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Keith RE, Wild GA, Keith MJ, Chen D, Pack S, Dumas TC. Individual NMDA receptor GluN2 subunit signaling domains differentially regulate the postnatal maturation of hippocampal excitatory synaptic transmission and plasticity but not dendritic morphology. Synapse 2024; 78:e22292. [PMID: 38813758 PMCID: PMC11141731 DOI: 10.1002/syn.22292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 04/16/2024] [Accepted: 04/30/2024] [Indexed: 05/31/2024]
Abstract
N-methyl-d-aspartate receptors (NMDARs) at hippocampal excitatory synapses undergo a late postnatal shift in subunit composition, from an initial prevalence of GluN2B subunit incorporation to a later predominance of GluN2A. This GluN2B to GluN2A shift alters NMDAR calcium conductance dynamics and intracellular molecular signaling that are individually regulated by distinct GluN2 signaling domains and temporally align with developmental alterations in dendritic and synaptic plasticity. However, the impacts of individual GluN2B to GluN2A signaling domains on neuronal development remain unknown. Ionotropic and intracellular signaling domains of GluN2 subunits were separated by creating chimeric GluN2 subunits that were expressed in two transgenic mouse lines. Western blot and immunoprecipitation revealed that roughly one third of native synaptic NMDARs were replaced by transformed NMDARs without altering total synaptic NMDAR content. Schaffer collateral synaptic strength was transiently increased in acutely prepared hippocampal slices at just over 3 weeks of age in animals overexpressing the GluN2B carboxy terminus. Long-term potentiation (LTP) induction following lower frequency stimulation was regulated by GluN2 ionotropic signaling domains in an age-dependent manner and LTP maintenance was enhanced by overexpression of the GluN2B CTD in mature animals. After higher frequency stimulation, the induction and maintenance of LTP were increased in young adult animals overexpressing the GluN2B ionotropic signaling domains but reduced in juveniles just over 3 weeks of age. Confocal imaging of green fluorescent protein (GFP)- labeled CA1 pyramidal neurons revealed no alterations in dendritic morphology or spine density in mice expressing chimeric GluN2 subunits. These results illustrate how individual GluN2 subunit signaling domains do or do not control physiological and morphological development of hippocampal excitatory neurons and better clarify the neurobiological factors that govern hippocampal maturation. SIGNIFICANCE STATEMENT: A developmental reduction in the magnitude of hippocampal long-term synaptic potentiation (LTP) and a concomitant improvement in spatial maze performance coincide with greater incorporation of GluN2A subunits into synaptic NMDARs. Corroborating our prior discovery that overexpression of GluN2A-type ionotropic signaling domains enables context-based navigation in immature mice, GluN2A-type ionotropic signaling domain overexpression reduces LTP induction threshold and magnitude in immature mice. Also, we previously found that GluN2B carboxy terminal domain (CTD) overexpression enhances long-term spatial memory in mature mice and now report that the GluN2B CTD is associated with greater amplitude of LTP after induction in mature mice. Thus, the late postnatal maturation of context encoding likely relies on a shift toward GluN2A-type ionotropic signaling and a reduction in the threshold to induce LTP while memory consolidation and LTP maintenance are regulated by GluN2B subunit CTD signaling.
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Affiliation(s)
- Rachel E. Keith
- Interdisciplinary Program in Neuroscience, College of Science; George Mason University, Fairfax, VA 22030
| | - Grace A. Wild
- Psychology Department, College of Humanities and Social Sciences; George Mason University, Fairfax, VA 22030
| | - Matthew J. Keith
- Interdisciplinary Program in Neuroscience, College of Science; George Mason University, Fairfax, VA 22030
| | - Diyi Chen
- Interdisciplinary Program in Neuroscience, College of Science; George Mason University, Fairfax, VA 22030
| | | | - Theodore C. Dumas
- Interdisciplinary Program in Neuroscience, College of Science; George Mason University, Fairfax, VA 22030
- Psychology Department, College of Humanities and Social Sciences; George Mason University, Fairfax, VA 22030
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2
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Leitch B. Parvalbumin Interneuron Dysfunction in Neurological Disorders: Focus on Epilepsy and Alzheimer's Disease. Int J Mol Sci 2024; 25:5549. [PMID: 38791587 PMCID: PMC11122153 DOI: 10.3390/ijms25105549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 05/11/2024] [Accepted: 05/16/2024] [Indexed: 05/26/2024] Open
Abstract
Parvalbumin expressing (PV+) GABAergic interneurons are fast spiking neurons that provide powerful but relatively short-lived inhibition to principal excitatory cells in the brain. They play a vital role in feedforward and feedback synaptic inhibition, preventing run away excitation in neural networks. Hence, their dysfunction can lead to hyperexcitability and increased susceptibility to seizures. PV+ interneurons are also key players in generating gamma oscillations, which are synchronized neural oscillations associated with various cognitive functions. PV+ interneuron are particularly vulnerable to aging and their degeneration has been associated with cognitive decline and memory impairment in dementia and Alzheimer's disease (AD). Overall, dysfunction of PV+ interneurons disrupts the normal excitatory/inhibitory balance within specific neurocircuits in the brain and thus has been linked to a wide range of neurodevelopmental and neuropsychiatric disorders. This review focuses on the role of dysfunctional PV+ inhibitory interneurons in the generation of epileptic seizures and cognitive impairment and their potential as targets in the design of future therapeutic strategies to treat these disorders. Recent research using cutting-edge optogenetic and chemogenetic technologies has demonstrated that they can be selectively manipulated to control seizures and restore the balance of neural activity in the brains of animal models. This suggests that PV+ interneurons could be important targets in developing future treatments for patients with epilepsy and comorbid disorders, such as AD, where seizures and cognitive decline are directly linked to specific PV+ interneuron deficits.
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Affiliation(s)
- Beulah Leitch
- Department of Anatomy, School of Biomedical Sciences, Brain Health Research Centre, University of Otago, Dunedin 9016, New Zealand
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3
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Premachandran H, Wilkin J, Arruda-Carvalho M. Minimizing Variability in Developmental Fear Studies in Mice: Toward Improved Replicability in the Field. Curr Protoc 2024; 4:e1040. [PMID: 38713136 DOI: 10.1002/cpz1.1040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
In rodents, the first weeks of postnatal life feature remarkable changes in fear memory acquisition, retention, extinction, and discrimination. Early development is also marked by profound changes in brain circuits underlying fear memory processing, with heightened sensitivity to environmental influences and stress, providing a powerful model to study the intersection between brain structure, function, and the impacts of stress. Nevertheless, difficulties related to breeding and housing young rodents, preweaning manipulations, and potential increased variability within that population pose considerable challenges to developmental fear research. Here we discuss several factors that may promote variability in studies examining fear conditioning in young rodents and provide recommendations to increase replicability. We focus primarily on experimental conditions, design, and analysis of rodent fear data, with an emphasis on mouse studies. The convergence of anatomical, synaptic, physiological, and behavioral changes during early life may increase variability, but careful practice and transparency in reporting may improve rigor and consensus in the field. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC.
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Affiliation(s)
- Hanista Premachandran
- Department of Psychology, University of Toronto Scarborough, Toronto, Ontario, Canada
- These authors contributed equally to this work
| | - Jennifer Wilkin
- Department of Psychology, University of Toronto Scarborough, Toronto, Ontario, Canada
- These authors contributed equally to this work
| | - Maithe Arruda-Carvalho
- Department of Psychology, University of Toronto Scarborough, Toronto, Ontario, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
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4
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Yang Y, Sakimoto Y, Mitsushima D. Postnatal Development of Synaptic Plasticity at Hippocampal CA1 Synapses: Correlation of Learning Performance with Pathway-Specific Plasticity. Brain Sci 2024; 14:382. [PMID: 38672030 PMCID: PMC11048295 DOI: 10.3390/brainsci14040382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/05/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024] Open
Abstract
To determine the critical timing for learning and the associated synaptic plasticity, we analyzed developmental changes in learning together with training-induced plasticity. Rats were subjected to an inhibitory avoidance (IA) task prior to weaning. While IA training did not alter latency at postnatal day (PN) 16, there was a significant increase in latency from PN 17, indicating a critical day for IA learning between PN 16 and 17. One hour after training, acute hippocampal slices were prepared for whole-cell patch clamp analysis following the retrieval test. In the presence of tetrodotoxin (0.5 µM), miniature excitatory postsynaptic currents (mEPSCs) and inhibitory postsynaptic currents (mIPSCs) were sequentially recorded from the same CA1 neuron. Although no changes in the amplitude of mEPSCs or mIPSCs were observed at PN 16 and 21, significant increases in both excitatory and inhibitory currents were observed at PN 23, suggesting a specific critical day for training-induced plasticity between PN 21 and 23. Training also increased the diversity of postsynaptic currents at PN 23 but not at PN 16 and 21, demonstrating a critical day for training-induced increase in the information entropy of CA1 neurons. Finally, we analyzed the plasticity at entorhinal cortex layer III (ECIII)-CA1 or CA3-CA1 synapses for each individual rat. At either ECIII-CA1 or CA3-CA1 synapses, a significant correlation between mean α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid/N-methyl-D-aspartic acid (AMPA/NMDA) ratio and learning outcomes emerged at PN 23 at both synapses, demonstrating a critical timing for the direct link between AMPA receptor-mediated synaptic plasticity and learning efficacy. Here, we identified multiple critical periods with respect to training-induced synaptic plasticity and delineated developmental trajectories of learning mechanisms at hippocampal CA1 synapses.
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Affiliation(s)
- Yuheng Yang
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan; (Y.Y.); (Y.S.)
| | - Yuya Sakimoto
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan; (Y.Y.); (Y.S.)
| | - Dai Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan; (Y.Y.); (Y.S.)
- The Research Institute for Time Studies, Yamaguchi University, Yamaguchi 753-8511, Japan
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5
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Mucignat-Caretta C, Caretta A. Estimation of cAMP binding in hippocampus CA1 field by a fluorescent probe. Front Cell Dev Biol 2023; 11:1267956. [PMID: 37842083 PMCID: PMC10570460 DOI: 10.3389/fcell.2023.1267956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/20/2023] [Indexed: 10/17/2023] Open
Abstract
The hippocampus is an allocortex structure involved in many complex processes, from memory formation to spatial navigation. It starts developing during prenatal life but acquires its adult functional properties around the peripubertal age, in both humans and mice. Such prolonged maturation is accompanied by structural changes in microcircuitry and functional changes involving biochemical and electrophysiological events. Moreover, hippocampus undergoes plasticity phenomena throughout life. In murine rodents, the most relevant maturation steps in Cornu Ammonis 1 (CA1) hippocampal subfield occur during the third-fourth weeks of life. During this period, also the expression and localization of cAMP-dependent protein kinases (PKA) refines: many regulatory (R1A) PKA clusters appear, bound to the cytoskeleton. Here the binding characteristics of R1A are determined in CA1 by using confocal microscopy. Apparently, two binding sites are present with no evidence of cooperativity. Equilibrium dissociation constant is estimated around 22.9 nM. This value is lower from that estimated for R1A in soluble form, suggesting a different binding site conformation or accessibility in the tissue. The method described here may be useful to track the developmental changes in binding activity, which affects cAMP availability at selected intracellular microzones. Possible relations with functional consequences are discussed.
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Affiliation(s)
| | - Antonio Caretta
- Department of Food and Drug Science, University of Parma, Parma, Italy
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Ramsaran AI, Wang Y, Golbabaei A, Aleshin S, de Snoo ML, Yeung BRA, Rashid AJ, Awasthi A, Lau J, Tran LM, Ko SY, Abegg A, Duan LC, McKenzie C, Gallucci J, Ahmed M, Kaushik R, Dityatev A, Josselyn SA, Frankland PW. A shift in the mechanisms controlling hippocampal engram formation during brain maturation. Science 2023; 380:543-551. [PMID: 37141366 DOI: 10.1126/science.ade6530] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The ability to form precise, episodic memories develops with age, with young children only able to form gist-like memories that lack precision. The cellular and molecular events in the developing hippocampus that underlie the emergence of precise, episodic-like memory are unclear. In mice, the absence of a competitive neuronal engram allocation process in the immature hippocampus precluded the formation of sparse engrams and precise memories until the fourth postnatal week, when inhibitory circuits in the hippocampus mature. This age-dependent shift in precision of episodic-like memories involved the functional maturation of parvalbumin-expressing interneurons in subfield CA1 through assembly of extracellular perineuronal nets, which is necessary and sufficient for the onset of competitive neuronal allocation, sparse engram formation, and memory precision.
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Affiliation(s)
- Adam I Ramsaran
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Ying Wang
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Ali Golbabaei
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Stepan Aleshin
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases, Magdeburg, Germany
| | - Mitchell L de Snoo
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Bi-Ru Amy Yeung
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Asim J Rashid
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ankit Awasthi
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jocelyn Lau
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Lina M Tran
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Vector Institute, Toronto, Ontario, Canada
| | - Sangyoon Y Ko
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Andrin Abegg
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Lana Chunan Duan
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Cory McKenzie
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Julia Gallucci
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Moriam Ahmed
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Rahul Kaushik
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Alexander Dityatev
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Germany
- Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Sheena A Josselyn
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Brain, Mind, & Consciousness Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada
| | - Paul W Frankland
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Child & Brain Development Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada
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7
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Nugent M, St Pierre M, Brown A, Nassar S, Parmar P, Kitase Y, Duck SA, Pinto C, Jantzie L, Fung C, Chavez-Valdez R. Sexual Dimorphism in the Closure of the Hippocampal Postnatal Critical Period of Synaptic Plasticity after Intrauterine Growth Restriction: Link to Oligodendrocyte and Glial Dysregulation. Dev Neurosci 2023; 45:234-254. [PMID: 37019088 DOI: 10.1159/000530451] [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: 11/03/2022] [Accepted: 03/20/2023] [Indexed: 04/07/2023] Open
Abstract
Intrauterine growth restriction (IUGR) resulting from hypertensive disease of pregnancy (HDP) leads to sexually dimorphic hippocampal-dependent cognitive and memory impairment in humans. In our translationally relevant mouse model of IUGR incited by HDP, we have previously shown that the synaptic development in the dorsal hippocampus including GABAergic development, NPTX2+ excitatory synaptic formation, axonal myelination, and perineural net (PNN) formation were perturbed by IUGR at adolescent equivalence in humans (P40). The persistence of these disturbances through early adulthood and the potential upstream mechanisms are currently unknown. Thus, we hypothesized that NPTX2+ expression, PNN formation, axonal myelination, all events closing synaptic development in the hippocampus, will be persistently perturbed, particularly affecting IUGR female mice through P60 given the fact that they had worse short-term recognition memory in this model. We additionally hypothesized that such sexual dimorphism is linked to persistent glial dysregulation. We induced IUGR by a micro-osmotic pump infusion of a potent vasoconstrictor U-46619, a thromboxane A2-analog, in the last week of the C57BL/6 mouse gestation to precipitate HDP. Sham-operated mice were used as controls. At P60, we assessed hippocampal and hemispheric volumes, NPTX2 expression, PNN formation, as well as myelin basic protein (MBP), Olig2, APC/CC1, and M-NF expression. We also evaluated P60 astrocytic (GFAP) reactivity and microglial (Iba1 and TMEM119) activation using immunofluorescent-immunohistochemistry and Imaris morphological analysis plus cytokine profiling using Meso Scale Discovery platform. IUGR offspring continued to have smaller hippocampal volumes at P60 not related to changes in hemisphere volume. NPTX2+ puncta counts and volumes were decreased in IUGR hippocampal CA subregions of female mice compared to sex-matched shams. Intriguingly, NPTX2+ counts and volumes were concurrently increased in the dentate gyrus (DG) subregion. PNN volumes were smaller in CA1 and CA3 of IUGR female mice along with PNN intensity in CA3 but they had larger volumes in the CA3 of IUGR male mice. The myelinated axon (MBP+) areas, volumes, and lengths were all decreased in the CA1 of IUGR female mice compared to sex-matched shams, which correlated with a decrease in Olig2 nuclear expression. No decrease in the number of APC/CC1+ mature oligodendrocytes was identified. We noted an increase in M-NF expression in the mossy fibers connecting DG to CA3 only in IUGR female mice. Reactive astrocytes denoted by GFAP areas, volumes, lengths, and numbers of branching were increased in IUGR female CA1 but not in IUGR male CA3 compared to sex-matched shams. Lastly, activated microglia were only detected in IUGR female CA1 and CA3 subregions. We detected no difference in the cytokine profile between sham and IUGR adult mice of either sex. Collectively, our data support a sexually dimorphic impaired closure of postnatal critical period of synaptic plasticity in the hippocampus of young adult IUGR mice with greater effects on females. A potential mechanism supporting such dimorphism may include oligodendrocyte dysfunction in IUGR females limiting myelination, allowing axonal overgrowth followed by a reactive glial-mediated synaptic pruning.
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Affiliation(s)
- Michael Nugent
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Mark St Pierre
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Ashley Brown
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - Salma Nassar
- Department of Neurosciences, Johns Hopkins University Krieger School of Arts and Sciences, Baltimore, Maryland, USA
| | - Pritika Parmar
- Department of Neurosciences, Johns Hopkins University Krieger School of Arts and Sciences, Baltimore, Maryland, USA
| | - Yuma Kitase
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Sarah Ann Duck
- Department of Molecular and Cellular Biology, Johns Hopkins University Krieger School of Arts and Sciences, Baltimore, Maryland, USA
| | - Charles Pinto
- Department of Human Biology, University of Toronto, Toronto, Ontario, Canada
| | - Lauren Jantzie
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Camille Fung
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - Raul Chavez-Valdez
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
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8
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Fung CM. Effects of intrauterine growth restriction on embryonic hippocampal dentate gyrus neurogenesis and postnatal critical period of synaptic plasticity that govern learning and memory function. Front Neurosci 2023; 17:1092357. [PMID: 37008232 PMCID: PMC10064986 DOI: 10.3389/fnins.2023.1092357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 02/28/2023] [Indexed: 03/18/2023] Open
Abstract
Intrauterine growth restriction (IUGR) complicates up to 10% of human pregnancies and is the second leading cause of perinatal morbidity and mortality after prematurity. The most common etiology of IUGR in developed countries is uteroplacental insufficiency (UPI). For survivors of IUGR pregnancies, long-term studies consistently show a fivefold increased risk for impaired cognition including learning and memory deficits. Among these, only a few human studies have highlighted sex differences with males and females having differing susceptibilities to different impairments. Moreover, it is well established from brain magnetic resonance imaging that IUGR affects both white and gray matter. The hippocampus, composed of the dentate gyrus (DG) and cornu ammonis (CA) subregions, is an important gray matter structure critical to learning and memory, and is particularly vulnerable to the chronic hypoxic-ischemic effects of UPI. Decreased hippocampal volume is a strong predictor for learning and memory deficits. Decreased neuron number and attenuated dendritic and axonal morphologies in both the DG and CA are additionally seen in animal models. What is largely unexplored is the prenatal changes that predispose an IUGR offspring to postnatal learning and memory deficits. This lack of knowledge will continue to hinder the design of future therapy to improve learning and memory. In this review, we will first present the clinical susceptibilities and human epidemiology data regarding the neurological sequelae after IUGR. We will follow with data generated using our laboratory’s mouse model of IUGR, that mimics the human IUGR phenotype, to dissect at the cellular and molecular alterations in embryonic hippocampal DG neurogenesis. We will lastly present a newer topic of postnatal neuron development, namely the critical period of synaptic plasticity that is crucial in achieving an excitatory/inhibitory balance in the developing brain. To our knowledge, these findings are the first to describe the prenatal changes that lead to an alteration in postnatal hippocampal excitatory/inhibitory imbalance, a mechanism that is now recognized to be a cause of neurocognitive/neuropsychiatric disorders in at-risk individuals. Studies are ongoing in our laboratory to elucidate additional mechanisms that underlie IUGR-induced learning and memory impairment and to design therapy aimed at ameliorating such impairment.
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9
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Velasquez F, Dickson C, Kloc ML, Schneur CA, Barry JM, Holmes GL. Optogenetic modulation of hippocampal oscillations ameliorates spatial cognition and hippocampal dysrhythmia following early-life seizures. Neurobiol Dis 2023; 178:106021. [PMID: 36720444 DOI: 10.1016/j.nbd.2023.106021] [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: 09/14/2022] [Revised: 01/22/2023] [Accepted: 01/24/2023] [Indexed: 01/30/2023] Open
Abstract
There is increasing human and animal evidence that brain oscillations play a critical role in the development of spatial cognition. In rat pups, disruption of hippocampal rhythms via optogenetic stimulation during the critical period for memory development impairs spatial cognition. Early-life seizures are associated with long-term deficits in spatial cognition and aberrant hippocampal oscillatory activity. Here we asked whether modulation of hippocampal rhythms following early-life seizures can reverse or improve hippocampal connectivity and spatial cognition. We used optogenetic stimulation of the medial septum to induce physiological 7 Hz theta oscillations in the hippocampus during the critical period of spatial cognition following early-life seizures. Optogenetic stimulation of the medial septum in control and rats subjected to early-life seizures resulted in precisely regulated frequency-matched hippocampal oscillations. Rat pups receiving active blue light stimulation performed better than the rats receiving inert yellow light in a test of spatial cognition. The improvement in spatial cognition in these rats was associated with a faster theta frequency and higher theta power, coherence and phase locking value in the hippocampus than rats with early-life seizures receiving inert yellow light. These findings indicate that following early life seizures, modification of hippocampal rhythms may be a potential novel therapeutic modality.
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Affiliation(s)
- Francisco Velasquez
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Conor Dickson
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Michelle L Kloc
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Carmel A Schneur
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Jeremy M Barry
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Gregory L Holmes
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA.
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10
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Miranda JM, Cruz E, Bessières B, Alberini CM. Hippocampal parvalbumin interneurons play a critical role in memory development. Cell Rep 2022; 41:111643. [PMID: 36384113 PMCID: PMC9737056 DOI: 10.1016/j.celrep.2022.111643] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 08/16/2022] [Accepted: 10/19/2022] [Indexed: 11/18/2022] Open
Abstract
Episodic memories formed in early childhood rapidly decay, but their latent traces remain stored long term. These memories require the dorsal hippocampus (dHPC) and seem to undergo a developmental critical period. It remains to be determined whether the maturation of parvalbumin interneurons (PVIs), a major mechanism of critical periods, contributes to memory development. Here, we show that episodic infantile learning significantly increases the levels of parvalbumin in the dHPC 48 h after training. Chemogenetic inhibition of PVIs before learning indicated that these neurons are required for infantile memory formation. A bilateral dHPC injection of the γ-aminobutyric acid type A receptor agonist diazepam after training elicited long-term memory expression in infant rats, although direct PVI chemogenetic activation had no effect. Finally, PVI activity was required for brain-derived neurotrophic factor (BDNF)-dependent maturation of memory competence, i.e., adult-like long-term memory expression. Thus, dHPC PVIs are critical for the formation of infantile memories and for memory development.
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Affiliation(s)
- Janelle M Miranda
- Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA
| | - Emmanuel Cruz
- Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA
| | - Benjamin Bessières
- Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA
| | - Cristina M Alberini
- Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA.
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Zhang Y, Smolen P, Alberini CM, Baxter DA, Byrne JH. Computational analysis of memory consolidation following inhibitory avoidance (IA) training in adult and infant rats: Critical roles of CaMKIIα and MeCP2. PLoS Comput Biol 2022; 18:e1010239. [PMID: 35759520 PMCID: PMC9269953 DOI: 10.1371/journal.pcbi.1010239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 07/08/2022] [Accepted: 05/23/2022] [Indexed: 11/18/2022] Open
Abstract
Key features of long-term memory (LTM), such as its stability and persistence, are acquired during processes collectively referred to as consolidation. The dynamics of biological changes during consolidation are complex. In adult rodents, consolidation exhibits distinct periods during which the engram is more or less resistant to disruption. Moreover, the ability to consolidate memories differs during developmental periods. Although the molecular mechanisms underlying consolidation are poorly understood, the initial stages rely on interacting signaling pathways that regulate gene expression, including brain-derived neurotrophic factor (BDNF) and Ca2+/calmodulin-dependent protein kinase II α (CaMKIIα) dependent feedback loops. We investigated the ways in which these pathways may contribute to developmental and dynamical features of consolidation. A computational model of molecular processes underlying consolidation following inhibitory avoidance (IA) training in rats was developed. Differential equations described the actions of CaMKIIα, multiple feedback loops regulating BDNF expression, and several transcription factors including methyl-CpG binding protein 2 (MeCP2), histone deacetylase 2 (HDAC2), and SIN3 transcription regulator family member A (Sin3a). This model provides novel explanations for the (apparent) rapid forgetting of infantile memory and the temporal progression of memory consolidation in adults. Simulations predict that dual effects of MeCP2 on the expression of bdnf, and interaction between MeCP2 and CaMKIIα, play critical roles in the rapid forgetting of infantile memory and the progress of memory resistance to disruptions. These insights suggest new potential targets of therapy for memory impairment.
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Affiliation(s)
- Yili Zhang
- Department of Neurobiology and Anatomy; W.M. Keck Center for the Neurobiology of Learning and Memory; The University of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Paul Smolen
- Department of Neurobiology and Anatomy; W.M. Keck Center for the Neurobiology of Learning and Memory; The University of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Cristina M. Alberini
- Center for Neural Science, New York University, New York City, New York, United States of America
| | - Douglas A. Baxter
- Department of Neurobiology and Anatomy; W.M. Keck Center for the Neurobiology of Learning and Memory; The University of Texas Medical School at Houston, Houston, Texas, United States of America
- Department of Neurobiology and Experimental Therapeutics, College of Medicine, Texas A&M University, Houston, Texas, United States of America
| | - John H. Byrne
- Department of Neurobiology and Anatomy; W.M. Keck Center for the Neurobiology of Learning and Memory; The University of Texas Medical School at Houston, Houston, Texas, United States of America
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Ohana O, Alberini CM, Donato F. Introduction to the special issue on the ontogeny of hippocampal functions. Hippocampus 2022; 32:69-72. [PMID: 35005808 PMCID: PMC9303776 DOI: 10.1002/hipo.23406] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Ora Ohana
- Institute for Molecular and Cellular Cognition, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Flavio Donato
- Biozentrum of the University of Basel, Basel, Switzerland
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St. Pierre M, Rastogi N, Brown A, Parmar P, Lechner C, Fung C, Chavez-Valdez R. Intrauterine Growth Restriction Disrupts the Postnatal Critical Period of Synaptic Plasticity in the Mouse Dorsal Hippocampus in a Model of Hypertensive Disease of Pregnancy. Dev Neurosci 2022; 44:214-232. [PMID: 34933306 PMCID: PMC9209574 DOI: 10.1159/000521611] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 12/16/2021] [Indexed: 01/03/2023] Open
Abstract
INTRODUCTION Intrauterine growth restriction (IUGR) from hypertensive disease of pregnancy complicates up to 10% of all pregnancies. Significant hippocampal-dependent cognitive and memory impairments as well as neuropsychiatric disorders have been linked to IUGR. Because disturbance of the hippocampal critical period (CPd) of synaptic plasticity leads to impairments similar to those described in IUGR human offspring, we hypothesized that IUGR would perturb the CPd of synaptic plasticity in the mouse hippocampus in our model. METHODS IUGR was produced by a micro-osmotic pump infusion of the potent vasoconstrictor U-46619, a thromboxane A2-agonist, at embryonic day 12.5 in C57BL/6J mouse dams to precipitate hypertensive disease of pregnancy and IUGR. Sham-operated mice acted as controls. At P10, P18, and P40, we assessed astrogliosis using GFAP-IHC. In dorsal CA1 and CA3 subfields, we assessed the immunoreactivities (IR) (IF-IHC) to (i) parvalbumin (PV) and glutamate decarboxylase (GAD) 65/67, involved in CPd onset; (ii) PSA-NCAM that antagonizes CPd onset; (iii) NPTX2, necessary for excitatory synapse formation and engagement of CPd; and (iv) MBP and WFA, staining perineural nets (PNNs), marking CPd closure. ImageJ/Fiji and IMARIS were used for image processing and SPSS v24 for statistical analysis. RESULTS Although PV+ interneuron numbers and IR intensity were unchanged, development of GAD65/67+ synaptic boutons was accelerated at P18 IUGR mice and inversely correlated with decreased expression of PSA-NCAM in the CA of P18 IUGR mice at P18. NPTX2+ puncta and total volume were persistently decreased in the CA3 pyramidal and radiatum layers of IUGR mice from P18 to P40. At P40, axonal myelination (MBP+) in CA3 of IUGR mice was decreased and correlated with NPTX2 deficits. Lastly, the volume and integrity of the PNNs in the dorsal CA was disrupted in IUGR mice at P40. DISCUSSION/CONCLUSION IUGR disrupts the molecular and structural initiation, consolidation, and closure of the CPd of synaptic plasticity in the mouse hippocampus in our model, which may explain the learning and memory deficits observed in juvenile IUGR mice and the cognitive disorders seen in human IUGR offspring. The mechanistic links warrant further investigation, to identify therapeutic targets to prevent neurodevelopmental deficits in patients affected by IUGR.
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Affiliation(s)
- Mark St. Pierre
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Johns Hopkins School of Medicine. Baltimore, MD
| | - Neetika Rastogi
- Department of Neurosciences, Johns Hopkins University Krieger School of Arts and Sciences, Baltimore, MD
| | - Ashley Brown
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, UT
| | - Pritika Parmar
- Department of Neurosciences, Johns Hopkins University Krieger School of Arts and Sciences, Baltimore, MD
| | - Charles Lechner
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Johns Hopkins School of Medicine. Baltimore, MD
| | - Camille Fung
- Division of Neonatology, Department of Pediatrics, University of Utah, Salt Lake City, UT
| | - Raul Chavez-Valdez
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Johns Hopkins School of Medicine. Baltimore, MD,Corresponding author: Dr. Raul Chavez-Valdez. Associate Professor. Department of Pediatrics, Division of Neonatology, Johns Hopkins Hospital, 600 N. Wolfe Street, CMSC 6-104, Baltimore, MD 21287, USA. Telephone: (410) 955-7156,
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14
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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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15
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Rodríguez-Manzo G, González-Morales E, Garduño-Gutiérrez R. Endocannabinoids Released in the Ventral Tegmental Area During Copulation to Satiety Modulate Changes in Glutamate Receptors Associated With Synaptic Plasticity Processes. Front Synaptic Neurosci 2021; 13:701290. [PMID: 34483875 PMCID: PMC8416467 DOI: 10.3389/fnsyn.2021.701290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/08/2021] [Indexed: 11/13/2022] Open
Abstract
Endocannabinoids modulate mesolimbic (MSL) dopamine (DA) neurons firing at the ventral tegmental area (VTA). These neurons are activated by copulation, increasing DA release in nucleus accumbens (NAcc). Copulation to satiety in male rats implies repeated ejaculation within a short period (around 2.5 h), during which NAcc dopamine concentrations remain elevated, suggesting continuous neuronal activation. During the 72 h that follow copulation to satiety, males exhibit long-lasting changes suggestive of brain plasticity processes. Enhanced DA neuron activity triggers the synthesis and release of endocannabinoids (eCBs) in the VTA, which participate in several long-term synaptic plasticity processes. Blockade of cannabinoid type 1 receptors (CB1Rs) during copulation to satiety interferes with the appearance of the plastic changes. Glutamatergic inputs to the VTA express CB1Rs and contribute to DA neuron burst firing and synaptic plasticity. We hypothesized that eCBs, released during copulation to satiety, would activate VTA CB1Rs and modulate synaptic plasticity processes involving glutamatergic transmission. To test this hypothesis, we determined changes in VTA CB1R density, phosphorylation, and internalization in rats that copulated to satiety 24 h earlier as compared both to animals that ejaculated only once and to sexually experienced unmated males. Changes in glutamate AMPAR and NMDAR densities and subunit composition and in ERK1/2 activation were determined in the VTA of males that copulated to satiety in the presence or absence of AM251, a CB1R antagonist. The CB1R density decreased and the proportion of phosphorylated CB1Rs increased in the animals that copulated compared to control rats. The CB1R internalization was detected only in sexually satiated males. A decrease in α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor (AMPAR) density, blocked by AM251 pretreatment, and an increase in the proportion of GluA2-AMPARs occurred in sexually satiated rats. GluN2A- N-methyl-D-aspartate receptor (NMDAR) expression decreased, and GluN2B-NMDARs increased in these animals, both of which were prevented by AM251 pre-treatment. An increase in phosphorylated ERK1/2 emerged in males copulating to satiety in the presence of AM251. Results demonstrate that during copulation to satiety, eCBs activate CB1Rs in the VTA, producing changes in glutamate receptors compatible with a reduced neuronal activation. These changes could play a role in the induction of the long-lasting physiological changes that characterize sexually satiated rats.
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Affiliation(s)
- Gabriela Rodríguez-Manzo
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados (Cinvestav-Sede Sur), Ciudad de México, Mexico
| | - Estefanía González-Morales
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados (Cinvestav-Sede Sur), Ciudad de México, Mexico
| | - René Garduño-Gutiérrez
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados (Cinvestav-Sede Sur), Ciudad de México, Mexico
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16
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Bessières B, Cruz E, Alberini CM. Metabolomic profiling reveals a differential role for hippocampal glutathione reductase in infantile memory formation. eLife 2021; 10:68590. [PMID: 34825649 PMCID: PMC8626085 DOI: 10.7554/elife.68590] [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: 03/19/2021] [Accepted: 11/09/2021] [Indexed: 01/12/2023] Open
Abstract
The metabolic mechanisms underlying the formation of early-life episodic memories remain poorly characterized. Here, we assessed the metabolomic profile of the rat hippocampus at different developmental ages both at baseline and following episodic learning. We report that the hippocampal metabolome significantly changes over developmental ages and that learning regulates differential arrays of metabolites according to age. The infant hippocampus had the largest number of significant changes following learning, with downregulation of 54 metabolites. Of those, a large proportion was associated with the glutathione-mediated cellular defenses against oxidative stress. Further biochemical, molecular, and behavioral assessments revealed that infantile learning evokes a rapid and persistent increase in the activity of neuronal glutathione reductase, the enzyme that regenerates reduced glutathione from its oxidized form. Inhibition of glutathione reductase selectively impaired long-term memory formation in infant but not in juvenile and adult rats, confirming its age-specific role. Thus, metabolomic profiling revealed that the hippocampal glutathione-mediated antioxidant pathway is differentially required for the formation of infantile memory.
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Affiliation(s)
| | - Emmanuel Cruz
- Center for Neural Science, New York UniversityNew YorkUnited States
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17
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Zhao Z, Ren Y, Jiang H, Huang Y. Dexmedetomidine inhibits the PSD95-NMDA receptor interaction to promote functional recovery following traumatic brain injury. Exp Ther Med 2020; 21:4. [PMID: 33235613 PMCID: PMC7678629 DOI: 10.3892/etm.2020.9436] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 10/10/2019] [Indexed: 01/02/2023] Open
Abstract
The present study examined the effects of dexmedetomidine (Dex) on cognitive and motor recovery in mice following traumatic brain injury (TBI). TBI induces synaptic damage, which leads to motor dysfunction and cognitive decline. Although Dex is known to induce neuroprotection, its role following TBI remains unknown. In the present study, male C57BL/6 mice (8 weeks old; n=72) were subjected to cortical impact injury to generate a TBI mice model. Mice were divided into four groups: TBI, sham, TBI + vehicle, and TBI + Dex. Mice in the TBI + vehicle and TBI + Dex groups received intraperitoneal injections of saline (n=18) and 100 µg/kg Dex (n=18), respectively, at 1 and 12 h following surgery. At 24 h post-injury, 10 animals from each group were sacrificed, and brain tissue was isolated for Fluoro-Jade B staining and RNA and protein extraction. At 72 h post-TBI, motor function was evaluated. Furthermore, cognitive impairment was assessed between day 14 and 19 using the Morris water maze. The results demonstrated that the mRNA and protein expression of post-synaptic density 95 (PSD95) was reduced post-TBI. In addition, neuronal degeneration was evaluated using FJB staining, where PSD95 formed a complex with the N-methyl-D-aspartic acid (NMDA) receptor subunit (NR2B) and neuronal nitric oxide synthase (nNOS) inducing neuronal death post-TBI. Treatment with Dex efficiently decreased the PSD95-NR2B-nNOS interaction, which reduced the TBI-induced neuronal death. Furthermore, Dex treatment contributed to the enhanced cognitive and motor recovery following TBI. The results from the present study reported a potential mechanistic action of Dex treatment post-TBI, which may be associated with the inhibition of PSD95-NMDA interaction.
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Affiliation(s)
- Zhongbai Zhao
- Department of Anesthesiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, P.R. China
| | - Yu Ren
- Department of Anesthesiology, Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China
| | - Hong Jiang
- Department of Anesthesiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, P.R. China
| | - Yan Huang
- Department of Anesthesiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, P.R. China
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Kloc ML, Velasquez F, Niedecker RW, Barry JM, Holmes GL. Disruption of hippocampal rhythms via optogenetic stimulation during the critical period for memory development impairs spatial cognition. Brain Stimul 2020; 13:1535-1547. [PMID: 32871261 DOI: 10.1016/j.brs.2020.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/14/2020] [Accepted: 08/18/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Hippocampal oscillations play a critical role in the ontogeny of allocentric memory in rodents. During the critical period for memory development, hippocampal theta is the driving force behind the temporal coordination of neuronal ensembles underpinning spatial memory. While known that hippocampal oscillations are necessary for normal spatial cognition, whether disrupted hippocampal oscillatory activity during the critical period impairs long-term spatial memory is unknown. Here we investigated whether disruption of normal hippocampal rhythms during the critical period have enduring effects on allocentric memory in rodents. OBJECTIVE/HYPOTHESIS We hypothesized that disruption of hippocampal oscillations via artificial regulation of the medial septum during the critical period for memory development results in long-standing deficits in spatial cognition. METHODS After demonstrating that pan-neuronal medial septum (MS) optogenetic stimulation (465 nm activated) regulated hippocampal oscillations in weanling rats we used a random pattern of stimulation frequencies to disrupt hippocampal theta rhythms for either 1Hr or 5hr a day between postnatal (P) days 21-25. Non-stimulated and yellow light-stimulated (590 nm) rats served as controls. At P50-60 all rats were tested for spatial cognition in the active avoidance task. Rats were then sacrificed, and the MS and hippocampus assessed for cell loss. Power spectrum density of the MS and hippocampus, coherences and voltage correlations between MS and hippocampus were evaluated at baseline for a range of stimulation frequencies from 0.5 to 110 Hz and during disruptive hippocampal stimulation. Unpaired t-tests and ANOVA were used to compare oscillatory parameters, behavior and cell density in all animals. RESULTS Non-selective optogenetic stimulation of the MS in P21 rats resulted in precise regulation of hippocampal oscillations with 1:1 entrainment between stimulation frequency (0.5-110 Hz) and hippocampal local field potentials. Across bandwidths MS stimulation increased power, coherence and voltage correlation at all frequencies whereas the disruptive stimulation increased power and reduced coherence and voltage correlations with most statistical measures highly significant (p < 0.001, following correction for false detection). Rats receiving disruptive hippocampal stimulation during the critical period for memory development for either 1Hr or 5hr had marked impairment in spatial learning as measured in active avoidance test compared to non-stimulated or yellow light-control rats (p < 0.001). No cell loss was measured between the blue-stimulated and non-stimulated or yellow light-stimulated controls in either the MS or hippocampus. CONCLUSION The results demonstrated that robust regulation of hippocampal oscillations can be achieved with non-selective optogenetic stimulation of the MS in rat pups. A disruptive hippocampal stimulation protocol, which markedly increases power and reduces coherence and voltage correlations between the MS and hippocampus during the critical period of memory development, results in long-standing spatial cognitive deficits. This spatial cognitive impairment is not a result of optogenetic stimulation-induced cell loss.
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Affiliation(s)
- Michelle L Kloc
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Francisco Velasquez
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Rhys W Niedecker
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Jeremy M Barry
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Gregory L Holmes
- Epilepsy Development and Cognition Group, Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA.
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19
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Short AK, Maras PM, Pham AL, Ivy AS, Baram TZ. Blocking CRH receptors in adults mitigates age-related memory impairments provoked by early-life adversity. Neuropsychopharmacology 2020; 45:515-523. [PMID: 31698409 PMCID: PMC6969076 DOI: 10.1038/s41386-019-0562-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 10/26/2019] [Accepted: 10/28/2019] [Indexed: 01/06/2023]
Abstract
In humans, early-life adversity is associated with impairments in learning and memory that may emerge later in life. In rodent models, early-life adversity directly impacts hippocampal neuron structure and connectivity with progressive deficits in long-term potentiation and spatial memory function. Previous work has demonstrated that augmented release and actions of the stress-activated neuropeptide, CRH, contribute to the deleterious effects of early-life adversity on hippocampal dendritic arborization, synapse number and memory-function. Early-life adversity increases hippocampal CRH expression, and blocking hippocampal CRH receptor type-1 (CRHR1) immediately following early-life adversity prevented the consequent memory and LTP defects. Here, we tested if blocking CRHR1 in young adults ameliorates early-life adversity-provoked memory deficits later in life. A weeklong course of a CRHR1 antagonist in 2-month-old male rats prevented early-life adversity-induced deficits in object recognition memory that emerged by 12 months of age. Surprisingly, whereas the intervention did not mitigate early-life adversity-induced spatial memory losses at 4 and 8 months, it restored hippocampus-dependent location memory in 12-month-old rats that experienced early-life adversity. Neither early-life adversity nor CRHR1 blockade in the adult influenced anxiety- or depression-related behaviors. Altogether, these findings suggest that cognitive deficits attributable to adversity during early-life-sensitive periods are at least partially amenable to interventions later in life.
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Affiliation(s)
- Annabel K Short
- Department of Anatomy and Neurobiology, University of California- Irvine, Irvine, CA, USA.
- Department of Pediatrics, University of California-Irvine, Irvine, CA, USA.
| | - Pamela M Maras
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
| | - Aidan L Pham
- Department of Anatomy and Neurobiology, University of California- Irvine, Irvine, CA, USA
- Department of Pediatrics, University of California-Irvine, Irvine, CA, USA
| | - Autumn S Ivy
- Department of Anatomy and Neurobiology, University of California- Irvine, Irvine, CA, USA
- Department of Pediatrics, University of California-Irvine, Irvine, CA, USA
| | - Tallie Z Baram
- Department of Anatomy and Neurobiology, University of California- Irvine, Irvine, CA, USA
- Department of Pediatrics, University of California-Irvine, Irvine, CA, USA
- Department of Neurology, University of California-Irvine, Irvine, CA, USA
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20
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Bessières B, Travaglia A, Mowery TM, Zhang X, Alberini CM. Early life experiences selectively mature learning and memory abilities. Nat Commun 2020; 11:628. [PMID: 32005863 PMCID: PMC6994621 DOI: 10.1038/s41467-020-14461-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 01/09/2020] [Indexed: 01/24/2023] Open
Abstract
The mechanisms underlying the maturation of learning and memory abilities are poorly understood. Here we show that episodic learning produces unique biological changes in the hippocampus of infant rats and mice compared to juveniles and adults. These changes include persistent neuronal activation, BDNF-dependent increase in the excitatory synapse markers synaptophysin and PSD-95, and significant maturation of AMPA receptor synaptic responses. Inhibition of PSD-95 induction following learning impairs both AMPA receptor response maturation and infantile memory, indicating that the synapse formation/maturation is necessary for creating infantile memories. Conversely, capturing the learning-induced changes by presenting a subsequent learning experience or by chemogenetic activation of the neural ensembles tagged by learning matures memory functional competence. This memory competence is selective for the type of experience encountered, as it transfers within similar hippocampus-dependent learning domains but not to other hippocampus-dependent types of learning. Thus, experiences in early life produce selective maturation of memory abilities.
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Affiliation(s)
- Benjamin Bessières
- Center for Neural Science, New York University, New York, NY, 10003, USA
| | - Alessio Travaglia
- Center for Neural Science, New York University, New York, NY, 10003, USA
| | - Todd M Mowery
- Center for Neural Science, New York University, New York, NY, 10003, USA
| | - Xinying Zhang
- Center for Neural Science, New York University, New York, NY, 10003, USA
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21
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Odor-mediated contextual learning induced memory consolidation and hippocampus development in neonate rat. Neuroreport 2020; 31:64-68. [PMID: 31789755 DOI: 10.1097/wnr.0000000000001368] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The hippocampus in neonatal rats is not fully developed after birth, and the effect of odor-aversion learning on memory consolidation in the immature hippocampus is not well understood. Therefore, the aim of the present study was to explore the effects of odor-aversion learning in neonatal rats on memory consolidation and neurodevelopment in the immature hippocampus. The effect of hippocampal-induced learning was measured at two different developmental stages using the Y-maze and c-Fos protein levels. Furthermore, hippocampal cell proliferation and growth-associated protein 43 (GAP-43) expression were evaluated at different developmental stages, namely, postnatal day 7 (PN7) and PN24, after odor-aversion learning. Both PN7 and PN24 rats avoided conditioned odor stimuli after odor-aversion learning. PN7 and PN24 rats in the odor-averse learning groups exhibited high c-Fos protein levels. PN7 rats exhibited high cell proliferation rates and GAP-43 protein levels after odor-aversion learning. These results showed that the immature hippocampus can participated in odor-aversion learning, which may induce cell proliferation and axonal development.
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22
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Bessières B, Jia M, Travaglia A, Alberini CM. Developmental changes in plasticity, synaptic, glia, and connectivity protein levels in rat basolateral amygdala. ACTA ACUST UNITED AC 2019; 26:436-448. [PMID: 31615855 PMCID: PMC6796789 DOI: 10.1101/lm.049866.119] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/09/2019] [Indexed: 01/01/2023]
Abstract
The basolateral complex of amygdala (BLA) processes emotionally arousing aversive and rewarding experiences. The BLA is critical for acquisition and storage of threat-based memories and the modulation of the consolidation of arousing explicit memories, that is, the memories that are encoded and stored by the medial temporal lobe. In addition, in conjunction with the medial prefrontal cortex (mPFC), the BLA plays an important role in fear memory extinction. The BLA develops relatively early in life, but little is known about the molecular changes that accompany its development. Here, we quantified relative basal expression levels of sets of plasticity, synaptic, glia, and connectivity proteins in the rat BLA at various developmental ages: postnatal day 17 (PN17, infants), PN24 (juveniles), and PN80 (young adults). We found that the levels of activation markers of brain plasticity, including phosphorylation of CREB at Ser133, CamKIIα at Thr286, pERK1/pERK2 at Thr202/Tyr204, and GluA1 at Ser831 and Ser845, were significantly higher in infant and juvenile compared with adult brain. In contrast, age increase was accompanied by a significant augmentation in the levels of proteins that mark synaptogenesis and synapse maturation, such as synaptophysin, PSD95, SynCAM, GAD65, GAD67, and GluN2A/GluN2B ratio. Finally, we observed significant age-associated changes in structural markers, including MAP2, MBP, and MAG, suggesting that the structural connectivity of the BLA increases over time. The biological differences in the BLA between developmental ages compared with adulthood suggest the need for caution in extrapolating conclusions based on BLA-related brain plasticity and behavioral studies conducted at different developmental stages.
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Affiliation(s)
- Benjamin Bessières
- Center for Neural Science, New York University, New York, New York 10003, USA
| | - Margaret Jia
- Center for Neural Science, New York University, New York, New York 10003, USA
| | - Alessio Travaglia
- Center for Neural Science, New York University, New York, New York 10003, USA
| | - Cristina M Alberini
- Center for Neural Science, New York University, New York, New York 10003, USA
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Wirawati V, Widiati NDA, Gunawan G, Saragih GR, Hening P, Wihadmadyatami H. The distribution of serotonergic nerve on the hippocampus of the fruit bats ( Rousettus amplexicaudatus). Vet World 2019; 12:1460-1466. [PMID: 31749582 PMCID: PMC6813612 DOI: 10.14202/vetworld.2019.1460-1466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 08/13/2019] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Rousettus amplexicaudatus is one of the old world fruit bats, commonly known in Javanese word as codot belongs to Order Chiroptera and suborder Megachiroptera. R. amplexicaudatus possessed an outstanding visual ability, which helps in the process of searching for food. Those activities process and save within the brain involving the learning and memory activities. Learning and memory activities are centered around the hippocampus with the help of serotonergic nerve. AIM This study conducted to identify the morphology and distribution of serotonergic nerve (5-hydroxytryptamine) in the hippocampus of R. amplexicaudatus, which related to the function of serotonin within the learning and memory process. MATERIALS AND METHODS Five R. amplexicaudatus bats were brought from Gunung Kidul cave, Yogyakarta, Java Island, Indonesia. The bats were anesthetized using ketamine and xylazine. R. amplexicaudatus then perfused intracardially. The brain samples were collected processed into paraffin block, and a further cut in 8 µm thickness serially. The tissue slides were stained using hematoxylin-eosin, cresyl echt violet, and immunohistochemistry with rabbit's anti-serotonin (1:200). The results observed and analyzed quantitatively and qualitatively using image J (https://imagej.nih.gov/ij/) (Bethesda, Maryland, USA) and GraphPad Prism 7 (La Jolla, CA, USA). RESULTS The hippocampus of R. amplexicaudatus composed of the dentate gyrus (DG), hippocampus proper (cornu ammonis 3 [CA3], and CA1 as the main area for learning memory), and subiculum. On the DG serotonin immunoreactive cells found within the granular layer (132±35.03 cells/mm2), polymorphic stratum (86.33±11.23 cells/mm2), and molecular layer (93±1 cells/mm2). Meanwhile, on CA3 area, the immunoreactive cells for serotonin found in each stratum. The number of immunoreactive cells on each stratum from highest to the lowest are stratum pyramidal 123.33±15.88 cell/mm2, stratum molecular 63±13.11 cell/mm2, stratum lucidum 62.67±8.08 cell/mm2, stratum radiatum 55.33±510.21 cell/mm2, stratum oriens 48±3.46 cell/mm2, and stratum alveus 28.67±2,52 cell/mm2. In addition, in CA1 also hampers the immunoreactive cells in the pyramidal stratum, molecular, lucidum, oriens, radiatum, and alveus layer, respectively, of each 91±27.40 cell/mm2, 60.33±20.65 cell/mm2, 53.67±4.51 cell/mm244.33±10.40 cell/mm2, 41.33±5.51 cell/mm2, and 27±4 cell/mm2. CONCLUSION Taking together the distribution of serotonin-immunoreactive cells in the hippocampus of R. amplexicaudatus mostly found on CA3 followed by CA 1 and DG.
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Affiliation(s)
- Vivin Wirawati
- Department of Anatomy, Faculty of Veterinary Medicine, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Nourrisma D. A. Widiati
- Department of Anatomy, Faculty of Veterinary Medicine, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Geraldus Gunawan
- Department of Anatomy, Faculty of Veterinary Medicine, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Golda R. Saragih
- Department of Anatomy, Faculty of Veterinary Medicine, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Puspa Hening
- Integrated Laboratory for Research and Testing, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Hevi Wihadmadyatami
- Department of Anatomy, Faculty of Veterinary Medicine, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
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Baram TZ, Donato F, Holmes GL. Construction and disruption of spatial memory networks during development. Learn Mem 2019; 26:206-218. [PMID: 31209115 PMCID: PMC6581006 DOI: 10.1101/lm.049239.118] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 04/02/2019] [Indexed: 01/18/2023]
Abstract
Spatial memory, the aspect of memory involving encoding and retrieval of information regarding one's environment and spatial orientation, is a complex biological function incorporating multiple neuronal networks. Hippocampus-dependent spatial memory is not innate and emerges during development in both humans and rodents. In children, nonhippocampal dependent egocentric (self-to-object) memory develops before hippocampal-dependent allocentric (object-to-object) memory. The onset of allocentric spatial memory abilities in children around 22 mo of age occurs at an age-equivalent time in rodents when spatially tuned grid and place cells arise from patterned activity propagating through the entorhinal-hippocampal circuit. Neuronal activity, often driven by specific sensory signals, is critical for the normal maturation of brain circuits This patterned activity fine-tunes synaptic connectivity of the network and drives the emergence of specific firing necessary for spatial memory. Whereas normal activity patterns are required for circuit maturation, aberrant neuronal activity during development can have major adverse consequences, disrupting the development of spatial memory. Seizures during infancy, involving massive bursts of synchronized network activity, result in impaired spatial memory when animals are tested as adolescents or adults. This impaired spatial memory is accompanied by alterations in spatial and temporal coding of place cells. The molecular mechanisms by which early-life seizures lead to disruptions at the cellular and network levels are now becoming better understood, and provide a target for intervention, potentially leading to improved cognitive outcome in individuals experiencing early-life seizures.
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Affiliation(s)
- Tallie Z Baram
- Department of Anatomy/Neurobiology, University of California-Irvine, Irvine, California 92697, USA
- Department of Pediatrics, University of California-Irvine, Irvine, California 92697, USA
- Department of Neurology, University of California-Irvine, Irvine, California 92697, USA
| | - Flavio Donato
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim 7491, Norway
- Biozentrum, Department of Cell Biology, University of Basel 4056, Switzerland
| | - Gregory L Holmes
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont 05401, USA
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Ramsaran AI, Schlichting ML, Frankland PW. The ontogeny of memory persistence and specificity. Dev Cogn Neurosci 2019; 36:100591. [PMID: 30316637 PMCID: PMC6969236 DOI: 10.1016/j.dcn.2018.09.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/06/2018] [Accepted: 09/25/2018] [Indexed: 02/01/2023] Open
Abstract
Interest in the ontogeny of memory blossomed in the twentieth century following the initial observations that memories from infancy and early childhood are rapidly forgotten. The intense exploration of infantile amnesia in subsequent years has led to a thorough characterization of its psychological determinants, although the neurobiology of memory persistence has long remained elusive. By contrast, other phenomena in the ontogeny of memory like infantile generalization have received relatively less attention. Despite strong evidence for reduced memory specificity during ontogeny, infantile generalization is poorly understood from psychological and neurobiological perspectives. In this review, we examine the ontogeny of memory persistence and specificity in humans and nonhuman animals at the levels of behavior and the brain. To this end, we first describe the behavioral phenotypes associated with each phenomenon. Looking into the brain, we then discuss neurobiological mechanisms in the hippocampus that contribute to the ontogeny of memory. Hippocampal neurogenesis and critical period mechanisms have recently been discovered to underlie amnesia during early development, and at the same time, we speculate that similar processes may contribute to the early bias towards memory generalization.
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Affiliation(s)
- Adam I Ramsaran
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, M5G 1X8, Canada; Department of Psychology, University of Toronto, Toronto, M5S 3G3, Canada
| | | | - Paul W Frankland
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, M5G 1X8, Canada; Department of Psychology, University of Toronto, Toronto, M5S 3G3, Canada; Department of Physiology, University of Toronto, Toronto, M5S 1A8, Canada; Institute of Medical Science, University of Toronto, Toronto, M5S 1A8, Canada; Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, M5G 1M1, Canada.
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26
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Arc/Arg3.1 mediates a critical period for spatial learning and hippocampal networks. Proc Natl Acad Sci U S A 2018; 115:12531-12536. [PMID: 30442670 DOI: 10.1073/pnas.1810125115] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During early postnatal development, sensory regions of the brain undergo periods of heightened plasticity which sculpt neural networks and lay the foundation for adult sensory perception. Such critical periods were also postulated for learning and memory but remain elusive and poorly understood. Here, we present evidence that the activity-regulated and memory-linked gene Arc/Arg3.1 is transiently up-regulated in the hippocampus during the first postnatal month. Conditional removal of Arc/Arg3.1 during this period permanently alters hippocampal oscillations and diminishes spatial learning capacity throughout adulthood. In contrast, post developmental removal of Arc/Arg3.1 leaves learning and network activity patterns intact. Long-term memory storage continues to rely on Arc/Arg3.1 expression throughout life. These results demonstrate that Arc/Arg3.1 mediates a critical period for spatial learning, during which Arc/Arg3.1 fosters maturation of hippocampal network activity necessary for future learning and memory storage.
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27
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Jia M, Travaglia A, Pollonini G, Fedele G, Alberini CM. Developmental changes in plasticity, synaptic, glia, and connectivity protein levels in rat medial prefrontal cortex. ACTA ACUST UNITED AC 2018; 25:533-543. [PMID: 30224556 PMCID: PMC6149953 DOI: 10.1101/lm.047753.118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/06/2018] [Indexed: 12/22/2022]
Abstract
The medial prefrontal cortex (mPFC) plays a critical role in complex brain functions including decision-making, integration of emotional, and cognitive aspects in memory processing and memory consolidation. Because relatively little is known about the molecular mechanisms underlying its development, we quantified rat mPFC basal expression levels of sets of plasticity, synaptic, glia, and connectivity proteins at different developmental ages. Specifically, we compared the mPFC of rats at postnatal day 17 (PN17), when they are still unable to express long-term contextual and spatial memories, to rat mPFC at PN24, when they have acquired the ability of long-term memory expression and finally to the mPFC of adult rats. We found that, with increased age, there are remarkable and significant decreases in markers of cell activation and significant increases in proteins that mark synaptogenesis and synapse maturation. Furthermore, we found significant changes in structural markers over the ages, suggesting that structural connectivity of the mPFC increases over time. Finally, the substantial biological difference in mPFC at different ages suggest caution in extrapolating conclusions from brain plasticity studies conducted at different developmental stages.
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Affiliation(s)
- Margaret Jia
- Center for Neural Science, New York University, New York, New York 10003, USA
| | - Alessio Travaglia
- Center for Neural Science, New York University, New York, New York 10003, USA
| | - Gabriella Pollonini
- Center for Neural Science, New York University, New York, New York 10003, USA
| | - Giuseppe Fedele
- Center for Neural Science, New York University, New York, New York 10003, USA
| | - Cristina M Alberini
- Center for Neural Science, New York University, New York, New York 10003, USA
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28
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Alberini CM, Cruz E, Descalzi G, Bessières B, Gao V. Astrocyte glycogen and lactate: New insights into learning and memory mechanisms. Glia 2018; 66:1244-1262. [PMID: 29076603 PMCID: PMC5903986 DOI: 10.1002/glia.23250] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 09/05/2017] [Accepted: 10/04/2017] [Indexed: 12/12/2022]
Abstract
Memory, the ability to retain learned information, is necessary for survival. Thus far, molecular and cellular investigations of memory formation and storage have mainly focused on neuronal mechanisms. In addition to neurons, however, the brain comprises other types of cells and systems, including glia and vasculature. Accordingly, recent experimental work has begun to ask questions about the roles of non-neuronal cells in memory formation. These studies provide evidence that all types of glial cells (astrocytes, oligodendrocytes, and microglia) make important contributions to the processing of encoded information and storing memories. In this review, we summarize and discuss recent findings on the critical role of astrocytes as providers of energy for the long-lasting neuronal changes that are necessary for long-term memory formation. We focus on three main findings: first, the role of glucose metabolism and the learning- and activity-dependent metabolic coupling between astrocytes and neurons in the service of long-term memory formation; second, the role of astrocytic glucose metabolism in arousal, a state that contributes to the formation of very long-lasting and detailed memories; and finally, in light of the high energy demands of the brain during early development, we will discuss the possible role of astrocytic and neuronal glucose metabolisms in the formation of early-life memories. We conclude by proposing future directions and discussing the implications of these findings for brain health and disease. Astrocyte glycogenolysis and lactate play a critical role in memory formation. Emotionally salient experiences form strong memories by recruiting astrocytic β2 adrenergic receptors and astrocyte-generated lactate. Glycogenolysis and astrocyte-neuron metabolic coupling may also play critical roles in memory formation during development, when the energy requirements of brain metabolism are at their peak.
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Affiliation(s)
- Cristina M Alberini
- Center for Neural Science, New York University, New York, New York, 10003
- Associate Investigator, Neuroscience Institute, NYU Langone Medical Center, New York, New York, 10016
| | - Emmanuel Cruz
- Center for Neural Science, New York University, New York, New York, 10003
| | - Giannina Descalzi
- Center for Neural Science, New York University, New York, New York, 10003
| | - Benjamin Bessières
- Center for Neural Science, New York University, New York, New York, 10003
| | - Virginia Gao
- Center for Neural Science, New York University, New York, New York, 10003
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29
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Sanders EM, Nyarko-Odoom AO, Zhao K, Nguyen M, Liao HH, Keith M, Pyon J, Kozma A, Sanyal M, McHail DG, Dumas TC. Separate functional properties of NMDARs regulate distinct aspects of spatial cognition. ACTA ACUST UNITED AC 2018; 25:264-272. [PMID: 29764972 PMCID: PMC5959228 DOI: 10.1101/lm.047290.118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/12/2018] [Indexed: 11/25/2022]
Abstract
N-methyl-d-aspartate receptors (NMDARs) at excitatory synapses are central to activity-dependent synaptic plasticity and learning and memory. NMDARs act as ionotropic and metabotropic receptors by elevating postsynaptic calcium concentrations and by direct intracellular protein signaling. In the forebrain, these properties are controlled largely by the auxiliary GluN2 subunits, GluN2A and GluN2B. While calcium conductance through NMDAR channels and intracellular protein signaling make separate contributions to synaptic plasticity, it is not known if these properties individually influence learning and memory. To address this issue, we created chimeric GluN2 subunits containing the amino-terminal domain and transmembrane domains from GluN2A or GluN2B fused to the carboxy-terminal domain of GluN2B (termed ABc) or GluN2A ATD (termed BAc), respectively, and expressed these mutated GluN2 subunits in transgenic mice. Expression was confirmed at the mRNA level and protein subunit translation and translocation into dendrites were observed in forebrain neurons. In the spatial version of the Morris water maze, BAc mice displayed signs of a learning deficit. In contrast, ABc animals performed similarly to wild-types during training, but showed a more direct approach to the goal location during a long-term memory test. There was no effect of ABc or BAc expression in a nonspatial water escape task. Since background expression is predominantly GluN2A in mature animals, the results suggest that spatial learning is more sensitive to manipulations of the amino-terminal domain and transmembrane domains (calcium conductance) and long-term memory is regulated more by the carboxy-terminal domain (intracellular protein signaling).
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Affiliation(s)
- Erin M Sanders
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA
| | - Akua O Nyarko-Odoom
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA
| | - Kevin Zhao
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA
| | - Michael Nguyen
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA
| | - Hong Hong Liao
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA
| | - Matthew Keith
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA
| | - Jane Pyon
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA
| | - Alyssa Kozma
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA
| | - Mohima Sanyal
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA
| | - Daniel G McHail
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA
| | - Theodore C Dumas
- Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA.,Psychology Department, George Mason University, Fairfax, Virginia 22030, USA
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30
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Colon L, Odynocki N, Santarelli A, Poulos AM. Sexual differentiation of contextual fear responses. ACTA ACUST UNITED AC 2018; 25:230-240. [PMID: 29661835 PMCID: PMC5903402 DOI: 10.1101/lm.047159.117] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 02/05/2018] [Indexed: 12/11/2022]
Abstract
Development and sex differentiation impart an organizational influence on the neuroanatomy and behavior of mammalian species. Prior studies suggest that brain regions associated with fear motivated defensive behavior undergo a protracted and sex-dependent development. Outside of adult animals, evidence for developmental sex differences in conditioned fear is sparse. Here, we examined in male and female Long-Evans rats how developmental age and sex affect the long-term retention and generalization of Pavlovian fear responses. Experiments 1 and 2 describe under increasing levels of aversive learning (three and five trials) the long-term retrieval of cued and context fear in preadolescent (P24 and P33), periadolescent (P37), and adult (P60 and P90) rats. Experiments 3 and 4 examined contextual processing under minimal aversive learning (1 trial) procedures in infant (P19, P21), preadolescent (P24), and adult (P60) rats. Here, we found that male and female rats display a divergent developmental trajectory in the expression of context-mediated freezing, such that context fear expression in males tends to increase toward adulthood, while females displayed an opposite pattern of decreasing context fear expression toward adulthood. Longer (14 d) retention intervals produced an overall heightened context fear expression relative to shorter (1 d) retention intervals an observation consistent with fear incubation. Male, but not Female rats showed increasing generalization of context fear across development. Collectively, these findings provide an initial demonstration that sexual differentiation of contextual fear conditioning emerges prior to puberty and follows a distinct developmental trajectory toward adulthood that strikingly parallels sex differences in the etiology and epidemiology of anxiety and trauma- and stressor-related disorders.
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Affiliation(s)
- Lorianna Colon
- Department of Psychology and Center for Neuroscience, University at Albany, State University of New York, Albany, New York, USA
| | - Natalie Odynocki
- Department of Psychology and Center for Neuroscience, University at Albany, State University of New York, Albany, New York, USA
| | - Anthony Santarelli
- Department of Psychology and Center for Neuroscience, University at Albany, State University of New York, Albany, New York, USA
| | - Andrew M Poulos
- Department of Psychology and Center for Neuroscience, University at Albany, State University of New York, Albany, New York, USA
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Travaglia A, Steinmetz AB, Miranda JM, Alberini CM. Mechanisms of critical period in the hippocampus underlie object location learning and memory in infant rats. ACTA ACUST UNITED AC 2018; 25:176-182. [PMID: 29545389 PMCID: PMC5855526 DOI: 10.1101/lm.046946.117] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 01/12/2018] [Indexed: 12/29/2022]
Abstract
Episodic memories in early childhood are rapidly forgotten, a phenomenon that is associated with “infantile amnesia,” the inability of adults to remember early-life experiences. We recently showed that early aversive contextual memory in infant rats, which is in fact rapidly forgotten, is actually not lost, as reminders presented later in life reinstate a long-lasting and context-specific memory. We also showed that the formation of this infantile memory recruits in the hippocampus mechanisms typical of developmental critical periods. Here, we tested whether similar mechanisms apply to a nonaversive, hippocampal type of learning. We report that novel object location (nOL) learned at postnatal day 17 (PN17) undergoes the typical rapid forgetting of infantile learning. However, a later reminder reinstates memory expression. Furthermore, as for aversive experiences, nOL learning at PN17 engages critical period mechanisms in the dorsal hippocampus: it induces a switch in the GluN2A/2B-NMDA receptor ratio, and brain-derived neurotrophic factor injected bilaterally into the dorsal hippocampus immediately after training results in long-lasting memory expression. We conclude that in infancy the hippocampus plays a necessary role in processing episodic and contextual memories, including nonaversive ones, and matures through a developmental critical period.
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Affiliation(s)
- Alessio Travaglia
- Center for Neural Science, New York University, New York, New York 10003, USA
| | - Adam B Steinmetz
- Center for Neural Science, New York University, New York, New York 10003, USA
| | - Janelle M Miranda
- Center for Neural Science, New York University, New York, New York 10003, USA
| | - Cristina M Alberini
- Center for Neural Science, New York University, New York, New York 10003, USA.,Neuroscience Institute, NYU Langone Medical Center, New York, New York 10016, USA
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Robinson-Drummer PA, Chakraborty T, Heroux NA, Rosen JB, Stanton ME. Age and experience dependent changes in Egr-1 expression during the ontogeny of the context preexposure facilitation effect (CPFE). Neurobiol Learn Mem 2018; 150:1-12. [PMID: 29452227 DOI: 10.1016/j.nlm.2018.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 01/29/2018] [Accepted: 02/08/2018] [Indexed: 12/19/2022]
Abstract
The context preexposure facilitation effect (CPFE) is a variant of contextual fear conditioning in which acquisition of the contextual representation and association of the retrieved contextual memory with an immediate foot-shock are separated by 24 h. During the CPFE, learning- related expression patterns of the early growth response-1 gene (Egr-1) vary based on training phase and brain sub-region in adult and adolescent rats (Asok, Schreiber, Jablonski, Rosen, & Stanton, 2013; Schreiber, Asok, Jablonski, Rosen, & Stanton, 2014; Chakraborty, Asok, Stanton, & Rosen, 2016). The current experiments extended our previous findings by examining Egr-1 expression in infant (PD17) and juvenile (PD24) rats during the CPFE using preexposure protocols involving single-exposure (SE) or multiple-exposure (ME) to context. Following a 5 min preexposure to the training context (i.e. the SE protocol), Egr-1 expression in the medial prefrontal cortex (mPFC), dorsal hippocampus (dHPC) and lateral nucleus of the amygdala (LA) was differentially increased in PD24 rats relative to PD17 rats. In contrast, increased Egr-1 expression following an immediate foot-shock (2s, 1.5 mA) did not differ between PD17 and PD24 rats, and was not learning-related. Interestingly, increasing the number of exposures to the training chamber on the preexposure day (i.e. ME protocol) altered training-day expression such that a learning-related increase in expression was observed in the mPFC in PD24 but not PD17 rats. Together, these results illustrate a clear maturation of Egr-1 expression that is both age- and experience-dependent. In addition, the data suggest that regional activity and plasticity within the mPFC on the preexposure but not the training day may contribute to the ontogenetic profile of the effect. Further studies are necessary to elucidate the causal role of sub-region-specific neuroplasticity in the ontogeny of the CPFE.
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Affiliation(s)
- P A Robinson-Drummer
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States.
| | - T Chakraborty
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States
| | - N A Heroux
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States
| | - J B Rosen
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States
| | - M E Stanton
- Department of Psychological and Brain Sciences, University of Delaware, Newark, DE 19716, United States
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Marshad RA, Khatib RA, Amer H, Shammari MA, Otaibi AA, Otaibi FA, Behbehani N, Sayed AA, Hoty NA, Hassan Z, Kamal A. Streptozotocin-induced diabetes mellitus affects the NMDA receptors: Role of caffeine administration in enhancing learning, memory and locomotor deficits. Int J Health Sci (Qassim) 2018; 12:10-17. [PMID: 29896066 PMCID: PMC5969783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVE To investigate the deterioration of the brain functions by diabetes mellitus (DM) and the beneficial effect of caffeine. MATERIALS AND METHODS First, the component of N-methyl-D-aspartate receptors (NMDA) of the field excitatory postsynaptic potential (fEPSP) were recorded in streptozotocin (STZ)-induced DM and compared with control animals. Later, 40 mice were divided randomly into five groups (8 mice in each): (1) Normal control (Cont), (2) diabetic group (DM), (3) animals pretreated with i.p. caffeine before the induction of DM (Pre Caf), (4) acute caffeine-treated group (Ac Caf), and (5) chronic caffeine group (Ch Caf). Learning and memory were assessed in Morris-Water maze, and motor coordination was tested by rotarod. RESULTS A significant reduction in the NMDA-component of the fEPSPs responses was recorded in the hippocampus of the diabetic animals. All the DM-groups demonstrated defects in learning and memory tasks; only the Ac Caf group could reverse the deteriorating effect of DM. This group showed a significantly lower latency values to reach their target (submerged platform) in the water maze in comparison to the DM, Pre Caf, and Ch Caf groups. Their performance was not significantly different from the control animals. Rotarod testing showed significant role of acute, but not chronic, caffeine administration in enhancing the motor skills. CONCLUSION STZ -induced DM resulted into defects in memory tasks which are associated with a reduction in the hippocampal NMDA-receptor component of the fEPSP. Acute, but not chronic administration of caffeine could reverse the deteriorating effect of DM on learning and memory.
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Affiliation(s)
- Reem Al Marshad
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Kingdom of Bahrain
| | - Razan Al Khatib
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Kingdom of Bahrain
| | - Hanine Amer
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Kingdom of Bahrain
| | - Munirah Al Shammari
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Kingdom of Bahrain
| | - Aysha Al Otaibi
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Kingdom of Bahrain
| | - Fahad Al Otaibi
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Kingdom of Bahrain
| | - Nadiah Behbehani
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Kingdom of Bahrain
| | - Anwaar Al Sayed
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Kingdom of Bahrain
| | - Norah Al Hoty
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Kingdom of Bahrain
| | - Zuheir Hassan
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Kingdom of Bahrain
| | - Amer Kamal
- Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Kingdom of Bahrain,Address for correspondence: Amer Kamal, Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, Kingdom of Bahrain. Tel: (+) 973 17239767. Mobile: +973 36622801. Fax.: (+) 973 17271090. E-mail:
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Edwards D, Sommerhage F, Berry B, Nummer H, Raquet M, Clymer B, Stancescu M, Hickman JJ. Comparison of NMDA and AMPA Channel Expression and Function between Embryonic and Adult Neurons Utilizing Microelectrode Array Systems. ACS Biomater Sci Eng 2017; 3:3525-3533. [PMID: 29250595 PMCID: PMC5728088 DOI: 10.1021/acsbiomaterials.7b00596] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 11/13/2017] [Indexed: 12/27/2022]
Abstract
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Microelectrode
arrays (MEAs) are innovative tools used to perform
electrophysiological experiments for the study of electrical activity
and connectivity in populations of neurons from dissociated cultures.
Reliance upon neurons derived from embryonic tissue is a common limitation
of neuronal/MEA hybrid systems and perhaps of neuroscience research
in general, and the use of adult neurons could model fully functional
in vivo parameters more closely. Spontaneous network activity was
concurrently recorded from both embryonic and adult rat neurons cultured
on MEAs for up to 10 weeks in vitro to characterize the synaptic connections
between cell types. The cultures were exposed to synaptic transmission
antagonists against NMDA and AMPA channels, which revealed significantly
different receptor profiles of adult and embryonic networks in vitro.
In addition, both embryonic and adult neurons were evaluated for NMDA
and AMPA channel subunit expression over five weeks in vitro. The
results established that neurons derived from embryonic tissue did
not express mature synaptic channels for several weeks in vitro under
defined conditions. Consequently, the embryonic response to synaptic
antagonists was significantly different than that of neurons derived
from adult tissue sources. These results are especially significant
because most studies reported with embryonic hippocampal neurons do
not begin at two to four weeks in culture. In addition, the utilization
of MEAs in lieu of patch-clamp electrophysiology avoided a large-scale,
labor-intensive study. These results establish the utility of this
unique hybrid system derived from adult hippocampal tissue in combination
with MEAs and offer a more appropriate representation of in vivo function
for drug discovery. It has application for neuronal development and
regeneration as well as for investigations into neurodegenerative
disease, traumatic brain injury, and stroke.
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Affiliation(s)
- Darin Edwards
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, Florida 32826, United States.,The Burnett School of Biomedical Sciences, University of Central Florida, UCF College of Medicine, 6850 Lake Nona Blvd, Orlando, Florida 32827, United States
| | - Frank Sommerhage
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, Florida 32826, United States
| | - Bonnie Berry
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, Florida 32826, United States.,The Burnett School of Biomedical Sciences, University of Central Florida, UCF College of Medicine, 6850 Lake Nona Blvd, Orlando, Florida 32827, United States
| | - Hanna Nummer
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, Florida 32826, United States
| | - Martina Raquet
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, Florida 32826, United States
| | - Brad Clymer
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, Florida 32826, United States
| | - Maria Stancescu
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, Florida 32826, United States
| | - James J Hickman
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, Florida 32826, United States.,The Burnett School of Biomedical Sciences, University of Central Florida, UCF College of Medicine, 6850 Lake Nona Blvd, Orlando, Florida 32827, United States
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Infantile Amnesia: A Critical Period of Learning to Learn and Remember. J Neurosci 2017; 37:5783-5795. [PMID: 28615475 DOI: 10.1523/jneurosci.0324-17.2017] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 05/04/2017] [Accepted: 05/15/2017] [Indexed: 12/11/2022] Open
Abstract
Infantile amnesia, the inability of adults to recollect early episodic memories, is associated with the rapid forgetting that occurs in childhood. It has been suggested that infantile amnesia is due to the underdevelopment of the infant brain, which would preclude memory consolidation, or to deficits in memory retrieval. Although early memories are inaccessible to adults, early-life events, such as neglect or aversive experiences, can greatly impact adult behavior and may predispose individuals to various psychopathologies. It remains unclear how a brain that rapidly forgets, or is not yet able to form long-term memories, can exert such a long-lasting and important influence. Here, with a particular focus on the hippocampal memory system, we review the literature and discuss new evidence obtained in rats that illuminates the paradox of infantile amnesia. We propose that infantile amnesia reflects a developmental critical period during which the learning system is learning how to learn and remember.
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Claflin DI, Schmidt KD, Vallandingham ZD, Kraszpulski M, Hennessy MB. Influence of postnatal glucocorticoids on hippocampal-dependent learning varies with elevation patterns and administration methods. Neurobiol Learn Mem 2017; 143:77-87. [PMID: 28545908 DOI: 10.1016/j.nlm.2017.05.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 05/12/2017] [Accepted: 05/16/2017] [Indexed: 11/17/2022]
Abstract
Recent interest in the lasting effects of early-life stress has expanded to include effects on cognitive performance. An increase in circulating glucocorticoids is induced by stress exposure and glucocorticoid effects on the hippocampus likely underlie many of the cognitive consequences. Here we review studies showing that corticosterone administered to young rats at the conclusion of the stress-hyporesponsiveness period affects later performance in hippocampally-mediated trace eyeblink conditioning. The nature and even direction of these effects varies with the elevation patterns (level, duration, temporal fluctuation) achieved by different administration methods. We present new time course data indicating that constant glucocorticoid elevations generally corresponded with hippocampus-mediated learning deficits, whereas acute, cyclical elevations corresponded with improved initial acquisition. Sensitivity was greater for males than for females. Further, changes in hippocampal neurogenesis paralleled some but not all effects. The findings demonstrate that specific patterns of glucocorticoid elevation produced by different drug administration procedures can have markedly different, sex-specific consequences on basic cognitive performance and underlying hippocampal physiology. Implications of these findings for glucocorticoid medications prescribed in childhood are discussed.
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Affiliation(s)
- Dragana I Claflin
- Department of Psychology, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435, USA.
| | - Kevin D Schmidt
- Department of Psychology, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435, USA; Applied Neuroscience Branch, Air Force Research Laboratory, 2510 Fifth St., Wright-Patterson AFB, OH 45433, USA.
| | - Zachary D Vallandingham
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435, USA.
| | - Michal Kraszpulski
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435, USA.
| | - Michael B Hennessy
- Department of Psychology, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435, USA.
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Postnatal LPS Challenge Impacts Escape Learning and Expression of Plasticity Factors Mmp9 and Timp1 in Rats: Effects of Repeated Training. Neurotox Res 2017; 32:175-186. [PMID: 28421528 PMCID: PMC5493723 DOI: 10.1007/s12640-017-9720-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 03/01/2017] [Accepted: 03/03/2017] [Indexed: 10/24/2022]
Abstract
Bacterial intoxication associated with inflammatory conditions during development can impair brain functions, in particular evolutionarily novel forms of memory, such as explicit learning. Little is known about the dangers of early-life inflammation on more basic forms of learning, for example, the acquisition of motor escape abilities, which are generally better preserved under pathological conditions. To address this limitation in knowledge, an inflammatory response was elicited in Wistar pups by lipopolysaccharide (LPS) injections (25 μg/kg) on postnatal days P15, P18 and P21. The acquisition of escape behaviour was tested from P77 by active avoidance footshock model and water maze. Open-field behaviour and blood corticosterone levels were also measured. Rat brain tissue was collected from pups 2 h post-injection and from adult rats which either underwent escape training on P77-P81 or remained untrained. mRNA levels of developmental brain plasticity factors MMP-9 and TIMP-1 were investigated in the medial prefrontal cortex and ventral/dorsal hippocampus. LPS-challenged rats displayed moderately deficient escape responses in both memory tests, increased freezing behaviour and, surprisingly, reduced blood cortisol levels. Mmp9 and Timp1, and their ratio to one another, were differentially altered in pups versus adult untrained rats but remained unchanged overall in rats trained in either learning task. Together, our data indicate that systemic pro-inflammatory response during early postnatal development has long-lasting effects, including on the acquisition of motor escape abilities and plasticity factor expression, into adulthood. Our data suggest that altered stress response could possibly mediate these deviations and repeated training might generate positive effects on plasticity under the employed conditions.
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Therapeutic Potentials of Synapses after Traumatic Brain Injury: A Comprehensive Review. Neural Plast 2017; 2017:4296075. [PMID: 28491479 PMCID: PMC5405590 DOI: 10.1155/2017/4296075] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/09/2017] [Accepted: 03/14/2017] [Indexed: 12/26/2022] Open
Abstract
Massive studies have focused on the understanding of the pathobiology of cellular and molecular changes and injury mechanisms after traumatic brain injury (TBI), but very few studies have specially discussed the role of synapses in the context of TBI. This paper specifically highlights the role and therapeutic potentials of synapses after TBI. First, we review and conclude how synapses interact with constant structural, metabolic, neuroendocrine, and inflammatory mechanisms after TBI. Second, we briefly describe several key synaptic proteins involved in neuroplasticity, which may be novel neuronal targets for specific intervention. Third, we address therapeutic interventions in association with synapses after TBI. Finally, we concisely discuss the study gaps in the synapses after TBI, in hopes that this would provide more insights for future studies. Synapses play an important role in TBI; while the understandings on the synaptic participation in the treatments and prognosis of TBI are lacking, more studies in this area are warranted.
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