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Samona EA, Chowdury A, Kopchick J, Thomas P, Rajan U, Khatib D, Zajac-Benitez C, Amirsadri A, Haddad L, Stanley JA, Diwadkar VA. The importance of covert memory consolidation in schizophrenia: Dysfunctional network profiles of the hippocampus and the dorsolateral prefrontal cortex. Psychiatry Res Neuroimaging 2024; 340:111805. [PMID: 38447230 PMCID: PMC11188056 DOI: 10.1016/j.pscychresns.2024.111805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 01/24/2024] [Accepted: 02/20/2024] [Indexed: 03/08/2024]
Abstract
Altered brain network profiles in schizophrenia (SCZ) during memory consolidation are typically observed during task-active periods such as encoding or retrieval. However active processes are also sub served by covert periods of memory consolidation. These periods are active in that they allow memories to be recapitulated even in the absence of overt sensorimotor processing. It is plausible that regions central to memory formation like the dlPFC and the hippocampus, exert network signatures during covert periods. Are these signatures altered in patients? The question is clinically relevant because real world learning and memory is facilitated by covert processing, and may be impaired in schizophrenia. Here, we compared network signatures of the dlPFC and the hippocampus during covert periods of a learning and memory task. Because behavioral proficiency increased non-linearly, functional connectivity of the dlPFC and hippocampus [psychophysiological interaction (PPI)] was estimated for each of the Early (linear increases in performance) and Late (asymptotic performance) covert periods. During Early periods, we observed hypo-modulation by the hippocampus but hyper-modulation by dlPFC. Conversely, during Late periods, we observed hypo-modulation by both the dlPFC and the hippocampus. We stitch these results into a conceptual model of network deficits during covert periods of memory consolidation.
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Affiliation(s)
- Elias A Samona
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Asadur Chowdury
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - John Kopchick
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Patricia Thomas
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Usha Rajan
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Dalal Khatib
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Caroline Zajac-Benitez
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Alireza Amirsadri
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Luay Haddad
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Jeffrey A Stanley
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Vaibhav A Diwadkar
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States.
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2
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Lopez MR, Wasberg SMH, Gagliardi CM, Normandin ME, Muzzio IA. Mystery of the memory engram: History, current knowledge, and unanswered questions. Neurosci Biobehav Rev 2024; 159:105574. [PMID: 38331127 DOI: 10.1016/j.neubiorev.2024.105574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/22/2023] [Accepted: 02/03/2024] [Indexed: 02/10/2024]
Abstract
The quest to understand the memory engram has intrigued humans for centuries. Recent technological advances, including genetic labelling, imaging, optogenetic and chemogenetic techniques, have propelled the field of memory research forward. These tools have enabled researchers to create and erase memory components. While these innovative techniques have yielded invaluable insights, they often focus on specific elements of the memory trace. Genetic labelling may rely on a particular immediate early gene as a marker of activity, optogenetics may activate or inhibit one specific type of neuron, and imaging may capture activity snapshots in a given brain region at specific times. Yet, memories are multifaceted, involving diverse arrays of neuronal subpopulations, circuits, and regions that work in concert to create, store, and retrieve information. Consideration of contributions of both excitatory and inhibitory neurons, micro and macro circuits across brain regions, the dynamic nature of active ensembles, and representational drift is crucial for a comprehensive understanding of the complex nature of memory.
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Affiliation(s)
- M R Lopez
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine and Science, Rochester, MN, United States
| | - S M H Wasberg
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - C M Gagliardi
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - M E Normandin
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - I A Muzzio
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA 52242, USA.
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3
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Krasne FB, Fanselow MS. Remote memory in a Bayesian model of context fear conditioning (BaconREM). Front Behav Neurosci 2024; 17:1295969. [PMID: 38515786 PMCID: PMC10955142 DOI: 10.3389/fnbeh.2023.1295969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 12/13/2023] [Indexed: 03/23/2024] Open
Abstract
Here, we propose a model of remote memory (BaconREM), which is an extension of a previously published Bayesian model of context fear learning (BACON) that accounts for many aspects of recently learned context fear. BaconREM simulates most known phenomenology of remote context fear as studied in rodents and makes new predictions. In particular, it predicts the well-known observation that fear that was conditioned to a recently encoded context becomes hippocampus-independent and shows much-enhanced generalization ("hyper-generalization") when systems consolidation occurs (i.e., when memory becomes remote). However, the model also predicts that there should be circumstances under which the generalizability of remote fear may not increase or even decrease. It also predicts the established finding that a "reminder" exposure to a feared context can abolish hyper-generalization while at the same time making remote fear again hippocampus-dependent. This observation has in the past been taken to suggest that reminders facilitate access to detail memory that remains permanently in the hippocampus even after systems consolidation is complete. However, the present model simulates this result even though it totally moves all the contextual memory that it retains to the neo-cortex when context fear becomes remote.
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Affiliation(s)
- Franklin B. Krasne
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, United States
- Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Michael S. Fanselow
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, United States
- Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, United States
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Naffaa MM. Significance of the anterior cingulate cortex in neurogenesis plasticity: Connections, functions, and disorders across postnatal and adult stages. Bioessays 2024; 46:e2300160. [PMID: 38135889 DOI: 10.1002/bies.202300160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 12/12/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023]
Abstract
The anterior cingulate cortex (ACC) is a complex and continually evolving brain region that remains a primary focus of research due to its multifaceted functions. Various studies and analyses have significantly advanced our understanding of how the ACC participates in a wide spectrum of memory and cognitive processes. However, despite its strong connections to brain areas associated with hippocampal and olfactory neurogenesis, the functions of the ACC in regulating postnatal and adult neurogenesis in these regions are still insufficiently explored. Investigating the intricate involvement of the ACC in neurogenesis could enhance our comprehension of essential aspects of brain plasticity. This involvement stems from its complex circuitry with other relevant brain regions, thereby exerting both direct and indirect impacts on the neurogenesis process. This review sheds light on the promising significance of the ACC in orchestrating postnatal and adult neurogenesis in conditions related to memory, cognitive behavior, and associated disorders.
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Affiliation(s)
- Moawiah M Naffaa
- Department of Psychology and Neuroscience, Duke University, Durham, North Carolina, USA
- Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina, USA
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5
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Guskjolen A, Cembrowski MS. Engram neurons: Encoding, consolidation, retrieval, and forgetting of memory. Mol Psychiatry 2023; 28:3207-3219. [PMID: 37369721 PMCID: PMC10618102 DOI: 10.1038/s41380-023-02137-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 06/02/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023]
Abstract
Tremendous strides have been made in our understanding of the neurobiological substrates of memory - the so-called memory "engram". Here, we integrate recent progress in the engram field to illustrate how engram neurons transform across the "lifespan" of a memory - from initial memory encoding, to consolidation and retrieval, and ultimately to forgetting. To do so, we first describe how cell-intrinsic properties shape the initial emergence of the engram at memory encoding. Second, we highlight how these encoding neurons preferentially participate in synaptic- and systems-level consolidation of memory. Third, we describe how these changes during encoding and consolidation guide neural reactivation during retrieval, and facilitate memory recall. Fourth, we describe neurobiological mechanisms of forgetting, and how these mechanisms can counteract engram properties established during memory encoding, consolidation, and retrieval. Motivated by recent experimental results across these four sections, we conclude by proposing some conceptual extensions to the traditional view of the engram, including broadening the view of cell-type participation within engrams and across memory stages. In collection, our review synthesizes general principles of the engram across memory stages, and describes future avenues to further understand the dynamic engram.
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Affiliation(s)
- Axel Guskjolen
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada.
| | - Mark S Cembrowski
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada.
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada.
- Department of Mathematics, University of British Columbia, Vancouver, BC, Canada.
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Correa-Netto NF, Masukawa MY, Silva-Gomes AM, Linardi A, Santos-Junior JG. Memory reactivation mediates emotional valence updating of contextual memory in mice with protracted morphine withdrawal. Behav Brain Res 2023; 438:114212. [PMID: 36370948 DOI: 10.1016/j.bbr.2022.114212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/29/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022]
Abstract
Mice subjected to morphine locomotor sensitization develop increased anxiety-behavior expression during protracted morphine withdrawal. This behavioral change is dependent on reexposure to the context of locomotor sensitization and reflects a state of conditioned anxiety. In this study, the effect of memory reconsolidation on the expression of conditioned anxiety in mice with protracted morphine withdrawal was examined. Five experimental protocols involving male C57BL/6 mice were used in which the animals were subjected to locomotor sensitization induced by morphine and reexposed to the context associated with the drug effect 28 days after locomotor sensitization and immediately after subjected to elevated plus maze. In experiment 1, mice were subjected or not to memory reactivation session and was observed that memory reactivation 27 days after sensitization reduced conditioned anxiety. In experiment 2, mice were subjected to memory reactivation, 24 h, 6 h or 1 h before contextual reexposure, and the effect of memory reactivation coincided with the temporal requirement for reconsolidation. In experiment 3, which involved exposure to a situation of acute stress immediately before memory reactivation, the mice demonstrated a return to increased conditioned anxiety. To confirm the influence of reconsolidation, in experiments 4 and 5, mice subjected to memory reactivation were treated with Nimodipine, diazepam or cyclohexamine, substances commonly used as pharmacological controls in reconsolidation experiments. Treatment with each substance separately inhibited the effect of reactivation in experiment 5 (presence of acute stressor) but not in experiment 4 (absence of acute stressor). These results suggest that, in our experimental model, reconsolidation is mediated through updating of the emotional valence of contextual memory associated with the administration of morphine.
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Affiliation(s)
- Nelson Francisco Correa-Netto
- Department of Physiological Sciences, Santa Casa of São Paulo Medical School, Rua Cesário Mota Junior, 61, Vila Buarque, São Paulo 01221-020, SP, Brazil.
| | - Márcia Yuriko Masukawa
- Department of Physiological Sciences, Santa Casa of São Paulo Medical School, Rua Cesário Mota Junior, 61, Vila Buarque, São Paulo 01221-020, SP, Brazil
| | - Alessandro Marcos Silva-Gomes
- Department of Physiological Sciences, Santa Casa of São Paulo Medical School, Rua Cesário Mota Junior, 61, Vila Buarque, São Paulo 01221-020, SP, Brazil
| | - Alessandra Linardi
- Department of Physiological Sciences, Santa Casa of São Paulo Medical School, Rua Cesário Mota Junior, 61, Vila Buarque, São Paulo 01221-020, SP, Brazil
| | - Jair Guilherme Santos-Junior
- Department of Physiological Sciences, Santa Casa of São Paulo Medical School, Rua Cesário Mota Junior, 61, Vila Buarque, São Paulo 01221-020, SP, Brazil
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7
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Tomé DF, Sadeh S, Clopath C. Coordinated hippocampal-thalamic-cortical communication crucial for engram dynamics underneath systems consolidation. Nat Commun 2022; 13:840. [PMID: 35149680 PMCID: PMC8837777 DOI: 10.1038/s41467-022-28339-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 01/13/2022] [Indexed: 11/09/2022] Open
Abstract
Systems consolidation refers to the time-dependent reorganization of memory representations or engrams across brain regions. Despite recent advancements in unravelling this process, the exact mechanisms behind engram dynamics and the role of associated pathways remain largely unknown. Here we propose a biologically-plausible computational model to address this knowledge gap. By coordinating synaptic plasticity timescales and incorporating a hippocampus-thalamus-cortex circuit, our model is able to couple engram reactivations across these regions and thereby reproduce key dynamics of cortical and hippocampal engram cells along with their interdependencies. Decoupling hippocampal-thalamic-cortical activity disrupts systems consolidation. Critically, our model yields testable predictions regarding hippocampal and thalamic engram cells, inhibitory engrams, thalamic inhibitory input, and the effect of thalamocortical synaptic coupling on retrograde amnesia induced by hippocampal lesions. Overall, our results suggest that systems consolidation emerges from coupled reactivations of engram cells in distributed brain regions enabled by coordinated synaptic plasticity timescales in multisynaptic subcortical-cortical circuits.
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Affiliation(s)
| | - Sadra Sadeh
- Department of Bioengineering, Imperial College London, London, UK
| | - Claudia Clopath
- Department of Bioengineering, Imperial College London, London, UK.
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8
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Duran JM, Sierra RO, Corredor K, Cardenas FP. Cathodal transcranial direct current stimulation on the prefrontal cortex applied after reactivation attenuates fear memories and prevent reinstatement after extinction. J Psychiatr Res 2021; 145:213-221. [PMID: 34929471 DOI: 10.1016/j.jpsychires.2021.12.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 12/04/2021] [Accepted: 12/11/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND In the last decade, pharmacological strategies targeting reconsolidation after memory retrieval have shown promising efforts to attenuate persistent memories and overcome fear recovery. However, most reconsolidation inhibiting agents have not been approved for human testing. While non-invasive neuromodulation can be considered an alternative approach to pharmacological treatments, there is a lack of evidence about the efficacy of these technologies when modifying memory traces via reactivation/reconsolidation mechanism. OBJECTIVE In this study, we evaluate the effect of cathodal (c-tDCS) and anodal (a-DCS) transcranial direct current stimulation applied after memory reactivation and extinction in rats. METHODS Male Wistar rats were randomly assigned into three groups: one sham group, one anodal tDCS group, and one cathodal tDCS group (500 μA, 20 min). Reconsolidation and extinction of fear memories were evaluated using a contextual fear conditioning. RESULTS Our results showed that c-tDCS and a-tDCS after memory reactivation can attenuate mild fear memories. However, only c-tDCS stimulation prevented both fear expression under strong fear learning and fear recovery after a reinstatement protocol without modification of learning rate or extinction retrieval. Nevertheless, the remote memories were resistant to modification through this type of neuromodulation. Our results are discussed considering the interaction between intrinsic excitability promoted by learning and memory retrieval and the electric field applied during tDCS. CONCLUSION These results point out some of the boundary conditions influencing the efficacy of tDCS in fear attenuation and open new ways for the development of noninvasive interventions aimed to control fear-related disorders via reconsolidation.
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Affiliation(s)
- Johanna M Duran
- Laboratory of Neuroscience and Behavior, Department of Psychology, Universidad de Los Andes, Colombia.
| | | | - Karen Corredor
- Laboratory of Neuroscience and Behavior, Department of Psychology, Universidad de Los Andes, Colombia
| | - Fernando P Cardenas
- Laboratory of Neuroscience and Behavior, Department of Psychology, Universidad de Los Andes, Colombia.
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Gisquet-Verrier P, Riccio DC. Revisiting systems consolidation and the concept of consolidation. Neurosci Biobehav Rev 2021; 132:420-432. [PMID: 34875279 DOI: 10.1016/j.neubiorev.2021.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 11/06/2021] [Accepted: 12/02/2021] [Indexed: 10/19/2022]
Abstract
For more than 50 years, knowledge of memory processes has been based on the consolidation hypothesis, which postulates that new memories require time to become stabilized. Two forms of the consolidation model exist. The Cellular Consolidation concept is based upon retrograde amnesia induced by amnesic treatments, the severity of which decreases as the learning to treatment increases over minutes or hours. In contrast, The Systems Consolidation model is based on post-training hippocampal lesions, which produce more severe retrograde amnesia when induced after days than after weeks. Except for the temporal parameters, Cellular and Systems Consolidation show many similarities. Here we propose that Systems consolidation, much as Cellular Consolidation (see Gisquet- Verrier and Riccio, 2018), can be explained in terms of a form of state-dependency. Accordingly, lesions of the hippocampus induce a change in the internal state of the animal, which disrupts retrieval processes. But the effect of contextual change is known to decrease with the length of the retention intervals, consistent with time-dependent retrograde amnesia. We provide evidence supporting this new view.
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Affiliation(s)
| | - David C Riccio
- Department of Psychological Sciences, Kent State University, Kent, OH, 44242, USA
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10
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Lemaire JJ, Pontier B, Chaix R, El Ouadih Y, Khalil T, Sinardet D, Achim V, Postelnicu A, Coste J, Germain V, Sarret C, Sontheimer A. Neural correlates of consciousness and related disorders: From phenotypic descriptors of behavioral and relative consciousness to cortico-subcortical circuitry. Neurochirurgie 2021; 68:212-222. [PMID: 34051246 DOI: 10.1016/j.neuchi.2021.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/13/2021] [Accepted: 05/09/2021] [Indexed: 01/01/2023]
Abstract
We report a review of medical aspects of the consciousness. The behavioral dimension, phenotypic descriptors, relative consciousness and neural correlates of consciousness and related disorders were addressed successively in a holistic and chronological approach. Consciousness is relative, specific to each individual across time and space. Historically defined as the perception of the self and the environment, it cannot be separated from behaviors, entailing an idea of conscious behavior with metapractic and metagnostic aspects. Observation of spontaneous and evoked overt behavior distinguishes three main types of disorder of consciousness (DoC): coma, vegetative state or unresponsive wakefulness, and minimally conscious or relationally impoverished state. Modern functional exploration techniques, such as imaging, increase the understanding of DoCs and consciousness. Whether consciousness is a superior function and/or an instrumental function is discussed. Neural correlates can be subdivided into two wakefulness pathways (superior thalamic cholinergic and inferior extra-thalamic), and cortico-subcortical circuitry. The deep brain structures are those described in the well-known sensorimotor, associative and limbic loops, as illustrated in the mesolimbic model of DoC. The cortices can be segregated into several overlapping networks: (1) a global workspace including thalamo-cortical loops; (2) the default mode network (DMN) and related intrinsic connectivity networks (i.e., central executive, medial DMN and salience networks); (3) a 3-fold network comprising the fronto-parietal control system and its dorsal and ventral attentional sub-networks, the fronto-parietal executive control network, and the cingulo-opercular salience network; (4) the internal and external cortices, respectively medial, turned toward the self, and lateral, turned toward the environment. The network dynamics is the reflection of consciousness, notably anticorrelations such as the decrease in activity of the posterior cingulate-precuneus regions during attentional tasks. Thanks to recent advances in DoC pathophysiology, further significative therapeutic progress is expected, taking into account the societal context. This depends notably on the dissemination of medical knowledge and its transfer to a wider public.
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Affiliation(s)
- J-J Lemaire
- Service de neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France; Institut Pascal, université Clermont Auvergne CNRS SIGMA, Clermont-Ferrand, France.
| | - B Pontier
- Service de neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France; Institut Pascal, université Clermont Auvergne CNRS SIGMA, Clermont-Ferrand, France
| | - R Chaix
- Service de neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Y El Ouadih
- Service de neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - T Khalil
- Service de neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France; Institut Pascal, université Clermont Auvergne CNRS SIGMA, Clermont-Ferrand, France
| | - D Sinardet
- Service de neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - V Achim
- Service de neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - A Postelnicu
- Service de neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - J Coste
- Service de neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France; Institut Pascal, université Clermont Auvergne CNRS SIGMA, Clermont-Ferrand, France
| | - V Germain
- Service de neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France; Institut Pascal, université Clermont Auvergne CNRS SIGMA, Clermont-Ferrand, France
| | - C Sarret
- Institut Pascal, université Clermont Auvergne CNRS SIGMA, Clermont-Ferrand, France
| | - A Sontheimer
- Service de neurochirurgie, CHU Clermont-Ferrand, Clermont-Ferrand, France; Institut Pascal, université Clermont Auvergne CNRS SIGMA, Clermont-Ferrand, France
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11
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Intact Behavioral Expression of Contextual Fear, Context Discrimination, and Object Discrimination Memories Acquired in the Absence of the Hippocampus. J Neurosci 2021; 41:2437-2446. [PMID: 33303680 DOI: 10.1523/jneurosci.0546-20.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/07/2020] [Accepted: 06/21/2020] [Indexed: 11/21/2022] Open
Abstract
We test the hypothesis that the stability and precision of context and visual discrimination memories depend on interactions between the hippocampus (HPC) and other memory storage networks. In four experiments we tested the properties of memories acquired in the absence of the HPC. Long-Evans male rats were exclusively used in all experiments. Experiment 1 evaluated acquisition and retention of context fear memories in rats with prior partial or complete HPC damage. Confirming an earlier report (Zelikowsky et al., 2012) a very small but statistically reliable slowing in a single session of context fear conditioning was found after HPC damage. In contrast, retention of context fear memory was normal after HPC damage up to 30 d after learning. In experiment 2, we found that discrimination between a context paired with foot shocks and a different context never paired with foot shock was retained normally for 15 d. In experiment 3, we replicated the finding of intact context discrimination for at least 15 d in rats who display a significant impairment in acquisition of place learning in the Morris water task (MWT). In final experiment using an appetitive object discrimination task, we showed normal retention of the discrimination for at least 30 d after training in rats with complete HPC damage. These finding score against the idea that non HPC memory storage requires a period of interaction with HPC to establish a stable, precise memory.SIGNIFICANCE STATEMENT Contrary to expectations from systems memory consolidation, we find that in the absence of a functional hippocampus (HPC) context and visual memories are formed rapidly and exhibit normal persistence and precision. The findings suggest that the HPC is not obligatory for these features of long-term memories.
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12
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Krueger JN, Wilmot JH, Teratani-Ota Y, Puhger KR, Nemes SE, Crestani AP, Lafreniere MM, Wiltgen BJ. Amnesia for context fear is caused by widespread disruption of hippocampal activity. Neurobiol Learn Mem 2020; 175:107295. [PMID: 32822864 PMCID: PMC8562570 DOI: 10.1016/j.nlm.2020.107295] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/28/2020] [Accepted: 07/31/2020] [Indexed: 12/26/2022]
Abstract
The hippocampus plays an essential role in the formation and retrieval of episodic memories in humans and contextual memories in animals. However, amnesia is not always observed when this structure is compromised. To determine why this is the case, we compared the effects of several different circuit manipulations on memory retrieval and hippocampal activity. Mice were first trained on context fear conditioning and then optogenetic and chemogenetic tools were used to alter activity during memory retrieval. We found that retrieval was only impaired when manipulations caused widespread changes (increases or decreases) in hippocampal activity. Widespread increases occurred when pyramidal cells were excited and widespread decreases were found when GABAergic neurons were stimulated. Direct hyperpolarization of excitatory neurons only moderately reduced activity and did not produce amnesia. Surprisingly, widespread decreases in hippocampal activity did not prevent retrieval if they occurred gradually prior to testing. This suggests that intact brain regions can express contextual memories if they are given adequate time to compensate for the loss of the hippocampus.
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Affiliation(s)
- Jamie N Krueger
- Center for Neuroscience, University of California Davis, 1544 Newton Ct., Davis, CA 95618, United States.
| | - Jacob H Wilmot
- Department of Psychology, University of California Davis, 135 Young Hall, Davis, CA 95616, United States.
| | - Yusuke Teratani-Ota
- Department of Psychology, University of California Davis, 135 Young Hall, Davis, CA 95616, United States.
| | - Kyle R Puhger
- Department of Psychology, University of California Davis, 135 Young Hall, Davis, CA 95616, United States.
| | - Sonya E Nemes
- Center for Neuroscience, University of California Davis, 1544 Newton Ct., Davis, CA 95618, United States.
| | - Ana P Crestani
- Department of Psychology, University of California Davis, 135 Young Hall, Davis, CA 95616, United States.
| | - Marrisa M Lafreniere
- Center for Neuroscience, University of California Davis, 1544 Newton Ct., Davis, CA 95618, United States.
| | - Brian J Wiltgen
- Center for Neuroscience, University of California Davis, 1544 Newton Ct., Davis, CA 95618, United States; Department of Psychology, University of California Davis, 135 Young Hall, Davis, CA 95616, United States.
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13
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Norepinephrine and glucocorticoid effects on the brain mechanisms underlying memory accuracy and generalization. Mol Cell Neurosci 2020; 108:103537. [DOI: 10.1016/j.mcn.2020.103537] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/31/2020] [Accepted: 08/10/2020] [Indexed: 12/19/2022] Open
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14
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Baajour SJ, Chowdury A, Thomas P, Rajan U, Khatib D, Zajac-Benitez C, Falco D, Haddad L, Amirsadri A, Bressler S, Stanley JA, Diwadkar VA. Disordered directional brain network interactions during learning dynamics in schizophrenia revealed by multivariate autoregressive models. Hum Brain Mapp 2020; 41:3594-3607. [PMID: 32436639 PMCID: PMC7416040 DOI: 10.1002/hbm.25032] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 04/09/2020] [Accepted: 04/28/2020] [Indexed: 12/12/2022] Open
Abstract
Directional network interactions underpin normative brain function in key domains including associative learning. Schizophrenia (SCZ) is characterized by altered learning dynamics, yet dysfunctional directional functional connectivity (dFC) evoked during learning is rarely assessed. Here, nonlinear learning dynamics were induced using a paradigm alternating between conditions (Encoding and Retrieval). Evoked fMRI time series data were modeled using multivariate autoregressive (MVAR) models, to discover dysfunctional direction interactions between brain network constituents during learning stages (Early vs. Late), and conditions. A functionally derived subnetwork of coactivated (healthy controls [HC] ∩ SCZ] nodes was identified. MVAR models quantified directional interactions between pairs of nodes, and coefficients were evaluated for intergroup differences (HC ≠ SCZ). In exploratory analyses, we quantified statistical effects of neuroleptic dosage on performance and MVAR measures. During Early Encoding, SCZ showed reduced dFC within a frontal–hippocampal–fusiform network, though during Late Encoding reduced dFC was associated with pathways toward the dorsolateral prefrontal cortex (dlPFC). During Early Retrieval, SCZ showed increased dFC in pathways to and from the dorsal anterior cingulate cortex, though during Late Retrieval, patients showed increased dFC in pathways toward the dlPFC, but decreased dFC in pathways from the dlPFC. These discoveries constitute novel extensions of our understanding of task‐evoked dysconnection in schizophrenia and motivate understanding of the directional aspect of the dysconnection in schizophrenia. Disordered directionality should be investigated using computational psychiatric approaches that complement the MVAR method used in our work.
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Affiliation(s)
- Shahira J Baajour
- Department of Psychiatry and Behavioral Neuroscience, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Asadur Chowdury
- Department of Psychiatry and Behavioral Neuroscience, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Patricia Thomas
- Department of Psychiatry and Behavioral Neuroscience, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Usha Rajan
- Department of Psychiatry and Behavioral Neuroscience, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Dalal Khatib
- Department of Psychiatry and Behavioral Neuroscience, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Caroline Zajac-Benitez
- Department of Psychiatry and Behavioral Neuroscience, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Dimitri Falco
- Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, Florida, USA
| | - Luay Haddad
- Department of Psychiatry and Behavioral Neuroscience, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Alireza Amirsadri
- Department of Psychiatry and Behavioral Neuroscience, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Steven Bressler
- Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, Florida, USA.,Department of Psychology, Florida Atlantic University, Boca Raton, Florida, USA
| | - Jeffery A Stanley
- Department of Psychiatry and Behavioral Neuroscience, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Vaibhav A Diwadkar
- Department of Psychiatry and Behavioral Neuroscience, Wayne State University School of Medicine, Detroit, Michigan, USA
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15
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Mizuno K, Jeffries AR, Abel T, Giese KP. Long-lasting transcription in hippocampal area CA1 after contextual fear conditioning. Neurobiol Learn Mem 2020; 172:107250. [PMID: 32422278 DOI: 10.1016/j.nlm.2020.107250] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/27/2020] [Accepted: 05/12/2020] [Indexed: 01/25/2023]
Abstract
A fundamental question is how memory is stored for several weeks and even longer. A long-lasting increase in gene transcription has been suggested to mediate such long-term memory storage. Here, we used contextual fear conditioning in mice to search for lasting transcription that may contribute to long-term memory storage. Our study focussed on hippocampal area CA1, which has been suggested to have a role for at least one week in contextual fear memory. Using an unbiased microarray analysis followed by confirmatory quantitative real-time PCR, we identified an upregulation of two transcription factors, Fosl2 and Nfil3, which lasted for seven days after conditioning. To our knowledge these are the longest transcriptional changes ever detected in the hippocampus after contextual fear conditioning. Thus, our findings suggest novel transcriptional candidates for long-term memory storage.
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Affiliation(s)
- Keiko Mizuno
- Maurice Wohl Clinical Neuroscience Institute, Department of Basic and Clinical Neuroscience, King's College London, UK.
| | - Aaron R Jeffries
- Biosciences, College of Life and Environmental Sciences, Geoffrey Pope, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Ted Abel
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - K Peter Giese
- Maurice Wohl Clinical Neuroscience Institute, Department of Basic and Clinical Neuroscience, King's College London, UK.
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16
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Li C, Yang J. Role of the hippocampus in the spacing effect during memory retrieval. Hippocampus 2020; 30:703-714. [PMID: 32022387 DOI: 10.1002/hipo.23193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 12/19/2019] [Accepted: 01/05/2020] [Indexed: 11/11/2022]
Abstract
It is well known that distributed learning (DL) leads to improved memory performance compared with massed learning (ML) (i.e., spacing effect). However, the extent to which the hippocampus is involved in the spacing effect at shorter and longer retention intervals remains unclear. To address this issue, two groups of participants were asked to encode face-scene pairs at 20-min, 1-day, and 1-month intervals before they were scanned using fMRI during an associative recognition task. The pairs were repeated six times in either a massed (i.e., six times in 1 day) or a distributed (i.e., six times over 3 days, twice per day) manner. The results showed that compared with that in the ML group, the activation of the left hippocampus was stronger in the DL group when the participants retrieved old pairs correctly and rejected new pairs correctly at different retention intervals. In addition, the posterior hippocampus was more strongly activated when the new associations were rejected correctly after DL than ML, especially at the 1-month interval. Hence, our results provide evidence that the hippocampus is involved in better memory performance after DL compared to ML at both shorter and longer retention intervals.
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Affiliation(s)
- Cuihong Li
- School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| | - Jiongjiong Yang
- School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
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17
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Tronson NC, Keiser AA. A Dynamic Memory Systems Framework for Sex Differences in Fear Memory. Trends Neurosci 2019; 42:680-692. [PMID: 31473031 DOI: 10.1016/j.tins.2019.07.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 06/17/2019] [Accepted: 07/29/2019] [Indexed: 01/04/2023]
Abstract
Emerging research demonstrates that a pattern of overlapping but distinct molecular and circuit mechanisms are engaged by males and females during memory tasks. Importantly, sex differences in neural mechanisms and behavioral strategies are evident even when performance on a memory task is similar between females and males. We propose that sex differences in memory may be best understood within a dynamic memory systems framework. Specifically, sex differences in hormonal influences and neural circuit development result in biases in the circuits engaged and the information preferentially stored or retrieved in males and females. By using animal models to understand the neural networks and molecular mechanisms required for memory in both sexes, we can gain crucial insights into sex and gender biases in disorders including post-traumatic stress disorder (PTSD) in humans.
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Affiliation(s)
- Natalie C Tronson
- Psychology Department, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Ashley A Keiser
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
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18
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Yamawaki N, Corcoran KA, Guedea AL, Shepherd GMG, Radulovic J. Differential Contributions of Glutamatergic Hippocampal→Retrosplenial Cortical Projections to the Formation and Persistence of Context Memories. Cereb Cortex 2019; 29:2728-2736. [PMID: 29878069 PMCID: PMC6519694 DOI: 10.1093/cercor/bhy142] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/02/2018] [Indexed: 12/20/2022] Open
Abstract
Learning to associate stressful events with specific environmental contexts depends on excitatory transmission in the hippocampus, but how this information is transmitted to the neocortex for lasting memory storage is unclear. We identified dorsal hippocampal (DH) projections to the retrosplenial cortex (RSC), which arise mainly from the subiculum and contain either the vesicular glutamate transporter 1 (vGlut1) or vGlut2. Both vGlut1+ and vGlut2+ axons strongly excite and disynaptically inhibit RSC pyramidal neurons in superficial layers, but vGlut2+ axons trigger greater inhibition that spreads to deep layers, indicating that these pathways engage RSC circuits via partially redundant, partially differentiated cellular mechanisms. Using contextual fear conditioning in mice to model contextual associative memories, together with chemogenetic axonal silencing, we found that vGlut1+ projections are principally involved in processing recent context memories whereas vGlut2+ projections contribute to their long-lasting storage. Thus, within the DH→RSC pathway, engagement of vGlut1+ and vGlut2+ circuits differentially contribute to the formation and persistence of fear-inducing context memories.
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Affiliation(s)
- Naoki Yamawaki
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Kevin A Corcoran
- Department of Psychiatry and Behavioral Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Anita L Guedea
- Department of Psychiatry and Behavioral Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Gordon M G Shepherd
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Jelena Radulovic
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
- Department of Psychiatry and Behavioral Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
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19
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Anterior Cingulate Cortex to Ventral Hippocampus Circuit Mediates Contextual Fear Generalization. J Neurosci 2019; 39:5728-5739. [PMID: 31097621 DOI: 10.1523/jneurosci.2739-18.2019] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 04/29/2019] [Accepted: 05/11/2019] [Indexed: 12/29/2022] Open
Abstract
Contextual fear memory becomes less context-specific over time, a phenomenon referred to as contextual fear generalization. Overgeneralization of contextual fear memory is a core symptom of post-traumatic stress disorder (PTSD), but circuit mechanisms underlying the generalization remain unclear. We show here that neural projections from the anterior cingulate cortex (ACC) to ventral hippocampus (vHPC) mediate contextual fear generalization in male mice. Retrieval of contextual fear in a novel context at a remote time point activated cells in the ACC and vHPC, as indicated by significantly increased C-fos+ cells. Using chemogenetic or photogenetic manipulations, we observed that silencing the activity of ACC or vHPC neurons reduced contextual fear generalization at the remote time point, whereas stimulating the activity of ACC or vHPC neurons facilitated contextual fear generalization at a recent time point. We found that ACC neurons projected to the vHPC unidirectionally, and importantly, silencing the activity of projection fibers from the ACC to vHPC inhibited contextual fear generalization at the remote time point. Together, our findings reveal an ACC to vHPC circuit that controls expression of fear generalization and may offer new strategies to prevent or reverse contextual fear generalization in subjects with anxiety disorders, especially in PTSD.SIGNIFICANCE STATEMENT Overgeneralization of contextual fear memory is a cardinal feature of PTSD, but circuit mechanisms underlying it remain unclear. Our study indicates that neural projections from the anterior cingulate cortex to ventral hippocampus control the expression of contextual fear generalization. Thus, manipulating the circuit may prevent or reverse fear overgeneralization in subjects with PTSD.
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20
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Kida S. Reconsolidation/destabilization, extinction and forgetting of fear memory as therapeutic targets for PTSD. Psychopharmacology (Berl) 2019; 236:49-57. [PMID: 30374892 PMCID: PMC6373183 DOI: 10.1007/s00213-018-5086-2] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 10/16/2018] [Indexed: 12/11/2022]
Abstract
Post-traumatic stress disorder (PTSD) is a psychiatric disorder associated with memories of traumatic experiences. Conditioned fear memory, a representative model of traumatic memories, is observed across species from lower to higher animals, including humans. Numerous studies have investigated the mechanisms of conditioned fear memory and have led to the identification of the underlying processes involved in fear memory regulation, including cellular and systems consolidation of fear conditioning, destabilization/reconsolidation and extinction after fear memory retrieval, and forgetting of fear memory. These studies suggested that mechanisms for fear memory regulation are shared by humans and other higher animals. Additionally, rodent studies have identified the mechanisms of fear memory at the molecular, cellular, and circuit levels. Findings from these studies in rodents have been applied to facilitate the development and improvement of PTSD intervention. For instance, reconsolidation and extinction of fear memories have been applied for PTSD treatment to improve prolonged exposure (PE) therapy, an effective psychotherapy for PTSD. Combination of medications weakening retrieved traumatic memory (e.g., by facilitating both destabilization and extinction) with PE therapy may contribute to improvement of PTSD. Interestingly, a recent study in mice identified forgetting of fear memory as another potential therapeutic target for PTSD. A better understanding of the mechanisms involved in fear memory processes is likely to facilitate the development of better treatments for PTSD. This review describes fear memory processes and their mechanisms and discusses the pros and cons of applying how this knowledge can be applied in the development of interventions for PTSD.
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Affiliation(s)
- Satoshi Kida
- Department of Bioscience, Faculty of Life Science, Tokyo University of Agriculture, Tokyo, Japan. .,Department of Bioscience, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan.
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21
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Neuronal Chromatin Architecture Regulator CTCF Dictates Remote Memory. J Neurosci 2018; 38:10239-10240. [PMID: 30487296 DOI: 10.1523/jneurosci.1869-18.2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/04/2018] [Accepted: 10/05/2018] [Indexed: 11/21/2022] Open
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22
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Blocking H2A.Z Incorporation via Tip60 Inhibition Promotes Systems Consolidation of Fear Memory in Mice. eNeuro 2018; 5:eN-CFN-0378-18. [PMID: 30417078 PMCID: PMC6223110 DOI: 10.1523/eneuro.0378-18.2018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 10/12/2018] [Indexed: 01/08/2023] Open
Abstract
Memory formation is a protracted process that initially involves the hippocampus and becomes increasingly dependent on the cortex over time, but the mechanisms of this transfer are unclear. We recently showed that hippocampal depletion of the histone variant H2A.Z enhances both recent and remote memories, but the use of virally mediated depletion reduced H2A.Z levels throughout testing, making its temporally specific function unclear. Given the lack of drugs that target histone variants, we tested existing drugs for efficacy against H2A.Z based on their targeting of known H2A.Z regulators. The Tip60 (part of H2A.Z deposition complex) inhibitor Nu9056 reduced H2A.Z binding, whereas the histone deacetylase (HDAC) inhibitor Trichostatin-A increased H2A.Z acetylation without influencing total H2A.Z in cultured hippocampal neurons. Tip60 (but not HDAC) inhibition 23 h after learning enhanced remote (tested at 7 d) and not recent (tested at 24 h) contextual fear memory in mice. In contrast, Tip60 inhibition 30 d after learning impaired recall of remote memory after 1 h, but protected the memory from further decline 24 h later. These data provide the first evidence of a delayed postlearning role for histone variants in supporting memory transfer during systems consolidation.
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23
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Devan BD, Berger K, McDonald RJ. The Emergent Engram: A Historical Legacy and Contemporary Discovery. Front Behav Neurosci 2018; 12:168. [PMID: 30131682 PMCID: PMC6090515 DOI: 10.3389/fnbeh.2018.00168] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 07/16/2018] [Indexed: 01/10/2023] Open
Affiliation(s)
- Bryan D Devan
- Laboratory of Comparative Neuropsychology, Psychology Department, Towson University, Towson, MD, United States
| | - Kyle Berger
- Laboratory of Comparative Neuropsychology, Psychology Department, Towson University, Towson, MD, United States
| | - Robert J McDonald
- Canadian Center for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
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24
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Sekeres MJ, Winocur G, Moscovitch M. The hippocampus and related neocortical structures in memory transformation. Neurosci Lett 2018; 680:39-53. [DOI: 10.1016/j.neulet.2018.05.006] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 12/23/2022]
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25
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26
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Robinson-Drummer PA, Chakraborty T, Heroux NA, Rosen JB, Stanton ME. Age and experience dependent changes in Egr-1 expression during the ontogeny of the context preexposure facilitation effect (CPFE). Neurobiol Learn Mem 2018; 150:1-12. [PMID: 29452227 DOI: 10.1016/j.nlm.2018.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 01/29/2018] [Accepted: 02/08/2018] [Indexed: 12/19/2022]
Abstract
The context preexposure facilitation effect (CPFE) is a variant of contextual fear conditioning in which acquisition of the contextual representation and association of the retrieved contextual memory with an immediate foot-shock are separated by 24 h. During the CPFE, learning- related expression patterns of the early growth response-1 gene (Egr-1) vary based on training phase and brain sub-region in adult and adolescent rats (Asok, Schreiber, Jablonski, Rosen, & Stanton, 2013; Schreiber, Asok, Jablonski, Rosen, & Stanton, 2014; Chakraborty, Asok, Stanton, & Rosen, 2016). The current experiments extended our previous findings by examining Egr-1 expression in infant (PD17) and juvenile (PD24) rats during the CPFE using preexposure protocols involving single-exposure (SE) or multiple-exposure (ME) to context. Following a 5 min preexposure to the training context (i.e. the SE protocol), Egr-1 expression in the medial prefrontal cortex (mPFC), dorsal hippocampus (dHPC) and lateral nucleus of the amygdala (LA) was differentially increased in PD24 rats relative to PD17 rats. In contrast, increased Egr-1 expression following an immediate foot-shock (2s, 1.5 mA) did not differ between PD17 and PD24 rats, and was not learning-related. Interestingly, increasing the number of exposures to the training chamber on the preexposure day (i.e. ME protocol) altered training-day expression such that a learning-related increase in expression was observed in the mPFC in PD24 but not PD17 rats. Together, these results illustrate a clear maturation of Egr-1 expression that is both age- and experience-dependent. In addition, the data suggest that regional activity and plasticity within the mPFC on the preexposure but not the training day may contribute to the ontogenetic profile of the effect. Further studies are necessary to elucidate the causal role of sub-region-specific neuroplasticity in the ontogeny of the CPFE.
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Affiliation(s)
- P A Robinson-Drummer
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States.
| | - T Chakraborty
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States
| | - N A Heroux
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States
| | - J B Rosen
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States
| | - M E Stanton
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States
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27
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Robin J, Moscovitch M. Details, gist and schema: hippocampal–neocortical interactions underlying recent and remote episodic and spatial memory. Curr Opin Behav Sci 2017. [DOI: 10.1016/j.cobeha.2017.07.016] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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28
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Dunsmoor JE, Otto AR, Phelps EA. Stress promotes generalization of older but not recent threat memories. Proc Natl Acad Sci U S A 2017; 114:9218-9223. [PMID: 28784793 PMCID: PMC5576797 DOI: 10.1073/pnas.1704428114] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Stress broadly affects the ability to regulate emotions and may contribute to generalization of threat-related behaviors to harmless stimuli. Behavioral generalization also tends to increase over time as memory precision for recent events gives way to more gist-like representations. Thus, acute stress coupled with a delay in time from a negative experience may be a strong predictor of the transition from normal to generalized fear expression. Here, we investigated the effect of a single-episode acute stressor on generalization of aversive learning when stress is administered either immediately after an aversive learning event or following a delay. In a between-subjects design, healthy adult volunteers underwent threat (fear) conditioning using a tone-conditioned stimulus paired with an electric shock to the wrist and another tone not paired with shock. Behavioral generalization was tested to a range of novel tones either on the same day (experiment 1) or 24 h later (experiment 2) and was preceded by either an acute stress induction or a control task. Anticipatory sympathetic arousal [i.e., skin conductance responses (SCRs)] and explicit measures of shock expectancy served as dependent measures. Stress administered shortly after threat conditioning did not affect behavioral generalization. In contrast, stress administered following a delay led to heightened arousal and increased generalization of SCRs and explicit measures of shock expectancy. These findings show that acute stress increases generalization of older but not recent threat memories and have clinical relevance to understanding overgeneralization characteristics of anxiety and stress-related disorders.
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Affiliation(s)
- Joseph E Dunsmoor
- Department of Psychiatry, The University of Texas at Austin Dell Medical School, Austin, TX 78712;
| | - A Ross Otto
- Department of Psychology, McGill University, Montreal, QC, H3A 1G1 Canada
| | - Elizabeth A Phelps
- Department of Psychology and Center for Neural Sciences, New York University, New York, NY 10009
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962
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29
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Meyer MAA, Corcoran KA, Chen HJ, Gallego S, Li G, Tiruveedhula VV, Cook JM, Radulovic J. Neurobiological correlates of state-dependent context fear. ACTA ACUST UNITED AC 2017; 24:385-391. [PMID: 28814463 PMCID: PMC5580530 DOI: 10.1101/lm.045542.117] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 06/07/2017] [Indexed: 12/02/2022]
Abstract
Retrieval of fear memories can be state-dependent, meaning that they are best retrieved if the brain states at encoding and retrieval are similar. Such states can be induced by activating extrasynaptic γ-aminobutyric acid type A receptors (GABAAR) with the broad α-subunit activator gaboxadol. However, the circuit mechanisms and specific subunits underlying gaboxadol's effects are not well understood. Here we show that gaboxadol induces profound changes of local and network oscillatory activity, indicative of discoordinated hippocampal–cortical activity, that were accompanied by robust and long-lasting state-dependent conditioned fear. Episodic memories typically are hippocampus-dependent for a limited period after learning, but become cortex-dependent with the passage of time. In contrast, state-dependent memories continued to rely on hippocampal GABAergic mechanisms for memory retrieval. Pharmacological approaches with α-subunit-specific agonists targeting the hippocampus implicated the prototypic extrasynaptic subunits (α4) as the mediator of state-dependent conditioned fear. Together, our findings suggest that continued dependence on hippocampal rather than cortical mechanisms could be an important feature of state-dependent memories that contributes to their conditional retrieval.
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Affiliation(s)
- Mariah A A Meyer
- Department of Psychiatry and Behavioral Sciences, Northwestern University, Chicago, Illinois 60611, USA
| | - Kevin A Corcoran
- Department of Psychiatry and Behavioral Sciences, Northwestern University, Chicago, Illinois 60611, USA
| | - Helen J Chen
- Department of Psychiatry and Behavioral Sciences, Northwestern University, Chicago, Illinois 60611, USA
| | - Sonia Gallego
- Department of Psychiatry and Behavioral Sciences, Northwestern University, Chicago, Illinois 60611, USA
| | - Guanguan Li
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, USA
| | - Veda V Tiruveedhula
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, USA
| | - James M Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, USA
| | - Jelena Radulovic
- Department of Psychiatry and Behavioral Sciences, Northwestern University, Chicago, Illinois 60611, USA
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30
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Bessières B, Nicole O, Bontempi B. Assessing recent and remote associative olfactory memory in rats using the social transmission of food preference paradigm. Nat Protoc 2017; 12:1415-1436. [DOI: 10.1038/nprot.2017.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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31
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Robinson-Drummer PA, Heroux NA, Stanton ME. Antagonism of muscarinic acetylcholine receptors in medial prefrontal cortex disrupts the context preexposure facilitation effect. Neurobiol Learn Mem 2017; 143:27-35. [PMID: 28411153 DOI: 10.1016/j.nlm.2017.04.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 04/09/2017] [Accepted: 04/10/2017] [Indexed: 11/25/2022]
Abstract
Cholinergic function plays a role in a variant of context fear conditioning known as the context preexposure facilitation effect (CPFE; Robinson-Drummer, Dokovna, Heroux, & Stanton, 2016). In the CPFE, acquisition of a context representation, the context-shock association, and expression of context fear occur across successive phases, usually 24h apart. Systemic administration of scopolamine, a muscarinic acetylcholine receptor antagonist, prior to each phase (context preexposure, immediate-shock training, and testing) disrupts the CPFE in juvenile rats (Robinson-Drummer et al., 2016). Dorsal hippocampal (dHPC) cholinergic function contributes significantly to this effect, as local infusion of scopolamine into the dHPC prior to any individual phase of the CPFE produces a disruption identical to systemic administration (Robinson-Drummer et al., 2016). The current experiment extended these findings to another forebrain region implicated in the CPFE, the medial prefrontal cortex (mPFC). Adolescent rats received bilateral infusions of scopolamine (35μg/side) or PBS 10min before all three phases of the CPFE or only prior to a single phase. Intra-mPFC administration of scopolamine prior to all three phases significantly impaired fear conditioning suggesting that mPFC cholinergic function is necessary for successful CPFE performance. Analyses of the individual infusion days revealed a significant impairment of the CPFE when infusions occurred prior to preexposure or training (i.e. immediate footshock) but not prior to testing. In total, these findings suggests a role of mPFC cholinergic function in the acquisition and/or consolidation of a contextual representation and the context-shock association but not in retrieval or expression of fear memory. Implications for mPFC involvement in contextual fear conditioning and neurological dysfunction following neonatal alcohol exposure are discussed.
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Affiliation(s)
- P A Robinson-Drummer
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States.
| | - N A Heroux
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States
| | - M E Stanton
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States
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Zhou H, Zhou Q, Xu L. Unilateral hippocampal inactivation or lesion selectively impairs remote contextual fear memory. Psychopharmacology (Berl) 2016; 233:3639-46. [PMID: 27485536 DOI: 10.1007/s00213-016-4394-7] [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: 10/17/2015] [Accepted: 07/24/2016] [Indexed: 12/17/2022]
Abstract
RATIONALE Contextual fear memory depends on the hippocampus, but the role of unilateral hippocampus in this type of memory remains unclear. OBJECTIVES Herein, pharmacological inactivation or excitotoxic lesions were used to study the role of unilateral hippocampus in the stages of contextual fear memory. RESULTS The pharmacological experiments revealed that compared with the control groups, unilateral hippocampal blockade did not impair 1-day recent memory following learning, whereas bilateral hippocampal blockade significantly impaired this memory. The lesion experiments showed that compared with the control groups, the formed contextual fear memory was retained for 7 days and that 30-day remote memory was markedly reduced in unilateral hippocampal lesion groups. CONCLUSIONS These results indicate that an intact bilateral hippocampus is required for the formation of remote memory and that unilateral hippocampus is sufficient for recent contextual fear memory.
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Affiliation(s)
- Heng Zhou
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230027, People's Republic of China.,Laboratory of Learning and Memory, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, CAS, Kunming, 650223, People's Republic of China
| | - Qixin Zhou
- Laboratory of Learning and Memory, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, CAS, Kunming, 650223, People's Republic of China.
| | - Lin Xu
- Laboratory of Learning and Memory, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, CAS, Kunming, 650223, People's Republic of China. .,Kunming College of Life Sciences, University of Chinese Academy of Sciences, Kunming, People's Republic of China.
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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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Haubrich J, Cassini LF, Diehl F, Santana F, Fürstenau de Oliveira L, de Oliveira Alvares L, Quillfeldt JA. Novel learning accelerates systems consolidation of a contextual fear memory. Hippocampus 2016; 26:924-32. [DOI: 10.1002/hipo.22575] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/04/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Josue Haubrich
- Departamento de Biofísica, Laboratório de Psicobiologia e Neurocomputação, Instituto de Biociências; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas Da Saúde; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
| | - Lindsey Freitas Cassini
- Departamento de Biofísica, Laboratório de Psicobiologia e Neurocomputação, Instituto de Biociências; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas Da Saúde; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
| | - Felipe Diehl
- Departamento de Biofísica, Laboratório de Psicobiologia e Neurocomputação, Instituto de Biociências; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas Da Saúde; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
| | - Fabiana Santana
- Departamento de Biofísica, Laboratório de Psicobiologia e Neurocomputação, Instituto de Biociências; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas Da Saúde; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
| | - Lucas Fürstenau de Oliveira
- Departamento de Biofísica, Laboratório de Psicobiologia e Neurocomputação, Instituto de Biociências; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas Da Saúde; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
| | - Lucas de Oliveira Alvares
- Departamento de Biofísica, Laboratório de Psicobiologia e Neurocomputação, Instituto de Biociências; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas Da Saúde; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
- Departamento de Biofísica, Laboratório de Neurobiologia da Memória, Instituto de Biociências; Universidade Federal Do Rio Grande do Sul-Porto Alegre; RS Brazil
| | - Jorge Alberto Quillfeldt
- Departamento de Biofísica, Laboratório de Psicobiologia e Neurocomputação, Instituto de Biociências; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas Da Saúde; Universidade Federal do Rio Grande do Sul-Porto Alegre; RS Brazil
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Walters BJ, Zovkic IB. Building up and knocking down: an emerging role for epigenetics and proteasomal degradation in systems consolidation. Neuroscience 2015; 300:39-52. [PMID: 25967264 DOI: 10.1016/j.neuroscience.2015.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/18/2015] [Accepted: 05/03/2015] [Indexed: 01/30/2023]
Abstract
Memory formation is a protracted process in which recently acquired events are consolidated to produce stable and specific associations. Initially, newly acquired information undergoes cellular consolidation in the hippocampus, which transiently supports the storage of recently acquired memories. In contrast, remote, or "old" memories are maintained in the cortex and show almost complete independence from the hippocampus. Memories are transferred from the hippocampus to the cortex through a process termed systems consolidation. Emerging evidence suggests that recurrent activation, or "training" of the cortex by the hippocampus is vital to systems consolidation. This process involves prolonged waves of memory-related gene activity in the hippocampus and cortex long after the learning event has terminated. Indeed, molecular events occurring within hours and days of fear conditioning are essential for stabilizing and eventually transitioning the memory to the cortex. It is increasingly evident that molecular mechanisms that exhibit a capacity for prolonged activation may underlie systems consolidation. Processes that have the capacity to control protein abundance over long time scales, such as epigenetic modifications, are prime candidates for the molecular mechanism of systems consolidation. Indeed, recent work has established two types of epigenetic modifications as integral for systems consolidation. First, localized nucleosomal histone variant exchange and histone modifications are integral for early stages of systems consolidation, whereas DNA methylation appears to be utilized to form stable marks that support memory maintenance. Since systems consolidation also requires discrete and time-sensitive changes in protein abundance, additional mechanisms, such as protein degradation, need also be considered, although their role in systems consolidation has yet to be investigated. Here, we discuss the role of molecular mechanisms in systems consolidation and their implications for understanding how memories persist over time.
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Affiliation(s)
- B J Walters
- The Hospital for Sick Children, Department of Neuroscience and Mental Health, Toronto, ON, Canada
| | - I B Zovkic
- University of Toronto Mississauga, Department of Psychology, Mississauga, ON, Canada.
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Navarrete-Opazo A, Vinit S, Dougherty BJ, Mitchell GS. Daily acute intermittent hypoxia elicits functional recovery of diaphragm and inspiratory intercostal muscle activity after acute cervical spinal injury. Exp Neurol 2015; 266:1-10. [PMID: 25687551 PMCID: PMC4716671 DOI: 10.1016/j.expneurol.2015.02.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 01/14/2015] [Accepted: 02/06/2015] [Indexed: 01/31/2023]
Abstract
A major cause of mortality after spinal cord injury is respiratory failure. In normal rats, acute intermittent hypoxia (AIH) induces respiratory motor plasticity, expressed as diaphragm (Dia) and second external intercostal (T2 EIC) long-term facilitation (LTF). Dia (not T2 EIC) LTF is enhanced by systemic adenosine 2A (A2A) receptor inhibition in normal rats. We investigated the respective contributions of Dia and T2 EIC to daily AIH-induced functional recovery of breathing capacity with/without A2A receptor antagonist (KW6002, i.p.) following C2 hemisection (C2HS). Rats received daily AIH (dAIH: 10, 5-min episodes, 10.5% O2; 5-min normoxic intervals; 7 successive days beginning 7days post-C2HS) or daily normoxia (dNx) with/without KW6002, followed by weekly (reminder) presentations for 8weeks. Ventilation and EMGs from bilateral diaphragm and T2 EIC muscles were measured with room air breathing (21% O2) and maximum chemoreceptor stimulation ( MCS 7% CO2, 10.5% O2). dAIH increased tidal volume (VT) in C2HS rats breathing room air (dAIH+vehicle: 0.47±0.02, dNx+vehicle: 0.40±0.01ml/100g; p<0.05) and MCS (dAIH+vehicle: 0.83±0.01, dNx+vehicle: 0.73±0.01ml/100g; p<0.001); KW6002 had no significant effect. dAIH enhanced contralateral (uninjured) diaphragm EMG activity, an effect attenuated by KW6002, during room air breathing and MCS (p<0.05). Although dAIH enhanced contralateral T2 EIC EMG activity during room air breathing, KW6002 had no effect. dAIH had no statistically significant effects on diaphragm or T2 EIC EMG activity ipsilateral to injury. Thus, two weeks post-C2HS: 1) dAIH enhances breathing capacity by effects on contralateral diaphragm and T2 EIC activity; and 2) dAIH-induced recovery is A2A dependent in diaphragm, but not T2 EIC. Daily AIH may be a useful in promoting functional recovery of breathing capacity after cervical spinal injury, but A2A receptor antagonists (e.g. caffeine) may undermine its effectiveness shortly after injury.
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Affiliation(s)
- A Navarrete-Opazo
- Department of Comparative Biosciences University of Wisconsin-Madison, Madison, WI 53706, USA
| | - S Vinit
- Department of Comparative Biosciences University of Wisconsin-Madison, Madison, WI 53706, USA
| | - B J Dougherty
- Department of Comparative Biosciences University of Wisconsin-Madison, Madison, WI 53706, USA
| | - G S Mitchell
- Department of Comparative Biosciences University of Wisconsin-Madison, Madison, WI 53706, USA.
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Do-Monte FH, Quinones-Laracuente K, Quirk GJ. A temporal shift in the circuits mediating retrieval of fear memory. Nature 2015; 519:460-3. [PMID: 25600268 PMCID: PMC4376623 DOI: 10.1038/nature14030] [Citation(s) in RCA: 334] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 11/03/2014] [Indexed: 01/16/2023]
Abstract
Fear memories allow animals to avoid danger, thereby increasing their chances of survival. Fear memories can be retrieved long after learning, but little is known about how retrieval circuits change with time. Here we show that the dorsal midline thalamus of rats is required for the retrieval of auditory conditioned fear at late (24 hours, 7 days, 28 days), but not early (0.5 hours, 6 hours) time points after learning. Consistent with this, the paraventricular nucleus of the thalamus (PVT), a subregion of the dorsal midline thalamus, showed increased c-Fos expression only at late time points, indicating that the PVT is gradually recruited for fear retrieval. Accordingly, the conditioned tone responses of PVT neurons increased with time after training. The prelimbic (PL) prefrontal cortex, which is necessary for fear retrieval, sends dense projections to the PVT. Retrieval at late time points activated PL neurons projecting to the PVT, and optogenetic silencing of these projections impaired retrieval at late, but not early, time points. In contrast, silencing of PL inputs to the basolateral amygdala impaired retrieval at early, but not late, time points, indicating a time-dependent shift in retrieval circuits. Retrieval at late time points also activated PVT neurons projecting to the central nucleus of the amygdala, and silencing these projections at late, but not early, time points induced a persistent attenuation of fear. Thus, the PVT may act as a crucial thalamic node recruited into cortico-amygdalar networks for retrieval and maintenance of long-term fear memories.
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Affiliation(s)
- Fabricio H. Do-Monte
- Corresponding Author: Fabricio H. Do-Monte, DVM, PhD., Departments of Psychiatry and Anatomy & Neurobiology, University of Puerto Rico School of Medicine, P.O. Box 365067, San Juan, Puerto Rico, 00936, Phone 787-999-3057,
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38
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Abstract
We examined timing-related signals in primate hippocampal cells as animals performed an object-place (OP) associative learning task. We found hippocampal cells with firing rates that incrementally increased or decreased across the memory delay interval of the task, which we refer to as incremental timing cells (ITCs). Three distinct categories of ITCs were identified. Agnostic ITCs did not distinguish between different trial types. The remaining two categories of cells signaled time and trial context together: One category of cells tracked time depending on the behavioral action required for a correct response (i.e., early vs. late release), whereas the other category of cells tracked time only for those trials cued with a specific OP combination. The context-sensitive ITCs were observed more often during sessions where behavioral learning was observed and exhibited reduced incremental firing on incorrect trials. Thus, single primate hippocampal cells signal information about trial timing, which can be linked with trial type/context in a learning-dependent manner.
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39
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Alberini CM, Kandel ER. The regulation of transcription in memory consolidation. Cold Spring Harb Perspect Biol 2014; 7:a021741. [PMID: 25475090 DOI: 10.1101/cshperspect.a021741] [Citation(s) in RCA: 216] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
De novo transcription of DNA is a fundamental requirement for the formation of long-term memory. It is required during both consolidation and reconsolidation, the posttraining and postreactivation phases that change the state of the memory from a fragile into a stable and long-lasting form. Transcription generates both mRNAs that are translated into proteins, which are necessary for the growth of new synaptic connections, as well as noncoding RNA transcripts that have regulatory or effector roles in gene expression. The result is a cascade of events that ultimately leads to structural changes in the neurons that mediate long-term memory storage. The de novo transcription, critical for synaptic plasticity and memory formation, is orchestrated by chromatin and epigenetic modifications. The complexity of transcription regulation, its temporal progression, and the effectors produced all contribute to the flexibility and persistence of long-term memory formation. In this article, we provide an overview of the mechanisms contributing to this transcriptional regulation underlying long-term memory formation.
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Affiliation(s)
| | - Eric R Kandel
- Zuckerman Mind Brain Behavior Institute, New York State Psychiatric Institute, New York, New York 10032 Department of Neuroscience, New York State Psychiatric Institute, New York, New York 10032 Kavli Institute for Brain Science, New York State Psychiatric Institute, New York, New York 10032 Howard Hughes Medical Institute, New York State Psychiatric Institute, New York, New York 10032 College of Physicians and Surgeons of Columbia University, New York State Psychiatric Institute, New York, New York 10032
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40
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Raybuck JD, Lattal KM. Differential effects of dorsal hippocampal inactivation on expression of recent and remote drug and fear memory. Neurosci Lett 2014; 569:1-5. [PMID: 24686177 DOI: 10.1016/j.neulet.2014.02.063] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 02/21/2014] [Accepted: 02/24/2014] [Indexed: 01/08/2023]
Abstract
Drugs of abuse generate strong drug-context associations, which can evoke powerful drug cravings that are linked to reinstatement in animal models and to relapse in humans. Work in learning and memory has demonstrated that contextual memories become more distributed over time, shifting from dependence on the hippocampus for retrieval to dependence on cortical structures. Implications for such changes in the structure of memory retrieval to addiction are unknown. Thus, to determine if the passage of time alters the substrates of conditioned place preference (CPP) memory retrieval, we investigated the effects of inactivation of the dorsal hippocampus (DH) with the GABA-A receptor agonist muscimol on expression of recent or remote CPP. We compared these effects with the same manipulation on expression of contextual fear conditioning. DH inactivation produced similar deficits in expression of both recent and remote CPP, but blocked expression of recent but not remote contextual fear memory. We describe the implications of these findings for mechanisms underlying long-term storage of contextual information.
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Affiliation(s)
- J D Raybuck
- Department of Behavioral Neuroscience, Oregon Health & Science University, 3181 SW Sam Jackson Park Road L470, Portland, OR 97239-3098, USA.
| | - K M Lattal
- Department of Behavioral Neuroscience, Oregon Health & Science University, 3181 SW Sam Jackson Park Road L470, Portland, OR 97239-3098, USA.
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Abstract
According to the standard model of systems consolidation (SMC), neocortical circuits are reactivated during the retrieval of declarative memories. This process initially requires the hippocampus. However, with the passage of time, neocortical circuits become strengthened and can eventually retrieve memory without input from the hippocampus. Although consistent with lesion data, these assumptions have been difficult to confirm experimentally. In the current review, we discuss recent methodological advances in behavioral neuroscience that are making it possible to test the basic assumptions of SMC for the first time. For example, new transgenic mice can be used to monitor the activity of individual neurons across the entire brain while optogenetic approaches provide precise control over the activity of these cells using light stimulation. These tools can be used to examine the reactivation of neocortical neurons during recent and remote memory retrieval and determine if this process requires the hippocampus.
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Affiliation(s)
- Kaycie K Tayler
- Department of Psychology, University of Virginia, Charlottesville, Virginia 22904, USA
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Remote context fear conditioning remains hippocampus-dependent irrespective of training protocol, training-surgery interval, lesion size, and lesion method. Neurobiol Learn Mem 2013; 106:300-8. [PMID: 23994542 DOI: 10.1016/j.nlm.2013.08.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 08/16/2013] [Accepted: 08/20/2013] [Indexed: 11/20/2022]
Abstract
Systems consolidation involves the reorganization of brain circuits that support long-term memory. It is a prolonged process that can take days, weeks, or longer. An animal model of systems consolidation was established in the early 1990s and provided compelling support for the initial observations in humans, that hippocampal damage disproportionally impairs recent memory compared to remote memory. Context fear conditioning was the most frequently and successfully used task to study systems consolidation and demonstrate temporally graded retrograde amnesia. However, recent studies have failed to support these early findings of temporal gradients and instead reported that both recent and remote memories are equally impaired. Thus, the status of context fear conditioning as method to study the process of systems consolidation is at present uncertain. Accordingly, we evaluated classically conditioned fear memory in large groups of rats with hippocampal damage by manipulating several procedural variables including the training protocol, the training-surgery interval, the extent of hippocampal damage, and the method of damaging the hippocampus. The results indicate that hippocampal damage profoundly impairs context fear conditioning. These findings are unambiguous and independent of any particular procedural manipulation we evaluated. We suggest that the preponderance of currently available evidence indicates that context fear memory remains hippocampus-dependent indefinitely.
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