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Shan X, Contreras MP, Sawangjit A, Dimitrov S, Born J, Inostroza M. Rearing is critical for forming spatial representations in pre-weanling rats. Behav Brain Res 2023; 452:114545. [PMID: 37321311 DOI: 10.1016/j.bbr.2023.114545] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/24/2023] [Accepted: 06/13/2023] [Indexed: 06/17/2023]
Abstract
Rearing, i.e., standing on the hind limbs in an upright posture, is part of a rat's innate exploratory motor program. Here, we examined in developing rats whether rearing is critical for the pup's capability to form spatial representations based on distal environmental cues. Pups (male) were tested at PD18, i.e., the first day they typically exhibit stable rearing, on a spatial habituation paradigm comprising a Familiarization session (with the pup exposed to an arena with a specific configuration of distal cues) followed, 3 h later, by a Test session where the pups were either re-exposed to the identical distal cue configuration (NoChange) or a changed configuration (DistalChange). In Experiment 1, rearing activity (rearing events, duration) decreased from Familiarization to Test in the NoChange pups but, remained elevated in the DistalChange group indicating that these pups recognized the distal novelty. Recognition of distal novelty was associated with increased c-Fos expression in hippocampal and medial prefrontal cortex (mPFC) areas, compared with NoChange pups. Analysis of GAD67+ cells suggested a parallel increase in excitation and inhibition specifically in prelimbic mPFC networks in response to distal cue changes. In Experiment 2, the pups were mechanically prevented from rearing while still seeing the distal cues during Familiarization. Rearing activity in the Test session of these pups did not differ between groups that were or were not exposed to a changed distal cue configuration at Test. The findings evidence a critical role of rearing for the emergence of allocentric representations integrating distal space during early development.
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Affiliation(s)
- Xia Shan
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; Graduate School of Neural & Behavioural Science, International Max Planck Research School, Tübingen, Germany
| | - María Paz Contreras
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; Graduate School of Neural & Behavioural Science, International Max Planck Research School, Tübingen, Germany
| | - Anuck Sawangjit
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Stoyan Dimitrov
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Jan Born
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; German Center for Diabetes Research (DZD), Institute for Diabetes Research & Metabolic Diseases of the Helmholtz Center Munich at the University Tübingen (IDM), Germany; Werner Reichert Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany; German Center for Mental Health (DZPG), Germany.
| | - Marion Inostroza
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.
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Kubová H, Mikulecká A, Mareš P. The outcome of early life status epilepticus—lessons from laboratory animals. Epilepsia Open 2022; 8 Suppl 1:S90-S109. [PMID: 36352789 PMCID: PMC10173850 DOI: 10.1002/epi4.12664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 10/18/2022] [Indexed: 11/11/2022] Open
Abstract
Status epilepticus (SE) is the most common neurologic emergency in children. Both clinical and laboratory studies have demonstrated that SE in early life can cause brain damage and permanent behavioral abnormalities, trigger epileptogenesis, and interfere with normal brain development. In experimental rodent models, the consequences of seizures are dependent upon age, the model used, and seizure duration. In studies involving neonatal and infantile animals, the model used, experimental design, conditions during the experiment, and manipulation of animals can significantly affect the course of the experiments as well as the results obtained. Standardization of laboratory approaches, harmonization of scientific methodology, and improvement in data collection can improve the comparability of data among laboratories.
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Affiliation(s)
- Hana Kubová
- Developmental Epileptology Institute of Physiology of the Czech Academy of Science Prague Czech Republic
| | - Anna Mikulecká
- Developmental Epileptology Institute of Physiology of the Czech Academy of Science Prague Czech Republic
| | - Pavel Mareš
- Developmental Epileptology Institute of Physiology of the Czech Academy of Science Prague Czech Republic
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Shan X, Contreras MP, Mendez M, Born J, Inostroza M. Unfolding of spatial representation at systems level in infant rats. Hippocampus 2021; 32:121-133. [PMID: 34786798 DOI: 10.1002/hipo.23392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 10/25/2021] [Accepted: 11/01/2021] [Indexed: 11/10/2022]
Abstract
Spatial representations enable navigation from early life on. However, the brain regions essential to form spatial representations, like the hippocampus, are considered functionally immature before weaning. Here, we examined the formation of representations of space in rat pups on postnatal day (PD) 16, using a simple habituation paradigm where the pups were exposed to an arena on three occasions, separated by ~140 min. Whereas on the first two occasions the arena was the same, on the third "test" occasion either proximal cues (Prox group), or distal cues (Dist group), or proximal and distal cues (Prox-Dist group), or no cues (No-change group) were rearranged. Locomotion (distance traveled) was used as behavioral measure of habituation, and c-Fos expression to measure regional brain activity at test. Locomotion generally decreased across the first two occasions. At test, it reached a minimum in the No-change group, indicating familiarity with the spatial conditions. By contrast, the Prox-Dist group displayed a significant increase in locomotion which was less robust in the Prox group and absent in the Dist group, a pattern suggesting that the pups relied more on proximal than distal cues during spatial exploration. c-Fos activity in the No-change group was significantly suppressed in the hippocampus (CA1, CA3, dentate gyrus) but simultaneously enhanced in the prelimbic area (PL) of the medial prefrontal cortex, compared with untreated Home-cage controls, pointing to a possible involvement of the PL in regulating locomotion in familiar spaces. By contrast, in both Prox-Dist and Prox groups c-Fos activity was enhanced in hippocampal CA1 and CA3 regions, suggesting these regions might be particularly involved in regulating exploration of spatial novelty. Our findings show that functional representations of space at a systems level are formed already in pre-weanling rats.
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Affiliation(s)
- Xia Shan
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,Graduate School of Neural & Behavioral Science, International Max Planck Research School, Tübingen, Germany
| | - María P Contreras
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,Graduate School of Neural & Behavioral Science, International Max Planck Research School, Tübingen, Germany
| | - Marta Mendez
- Laboratory of Neuroscience, Department of Psychology, Instituto de Neurociencias del Principado de Asturias (INEUROPA), University of Oviedo, Plaza Feijoo, Oviedo, Spain
| | - Jan Born
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD), Institute for Diabetes Research & Metabolic Diseases of the Helmholtz Center Munich at the University Tübingen (IDM), Tübingen, Germany.,Werner Reichert Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Marion Inostroza
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
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Contreras MP, Born J, Inostroza M. The expression of allocentric object-place recognition memory during development. Behav Brain Res 2019; 372:112013. [DOI: 10.1016/j.bbr.2019.112013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/03/2019] [Accepted: 06/04/2019] [Indexed: 02/04/2023]
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Cowan CSM, Richardson R. A Brief Guide to Studying Fear in Developing Rodents: Important Considerations and Common Pitfalls. ACTA ACUST UNITED AC 2019; 83:e44. [PMID: 30040208 DOI: 10.1002/cpns.44] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Development is a time of rapid change that sets the pathway to adult functioning across all aspects of physical and mental health. Developmental studies can therefore offer insight into the unique needs of individuals at different stages of normal development as well as the etiology of various disease states. The aim of this overview is to provide an introduction to the practical implementation of developmental studies in rats and mice, with an emphasis on the study of learned fear. We first discuss how developmental factors may influence experimental outcomes for any study. This is followed by a discussion of methodological issues to consider when conducting studies of developing rodents, highlighting examples from the literature on learned fear. Throughout, we offer some recommendations to guide researchers on best practice in developmental studies. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
| | - Rick Richardson
- School of Psychology, The University of New South Wales, Sydney, Australia
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Fitting S, McLaurin KA, Booze RM, Mactutus CF. Dose-dependent neurocognitive deficits following postnatal day 10 HIV-1 viral protein exposure: Relationship to hippocampal anatomy parameters. Int J Dev Neurosci 2018; 65:66-82. [PMID: 29111178 PMCID: PMC5889695 DOI: 10.1016/j.ijdevneu.2017.10.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 10/16/2017] [Accepted: 10/23/2017] [Indexed: 11/25/2022] Open
Abstract
Despite the availability of antiretroviral prophylactic treatment, pediatric human immunodeficiency virus type 1 (HIV-1) continues to be a significant risk factor in the post-cART era. The time of infection (i.e., during pregnancy, delivery or breastfeeding) may play a role in the development of neurocognitive deficits in pediatric HIV-1. HIV-1 viral protein exposure on postnatal day (P)1, preceding the postnatal brain growth spurt in rats, had deleterious effects on neurocognitive development and anatomical parameters of the hippocampus (Fitting et al., 2008a,b). In the present study, rats were stereotaxically injected with HIV-1 viral proteins, including Tat1-86 and gp120, on P10 to further examine the role of timing on neurocognitive development and anatomical parameters of the hippocampus (Fitting et al., 2010). The dose-dependent virotoxin effects observed across development following P10 Tat1-86 exposure were specific to spatial learning and absent from prepulse inhibition and locomotor activity. A relationship between alterations in spatial learning and/or memory and hippocampal anatomical parameters was noted. Specifically, the estimated number of neurons and astrocytes in the hilus of the dentate gyrus explained 70% of the variance of search behavior in Morris water maze acquisition training for adolescents and 65% of the variance for adults; a brain-behavior relationship consistent with observations following P1 viral protein exposure. Collectively, late viral protein exposure (P10) results in selective alterations in neurocognitive development without modifying measures of somatic growth, preattentive processing, or locomotor activity, as characterized by early viral protein exposure (P1). Thus, timing may be a critical factor in disease progression, with children infected with HIV earlier in life being more vulnerable to CNS disease.
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Affiliation(s)
- Sylvia Fitting
- University of South Carolina, Behavioral Neuroscience Program, Department of Psychology, Columbia, SC 29208, USA; University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Kristen A McLaurin
- University of South Carolina, Behavioral Neuroscience Program, Department of Psychology, Columbia, SC 29208, USA
| | - Rosemarie M Booze
- University of South Carolina, Behavioral Neuroscience Program, Department of Psychology, Columbia, SC 29208, USA
| | - Charles F Mactutus
- University of South Carolina, Behavioral Neuroscience Program, Department of Psychology, Columbia, SC 29208, USA.
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Albani SH, McHail DG, Dumas TC. Developmental studies of the hippocampus and hippocampal-dependent behaviors: insights from interdisciplinary studies and tips for new investigators. Neurosci Biobehav Rev 2014; 43:183-90. [PMID: 24769291 DOI: 10.1016/j.neubiorev.2014.04.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 04/01/2014] [Accepted: 04/15/2014] [Indexed: 01/17/2023]
Abstract
The hippocampus is not fully developed at birth and, with respect to spatial cognition, only begins to show signs of adult-like function at three postnatal weeks in rodents. Studying the developmental period spanning roughly two to four weeks of age permits an understanding of the neural framework necessary for the emergence of spatial navigation and, quite possibly, human episodic memory. However, due to developmental factors, behavior data collection and interpretation can be severely compromised if inappropriate designs are applied. As such, we propose methodological considerations for the behavioral assessment of hippocampal function in developing rats that take into account animal size, growth rate, and sensory and motor ability. We further summarize recent key interdisciplinary studies that are beginning to unravel the molecular machinery and physiological alterations responsible for hippocampal maturation. In general, hippocampal development is a protracted process during which unique contributions to spatial cognition and complex recognition memory come "on line" at different postnatal ages creating a unique situation for elucidating the neural bases of specific components of higher cognitive abilities.
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Affiliation(s)
- Sarah H Albani
- Molecular Neuroscience Department, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, United States
| | - Daniel G McHail
- Molecular Neuroscience Department, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, United States
| | - Theodore C Dumas
- Molecular Neuroscience Department, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, United States.
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Wills TJ, Muessig L, Cacucci F. The development of spatial behaviour and the hippocampal neural representation of space. Philos Trans R Soc Lond B Biol Sci 2013; 369:20130409. [PMID: 24366148 PMCID: PMC3866458 DOI: 10.1098/rstb.2013.0409] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The role of the hippocampal formation in spatial cognition is thought to be supported by distinct classes of neurons whose firing is tuned to an organism's position and orientation in space. In this article, we review recent research focused on how and when this neural representation of space emerges during development: each class of spatially tuned neurons appears at a different age, and matures at a different rate, but all the main spatial responses tested so far are present by three weeks of age in the rat. We also summarize the development of spatial behaviour in the rat, describing how active exploration of space emerges during the third week of life, the first evidence of learning in formal tests of hippocampus-dependent spatial cognition is observed in the fourth week, whereas fully adult-like spatial cognitive abilities require another few weeks to be achieved. We argue that the development of spatially tuned neurons needs to be considered within the context of the development of spatial behaviour in order to achieve an integrated understanding of the emergence of hippocampal function and spatial cognition.
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Affiliation(s)
- Thomas J Wills
- Department of Cell and Developmental Biology, University College London, , London WC1E 6BT, UK
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Grissom EM, Hawley WR, Hodges KS, Fawcett-Patel JM, Dohanich GP. Biological sex influences learning strategy preference and muscarinic receptor binding in specific brain regions of prepubertal rats. Hippocampus 2012; 23:313-22. [DOI: 10.1002/hipo.22085] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2012] [Indexed: 11/08/2022]
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Akers KG, Candelaria-Cook FT, Rice JP, Johnson TE, Hamilton DA. Cued platform training reveals early development of directional responding among preweanling rats in the Morris water task. Dev Psychobiol 2010; 53:1-12. [DOI: 10.1002/dev.20480] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Neonatal intrahippocampal injection of the HIV-1 proteins gp120 and Tat: differential effects on behavior and the relationship to stereological hippocampal measures. Brain Res 2008; 1232:139-54. [PMID: 18674522 DOI: 10.1016/j.brainres.2008.07.032] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 04/29/2008] [Accepted: 07/09/2008] [Indexed: 11/21/2022]
Abstract
HIV-1 proteins, such as Tat and gp120, are believed to play a crucial role in the central nervous system (CNS) pathology of acquired immune deficiency syndrome (AIDS). The present study sought to determine the potential role of Tat and/or gp120 on behavioral development and the relationship to the long-term effects of the HIV-1 proteins on the rat hippocampus. Male pups of 13 Sprague-Dawley litters were bilaterally injected on postnatal day (P)1. Every litter contributed an animal to each of four treatment condition: VEH (0.5 microl sterile buffer), gp120 (100 ng), Tat (25 microg) or combined gp120+Tat (100 ng+25 microg). Body weight was not affected by either protein treatment. Tat revealed a transient effect on many of the behavioral assessments early in development as well as on preattentive processes and spatial memory in adulthood. Gp120 had more selective effects on negative geotaxis (P8-P10) and on locomotor activity (P94-P96). Combined gp120+Tat effects were noted for eye opening with potential interactive effects of gp120 and Tat on negative geotaxis. Anatomical assessment at approximately 7 1/2 months of age was conducted by using design-based stereology to quantify the total cell number in five hippocampal subregions [granule layer (GL), hilus of the dentate gyrus (DGH), cornu ammonis fields (CA)2/3, CA1, and subiculum (SUB)] [Fitting, S., Booze, R.M., Hasselrot, U., Mactutus, C.F., 2007a. Differential long-term neurotoxicity of HIV-1 proteins in the rat hippocampal formation: a design-based stereological study. Hippocampus 18(2), 135-147]. A relationship between early reflex development and estimated cell number in the adult hippocampus was indicated by simple regression analyses. In addition, estimated number of neurons and astrocytes in the DGH explained 81% of the variance of the distribution of searching behavior in the probe test. Collectively, these data indicate that the DGH may participate in the spatial memory alterations observed in adulthood consequent to neonatal exposure to HIV-1 proteins.
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Lopez J, de Vasconcelos AP, Cassel JC. Environmental cue saliency influences the vividness of a remote spatial memory in rats. Neurobiol Learn Mem 2008; 90:285-9. [DOI: 10.1016/j.nlm.2008.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 02/06/2008] [Accepted: 02/06/2008] [Indexed: 10/22/2022]
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Baldi E, Efoudebe M, Lorenzini CA, Bucherelli C. Spatial navigation in the Morris water maze: working and long lasting reference memories. Neurosci Lett 2005; 378:176-80. [PMID: 15781154 DOI: 10.1016/j.neulet.2004.12.029] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Revised: 12/13/2004] [Accepted: 12/14/2004] [Indexed: 10/26/2022]
Abstract
Spatial navigation development in the Morris water maze (MWM) paradigm was studied in 70-day-old male Long-Evans hooded rats. During 5 consecutive days, rats' training consisted of a daily block of 10 trials. Escape latency was measured in each trial. Probe testing was performed every day immediately before and after the daily block of trials. In addition, a final probe was performed on Day 6. During the first 3 days of training, the escape latency became progressively shorter, showing an asymptotic trend on Days 4 and 5. Probe trials administered at the end of the first acquisition sessions showed clear preference for the target quadrant but this information was not recalled at probe trials given 24h later. The memory trace retrieved after 24-h delay was formed only after 30 trials received over three sessions. The probe trial given at the end of an acquisition session tests the efficiency of the working memory whereas the 24h delayed probe trial reflects better-consolidated spatial information corresponding to long lasting reference memory. It can be noted that the progressive shortening of escape latencies does not express closely the evolution of the rat's long lasting (consolidated) reference memory. This memory can be satisfactorily measured only by probe testing performed at an adequate delay after training. These considerations may be of some interest when interpreting the rat's performance in the MWM.
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Affiliation(s)
- Elisabetta Baldi
- Dipartimento di Scienze Fisiologiche, Università di Firenze, I-50134 Firenze, Italy
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