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Bertocchi I, Rocha-Almeida F, Romero-Barragán MT, Cambiaghi M, Carretero-Guillén A, Botta P, Dogbevia GK, Treviño M, Mele P, Oberto A, Larkum ME, Gruart A, Sprengel R, Delgado-García JM, Hasan MT. Pre- and postsynaptic N-methyl-D-aspartate receptors are required for sequential printing of fear memory engrams. iScience 2023; 26:108050. [PMID: 37876798 PMCID: PMC10590821 DOI: 10.1016/j.isci.2023.108050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/24/2023] [Accepted: 09/22/2023] [Indexed: 10/26/2023] Open
Abstract
The organization of fear memory involves the participation of multiple brain regions. However, it is largely unknown how fear memory is formed, which circuit pathways are used for "printing" memory engrams across brain regions, and the role of identified brain circuits in memory retrieval. With advanced genetic methods, we combinatorially blocked presynaptic output and manipulated N-methyl-D-aspartate receptor (NMDAR) in the basolateral amygdala (BLA) and medial prefrontal cortex (mPFC) before and after cued fear conditioning. Further, we tagged fear-activated neurons during associative learning for optogenetic memory recall. We found that presynaptic mPFC and postsynaptic BLA NMDARs are required for fear memory formation, but not expression. Our results provide strong evidence that NMDAR-dependent synaptic plasticity drives multi-trace systems consolidation for the sequential printing of fear memory engrams from BLA to mPFC and, subsequently, to the other regions, for flexible memory retrieval.
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Affiliation(s)
- Ilaria Bertocchi
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
- Department of Neuroscience "Rita Levi Montalcini", Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, 10043 Turin, Italy
| | - Florbela Rocha-Almeida
- Division of Neurosciences, University Pablo de Olavide, Ctra. de Utrera, km. 1 41013 Seville, Spain
| | | | - Marco Cambiaghi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada le Grazie 8, Verona, Italy
| | - Alejandro Carretero-Guillén
- Laboratory of Brain Circuits Therapeutics, Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Sede Building, Barrio Sarriena, s/n, 48940 Leioa, Spain
| | - Paolo Botta
- CNS drug development, Copenhagen, Capital Region, Denmark
| | - Godwin K. Dogbevia
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
- Health Canada, 70 Colombine Driveway, Ottawa, ON K1A0K9, Canada
| | - Mario Treviño
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
- Laboratorio de Plasticidad Cortical y Aprendizaje Perceptual, Instituto de Neurociencias, Universidad de Guadalajara, Guadalajara, Mexico
| | - Paolo Mele
- Department of Neuroscience "Rita Levi Montalcini", Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, 10043 Turin, Italy
| | - Alessandra Oberto
- Department of Neuroscience "Rita Levi Montalcini", Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, 10043 Turin, Italy
| | - Matthew E. Larkum
- NeuroCure, Charité-Universitatsmedizin, Virchowweg 6, 10117 Berlin, Germany
| | - Agnes Gruart
- Division of Neurosciences, University Pablo de Olavide, Ctra. de Utrera, km. 1 41013 Seville, Spain
| | - Rolf Sprengel
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | | | - Mazahir T. Hasan
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
- Laboratory of Brain Circuits Therapeutics, Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Sede Building, Barrio Sarriena, s/n, 48940 Leioa, Spain
- Ikerbasque – Basque Foundation for Science, Bilbao, Spain
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You Y, Novak LR, Clancy KJ, Li W. Pattern differentiation and tuning shift in human sensory cortex underlie long-term threat memory. Curr Biol 2022; 32:2067-2075.e4. [PMID: 35325599 PMCID: PMC9090975 DOI: 10.1016/j.cub.2022.02.076] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 01/18/2022] [Accepted: 02/28/2022] [Indexed: 12/12/2022]
Abstract
The amygdala-prefrontal-cortex circuit has long occupied the center of the threat system,1 but new evidence has rapidly amassed to implicate threat processing outside this canonical circuit.2-4 Through nonhuman research, the sensory cortex has emerged as a critical substrate for long-term threat memory,5-9 underpinned by sensory cortical pattern separation/completion10,11 and tuning shift.12,13 In humans, research has begun to associate the human sensory cortex with long-term threat memory,14,15 but the lack of mechanistic insights obscures a direct linkage. Toward that end, we assessed human olfactory threat conditioning and long-term (9 days) threat memory, combining affective appraisal, olfactory psychophysics, and functional magnetic resonance imaging (fMRI) over a linear odor-morphing continuum (five levels of binary mixtures of the conditioned stimuli/CS+ and CS- odors). Affective ratings and olfactory perceptual discrimination confirmed (explicit) affective and perceptual learning and memory via conditioning. fMRI representational similarity analysis (RSA) and voxel-based tuning analysis further revealed associative plasticity in the human olfactory (piriform) cortex, including immediate and lasting pattern differentiation between CS and neighboring non-CS and a late onset, lasting tuning shift toward the CS. The two plastic processes were especially salient and lasting in anxious individuals, among whom they were further correlated. These findings thus support an evolutionarily conserved sensory cortical system of long-term threat representation, which can underpin threat perception and memory. Importantly, hyperfunctioning of this sensory mnemonic system of threat in anxiety further implicates a hitherto underappreciated sensory mechanism of anxiety.
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Affiliation(s)
- Yuqi You
- Department of Psychology, Florida State University, 1107 W. Call St., Tallahassee, FL 32306, USA.
| | - Lucas R Novak
- Department of Psychology, Florida State University, 1107 W. Call St., Tallahassee, FL 32306, USA
| | - Kevin J Clancy
- Department of Psychology, Florida State University, 1107 W. Call St., Tallahassee, FL 32306, USA
| | - Wen Li
- Department of Psychology, Florida State University, 1107 W. Call St., Tallahassee, FL 32306, USA.
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Dissociated Role of Thalamic and Cortical Input to the Lateral Amygdala for Consolidation of Long-Term Fear Memory. J Neurosci 2021; 41:9561-9570. [PMID: 34667069 DOI: 10.1523/jneurosci.1167-21.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 10/08/2021] [Accepted: 10/09/2021] [Indexed: 12/25/2022] Open
Abstract
Post-encoding coordinated reactivation of memory traces distributed throughout interconnected brain regions is thought to be critical for consolidation of memories. However, little is known about the role of neural circuit pathways during post-learning periods for consolidation of memories. To investigate this question, we optogenetically silenced the inputs from both auditory cortex and thalamus in the lateral amygdala (LA) for 15 min immediately following auditory fear conditioning (FC) and examined its effect on fear memory formation in mice of both sexes. Optogenetic inhibition of both inputs disrupted long-term fear memory formation tested 24 h after FC. This effect was specific such that the same inhibition did not affect short-term memory and context-dependent memory. Moreover, long-term memory was intact if the inputs were inhibited at much later time points after FC (3 h or 1 d after FC), indicating that optical inhibition for 15 min itself does not produce any nonspecific deleterious effect on fear memory retrieval. Selective inhibition of thalamic input was sufficient to impair consolidation of auditory fear memory. In contrast, selective inhibition of cortical input disrupted remote fear memory without affecting recent memory. These results reveal a dissociated role of thalamic and cortical input to the LA during early post-learning periods for consolidation of long-term fear memory.SIGNIFICANCE STATEMENT Coordinated communications between brain regions are thought to be essential during post-learning periods for consolidation of memories. However, the role of specific neural circuit pathways in this process has been scarcely explored. Using a precise optogenetic inhibition of auditory input pathways, either thalamic or cortical or both, to the LA during post-training periods, we here show that thalamic input is required for consolidation of both recent and remote fear memory, whereas cortical input is crucial for consolidation of remote fear memory. These results reveal a dissociated role of auditory input pathways to the LA for consolidation of long-term fear memory.
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Developmental emergence of persistent memory for contextual and auditory fear in mice. Learn Mem 2021; 28:414-421. [PMID: 34663694 DOI: 10.1101/lm.053471.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 07/30/2021] [Indexed: 02/02/2023]
Abstract
The ability to generate memories that persist throughout a lifetime (that is, memory persistence) emerges in early development across species. Although it has been shown that persistent fear memories emerge between late infancy and adolescence in mice, it is unclear exactly when this transition takes place, and whether two major fear conditioning tasks, contextual and auditory fear, share the same time line of developmental onset. Here, we compared the ontogeny of remote contextual and auditory fear in C57BL/6J mice across early life. Mice at postnatal day (P)15, 21, 25, 28, and 30 underwent either contextual or auditory fear training and were tested for fear retrieval 1 or 30 d later. We found that mice displayed 30-d memory for context- and tone-fear starting at P25. We did not find sex differences in the ontogeny of either type of fear memory. Furthermore, 30-d contextual fear retrieval led to an increase in the number of c-Fos positive cells in the prelimbic region of the prefrontal cortex only at an age in which the contextual fear memory was successfully retrieved. These data delineate a precise time line for the emergence of persistent contextual and auditory fear memories in mice and suggest that the prelimbic cortex is only recruited for remote memory recall upon the onset of memory persistence.
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Human Sensory Cortex Contributes to the Long-Term Storage of Aversive Conditioning. J Neurosci 2021; 41:3222-3233. [PMID: 33622774 DOI: 10.1523/jneurosci.2325-20.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 01/24/2021] [Accepted: 02/11/2021] [Indexed: 11/21/2022] Open
Abstract
Growing animal data evince a critical role of the sensory cortex in the long-term storage of aversive conditioning, following acquisition and consolidation in the amygdala. Whether and how this function is conserved in the human sensory cortex is nonetheless unclear. We interrogated this question in a human aversive conditioning study using multidimensional assessments of conditioning and long-term (15 d) retention. Conditioned stimuli (CSs; Gabor patches) were calibrated to differentially activate the parvocellular (P) and magnocellular (M) visual pathways, further elucidating cortical versus subcortical mechanisms. Full-blown conditioning and long-term retention emerged for M-biased CS (vs limited effects for P-biased CS), especially among anxious individuals, in all four dimensions assessed: threat appraisal (threat ratings), physiological arousal (skin conductance response), perceptual learning [discrimination sensitivity (d') and response speed], and cortical plasticity [visual evoked potentials (VEPs) and cortical current density]. Interestingly, while behavioral, physiological, and VEP effects were comparable at immediate and delayed assessments, the cortical substrates evolved markedly over time, transferring from high-order cortices [inferotemporal/fusiform cortex and orbitofrontal cortex (OFC)] immediately to the primary and secondary visual cortex after the delay. In sum, the contrast between P- and M-biased conditioning confirms privileged conditioning acquisition via the subcortical pathway while the immediate cortical plasticity lends credence to the triadic amygdala-OFC-fusiform network thought to underlie threat processing. Importantly, long-term retention of conditioning in the basic sensory cortices supports the conserved role of the human sensory cortex in the long-term storage of aversive conditioning.SIGNIFICANCE STATEMENT A growing network of neural substrates has been identified in threat learning and memory. The sensory cortex plays a key role in long-term threat memory in animals, but such a function in humans remains unclear. To explore this problem, we conducted multidimensional assessments of immediate and delayed (15 d) effects of human aversive conditioning. Behavioral, physiological, and scalp electrophysiological data demonstrated conditioning effects and long-term retention. High-density EEG intracranial source analysis further revealed the cortical underpinnings, implicating high-order cortices immediately and primary and secondary visual cortices after the long delay. Therefore, while high-order cortices support aversive conditioning acquisition (i.e., threat learning), the human sensory cortex (akin to the animal homolog) underpins long-term storage of conditioning (i.e., long-term threat memory).
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Song SY, Zhai XM, Dai JH, Lu LL, Shan CJ, Hong J, Cao JL, Zhang LC. The CSF-Contacting Nucleus Receives Anatomical Inputs From the Cerebral Cortex: A Combination of Retrograde Tracing and 3D Reconstruction Study in Rat. Front Neuroanat 2020; 14:600555. [PMID: 33328908 PMCID: PMC7714914 DOI: 10.3389/fnana.2020.600555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 10/22/2020] [Indexed: 11/13/2022] Open
Abstract
Objective This study aimed to investigate the direct monosynaptic projections from cortical functional regions to the cerebrospinal fluid (CSF)-contacting nucleus for understanding the functions of the CSF-contacting nucleus. Methods The Sprague-Dawley rats received cholera toxin B subunit (CB) injections into the CSF-contacting nucleus. After 7-10 days of survival time, the rats were perfused, and the whole brain and spinal cord were sliced under a freezing microtome at 40 μm. All sections were treated with the CB immunofluorescence reaction. The retrogradely labeled neurons in different cortical areas were revealed under a confocal microscope. The distribution features were further illustrated under 3D reconstruction. Results The retrogradely labeled neurons were identified in the olfactory, orbital, cingulate, insula, retrosplenial, somatosensory, motor, visual, auditory, association, rhinal, and parietal cortical areas. A total of 12 functional areas and 34 functional subregions showed projections to the CSF-contacting nucleus in different cell intensities. Conclusion According to the connectivity patterns, we conclude that the CSF-contacting nucleus participates in cognition, emotion, pain, visceral activity, etc. The present study firstly reveals the cerebral cortex→CSF-contacting nucleus connections, which implies the multiple functions of this special nucleus in neural and body fluid regulations.
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Affiliation(s)
- Si-Yuan Song
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Xiao-Meng Zhai
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Jia-Hao Dai
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Lei-Lei Lu
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Cheng-Jing Shan
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Jia Hong
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Jun-Li Cao
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Li-Cai Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
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Oh JP, Han JH. A critical role of hippocampus for formation of remote cued fear memory. Mol Brain 2020; 13:112. [PMID: 32799906 PMCID: PMC7429722 DOI: 10.1186/s13041-020-00652-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/10/2020] [Indexed: 01/23/2023] Open
Abstract
A unique feature of fear memory is its persistence that is highly relevant to fear and anxiety-related mental disorders. Recurrent reactivation of neural representations acquired from a traumatic event is thought to contribute to the indelibility of fear memory. Given a well-established role of hippocampus for memory reactivation, hippocampus is likely involved in consolidation process of fear memory. However, evidence suggests that formation of fear memory to a discrete sensory cue is hippocampus-independent. Here, using a pharmacological reversible inactivation of dorsal hippocampus in auditory cued fear conditioning by local infusion of muscimol, we demonstrate in mice that hippocampus is critical for remote memory formation of learned fear to the discrete sensory cue. Muscimol infusion before conditioning did not affect formation of recent auditory fear memory as previously reported. Same muscimol infusion, however, impaired remote auditory fear memory. Muscimol infusion before remote test of auditory fear memory did not affect memory retrieval, indicating hippocampus is not a brain site for storage of remote cued fear memory. Moreover, memory reactivation enforced by re-exposure to the conditioned tone could compensate for hippocampal inactivation, as memory-reactivated mice showed normal remote auditory fear memory despite hippocampal inactivation. Our findings support that hippocampus may have a general role for consolidation of remote associative memory through reactivation of memory trace, giving an insight into how learned fear persists over time.
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Affiliation(s)
- Jung-Pyo Oh
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.,KAIST Institute for the BioCentury (KIB), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Jin-Hee Han
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea. .,KAIST Institute for the BioCentury (KIB), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
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Chipika RH, Christidi F, Finegan E, Li Hi Shing S, McKenna MC, Chang KM, Karavasilis E, Doherty MA, Hengeveld JC, Vajda A, Pender N, Hutchinson S, Donaghy C, McLaughlin RL, Hardiman O, Bede P. Amygdala pathology in amyotrophic lateral sclerosis and primary lateral sclerosis. J Neurol Sci 2020; 417:117039. [PMID: 32713609 DOI: 10.1016/j.jns.2020.117039] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/19/2020] [Accepted: 07/13/2020] [Indexed: 12/26/2022]
Abstract
Temporal lobe studies in motor neuron disease overwhelmingly focus on white matter alterations and cortical grey matter atrophy. Reports on amygdala involvement are conflicting and the amygdala is typically evaluated as single structure despite consisting of several functionally and cytologically distinct nuclei. A prospective, single-centre, neuroimaging study was undertaken to comprehensively characterise amygdala pathology in 100 genetically-stratified ALS patients, 33 patients with PLS and 117 healthy controls. The amygdala was segmented into groups of nuclei using a Bayesian parcellation algorithm based on a probabilistic atlas and shape deformations were additionally assessed by vertex analyses. The accessory basal nucleus (p = .021) and the cortical nucleus (p = .022) showed significant volume reductions in C9orf72 negative ALS patients compared to controls. The lateral nucleus (p = .043) and the cortico-amygdaloid transition (p = .024) were preferentially affected in C9orf72 hexanucleotide carriers. A trend of total volume reduction was identified in C9orf72 positive ALS patients (p = .055) which was also captured in inferior-medial shape deformations on vertex analyses. Our findings highlight that the amygdala is affected in ALS and our study demonstrates the selective involvement of specific nuclei as opposed to global atrophy. The genotype-specific patterns of amygdala involvement identified by this study are consistent with the growing literature of extra-motor clinical features. Mesial temporal lobe pathology in ALS is not limited to hippocampal pathology but, as a key hub of the limbic system, the amygdala is also affected in ALS.
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Affiliation(s)
- Rangariroyashe H Chipika
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland
| | - Foteini Christidi
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland; Department of Neurology, Aeginition Hospital, University of Athens, Greece
| | - Eoin Finegan
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland
| | - Stacey Li Hi Shing
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland
| | - Mary Clare McKenna
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland
| | - Kai Ming Chang
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland; Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Efstratios Karavasilis
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland; 2nd Department of Radiology, Attikon University Hospital, University of Athens, Athens, Greece
| | - Mark A Doherty
- Complex Trait Genomics Laboratory, Smurfit Institute of Genetics, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland
| | - Jennifer C Hengeveld
- Complex Trait Genomics Laboratory, Smurfit Institute of Genetics, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland
| | - Alice Vajda
- Complex Trait Genomics Laboratory, Smurfit Institute of Genetics, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland
| | - Niall Pender
- Department of psychology, Beaumont Hospital Dublin, Ireland
| | - Siobhan Hutchinson
- Department of Neurology, St James's Hospital, James's St, Ushers, Dublin 8 D08 NHY1, Ireland
| | - Colette Donaghy
- Department of Neurology, Belfast, Western Health & Social Care Trust, UK
| | - Russell L McLaughlin
- Complex Trait Genomics Laboratory, Smurfit Institute of Genetics, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland
| | - Orla Hardiman
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland
| | - Peter Bede
- Computational Neuroimaging Group, Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland.
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Lee J, Lee HR, Kim JI, Baek J, Jang EH, Lee J, Kim M, Lee RU, Kim S, Park P, Kaang BK. Transient cAMP elevation during systems consolidation enhances remote contextual fear memory. Neurobiol Learn Mem 2020; 169:107171. [PMID: 31978552 DOI: 10.1016/j.nlm.2020.107171] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/31/2019] [Accepted: 01/19/2020] [Indexed: 11/30/2022]
Abstract
Memory is stored in our brains over a temporally graded transition. With time, recently formed memories are transformed into remote memories for permanent storage; multiple brain regions, such as the hippocampus and neocortex, participate in this process. In this study, we aimed to understand the molecular mechanism of systems consolidation of memory and to investigate the brain regions that contribute to this regulation. We first carried out a contextual fear memory test using a transgenic mouse line, which expressed exogenously-derived Aplysia octopamine receptors in the forebrain region, such that, in response to octopamine treatment, cyclic adenosine monophosphate (cAMP) levels could be transiently elevated. From this experiment, we revealed that transient elevation of cAMP levels in the forebrain during systems consolidation led to an enhancement in remote fear memory and increased miniature excitatory synaptic currents in layer II/III of the anterior cingulate cortex (ACC). Furthermore, using an adeno-associated-virus-driven DREADD system, we investigated the specific regions in the forebrain that contribute to the regulation of memory transfer into long-term associations. Our results implied that transient elevation of cAMP levels was induced chemogenetically in the ACC, but not in the hippocampus, and showed a significant enhancement of remote memory. This finding suggests that neuronal activation during systems consolidation through the elevation of cAMP levels in the ACC contributes to remote memory enhancement.
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Affiliation(s)
- Jaehyun Lee
- Interdisciplinary Program in Neuroscience, Seoul National University, 1 Gwanangno, Gwanak-gu, Seoul 08826, Republic of Korea; Neurobiology Laboratory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Hye-Ryeon Lee
- Neurobiology Laboratory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Jae-Ick Kim
- Neurobiology Laboratory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Jinhee Baek
- Neurobiology Laboratory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Eun-Hae Jang
- Neurobiology Laboratory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Jihye Lee
- Neurobiology Laboratory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Myeongwon Kim
- Neurobiology Laboratory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Ro Un Lee
- Neurobiology Laboratory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Somi Kim
- Neurobiology Laboratory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Pojeong Park
- Neurobiology Laboratory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Bong-Kiun Kaang
- Interdisciplinary Program in Neuroscience, Seoul National University, 1 Gwanangno, Gwanak-gu, Seoul 08826, Republic of Korea; Neurobiology Laboratory, Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanangno 599, Gwanak-Gu, Seoul 08826, Republic of Korea.
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10
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Pollack GA, Bezek JL, Lee SH, Scarlata MJ, Weingast LT, Bergstrom HC. Cued fear memory generalization increases over time. Learn Mem 2018; 25:298-308. [PMID: 29907637 PMCID: PMC6004064 DOI: 10.1101/lm.047555.118] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 04/13/2018] [Indexed: 01/04/2023]
Abstract
Fear memory is a highly stable and durable form of memory, even over vast (remote) time frames. Nevertheless, some elements of fear memory can be forgotten, resulting in generalization. The purpose of this study is to determine how cued fear memory generalizes over time and measure underlying patterns of cortico-amygdala synaptic plasticity. We established generalization gradients at recent (1-d) and remote (30-d) retention intervals following auditory cued fear conditioning in adult male C57BL/6 mice. Results revealed a flattening of the generalization gradient (increased generalization) that was dissociated from contextual fear generalization, indicating a specific influence of time on cued fear memory performance. This effect reversed after a brief exposure to the novel stimulus soon after learning. Measurements from cortico-amygdala imaging of the activity-regulated cytoskeletal Arc/arg 3.1 (Arc) protein using immunohistochemistry after cued fear memory retrieval revealed a stable pattern of Arc expression in the dorsolateral amygdala, but temporally dynamic expression in the cortex. Over time, increased fear memory generalization was associated with a reduction in Arc expression in the agranular insular and infralimbic cortices while discrimination learning was associated with increased Arc expression in the prelimbic cortex. These data identify the dorsolateral amygdala, medial prefrontal, and insular cortices as loci for synaptic plasticity underlying cued fear memory generalization over time.
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Affiliation(s)
- Gabrielle A Pollack
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York 12604 USA
| | - Jessica L Bezek
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York 12604 USA
| | - Serena H Lee
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York 12604 USA
| | - Miranda J Scarlata
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York 12604 USA
| | - Leah T Weingast
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York 12604 USA
| | - Hadley C Bergstrom
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York 12604 USA
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Gallo FT, Katche C, Morici JF, Medina JH, Weisstaub NV. Immediate Early Genes, Memory and Psychiatric Disorders: Focus on c-Fos, Egr1 and Arc. Front Behav Neurosci 2018; 12:79. [PMID: 29755331 PMCID: PMC5932360 DOI: 10.3389/fnbeh.2018.00079] [Citation(s) in RCA: 214] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 04/10/2018] [Indexed: 01/08/2023] Open
Abstract
Many psychiatric disorders, despite their specific characteristics, share deficits in the cognitive domain including executive functions, emotional control and memory. However, memory deficits have been in many cases undervalued compared with other characteristics. The expression of Immediate Early Genes (IEGs) such as, c-fos, Egr1 and arc are selectively and promptly upregulated in learning and memory among neuronal subpopulations in regions associated with these processes. Changes in expression in these genes have been observed in recognition, working and fear related memories across the brain. Despite the enormous amount of data supporting changes in their expression during learning and memory and the importance of those cognitive processes in psychiatric conditions, there are very few studies analyzing the direct implication of the IEGs in mental illnesses. In this review, we discuss the role of some of the most relevant IEGs in relation with memory processes affected in psychiatric conditions.
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Affiliation(s)
- Francisco T Gallo
- Instituto de Fisiología y Biofísica Bernardo Houssay, Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Cynthia Katche
- Instituto de Biología Celular y Neurociencias (IBCN) Dr. Eduardo de Robertis, Facultad de Medicina, CONICET, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Juan F Morici
- Instituto de Fisiología y Biofísica Bernardo Houssay, Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Jorge H Medina
- Instituto de Biología Celular y Neurociencias (IBCN) Dr. Eduardo de Robertis, Facultad de Medicina, CONICET, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina.,Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos (UBA), Buenos Aires, Argentina
| | - Noelia V Weisstaub
- Instituto de Fisiología y Biofísica Bernardo Houssay, Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
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12
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Grosso A, Cambiaghi M, Milano L, Renna A, Sacco T, Sacchetti B. Region- and Layer-Specific Activation of the Higher Order Auditory Cortex Te2 after Remote Retrieval of Fear or Appetitive Memories. Cereb Cortex 2018; 27:3140-3151. [PMID: 27252348 DOI: 10.1093/cercor/bhw159] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The auditory cortex is involved in encoding sounds which have acquired an emotional-motivational charge. However, the neural circuitry engaged by emotional memory processes in the auditory cortex is poorly understood. In this study, we investigated the layers and regions that are recruited in the higher order auditory cortex Te2 by a tone previously paired to either fear or appetitive stimuli in rats. By tracking the protein coded by the immediate early gene zif268, we found that fear memory retrieval engages layers II-III in most regions of Te2. These results were neither due to an enhanced fear state nor to fear-evoked motor responses, as they were absent in animals retrieving an olfactory fear memory. These layers were also activated by appetitive auditory memory retrieval. Strikingly, layer IV was recruited by fear, but not appetitive memories, whereas layer V activity was related to the behavioral responses displayed to the CS. In addition to revealing the layers and regions that are recruited in the Te2 by either fear or appetitive remote memories, our study also shows that the neural circuitry within the Te2 that processes and stores emotional memories varies on the basis of the affective motivational charge of tones.
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Affiliation(s)
- Anna Grosso
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, I-10125 Turin, Italy
| | - Marco Cambiaghi
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, I-10125 Turin, Italy
| | - Luisella Milano
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, I-10125 Turin, Italy
| | - Annamaria Renna
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, I-10125 Turin, Italy
| | - Tiziana Sacco
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, I-10125 Turin, Italy
| | - Benedetto Sacchetti
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, I-10125 Turin, Italy.,National Institute of Neuroscience-Turin, I-10125 Turin, Italy
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13
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Thompson EH, Lensjø KK, Wigestrand MB, Malthe-Sørenssen A, Hafting T, Fyhn M. Removal of perineuronal nets disrupts recall of a remote fear memory. Proc Natl Acad Sci U S A 2018; 115:607-612. [PMID: 29279411 PMCID: PMC5776974 DOI: 10.1073/pnas.1713530115] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Throughout life animals learn to recognize cues that signal danger and instantaneously initiate an adequate threat response. Memories of such associations may last a lifetime and far outlast the intracellular molecules currently found to be important for memory processing. The memory engram may be supported by other more stable molecular components, such as the extracellular matrix structure of perineuronal nets (PNNs). Here, we show that recall of remote, but not recent, visual fear memories in rats depend on intact PNNs in the secondary visual cortex (V2L). Supporting our behavioral findings, increased synchronized theta oscillations between V2L and basolateral amygdala, a physiological correlate of successful recall, was absent in rats with degraded PNNs in V2L. Together, our findings suggest a role for PNNs in remote memory processing by stabilizing the neural network of the engram.
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Affiliation(s)
- Elise Holter Thompson
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway
- Center for Integrative Neuroplasticity, University of Oslo, 0316 Oslo, Norway
| | - Kristian Kinden Lensjø
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway
- Center for Integrative Neuroplasticity, University of Oslo, 0316 Oslo, Norway
| | - Mattis Brænne Wigestrand
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway
- Center for Integrative Neuroplasticity, University of Oslo, 0316 Oslo, Norway
| | - Anders Malthe-Sørenssen
- Center for Integrative Neuroplasticity, University of Oslo, 0316 Oslo, Norway
- Department of Physics, University of Oslo, 0316 Oslo, Norway
| | - Torkel Hafting
- Center for Integrative Neuroplasticity, University of Oslo, 0316 Oslo, Norway
- Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway
| | - Marianne Fyhn
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway;
- Center for Integrative Neuroplasticity, University of Oslo, 0316 Oslo, Norway
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14
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Manassero E, Renna A, Milano L, Sacchetti B. Lateral and Basal Amygdala Account for Opposite Behavioral Responses during the Long-Term Expression of Fearful Memories. Sci Rep 2018; 8:518. [PMID: 29323226 PMCID: PMC5765149 DOI: 10.1038/s41598-017-19074-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 10/26/2017] [Indexed: 12/19/2022] Open
Abstract
Memories of fearful events can be maintained throughout the lifetime of animals. Here we showed that lesions of the lateral nucleus (LA) performed shortly after training impaired the retention of long-term memories, assessed by the concomitant measurement of two dissociable defensive responses, freezing and avoidance in rats. Strikingly, when LA lesions were performed four weeks after training, rats did not show freezing to a learned threat stimulus, but they were able to direct their responses away from it. Similar results were found when the central nucleus (CeA) was lesioned four weeks after training, whereas lesions of the basal nucleus (BA) suppressed avoidance without affecting freezing. LA and BA receive parallel inputs from the auditory cortex, and optogenetic inhibition of these terminals hampered both freezing and avoidance. We therefore propose that, at variance with the traditional serial flow of information model, long-term fearful memories recruit two parallel circuits in the amygdala, one relying on the LA-to-CeA pathway and the other relying solely on BA, which operate independently and mediate distinct defensive responses.
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Affiliation(s)
- Eugenio Manassero
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125, Turin, Italy
| | - Annamaria Renna
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125, Turin, Italy
| | - Luisella Milano
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125, Turin, Italy
| | - Benedetto Sacchetti
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125, Turin, Italy. .,National Institute of Neuroscience, Turin, Italy.
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15
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Cambiaghi M, Renna A, Milano L, Sacchetti B. Reversible Inactivation of the Higher Order Auditory Cortex during Fear Memory Consolidation Prevents Memory-Related Activity in the Basolateral Amygdala during Remote Memory Retrieval. Front Behav Neurosci 2017; 11:138. [PMID: 28790901 PMCID: PMC5524669 DOI: 10.3389/fnbeh.2017.00138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/13/2017] [Indexed: 02/03/2023] Open
Abstract
Recent findings have shown that the auditory cortex, and specifically the higher order Te2 area, is necessary for the consolidation of long-term fearful memories and that it interacts with the amygdala during the retrieval of long-term fearful memories. Here, we tested whether the reversible blockade of Te2 during memory consolidation may affect the activity changes occurring in the amygdala during the retrieval of fearful memories. To address this issue, we blocked Te2 in a reversible manner during memory consolidation processes. After 4 weeks, we assessed the activity of Te2 and individual nuclei of the amygdala during the retrieval of long-term memories. Rats in which Te2 was inactivated upon memory encoding showed a decreased freezing and failed to show Te2-to-basolateral amygdala (BLA) synchrony during memory retrieval. In addition, the expression of the immediate early gene zif268 in the lateral, basal and central amygdala nuclei did not show memory-related enhancement. As all sites were intact upon memory retrieval, we propose that the auditory cortex represents a key node in the consolidation of fear memories and it is essential for amygdala nuclei to support memory retrieval process.
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Affiliation(s)
- Marco Cambiaghi
- Rita Levi-Montalcini Department of Neuroscience, University of TurinTurin, Italy
| | - Annamaria Renna
- Rita Levi-Montalcini Department of Neuroscience, University of TurinTurin, Italy
| | - Luisella Milano
- Rita Levi-Montalcini Department of Neuroscience, University of TurinTurin, Italy
| | - Benedetto Sacchetti
- Rita Levi-Montalcini Department of Neuroscience, University of TurinTurin, Italy.,Institute of NeuroscienceTurin, Italy
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16
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Cho JH, Rendall SD, Gray JM. Brain-wide maps of Fos expression during fear learning and recall. ACTA ACUST UNITED AC 2017; 24:169-181. [PMID: 28331016 PMCID: PMC5362696 DOI: 10.1101/lm.044446.116] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 02/23/2017] [Indexed: 12/12/2022]
Abstract
Fos induction during learning labels neuronal ensembles in the hippocampus that encode a specific physical environment, revealing a memory trace. In the cortex and other regions, the extent to which Fos induction during learning reveals specific sensory representations is unknown. Here we generate high-quality brain-wide maps of Fos mRNA expression during auditory fear conditioning and recall in the setting of the home cage. These maps reveal a brain-wide pattern of Fos induction that is remarkably similar among fear conditioning, shock-only, tone-only, and fear recall conditions, casting doubt on the idea that Fos reveals auditory-specific sensory representations. Indeed, novel auditory tones lead to as much gene induction in visual as in auditory cortex, while familiar (nonconditioned) tones do not appreciably induce Fos anywhere in the brain. Fos expression levels do not correlate with physical activity, suggesting that they are not determined by behavioral activity-driven alterations in sensory experience. In the thalamus, Fos is induced more prominently in limbic than in sensory relay nuclei, suggesting that Fos may be most sensitive to emotional state. Thus, our data suggest that Fos expression during simple associative learning labels ensembles activated generally by arousal rather than specifically by a particular sensory cue.
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Affiliation(s)
- Jin-Hyung Cho
- Genetics Department, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Sam D Rendall
- Genetics Department, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Jesse M Gray
- Genetics Department, Harvard Medical School, Boston, Massachusetts 02115, USA
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17
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Patricio RR, Soares JCK, Oliveira MGM. M1 muscarinic receptors are necessary for retrieval of remote context fear memory. Physiol Behav 2017; 169:202-207. [PMID: 27940145 DOI: 10.1016/j.physbeh.2016.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/17/2016] [Accepted: 12/02/2016] [Indexed: 11/17/2022]
Abstract
Several studies have investigated the transition of consolidation of recent memory to remote memory in aversively motivated tasks, such as contextual fear conditioning (CFC) and inhibitory avoidance (IA). However, the mechanisms that serve the retrieval of remote memories, has not yet been fully understood. Some evidences suggest that the central cholinergic system appears be involved in the modulation of these processes. Therefore, the present study aimed to investigate the effects of a pre-test administration of dicyclomine, a high-affinity M1 muscarinic receptor antagonist, on the retrieval of remote memories in fear conditioning and IA tasks. Male Wistar rats were trained, and after 1 or 28days, the rats received dicyclomine (16 or 32mg/kg, intraperitoneally, i.p.) and were tested in CFC, tone fear conditioning (TFC) and IA tasks. At both time intervals, 32mg/kg dicyclomine induced impairment of CFC. In TFC task only the performance of the rats 28days after training was impaired. The IA task was not affected in any of the studied intervals. These findings suggest a differential contribution of muscarinic receptors on recent and remote memories retrieval revealing a more generalized role in remote memory.
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18
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Wigestrand MB, Schiff HC, Fyhn M, LeDoux JE, Sears RM. Primary auditory cortex regulates threat memory specificity. Learn Mem 2017; 24:55-58. [PMID: 27980076 PMCID: PMC5159661 DOI: 10.1101/lm.044362.116] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 10/24/2016] [Indexed: 01/26/2023]
Abstract
Distinguishing threatening from nonthreatening stimuli is essential for survival and stimulus generalization is a hallmark of anxiety disorders. While auditory threat learning produces long-lasting plasticity in primary auditory cortex (Au1), it is not clear whether such Au1 plasticity regulates memory specificity or generalization. We used muscimol infusions in rats to show that discriminatory threat learning requires Au1 activity specifically during memory acquisition and retrieval, but not during consolidation. Memory specificity was similarly disrupted by infusion of PKMζ inhibitor peptide (ZIP) during memory storage. Our findings show that Au1 is required at critical memory phases and suggest that Au1 plasticity enables stimulus discrimination.
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Affiliation(s)
- Mattis B Wigestrand
- Center for Neuroscience, New York University, New York, New York 10003, USA
- Department of Molecular Biosciences, University of Oslo, 0371 Oslo, Norway
| | - Hillary C Schiff
- Center for Neuroscience, New York University, New York, New York 10003, USA
| | - Marianne Fyhn
- Department of Molecular Biosciences, University of Oslo, 0371 Oslo, Norway
| | - Joseph E LeDoux
- Center for Neuroscience, New York University, New York, New York 10003, USA
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 10962, USA
| | - Robert M Sears
- Center for Neuroscience, New York University, New York, New York 10003, USA
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 10962, USA
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19
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Bergstrom HC. The neurocircuitry of remote cued fear memory. Neurosci Biobehav Rev 2016; 71:409-417. [PMID: 27693699 DOI: 10.1016/j.neubiorev.2016.09.028] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 09/25/2016] [Accepted: 09/27/2016] [Indexed: 11/16/2022]
Abstract
Memories of threatening, fear-evoking events can persist even over a lifetime. While fear memory is widely considered to be a highly persistent and durable form of memory, its circuits are not. This article reviews the dynamic temporal representation of remote fear memory in the brain, at the level of local circuits and distributed networks. Data from the study of Pavlovian cued fear conditioning suggests memory retrieval remains amygdala-dependent, even over protracted time scales, all the while interconnected cortical and subcortical circuits are newly recruited and progressively reorganized. A deeper understanding into how the neurocircuitry of cued fear memory reorganizes with the passage of time will advance our ongoing search for the elusive physical changes representing fear memories in the brain. Considering that persistent, pathological fear memories are a hallmark feature of post-traumatic stress disorder (PTSD), the behavioral and circuit-level study of remote cued fear memory retrieval adds a key element towards a systems understanding of PTSD.
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Affiliation(s)
- Hadley C Bergstrom
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, NY 12604, United States.
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20
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Cho JH, Huang BS, Gray JM. RNA sequencing from neural ensembles activated during fear conditioning in the mouse temporal association cortex. Sci Rep 2016; 6:31753. [PMID: 27557751 PMCID: PMC4997356 DOI: 10.1038/srep31753] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 07/25/2016] [Indexed: 12/13/2022] Open
Abstract
The stable formation of remote fear memories is thought to require neuronal gene induction in cortical ensembles that are activated during learning. However, the set of genes expressed specifically in these activated ensembles is not known; knowledge of such transcriptional profiles may offer insights into the molecular program underlying stable memory formation. Here we use RNA-Seq to identify genes whose expression is enriched in activated cortical ensembles labeled during associative fear learning. We first establish that mouse temporal association cortex (TeA) is required for remote recall of auditory fear memories. We then perform RNA-Seq in TeA neurons that are labeled by the activity reporter Arc-dVenus during learning. We identify 944 genes with enriched expression in Arc-dVenus+ neurons. These genes include markers of L2/3, L5b, and L6 excitatory neurons but not glial or inhibitory markers, confirming Arc-dVenus to be an excitatory neuron-specific but non-layer-specific activity reporter. Cross comparisons to other transcriptional profiles show that 125 of the enriched genes are also activity-regulated in vitro or induced by visual stimulus in the visual cortex, suggesting that they may be induced generally in the cortex in an experience-dependent fashion. Prominent among the enriched genes are those encoding potassium channels that down-regulate neuronal activity, suggesting the possibility that part of the molecular program induced by fear conditioning may initiate homeostatic plasticity.
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Affiliation(s)
- Jin-Hyung Cho
- Harvard Medical School, Genetics Department, 77 Ave Louis Pasteur NRB Room 356, Boston, Massachusetts 02115, USA
| | - Ben S Huang
- Harvard Medical School, Genetics Department, 77 Ave Louis Pasteur NRB Room 356, Boston, Massachusetts 02115, USA.,University of California at Los Angeles, David Geffen School of Medicine, Department of Neurology, 710 Westwood Plaza, Los Angeles, California 90095, USA
| | - Jesse M Gray
- Harvard Medical School, Genetics Department, 77 Ave Louis Pasteur NRB Room 356, Boston, Massachusetts 02115, USA
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21
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Do Monte FH, Quirk GJ, Li B, Penzo MA. Retrieving fear memories, as time goes by…. Mol Psychiatry 2016; 21:1027-36. [PMID: 27217148 PMCID: PMC4956525 DOI: 10.1038/mp.2016.78] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/22/2016] [Accepted: 04/05/2016] [Indexed: 12/12/2022]
Abstract
Research in fear conditioning has provided a comprehensive picture of the neuronal circuit underlying the formation of fear memories. In contrast, our understanding of the retrieval of fear memories is much more limited. This disparity may stem from the fact that fear memories are not rigid, but reorganize over time. To bring some clarity and raise awareness about the time-dependent dynamics of retrieval circuits, we review current evidence on the neuronal circuitry participating in fear memory retrieval at both early and late time points following auditory fear conditioning. We focus on the temporal recruitment of the paraventricular nucleus of the thalamus (PVT) for the retrieval and maintenance of fear memories. Finally, we speculate as to why retrieval circuits change with time, and consider the functional strategy of recruiting structures not previously considered as part of the retrieval circuit.
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Affiliation(s)
- Fabricio H. Do Monte
- Departments of Psychiatry and Anatomy & Neurobiology, University of Puerto Rico School of Medicine, PO Box 365067, San Juan 00936, Puerto Rico
| | - Gregory J. Quirk
- Departments of Psychiatry and Anatomy & Neurobiology, University of Puerto Rico School of Medicine, PO Box 365067, San Juan 00936, Puerto Rico
| | - Bo Li
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Mario A. Penzo
- National Institute of Mental Health, 35 Convent Drive, Bldg. 35A Room 2E621, Bethesda, MD 20850
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22
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The higher order auditory cortex is involved in the assignment of affective value to sensory stimuli. Nat Commun 2015; 6:8886. [PMID: 26619940 PMCID: PMC5482717 DOI: 10.1038/ncomms9886] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 10/14/2015] [Indexed: 11/16/2022] Open
Abstract
The sensory cortex participates in emotional memory but its role is poorly understood. Here we show that inactivation of the higher order auditory cortex Te2 in rats during early memory consolidation impairs remote first- and second-order fear memories but not the association between two neutral cues. Furthermore, Te2 inactivation prevents changes in the valence of such information. Following the presentation of two auditory cues previously paired with either pleasant or painful stimuli, a large percentage of cells responds to both experiences but also a small fraction of neurons responds exclusively to one of them. The latter type of neurons signals the valence rather than the salience or the motor responses associated with the stimuli, and reflects selective associative processes. Pharmacogenetic silencing of memory-activated neurons causes amnesia. Thus, Te2 represents a crucial node for the assignment of the affective value to sensory stimuli and for the storage of such information. The auditory cortex Te2 represents a key node for the assignment of the affective value to sensory stimuli in rodents. Using pharmacogenetic manipulations, this study shows that in Te2 there are neurons which respond to the emotional valence of sounds and their inactivation impairs emotional memories retrieval.
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23
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Cambiaghi M, Grosso A, Renna A, Concina G, Sacchetti B. Acute administration of nicotine into the higher order auditory Te2 cortex specifically decreases the fear-related charge of remote emotional memories. Neuropharmacology 2015; 99:577-88. [PMID: 26319210 PMCID: PMC4710760 DOI: 10.1016/j.neuropharm.2015.08.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 08/19/2015] [Accepted: 08/21/2015] [Indexed: 01/10/2023]
Abstract
Nicotine elicits several behavioural effects on mood as well as on stress and anxiety processes. Recently, it was found that the higher order components of the sensory cortex, such as the secondary auditory cortex Te2, are essential for the long-term storage of remote fear memories. Therefore, in the present study, we examined the effects of acute nicotine injection into the higher order auditory cortex Te2, on the remote emotional memories of either threat or incentive experiences in rats. We found that intra-Te2 nicotine injection decreased the fear-evoked responses to a tone previously paired with footshock. This effect was cue- and dose-specific and was not due to any interference with auditory stimuli processing, innate anxiety and fear processes, or with motor responses. Nicotine acts acutely in the presence of threat stimuli but it did not determine the permanent degradation of the fear-memory trace, since memories tested one week after nicotine injection were unaffected. Remarkably, nicotine did not affect the memory of a similar tone that was paired to incentive stimuli. We conclude from our results that nicotine, when acting acutely in the auditory cortex, relieves the fear charge embedded by learned stimuli. Nicotine reliefs fear memories. Nicotine acts on long-term memories. Nicotine modulates memory in auditory cortex.
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Affiliation(s)
- Marco Cambiaghi
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125 Turin, Italy.
| | - Anna Grosso
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125 Turin, Italy.
| | - Annamaria Renna
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125 Turin, Italy.
| | - Giulia Concina
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125 Turin, Italy.
| | - Benedetto Sacchetti
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125 Turin, Italy; National Institute of Neuroscience, Italy.
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24
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Grosso A, Cambiaghi M, Concina G, Sacco T, Sacchetti B. Auditory cortex involvement in emotional learning and memory. Neuroscience 2015; 299:45-55. [PMID: 25943482 DOI: 10.1016/j.neuroscience.2015.04.068] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 04/23/2015] [Accepted: 04/28/2015] [Indexed: 01/16/2023]
Abstract
Emotional memories represent the core of human and animal life and drive future choices and behaviors. Early research involving brain lesion studies in animals lead to the idea that the auditory cortex participates in emotional learning by processing the sensory features of auditory stimuli paired with emotional consequences and by transmitting this information to the amygdala. Nevertheless, electrophysiological and imaging studies revealed that, following emotional experiences, the auditory cortex undergoes learning-induced changes that are highly specific, associative and long lasting. These studies suggested that the role played by the auditory cortex goes beyond stimulus elaboration and transmission. Here, we discuss three major perspectives created by these data. In particular, we analyze the possible roles of the auditory cortex in emotional learning, we examine the recruitment of the auditory cortex during early and late memory trace encoding, and finally we consider the functional interplay between the auditory cortex and subcortical nuclei, such as the amygdala, that process affective information. We conclude that, starting from the early phase of memory encoding, the auditory cortex has a more prominent role in emotional learning, through its connections with subcortical nuclei, than is typically acknowledged.
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Affiliation(s)
- A Grosso
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125 Turin, Italy
| | - M Cambiaghi
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125 Turin, Italy
| | - G Concina
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125 Turin, Italy
| | - T Sacco
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125 Turin, Italy
| | - B Sacchetti
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, Corso Raffaello 30, I-10125 Turin, Italy; National Institute of Neuroscience, Italy.
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Daws SE, Vaissière T, Miller CA. Neuroepigenetic Regulation of Pathogenic Memories. NEUROEPIGENETICS 2015; 1:28-33. [PMID: 25642412 PMCID: PMC4310006 DOI: 10.1016/j.nepig.2014.10.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Our unique collection of memories determines our individuality and shapes our future interactions with the world. Remarkable advances into the neurobiological basis of memory have identified key epigenetic mechanisms that support the stability of memory. Various forms of epigenetic regulation at the levels of DNA methylation, histone modification, and non-coding RNAs (ncRNAs) can modulate transcriptional and translational events required for memory processes. By changing the cellular profile in the brain's emotional, reward, and memory circuits, these epigenetic modifications have also been linked to perseverant, pathogenic memories. In this review, we will delve into the relevance of epigenetic dysregulation to pathogenic memory mechanisms by focusing on two neuropsychiatric disorders perpetuated by aberrant memory associations: substance use disorder (SUD) and post-traumatic stress disorder (PTSD). As our understanding improves, neuroepigenetic mechanisms may someday be harnessed to develop novel therapeutic targets for the treatment of these chronic, relapsing disorders.
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Affiliation(s)
- Stephanie E Daws
- Department of Metabolism & Aging, Department of Neuroscience, The Scripps Research Institute, Jupiter, FL USA
| | - Thomas Vaissière
- Department of Metabolism & Aging, Department of Neuroscience, The Scripps Research Institute, Jupiter, FL USA
| | - Courtney A Miller
- Department of Metabolism & Aging, Department of Neuroscience, The Scripps Research Institute, Jupiter, FL USA
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Hebbian and neuromodulatory mechanisms interact to trigger associative memory formation. Proc Natl Acad Sci U S A 2014; 111:E5584-92. [PMID: 25489081 DOI: 10.1073/pnas.1421304111] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A long-standing hypothesis termed "Hebbian plasticity" suggests that memories are formed through strengthening of synaptic connections between neurons with correlated activity. In contrast, other theories propose that coactivation of Hebbian and neuromodulatory processes produce the synaptic strengthening that underlies memory formation. Using optogenetics we directly tested whether Hebbian plasticity alone is both necessary and sufficient to produce physiological changes mediating actual memory formation in behaving animals. Our previous work with this method suggested that Hebbian mechanisms are sufficient to produce aversive associative learning under artificial conditions involving strong, iterative training. Here we systematically tested whether Hebbian mechanisms are necessary and sufficient to produce associative learning under more moderate training conditions that are similar to those that occur in daily life. We measured neural plasticity in the lateral amygdala, a brain region important for associative memory storage about danger. Our findings provide evidence that Hebbian mechanisms are necessary to produce neural plasticity in the lateral amygdala and behavioral memory formation. However, under these conditions Hebbian mechanisms alone were not sufficient to produce these physiological and behavioral effects unless neuromodulatory systems were coactivated. These results provide insight into how aversive experiences trigger memories and suggest that combined Hebbian and neuromodulatory processes interact to engage associative aversive learning.
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Kwon JT, Nakajima R, Kim HS, Jeong Y, Augustine GJ, Han JH. Optogenetic activation of presynaptic inputs in lateral amygdala forms associative fear memory. ACTA ACUST UNITED AC 2014; 21:627-33. [PMID: 25322798 PMCID: PMC4201812 DOI: 10.1101/lm.035816.114] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In Pavlovian fear conditioning, the lateral amygdala (LA) has been highlighted as a key brain site for association between sensory cues and aversive stimuli. However, learning-related changes are also found in upstream sensory regions such as thalamus and cortex. To isolate the essential neural circuit components for fear memory association, we tested whether direct activation of presynaptic sensory inputs in LA, without the participation of upstream activity, is sufficient to form fear memory in mice. Photostimulation of axonal projections from the two main auditory brain regions, the medial geniculate nucleus of the thalamus and the secondary auditory cortex, was paired with aversive footshock. Twenty-four hours later the same photostimulation induced robust conditioned freezing and this fear memory formation was disrupted when glutamatergic synaptic transmission was locally blocked in the LA. Therefore, our results prove for the first time that synapses between sensory input areas and the LA, previously implicated as a crucial brain site for fear memory formation, actually are sufficient to serve as a conditioned stimulus. Our results strongly support the idea that the LA may be sufficient to encode and store associations between neutral cue and aversive stimuli during natural fear conditioning as a critical part of a broad fear memory engram.
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Affiliation(s)
- Jeong-Tae Kwon
- Department of Biological Sciences, KAIST Institute for the BioCentury (KIB), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea
| | - Ryuichi Nakajima
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul 136-791, Korea
| | - Hyung-Su Kim
- Department of Biological Sciences, KAIST Institute for the BioCentury (KIB), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul 136-791, Korea
| | - Yire Jeong
- Department of Biological Sciences, KAIST Institute for the BioCentury (KIB), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea
| | - George J Augustine
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul 136-791, Korea Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 637553, Singapore Institute of Molecular and Cell Biology, Singapore 138673, Singapore
| | - Jin-Hee Han
- Department of Biological Sciences, KAIST Institute for the BioCentury (KIB), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea
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Extinction of remotely acquired fear depends on an inhibitory NR2B/PKA pathway in the retrosplenial cortex. J Neurosci 2014; 33:19492-8. [PMID: 24336715 DOI: 10.1523/jneurosci.3338-13.2013] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
As memories age, their processing increasingly relies upon cortical rather than hippocampal circuits, but the adaptive significance and mechanisms of this shift are not fully understood. Here we investigated the behavioral features and cortical mechanisms underlying extinction of remotely versus recently acquired context fear in mice. Behaviorally, extinction and reinstatement were similar, but re-extinction of remote fear was significantly faster, suggesting time-dependent engagement of mechanisms specific for processing remote memory. Using pharmacological manipulations of NMDA receptors and associated signaling pathways in the in the retrosplenial cortex, we demonstrated that extinction of remote fear uniquely required NR2B-mediated downregulation of the cAMP-dependent protein kinase (PKA)/cAMP response element-binding protein pathway. Interestingly, NR2B/PKA interactions weakened independently of the age of the memory, but the functional significance of this molecular change was evident only as memory retrieval became PKA-dependent over time. Thus, cortical PKA signaling may provide a molecular signature of when a memory has become "remote," and inhibition of this pathway may open the door for modulation of remote memories.
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Veyrac A, Besnard A, Caboche J, Davis S, Laroche S. The transcription factor Zif268/Egr1, brain plasticity, and memory. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 122:89-129. [PMID: 24484699 DOI: 10.1016/b978-0-12-420170-5.00004-0] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The capacity to remember our past experiences and organize our future draws on a number of cognitive processes that allow our brain to form and store neural representations that can be recalled and updated at will. In the brain, these processes require mechanisms of neural plasticity in the activated circuits, brought about by cellular and molecular changes within the neurons activated during learning. At the cellular level, a wealth of experimental data accumulated in recent years provides evidence that signaling from synapses to nucleus and the rapid regulation of the expression of immediate early genes encoding inducible, regulatory transcription factors is a key step in the mechanisms underlying synaptic plasticity and the modification of neural networks required for the laying down of memories. In the activated neurons, these transcriptional events are thought to mediate the activation of selective gene programs and subsequent synthesis of proteins, leading to stable functional and structural remodeling of the activated networks, so that the memory can later be reactivated upon recall. Over the past few decades, novel insights have been gained in identifying key transcriptional regulators that can control the genomic response of synaptically activated neurons. Here, as an example of this approach, we focus on one such activity-dependent transcription factor, Zif268, known to be implicated in neuronal plasticity and memory formation. We summarize current knowledge about the regulation and function of Zif268 in different types of brain plasticity and memory processes.
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Affiliation(s)
- Alexandra Veyrac
- CNRS, Centre de Neurosciences Paris-Sud, UMR 8195, Orsay, France; Centre de Neurosciences Paris-Sud, Univ Paris-Sud, UMR 8195, Orsay, France
| | - Antoine Besnard
- Harvard Stem Cell Institute, Harvard Medical School, Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Jocelyne Caboche
- INSERM, UMRS 952, Physiopathologie des Maladies du Système Nerveux Central, Paris, France; CNRS, UMR7224, Physiopathologie des Maladies du Système Nerveux Central, Paris, France; UPMC University Paris 6, Paris, France
| | - Sabrina Davis
- CNRS, Centre de Neurosciences Paris-Sud, UMR 8195, Orsay, France; Centre de Neurosciences Paris-Sud, Univ Paris-Sud, UMR 8195, Orsay, France
| | - Serge Laroche
- CNRS, Centre de Neurosciences Paris-Sud, UMR 8195, Orsay, France; Centre de Neurosciences Paris-Sud, Univ Paris-Sud, UMR 8195, Orsay, France
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Recall and reconsolidation of contextual fear memory: differential control by ERK and Zif268 expression dosage. PLoS One 2013; 8:e72006. [PMID: 23977192 PMCID: PMC3745394 DOI: 10.1371/journal.pone.0072006] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 07/11/2013] [Indexed: 12/04/2022] Open
Abstract
Compelling evidence points to the existence of independent cellular processes involved in the consolidation and reconsolidation of memory. For instance, a double dissociation has been reported between hippocampal Extracellular-Regulated Kinase-1/2 (ERK1/2) activity being necessary for contextual fear conditioning (CFC) consolidation but not reconsolidation. Conversely, hippocampal expression of the immediate early gene Zif268 is necessary for CFC reconsolidation but not consolidation. Since we previously reported that ERK1/2 controls the transcription of Zif268 in the hippocampus, we examined the precise role of ERK1/2 activity and Zif268 gene expression dosage in CFC memory processing. For this, we first assessed performance of Zif268 homozygous and heterozygous mutant mice in a CFC paradigm. Whereas Zif268−/− mice displayed a deficit of both consolidation and reconsolidation, Zif268+/− mice displayed a selective deficit of reconsolidation only, therefore pointing to the relationship between Zif268 gene expression dosage and CFC memory processing. Zif268 gene expression dosage interfered with the reconsolidation process if and only if CFC memory was relatively recently encoded and directly reactivated. Furthermore, CFC memory strengthening previously reported to involve Zif268 expression in the hippocampus was spared in Zif268+/− mice. Finally, blocking ERK1/2 activity prior to CFC retrieval prevented the deficit of reconsolidation observed in Zif268+/− mice. Collectively, these results highlight a tight relationship between Zif268 gene expression dosage and CFC memory processing. They also suggest that ERK1/2 activity upon CFC memory recall is necessary for its retrieval, a prerequisite for its reactivation and subsequent reconsolidation.
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