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Dirven BCJ, van Melis L, Daneva T, Dillen L, Homberg JR, Kozicz T, Henckens MJAG. Hippocampal Trauma Memory Processing Conveying Susceptibility to Traumatic Stress. Neuroscience 2024; 540:87-102. [PMID: 38220126 DOI: 10.1016/j.neuroscience.2024.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 12/04/2023] [Accepted: 01/10/2024] [Indexed: 01/16/2024]
Abstract
While the majority of the population is ever exposed to a traumatic event during their lifetime, only a fraction develops posttraumatic stress disorder (PTSD). Disrupted trauma memory processing has been proposed as a core factor underlying PTSD symptomatology. We used transgenic Targeted-Recombination-in-Active-Populations (TRAP) mice to investigate potential alterations in trauma-related hippocampal memory engrams associated with the development of PTSD-like symptomatology. Mice were exposed to a stress-enhanced fear learning paradigm, in which prior exposure to a stressor affects the learning of a subsequent fearful event (contextual fear conditioning using foot shocks), during which neuronal activity was labeled. One week later, mice were behaviorally phenotyped to identify mice resilient and susceptible to developing PTSD-like symptomatology. Three weeks post-learning, mice were re-exposed to the conditioning context to induce remote fear memory recall, and associated hippocampal neuronal activity was assessed. While no differences in the size of the hippocampal neuronal ensemble activated during fear learning were observed between groups, susceptible mice displayed a smaller ensemble activated upon remote fear memory recall in the ventral CA1, higher regional hippocampal parvalbuminneuronal density and a relatively lower activity of parvalbumininterneurons upon recall. Investigation of potential epigenetic regulators of the engram revealed rather generic (rather than engram-specific) differences between groups, with susceptible mice displaying lower hippocampal histone deacetylase 2 expression, and higher methylation and hydroxymethylation levels. These finding implicate variation in epigenetic regulation within the hippocampus, as well as reduced regional hippocampal activity during remote fear memory recall in interindividual differences in susceptibility to traumatic stress.
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Affiliation(s)
- Bart C J Dirven
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands; Department of Medical Imaging, Anatomy, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Lennart van Melis
- Department of Medical Imaging, Anatomy, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Teya Daneva
- Department of Medical Imaging, Anatomy, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Lieke Dillen
- Department of Medical Imaging, Anatomy, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Judith R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Tamas Kozicz
- Department of Medical Imaging, Anatomy, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands; Center for Individualized Medicine, Department of Clinical Genomics, and Biochemical Genetics Laboratory, Mayo Clinic, Rochester, MN 55905, USA; University of Pecs Medical School, Department of Anatomy, Pecs, Hungary
| | - Marloes J A G Henckens
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands.
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Chelini G, Trombetta EM, Fortunato-Asquini T, Ollari O, Pecchia T, Bozzi Y. Automated Segmentation of the Mouse Body Language to Study Stimulus-Evoked Emotional Behaviors. eNeuro 2023; 10:ENEURO.0514-22.2023. [PMID: 37648448 PMCID: PMC10496135 DOI: 10.1523/eneuro.0514-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 07/15/2023] [Accepted: 07/24/2023] [Indexed: 09/01/2023] Open
Abstract
Understanding the neural basis of emotions is a critical step to uncover the biological substrates of neuropsychiatric disorders. To study this aspect in freely behaving mice, neuroscientists have relied on the observation of ethologically relevant bodily cues to infer the affective content of the subject, both in neutral conditions or in response to a stimulus. The best example of that is the widespread assessment of freezing in experiments testing both conditioned and unconditioned fear responses. While robust and powerful, these approaches come at a cost: they are usually confined within selected time windows, accounting for only a limited portion of the complexity of emotional fluctuation. Moreover, they often rely on visual inspection and subjective judgment, resulting in inconsistency across experiments and questionable result interpretations. To overcome these limitations, novel tools are arising, fostering a new avenue in the study of the mouse naturalistic behavior. In this work we developed a computational tool [stimulus-evoked behavioral tracking in 3D for rodents (SEB3R)] to automate and standardize an ethologically driven observation of freely moving mice. Using a combination of machine learning-based behavioral tracking and unsupervised cluster analysis, we identified statistically meaningful postures that could be used for empirical inference on a subsecond scale. We validated the efficacy of this tool in a stimulus-driven test, the whisker nuisance (WN) task, where mice are challenged with a prolonged and invasive whisker stimulation, showing that identified postures can be reliably used as a proxy for stimulus-driven fearful and explorative behaviors.
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Affiliation(s)
- Gabriele Chelini
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Rovereto 38068, Italy
| | | | - Tommaso Fortunato-Asquini
- Department of Cellular, Computational, and Integrative Biology (CIBIO), University of Trento, Trento 38123, Italy
| | - Ottavia Ollari
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Rovereto 38068, Italy
| | - Tommaso Pecchia
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Rovereto 38068, Italy
| | - Yuri Bozzi
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Rovereto 38068, Italy
- Consiglio Nazionale delle Ricerche (National Council of Research) Neuroscience Institute, Pisa 56124, Italy
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