNAcylation is a novel mechanism that regulates PKA‐CREB signaling. Downregulation of O‐GlcNAcylation suppresses PKA‐CREB signaling and consequently causes learning and memory deficits in AD.
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Affiliation(s)
- Shutao Xie
- Jiangsu Key Laboratory of Neuroregeneration Co‐innovation Center of Neuroregeneration Nantong University Nantong Jiangsu 226001 China
- Department of Neurochemistry Inge Grundke‐Iqbal Research Floor New York State Institute for Basic Research in Developmental Disabilities Staten Island New York 10314 USA
| | - Nana Jin
- Jiangsu Key Laboratory of Neuroregeneration Co‐innovation Center of Neuroregeneration Nantong University Nantong Jiangsu 226001 China
- Department of Neurochemistry Inge Grundke‐Iqbal Research Floor New York State Institute for Basic Research in Developmental Disabilities Staten Island New York 10314 USA
| | - Jianlan Gu
- Jiangsu Key Laboratory of Neuroregeneration Co‐innovation Center of Neuroregeneration Nantong University Nantong Jiangsu 226001 China
- Department of Neurochemistry Inge Grundke‐Iqbal Research Floor New York State Institute for Basic Research in Developmental Disabilities Staten Island New York 10314 USA
| | - Jianhua Shi
- Jiangsu Key Laboratory of Neuroregeneration Co‐innovation Center of Neuroregeneration Nantong University Nantong Jiangsu 226001 China
| | - Jianming Sun
- Jiangsu Key Laboratory of Neuroregeneration Co‐innovation Center of Neuroregeneration Nantong University Nantong Jiangsu 226001 China
| | - Dandan Chu
- Jiangsu Key Laboratory of Neuroregeneration Co‐innovation Center of Neuroregeneration Nantong University Nantong Jiangsu 226001 China
| | - Liang Zhang
- Department of Neurochemistry Inge Grundke‐Iqbal Research Floor New York State Institute for Basic Research in Developmental Disabilities Staten Island New York 10314 USA
| | - Chun‐ling Dai
- Department of Neurochemistry Inge Grundke‐Iqbal Research Floor New York State Institute for Basic Research in Developmental Disabilities Staten Island New York 10314 USA
| | - Jin‐hua Gu
- Jiangsu Key Laboratory of Neuroregeneration Co‐innovation Center of Neuroregeneration Nantong University Nantong Jiangsu 226001 China
| | - Cheng‐Xin Gong
- Department of Neurochemistry Inge Grundke‐Iqbal Research Floor New York State Institute for Basic Research in Developmental Disabilities Staten Island New York 10314 USA
| | - Khalid Iqbal
- Department of Neurochemistry Inge Grundke‐Iqbal Research Floor New York State Institute for Basic Research in Developmental Disabilities Staten Island New York 10314 USA
| | - Fei Liu
- Jiangsu Key Laboratory of Neuroregeneration Co‐innovation Center of Neuroregeneration Nantong University Nantong Jiangsu 226001 China
- Department of Neurochemistry Inge Grundke‐Iqbal Research Floor New York State Institute for Basic Research in Developmental Disabilities Staten Island New York 10314 USA
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225
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Namburi P, Al-Hasani R, Calhoon GG, Bruchas MR, Tye KM. Architectural Representation of Valence in the Limbic System. Neuropsychopharmacology 2016; 41:1697-715. [PMID: 26647973 PMCID: PMC4869057 DOI: 10.1038/npp.2015.358] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 12/04/2015] [Accepted: 12/05/2015] [Indexed: 11/08/2022]
Abstract
In order to thrive, animals must be able to recognize aversive and appetitive stimuli within the environment and subsequently initiate appropriate behavioral responses. This assignment of positive or negative valence to a stimulus is a key feature of emotional processing, the neural substrates of which have been a topic of study for several decades. Until recently, the result of this work has been the identification of specific brain regions, such as the basolateral amygdala (BLA) and nucleus accumbens (NAc), as important to valence encoding. The advent of modern tools in neuroscience has allowed further dissection of these regions to identify specific populations of neurons signaling the valence of environmental stimuli. In this review, we focus upon recent work examining the mechanisms of valence encoding, and provide a model for the systematic investigation of valence within anatomically-, genetically-, and functionally defined populations of neurons.
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Affiliation(s)
- Praneeth Namburi
- Department of Brain and Cognitive Sciences, The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
- Neuroscience Graduate Program, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ream Al-Hasani
- Division of Basic Research, Department of Anesthesiology, Washington University School of Medicine, St Louis, MO, USA
- Washington University Pain Center, Washington University School of Medicine, St Louis, MO, USA
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO, USA
| | - Gwendolyn G Calhoon
- Department of Brain and Cognitive Sciences, The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Michael R Bruchas
- Division of Basic Research, Department of Anesthesiology, Washington University School of Medicine, St Louis, MO, USA
- Washington University Pain Center, Washington University School of Medicine, St Louis, MO, USA
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO, USA
- Division of Biology and Biomedical Sciences, Washington University School of Medicine, St Louis, MO, USA
| | - Kay M Tye
- Department of Brain and Cognitive Sciences, The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
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226
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Jercog P, Rogerson T, Schnitzer MJ. Large-Scale Fluorescence Calcium-Imaging Methods for Studies of Long-Term Memory in Behaving Mammals. Cold Spring Harb Perspect Biol 2016; 8:a021824. [PMID: 27048190 PMCID: PMC4852807 DOI: 10.1101/cshperspect.a021824] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
During long-term memory formation, cellular and molecular processes reshape how individual neurons respond to specific patterns of synaptic input. It remains poorly understood how such changes impact information processing across networks of mammalian neurons. To observe how networks encode, store, and retrieve information, neuroscientists must track the dynamics of large ensembles of individual cells in behaving animals, over timescales commensurate with long-term memory. Fluorescence Ca(2+)-imaging techniques can monitor hundreds of neurons in behaving mice, opening exciting avenues for studies of learning and memory at the network level. Genetically encoded Ca(2+) indicators allow neurons to be targeted by genetic type or connectivity. Chronic animal preparations permit repeated imaging of neural Ca(2+) dynamics over multiple weeks. Together, these capabilities should enable unprecedented analyses of how ensemble neural codes evolve throughout memory processing and provide new insights into how memories are organized in the brain.
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Affiliation(s)
- Pablo Jercog
- CNC Program, Stanford University, Stanford, California 94305
| | - Thomas Rogerson
- CNC Program, Stanford University, Stanford, California 94305
| | - Mark J Schnitzer
- CNC Program, Stanford University, Stanford, California 94305 Howard Hughes Medical Institute, Stanford University, Stanford, California 94305 James H. Clark Center for Biomedical Engineering & Sciences, Stanford University, Stanford, California 94305
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227
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Kim D, Samarth P, Feng F, Pare D, Nair SS. Synaptic competition in the lateral amygdala and the stimulus specificity of conditioned fear: a biophysical modeling study. Brain Struct Funct 2016; 221:2163-82. [PMID: 25859631 PMCID: PMC4600426 DOI: 10.1007/s00429-015-1037-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 03/31/2015] [Indexed: 12/20/2022]
Abstract
Competitive synaptic interactions between principal neurons (PNs) with differing intrinsic excitability were recently shown to determine which dorsal lateral amygdala (LAd) neurons are recruited into a fear memory trace. Here, we explored the contribution of these competitive interactions in determining the stimulus specificity of conditioned fear associations. To this end, we used a realistic biophysical computational model of LAd that included multi-compartment conductance-based models of 800 PNs and 200 interneurons. To reproduce the continuum of spike frequency adaptation displayed by PNs, the model included three subtypes of PNs with high, intermediate, and low spike frequency adaptation. In addition, the model network integrated spatially differentiated patterns of excitatory and inhibitory connections within LA, dopaminergic and noradrenergic inputs, extrinsic thalamic and cortical tone afferents to simulate conditioned stimuli as well as shock inputs for the unconditioned stimulus. Last, glutamatergic synapses in the model could undergo activity-dependent plasticity. Our results suggest that plasticity at both excitatory (PN-PN) and di-synaptic inhibitory (PN-ITN and, particularly, ITN-PN) connections are major determinants of the synaptic competition governing the assignment of PNs to the memory trace. The model also revealed that training-induced potentiation of PN-PN synapses promotes, whereas that of ITN-PN synapses opposes, stimulus generalization. Indeed, suppressing plasticity of PN-PN synapses increased, whereas preventing plasticity of interneuronal synapses decreased the CS specificity of PN recruitment. Overall, our results indicate that the plasticity configuration imprinted in the network by synaptic competition ensures memory specificity. Given that anxiety disorders are characterized by tendency to generalize learned fear to safe stimuli or situations, understanding how plasticity of intrinsic LAd synapses regulates the specificity of learned fear is an important challenge for future experimental studies.
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Affiliation(s)
- D Kim
- Electrical and Computer Engineering, University of Missouri, Columbia, MO, 65211, USA
| | - P Samarth
- Electrical and Computer Engineering, University of Missouri, Columbia, MO, 65211, USA
| | - F Feng
- Electrical and Computer Engineering, University of Missouri, Columbia, MO, 65211, USA
| | - D Pare
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, NJ, 07102, USA
| | - Satish S Nair
- Electrical and Computer Engineering, University of Missouri, Columbia, MO, 65211, USA.
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228
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Kim JI, Cho HY, Han JH, Kaang BK. Which Neurons Will Be the Engram - Activated Neurons and/or More Excitable Neurons? Exp Neurobiol 2016; 25:55-63. [PMID: 27122991 PMCID: PMC4844563 DOI: 10.5607/en.2016.25.2.55] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 04/06/2016] [Accepted: 04/06/2016] [Indexed: 11/19/2022] Open
Abstract
During past decades, the formation and storage principle of memory have received much attention in the neuroscience field. Although some studies have attempted to demonstrate the nature of the engram, elucidating the memory engram allocation mechanism was not possible because of the limitations of existing methods, which cannot specifically modulate the candidate neuronal population. Recently, the development of new techniques, which offer ways to mark and control specific populations of neurons, may accelerate solving this issue. Here, we review the recent advances, which have provided substantial evidence showing that both candidates (neuronal population that is activated by learning, and that has increased CREB level/excitability at learning) satisfy the criteria of the engram, which are necessary and sufficient for memory expression.
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Affiliation(s)
- Ji-Il Kim
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, Korea
| | - Hye-Yeon Cho
- Department of Biological Sciences, KAIST Institute for the BioCentury (KIB), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Jin-Hee Han
- Department of Biological Sciences, KAIST Institute for the BioCentury (KIB), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Bong-Kiun Kaang
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, Korea
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229
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Clem RL, Schiller D. New Learning and Unlearning: Strangers or Accomplices in Threat Memory Attenuation? Trends Neurosci 2016; 39:340-351. [PMID: 27079843 DOI: 10.1016/j.tins.2016.03.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 03/04/2016] [Accepted: 03/07/2016] [Indexed: 10/21/2022]
Abstract
To achieve greatest efficacy, therapies for attenuating fear and anxiety should preclude the re-emergence of emotional responses. Of relevance to this aim, preclinical models of threat memory reduction are considered to engage one of two discrete neural processes: either establishment of a new behavioral response that competes with, and thereby temporarily interferes with the expression of, threat memory (new learning) or one that modifies and thereby disrupts threat memory (unlearning). We contend that a strict dichotomy of new learning and unlearning does not provide a compelling explanation for current data. Instead, we suggest that the evidence warrants consideration of alternative models that assume cooperation rather than competition between formation of new cellular traces and the modification of preexisting ones.
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Affiliation(s)
- Roger L Clem
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Daniela Schiller
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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230
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Abstract
Fear memory is the best-studied form of memory. It was thoroughly investigated in the past 60 years mostly using two classical conditioning procedures (contextual fear conditioning and fear conditioning to a tone) and one instrumental procedure (one-trial inhibitory avoidance). Fear memory is formed in the hippocampus (contextual conditioning and inhibitory avoidance), in the basolateral amygdala (inhibitory avoidance), and in the lateral amygdala (conditioning to a tone). The circuitry involves, in addition, the pre- and infralimbic ventromedial prefrontal cortex, the central amygdala subnuclei, and the dentate gyrus. Fear learning models, notably inhibitory avoidance, have also been very useful for the analysis of the biochemical mechanisms of memory consolidation as a whole. These studies have capitalized on in vitro observations on long-term potentiation and other kinds of plasticity. The effect of a very large number of drugs on fear learning has been intensively studied, often as a prelude to the investigation of effects on anxiety. The extinction of fear learning involves to an extent a reversal of the flow of information in the mentioned structures and is used in the therapy of posttraumatic stress disorder and fear memories in general.
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Affiliation(s)
- Ivan Izquierdo
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Cristiane R. G. Furini
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Jociane C. Myskiw
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
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231
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Kuzniewska B, Nader K, Dabrowski M, Kaczmarek L, Kalita K. Adult Deletion of SRF Increases Epileptogenesis and Decreases Activity-Induced Gene Expression. Mol Neurobiol 2016; 53:1478-1493. [PMID: 25636686 PMCID: PMC4789231 DOI: 10.1007/s12035-014-9089-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 12/29/2014] [Indexed: 11/27/2022]
Abstract
Although the transcription factor serum response factor (SRF) has been suggested to play a role in activity-dependent gene expression and mediate plasticity-associated structural changes in the hippocampus, no unequivocal evidence has been provided for its role in brain pathology, such as epilepsy. A genome-wide program of activity-induced genes that are regulated by SRF also remains unknown. In the present study, we show that the inducible and conditional deletion of SRF in the adult mouse hippocampus increases the epileptic phenotype in the kainic acid model of epilepsy, reflected by more severe and frequent seizures. Moreover, we observe a robust decrease in activity-induced gene transcription in SRF knockout mice. We characterize the genetic program controlled by SRF in neurons and using functional annotation, we find that SRF target genes are associated with synaptic plasticity and epilepsy. Several of these SRF targets function as regulators of inhibitory or excitatory balance and the structural plasticity of neurons. Interestingly, mutations in those SRF targets have found to be associated with such human neuropsychiatric disorders, as autism and intellectual disability. We also identify novel direct SRF targets in hippocampus: Npas4, Gadd45g, and Zfp36. Altogether, our data indicate that proteins that are highly upregulated by neuronal stimulation, identified in the present study as SRF targets, may function as endogenous protectors against overactivation. Thus, the lack of these effector proteins in SRF knockout animals may lead to uncontrolled excitation and eventually epilepsy.
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Affiliation(s)
- Bozena Kuzniewska
- Laboratory of Neurobiology, Nencki Institute, 3 Pasteur Street, Warsaw, Poland
| | - Karolina Nader
- Laboratory of Neurobiology, Nencki Institute, 3 Pasteur Street, Warsaw, Poland
| | - Michal Dabrowski
- Laboratory of Bioinformatics, Neurobiology Center, Nencki Institute, 3 Pasteur Street, Warsaw, Poland
| | - Leszek Kaczmarek
- Laboratory of Neurobiology, Nencki Institute, 3 Pasteur Street, Warsaw, Poland
| | - Katarzyna Kalita
- Laboratory of Neurobiology, Nencki Institute, 3 Pasteur Street, Warsaw, Poland.
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232
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Vernon J, Irvine EE, Peters M, Jeyabalan J, Giese KP. Phosphorylation of K+ channels at single residues regulates memory formation. ACTA ACUST UNITED AC 2016; 23:174-81. [PMID: 26980786 PMCID: PMC4793203 DOI: 10.1101/lm.040816.115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/29/2016] [Indexed: 02/07/2023]
Abstract
Phosphorylation is a ubiquitous post-translational modification of proteins, and a known physiological regulator of K+ channel function. Phosphorylation of K+ channels by kinases has long been presumed to regulate neuronal processing and behavior. Although circumstantial evidence has accumulated from behavioral studies of vertebrates and invertebrates, the contribution to memory of single phosphorylation sites on K+ channels has never been reported. We have used gene targeting in mice to inactivate protein kinase A substrate residues in the fast-inactivating subunit Kv4.2 (T38A mutants), and in the small-conductance Ca2+-activated subunit SK1 (S105A mutants). Both manipulations perturbed a specific form of memory, leaving others intact. T38A mutants had enhanced spatial memory for at least 4 wk after training, whereas performance in three tests of fear memory was unaffected. S105A mutants were impaired in passive avoidance memory, sparing fear, and spatial memory. Together with recent findings that excitability governs the participation of neurons in a memory circuit, this result suggests that the memory type supported by neurons may depend critically on the phosphorylation of specific K+ channels at single residues.
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Affiliation(s)
- Jeffrey Vernon
- Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom
| | - Elaine E Irvine
- Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom MRC Clinical Sciences Centre, Imperial College London, Hammersmith Campus, London W12 ONN, United Kingdom
| | - Marco Peters
- Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom Dart Neuroscience, 12278 Scripps Summit Drive, San Diego, California 92131, USA
| | - Jeshmi Jeyabalan
- Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom
| | - K Peter Giese
- Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom Centre for the Cellular Basis of Behaviour, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9NU, United Kingdom
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233
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Feng F, Samarth P, Paré D, Nair SS. Mechanisms underlying the formation of the amygdalar fear memory trace: A computational perspective. Neuroscience 2016; 322:370-6. [PMID: 26944604 DOI: 10.1016/j.neuroscience.2016.02.059] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 02/19/2016] [Accepted: 02/24/2016] [Indexed: 12/24/2022]
Abstract
Recent experimental and modeling studies on the lateral amygdala (LA) have implicated intrinsic excitability and competitive synaptic interactions among principal neurons (PNs) in the formation of auditory fear memories. The present modeling studies, conducted over an expanded range of intrinsic excitability in the network, revealed that only excitable PNs that received tone inputs participate in the competition. Strikingly, the number of model PNs integrated into the fear memory trace remained constant despite the much larger range considered, and model runs highlighted several conditioning-induced tone responsive characteristics of the various PN populations. Furthermore, these studies showed that although excitation was important, disynaptic inhibition among PNs is the dominant mechanism that keeps the number of plastic PNs stable despite large variations in the network's excitability. Finally, we found that the overall level of inhibition in the model network determines the number of projection cells integrated into the fear memory trace.
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Affiliation(s)
- F Feng
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, MO, USA
| | - P Samarth
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, MO, USA
| | - D Paré
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - S S Nair
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, MO, USA.
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234
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Gouty-Colomer LA, Hosseini B, Marcelo IM, Schreiber J, Slump DE, Yamaguchi S, Houweling AR, Jaarsma D, Elgersma Y, Kushner SA. Arc expression identifies the lateral amygdala fear memory trace. Mol Psychiatry 2016; 21:364-75. [PMID: 25802982 PMCID: PMC4759206 DOI: 10.1038/mp.2015.18] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 11/28/2014] [Accepted: 01/08/2015] [Indexed: 12/21/2022]
Abstract
Memories are encoded within sparsely distributed neuronal ensembles. However, the defining cellular properties of neurons within a memory trace remain incompletely understood. Using a fluorescence-based Arc reporter, we were able to visually identify the distinct subset of lateral amygdala (LA) neurons activated during auditory fear conditioning. We found that Arc-expressing neurons have enhanced intrinsic excitability and are preferentially recruited into newly encoded memory traces. Furthermore, synaptic potentiation of thalamic inputs to the LA during fear conditioning is learning-specific, postsynaptically mediated and highly localized to Arc-expressing neurons. Taken together, our findings validate the immediate-early gene Arc as a molecular marker for the LA neuronal ensemble recruited during fear learning. Moreover, these results establish a model of fear memory formation in which intrinsic excitability determines neuronal selection, whereas learning-related encoding is governed by synaptic plasticity.
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Affiliation(s)
- L A Gouty-Colomer
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - B Hosseini
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - I M Marcelo
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands,Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - J Schreiber
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - D E Slump
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - S Yamaguchi
- Division of Morphological Neuroscience, Gifu University Graduate School of Medicine, Gifu, Japan,PRESTO, Japan Science and Technology Agency (JST), Saitama, Japan
| | - A R Houweling
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - D Jaarsma
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Y Elgersma
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - S A Kushner
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands,Department of Psychiatry, Erasmus University Medical Center, Dr Molewaterplein 50, Ee-1442, Rotterdam, 3015 GE, The Netherlands. E-mail:
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235
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Structural, Synaptic, and Epigenetic Dynamics of Enduring Memories. Neural Plast 2016; 2016:3425908. [PMID: 26933513 PMCID: PMC4736770 DOI: 10.1155/2016/3425908] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/23/2015] [Accepted: 11/24/2015] [Indexed: 11/17/2022] Open
Abstract
Our memories are the records of the experiences we gain in our everyday life. Over time, they slowly transform from an initially unstable state into a long-lasting form. Many studies have been investigating from different aspects how a memory could persist for sometimes up to decades. In this review, we highlight three of the greatly addressed mechanisms that play a central role for a given memory to endure: the allocation of the memory to a given neuronal population and what brain areas are recruited for its storage; the structural changes that underlie memory persistence; and finally the epigenetic control of gene expression that might regulate and support memory perseverance. Examining such key properties of a memory is essential towards a finer understanding of its capacity to last.
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236
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Adult Hippocampal Neurogenesis, Fear Generalization, and Stress. Neuropsychopharmacology 2016; 41:24-44. [PMID: 26068726 PMCID: PMC4677119 DOI: 10.1038/npp.2015.167] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 05/29/2015] [Accepted: 06/05/2015] [Indexed: 12/21/2022]
Abstract
The generalization of fear is an adaptive, behavioral, and physiological response to the likelihood of threat in the environment. In contrast, the overgeneralization of fear, a cardinal feature of posttraumatic stress disorder (PTSD), manifests as inappropriate, uncontrollable expression of fear in neutral and safe environments. Overgeneralization of fear stems from impaired discrimination of safe from aversive environments or discernment of unlikely threats from those that are highly probable. In addition, the time-dependent erosion of episodic details of traumatic memories might contribute to their generalization. Understanding the neural mechanisms underlying the overgeneralization of fear will guide development of novel therapeutic strategies to combat PTSD. Here, we conceptualize generalization of fear in terms of resolution of interference between similar memories. We propose a role for a fundamental encoding mechanism, pattern separation, in the dentate gyrus (DG)-CA3 circuit in resolving interference between ambiguous or uncertain threats and in preserving episodic content of remote aversive memories in hippocampal-cortical networks. We invoke cellular-, circuit-, and systems-based mechanisms by which adult-born dentate granule cells (DGCs) modulate pattern separation to influence resolution of interference and maintain precision of remote aversive memories. We discuss evidence for how these mechanisms are affected by stress, a risk factor for PTSD, to increase memory interference and decrease precision. Using this scaffold we ideate strategies to curb overgeneralization of fear in PTSD.
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237
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Structural foundations of optogenetics: Determinants of channelrhodopsin ion selectivity. Proc Natl Acad Sci U S A 2015; 113:822-9. [PMID: 26699459 DOI: 10.1073/pnas.1523341113] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The structure-guided design of chloride-conducting channelrhodopsins has illuminated mechanisms underlying ion selectivity of this remarkable family of light-activated ion channels. The first generation of chloride-conducting channelrhodopsins, guided in part by development of a structure-informed electrostatic model for pore selectivity, included both the introduction of amino acids with positively charged side chains into the ion conduction pathway and the removal of residues hypothesized to support negatively charged binding sites for cations. Engineered channels indeed became chloride selective, reversing near -65 mV and enabling a new kind of optogenetic inhibition; however, these first-generation chloride-conducting channels displayed small photocurrents and were not tested for optogenetic inhibition of behavior. Here we report the validation and further development of the channelrhodopsin pore model via crystal structure-guided engineering of next-generation light-activated chloride channels (iC++) and a bistable variant (SwiChR++) with net photocurrents increased more than 15-fold under physiological conditions, reversal potential further decreased by another ∼ 15 mV, inhibition of spiking faithfully tracking chloride gradients and intrinsic cell properties, strong expression in vivo, and the initial microbial opsin channel-inhibitor-based control of freely moving behavior. We further show that inhibition by light-gated chloride channels is mediated mainly by shunting effects, which exert optogenetic control much more efficiently than the hyperpolarization induced by light-activated chloride pumps. The design and functional features of these next-generation chloride-conducting channelrhodopsins provide both chronic and acute timescale tools for reversible optogenetic inhibition, confirm fundamental predictions of the ion selectivity model, and further elucidate electrostatic and steric structure-function relationships of the light-gated pore.
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238
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Mayford M, Reijmers L. Exploring Memory Representations with Activity-Based Genetics. Cold Spring Harb Perspect Biol 2015; 8:a021832. [PMID: 26684182 DOI: 10.1101/cshperspect.a021832] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The brain is thought to represent specific memories through the activity of sparse and distributed neural ensembles. In this review, we examine the use of immediate early genes (IEGs), genes that are induced by neural activity, to specifically identify and genetically modify neurons activated naturally by environmental experience. Recent studies using this approach have identified cellular and molecular changes specific to neurons activated during learning relative to their inactive neighbors. By using opto- and chemogenetic regulators of neural activity, the neurons naturally recruited during learning can be artificially reactivated to directly test their role in coding external information. In contextual fear conditioning, artificial reactivation of learning-induced neural ensembles in the hippocampus or neocortex can substitute for the context itself. That is, artificial stimulation of these neurons can apparently cause the animals to "think" they are in the context. This represents a powerful approach to testing the principles by which the brain codes for the external world and how these circuits are modified with learning.
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Affiliation(s)
- Mark Mayford
- Molecular and Cellular Neurosciences Department, The Scripps Research Institute, La Jolla, California 92037
| | - Leon Reijmers
- Department of Neuroscience, School of Medicine, Tufts University, Boston, Massachusetts 02111
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Loh DH, Jami SA, Flores RE, Truong D, Ghiani CA, O'Dell TJ, Colwell CS. Misaligned feeding impairs memories. eLife 2015; 4. [PMID: 26652002 PMCID: PMC4729691 DOI: 10.7554/elife.09460] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 11/19/2015] [Indexed: 01/23/2023] Open
Abstract
Robust sleep/wake rhythms are important for health and cognitive function. Unfortunately, many people are living in an environment where their circadian system is challenged by inappropriate meal- or work-times. Here we scheduled food access to the sleep time and examined the impact on learning and memory in mice. Under these conditions, we demonstrate that the molecular clock in the master pacemaker, the suprachiasmatic nucleus (SCN), is unaltered while the molecular clock in the hippocampus is synchronized by the timing of food availability. This chronic circadian misalignment causes reduced hippocampal long term potentiation and total CREB expression. Importantly this mis-timed feeding resulted in dramatic deficits in hippocampal-dependent learning and memory. Our findings suggest that the timing of meals have far-reaching effects on hippocampal physiology and learned behaviour. DOI:http://dx.doi.org/10.7554/eLife.09460.001 Many processes within the body follow an approximately 24-hour cycle. In addition to patterns of sleep and wakefulness, such circadian rhythms help to regulate body temperature, blood pressure and hormone levels. They also affect when we feel hungry, when our muscles work most efficiently, and when we are mentally at our sharpest. A region of the brain called the suprachiasmatic nucleus (SCN) generates and maintains circadian rhythms, and thus acts as the body’s master clock. Daily exposure to light keeps the SCN synchronized with the 24-hour day/night cycle. However, most organs, from the heart to the pancreas, also possess their own clocks, which help to regulate organ-specific processes. These secondary clocks normally operate in synchrony with the SCN. Exposure to light has long been known to influence circadian rhythms. However, more recent evidence suggests that the timing of meals may also affect circadian clocks, particularly those within the digestive system. Loh et al. therefore decided to investigate whether eating outside normal waking hours would also affect other key physiological processes, specifically the cognitive processes of learning and memory. Mice normally consume most of their food after sunset. Loh et al. showed that rodents that were instead fed during the day performed less well on cognitive tests than other mice who received the same food at night. The daytime-fed mice showed changes in a region of the brain called the hippocampus, which supports learning and memory. In particular, daytime feeding changed the timing of the secondary circadian clock within the hippocampus, although it had no effect on the master clock in the SCN. Loh et al. therefore suggest that the misalignment of these circadian clocks impairs cognition. Further experiments are needed to determine whether a similar relationship exists between the timing of meals and cognitive performance in humans. If so, these findings will have implications for the many individuals whose mealtimes, for work or social reasons, are out of synchrony with their body clocks. DOI:http://dx.doi.org/10.7554/eLife.09460.002
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Affiliation(s)
- Dawn H Loh
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,UCLA Integrative Center for Learning and Memory, University of California, Los Angeles, Los Angeles, United States
| | - Shekib A Jami
- UCLA Integrative Center for Learning and Memory, University of California, Los Angeles, Los Angeles, United States.,Molecular, Cellular, and Integrative Physiology PhD Program, University of California, Los Angeles, Los Angeles, United States
| | - Richard E Flores
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Danny Truong
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Cristina A Ghiani
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Thomas J O'Dell
- UCLA Integrative Center for Learning and Memory, University of California, Los Angeles, Los Angeles, United States.,Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Christopher S Colwell
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,UCLA Integrative Center for Learning and Memory, University of California, Los Angeles, Los Angeles, United States
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240
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Johnston ST, Shtrahman M, Parylak S, Gonçalves JT, Gage FH. Paradox of pattern separation and adult neurogenesis: A dual role for new neurons balancing memory resolution and robustness. Neurobiol Learn Mem 2015; 129:60-8. [PMID: 26549627 DOI: 10.1016/j.nlm.2015.10.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/22/2015] [Accepted: 10/27/2015] [Indexed: 01/31/2023]
Abstract
Hippocampal adult neurogenesis is thought to subserve pattern separation, the process by which similar patterns of neuronal inputs are transformed into distinct neuronal representations, permitting the discrimination of highly similar stimuli in hippocampus-dependent tasks. However, the mechanism by which immature adult-born dentate granule neurons cells (abDGCs) perform this function remains unknown. Two theories of abDGC function, one by which abDGCs modulate and sparsify activity in the dentate gyrus and one by which abDGCs act as autonomous coding units, are generally suggested to be mutually exclusive. This review suggests that these two mechanisms work in tandem to dynamically regulate memory resolution while avoiding memory interference and maintaining memory robustness.
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Affiliation(s)
- Stephen T Johnston
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, United States
| | - Matthew Shtrahman
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, United States
| | - Sarah Parylak
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, United States
| | - J Tiago Gonçalves
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, United States
| | - Fred H Gage
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, United States.
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241
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Gründemann J, Lüthi A. Ensemble coding in amygdala circuits for associative learning. Curr Opin Neurobiol 2015; 35:200-6. [PMID: 26531780 DOI: 10.1016/j.conb.2015.10.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/06/2015] [Accepted: 10/07/2015] [Indexed: 01/18/2023]
Abstract
Associative fear learning in the basolateral amygdala (BLA) is crucial for an animal's survival upon environmental threats. BLA neurons are defined on the basis of their projection target, genetic markers, and associated function. BLA principal neuron responses to threat signaling stimuli are potentiated upon associative fear learning, which is tightly controlled by defined interneuron subpopulations. In addition, BLA population activity correlates with behavioral states and threat or safety signals. BLA neuronal ensembles activated by different behavioral signals can be identified using immediate early gene markers. The next challenge will be to determine the activity patterns and coding properties of defined BLA ensembles in relation to the whole neuronal population.
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Affiliation(s)
- Jan Gründemann
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Andreas Lüthi
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.
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242
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Ehrlich DE, Josselyn SA. Plasticity-related genes in brain development and amygdala-dependent learning. GENES BRAIN AND BEHAVIOR 2015; 15:125-43. [PMID: 26419764 DOI: 10.1111/gbb.12255] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/12/2015] [Accepted: 09/14/2015] [Indexed: 12/31/2022]
Abstract
Learning about motivationally important stimuli involves plasticity in the amygdala, a temporal lobe structure. Amygdala-dependent learning involves a growing number of plasticity-related signaling pathways also implicated in brain development, suggesting that learning-related signaling in juveniles may simultaneously influence development. Here, we review the pleiotropic functions in nervous system development and amygdala-dependent learning of a signaling pathway that includes brain-derived neurotrophic factor (BDNF), extracellular signaling-related kinases (ERKs) and cyclic AMP-response element binding protein (CREB). Using these canonical, plasticity-related genes as an example, we discuss the intersection of learning-related and developmental plasticity in the immature amygdala, when aversive and appetitive learning may influence the developmental trajectory of amygdala function. We propose that learning-dependent activation of BDNF, ERK and CREB signaling in the immature amygdala exaggerates and accelerates neural development, promoting amygdala excitability and environmental sensitivity later in life.
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Affiliation(s)
- D E Ehrlich
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Langone Medical Center, New York, NY, USA.,Department of Otolaryngology, NYU Langone School of Medicine, New York, NY, USA
| | - S A Josselyn
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, ON, Canada.,Department of Psychology, University of Toronto, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
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243
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Letzkus J, Wolff S, Lüthi A. Disinhibition, a Circuit Mechanism for Associative Learning and Memory. Neuron 2015; 88:264-76. [PMID: 26494276 DOI: 10.1016/j.neuron.2015.09.024] [Citation(s) in RCA: 235] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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244
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245
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Ortega-Martínez S. A new perspective on the role of the CREB family of transcription factors in memory consolidation via adult hippocampal neurogenesis. Front Mol Neurosci 2015; 8:46. [PMID: 26379491 PMCID: PMC4549561 DOI: 10.3389/fnmol.2015.00046] [Citation(s) in RCA: 164] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 08/11/2015] [Indexed: 12/21/2022] Open
Abstract
Adult neurogenesis is the process by which new neurons are generated in the brains of adults. Since its discovery 50 years ago, adult neurogenesis has been widely studied in the mammalian brain and has provided a new perspective on the pathophysiology of many psychiatric and neurodegenerative disorders, some of which affect memory. In this regard, adult hippocampal neurogenesis (AHN), which occurs in the subgranular zone (SGZ) of the dentate gyrus (DG), has been suggested to play a role in the formation and consolidation of new memories. This process involves many transcription factors, of which cyclic AMP (cAMP)-responsive element-binding protein (CREB) is a well-documented one. In the developing brain, CREB regulates crucial cell stages (e.g., proliferation, differentiation, and survival), and in the adult brain, it participates in neuronal plasticity, learning, and memory. In addition, new evidence supports the hypothesis that CREB may also participate in learning and memory through its involvement in AHN. This review examines the CREB family of transcription factors, including the different members and known signaling pathways. It highlights the role of CREB as a modulator of AHN, which could underlie its function in memory consolidation mechanisms.
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Affiliation(s)
- Sylvia Ortega-Martínez
- Turku Centre for Biotechnology, Åbo Akademi University and University of Turku Turku, Finland
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246
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247
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Memory engram storage and retrieval. Curr Opin Neurobiol 2015; 35:101-9. [PMID: 26280931 DOI: 10.1016/j.conb.2015.07.009] [Citation(s) in RCA: 216] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 07/28/2015] [Accepted: 07/29/2015] [Indexed: 12/28/2022]
Abstract
A great deal of experimental investment is directed towards questions regarding the mechanisms of memory storage. Such studies have traditionally been restricted to investigation of the anatomical structures, physiological processes, and molecular pathways necessary for the capacity of memory storage, and have avoided the question of how individual memories are stored in the brain. Memory engram technology allows the labeling and subsequent manipulation of components of specific memory engrams in particular brain regions, and it has been established that cell ensembles labeled by this method are both sufficient and necessary for memory recall. Recent research has employed this technology to probe fundamental questions of memory consolidation, differentiating between mechanisms of memory retrieval from the true neurobiology of memory storage.
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248
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Piechota M, Golda S, Ficek J, Jantas D, Przewlocki R, Korostynski M. Regulation of alternative gene transcription in the striatum in response to antidepressant drugs. Neuropharmacology 2015; 99:328-36. [PMID: 26254862 DOI: 10.1016/j.neuropharm.2015.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 05/21/2015] [Accepted: 08/03/2015] [Indexed: 12/13/2022]
Abstract
The mechanisms that control the selection of transcription initiation and termination sites in response to pharmacological stimulation of neuronal cells are poorly understood. We used next-generation sequencing and bioinformatics to construct a genome-wide inventory of protein-coding and non-coding transcripts altered by antidepressant treatment. We analyzed available ChIP-seq data to identify mechanisms that control drug-inducible expression of alternative gene variants in the brain. We identified 153 transcripts of various biotypes regulated in the mouse striatum in response to tranylcypromine or mianserin (at a 0.1% FDR threshold). Five drug-responsive gene patterns are enriched in protein-coding variants (77%), regulated by different sets of transcriptional factors (including SRF/CREB1 and GR/CTCF) and expressed in separate cellular compartments of the brain. We found that alterations mediated by proximal promoters in neurons are more specific in the selection of regulated transcriptional isoforms compared with enhancer-dependent alterations in glia. The change in transcriptional programs, from housekeeping to inducible, provides cells with the resource of functionally distinct proteins. We conclude that the regulation of drug-induced brain plasticity may occur at the level of transcripts rather than genes. The expression of specific isoforms in response to antidepressants may constitute a trigger that initiates the long-lasting effects of these drugs.
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Affiliation(s)
- Marcin Piechota
- Department of Molecular Neuropharmacology, Institute of Pharmacology PAS, Krakow, Poland
| | - Slawomir Golda
- Department of Molecular Neuropharmacology, Institute of Pharmacology PAS, Krakow, Poland
| | - Joanna Ficek
- Department of Molecular Neuropharmacology, Institute of Pharmacology PAS, Krakow, Poland
| | - Danuta Jantas
- Department of Experimental Neuroendocrinology, Institute of Pharmacology PAS, Krakow, Poland
| | - Ryszard Przewlocki
- Department of Molecular Neuropharmacology, Institute of Pharmacology PAS, Krakow, Poland; Department of Neurobiology and Neuropsychology, IPS, UJ, Krakow, Poland
| | - Michal Korostynski
- Department of Molecular Neuropharmacology, Institute of Pharmacology PAS, Krakow, Poland.
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Abstract
Decades of research has identified the brain areas that are involved in fear, fear extinction, anxiety and related defensive behaviours. Newly developed genetic and viral tools, optogenetics and advanced in vivo imaging techniques have now made it possible to characterize the activity, connectivity and function of specific cell types within complex neuronal circuits. Recent findings that have been made using these tools and techniques have provided mechanistic insights into the exquisite organization of the circuitry underlying internal defensive states. This Review focuses on studies that have used circuit-based approaches to gain a more detailed, and also more comprehensive and integrated, view on how the brain governs fear and anxiety and how it orchestrates adaptive defensive behaviours.
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Affiliation(s)
- Philip Tovote
- 1] Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland. [2]
| | - Jonathan Paul Fadok
- 1] Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland. [2]
| | - Andreas Lüthi
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
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250
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Norepinephrine ignites local hotspots of neuronal excitation: How arousal amplifies selectivity in perception and memory. Behav Brain Sci 2015; 39:e200. [PMID: 26126507 DOI: 10.1017/s0140525x15000667] [Citation(s) in RCA: 328] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Emotional arousal enhances perception and memory of high-priority information but impairs processing of other information. Here, we propose that, under arousal, local glutamate levels signal the current strength of a representation and interact with norepinephrine (NE) to enhance high priority representations and out-compete or suppress lower priority representations. In our "glutamate amplifies noradrenergic effects" (GANE) model, high glutamate at the site of prioritized representations increases local NE release from the locus coeruleus (LC) to generate "NE hotspots." At these NE hotspots, local glutamate and NE release are mutually enhancing and amplify activation of prioritized representations. In contrast, arousal-induced LC activity inhibits less active representations via two mechanisms: 1) Where there are hotspots, lateral inhibition is amplified; 2) Where no hotspots emerge, NE levels are only high enough to activate low-threshold inhibitory adrenoreceptors. Thus, LC activation promotes a few hotspots of excitation in the context of widespread suppression, enhancing high priority representations while suppressing the rest. Hotspots also help synchronize oscillations across neural ensembles transmitting high-priority information. Furthermore, brain structures that detect stimulus priority interact with phasic NE release to preferentially route such information through large-scale functional brain networks. A surge of NE before, during, or after encoding enhances synaptic plasticity at NE hotspots, triggering local protein synthesis processes that enhance selective memory consolidation. Together, these noradrenergic mechanisms promote selective attention and memory under arousal. GANE not only reconciles apparently contradictory findings in the emotion-cognition literature but also extends previous influential theories of LC neuromodulation by proposing specific mechanisms for how LC-NE activity increases neural gain.
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