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Masella G, Silva F, Corti E, Azkona G, Madeira MF, Tomé ÂR, Ferreira SG, Cunha RA, Duarte CB, Santos M. The amygdala NT3-TrkC pathway underlies inter-individual differences in fear extinction and related synaptic plasticity. Mol Psychiatry 2024; 29:1322-1337. [PMID: 38233468 PMCID: PMC11189811 DOI: 10.1038/s41380-024-02412-z] [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: 06/13/2023] [Revised: 12/29/2023] [Accepted: 01/04/2024] [Indexed: 01/19/2024]
Abstract
Fear-related pathologies are among the most prevalent psychiatric conditions, having inappropriate learned fear and resistance to extinction as cardinal features. Exposure therapy represents a promising therapeutic approach, the efficiency of which depends on inter-individual variation in fear extinction learning, which neurobiological basis is unknown. We characterized a model of extinction learning, whereby fear-conditioned mice were categorized as extinction (EXT)-success or EXT-failure, according to their inherent ability to extinguish fear. In the lateral amygdala, GluN2A-containing NMDAR are required for LTP and stabilization of fear memories, while GluN2B-containing NMDAR are required for LTD and fear extinction. EXT-success mice showed attenuated LTP, strong LTD and higher levels of synaptic GluN2B, while EXT-failure mice showed strong LTP, no LTD and higher levels of synaptic GluN2A. Neurotrophin 3 (NT3) infusion in the lateral amygdala was sufficient to rescue extinction deficits in EXT-failure mice. Mechanistically, activation of tropomyosin receptor kinase C (TrkC) with NT3 in EXT-failure slices attenuated lateral amygdala LTP, in a GluN2B-dependent manner. Conversely, blocking endogenous NT3-TrkC signaling with TrkC-Fc chimera in EXT-success slices strengthened lateral amygdala LTP. Our data support a key role for the NT3-TrkC system in inter-individual differences in fear extinction in rodents, through modulation of amygdalar NMDAR composition and synaptic plasticity.
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Affiliation(s)
- Gianluca Masella
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research, University of Coimbra (iiiUC), Coimbra, Portugal
| | - Francisca Silva
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research, University of Coimbra (iiiUC), Coimbra, Portugal
| | - Elisa Corti
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research, University of Coimbra (iiiUC), Coimbra, Portugal
| | - Garikoitz Azkona
- Department of Basic Psychological Processes and Their Development, School of Psychology, University of the Basque Country (UPV/EHU), San Sebastian, Spain
| | - Maria Francisca Madeira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research, University of Coimbra (iiiUC), Coimbra, Portugal
| | - Ângelo R Tomé
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Samira G Ferreira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research, University of Coimbra (iiiUC), Coimbra, Portugal
| | - Rodrigo A Cunha
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Carlos B Duarte
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Mónica Santos
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
- Institute of Interdisciplinary Research, University of Coimbra (iiiUC), Coimbra, Portugal.
- Centre for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, Coimbra, Portugal.
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Trask J, MacCallum PE, Rideout H, Preisser EL, Blundell JJ. Rapamycin attenuates reconsolidation of a backwards-conditioned aversive stimuli in female mice. Psychopharmacology (Berl) 2024; 241:601-612. [PMID: 38311691 DOI: 10.1007/s00213-024-06544-6] [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: 08/21/2023] [Accepted: 01/20/2024] [Indexed: 02/06/2024]
Abstract
RATIONALE The mammalian target of rapamycin (mTOR) kinase is known to mediate consolidation and reconsolidation of aversive memories. Most studies in this area use a forward conditioning paradigm in which the conditioned stimulus (CS) precedes the unconditioned stimulus (US). Little is known, however, about the neurobiological underpinnings of backwards (BW) conditioning paradigms, particularly in female mice. In BW conditioning, the CS does not become directly associated with the US; it instead evokes conditioned fear by reactivating a memory of the conditioning context and indirectly retrieving a memory of the aversive US. OBJECTIVES We sought to examine BW conditioned fear memory processes in female mice. First, we examined whether freezing to a BW CS is mediated by fear to the conditioning context. Second, we tested whether blocking consolidation of a BW CS attenuated memory of the CS and conditioning context. Finally, we tested whether blocking reconsolidation of a BW CS attenuated memory of the conditioning context. RESULTS We show that conditioned freezing to a BW CS is mediated by fear to the conditioning context. Furthermore, rapamycin-an mTOR inhibitor, when given immediately following BW conditioning, impairs consolidation of both cued and contextual fear memory. Similarly, rapamycin given following retrieval of a BW CS blocks context recall. Rapamycin is acting on reconsolidation as CS retrieval is necessary to see the effects of rapamycin on context memory recall. CONCLUSIONS Our study provides novel evidence that indirect retrieval cues are sensitive to rapamycin in female mice. The capacity to indirectly reactivate memories and render them susceptible to disruption is critical in the translation of reconsolidation-based approaches to the clinic.
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Affiliation(s)
- Jared Trask
- Department of Psychology, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada
| | - Phillip E MacCallum
- Department of Psychology, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada
| | - Haley Rideout
- Department of Psychology, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada
| | - Evan L Preisser
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, 02881, USA
| | - Jacqueline J Blundell
- Department of Psychology, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada.
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Frankland PW. Editorial: Special Issue honouring Karim Nader's contributions to memory research. Brain Res Bull 2023; 198:53-54. [PMID: 37105360 DOI: 10.1016/j.brainresbull.2023.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Affiliation(s)
- Paul W Frankland
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Canada; Department of Psychology, University of Toronto, Toronto, Canada; Department of Physiology, University of Toronto, Toronto, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Canada; Child & Brain Development Program, Canadian Institute for Advanced Research, Toronto, Canada
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