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Amelchenko EM, Bezriadnov DV, Chekhov OA, Ivanova AA, Kedrov AV, Anokhin KV, Lazutkin AA, Enikolopov G. Cognitive Flexibility Is Selectively Impaired by Radiation and Is Associated with Differential Recruitment of Adult-Born Neurons. J Neurosci 2023; 43:6061-6083. [PMID: 37532464 PMCID: PMC10451007 DOI: 10.1523/jneurosci.0161-22.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 06/17/2023] [Accepted: 06/23/2023] [Indexed: 08/04/2023] Open
Abstract
Exposure to elevated doses of ionizing radiation, such as those in therapeutic procedures, catastrophic accidents, or space exploration, increases the risk of cognitive dysfunction. The full range of radiation-induced cognitive deficits is unknown, partly because commonly used tests may be insufficiently sensitive or may not be adequately tuned for assessing the fine behavioral features affected by radiation. Here, we asked whether γ-radiation might affect learning, memory, and the overall ability to adapt behavior to cope with a challenging environment (cognitive/behavioral flexibility). We developed a new behavioral assay, the context discrimination Morris water maze (cdMWM) task, which is hippocampus-dependent and requires the integration of various contextual cues and the adjustment of search strategies. We exposed male mice to 1 or 5 Gy of γ rays and, at different time points after irradiation, trained them consecutively in spatial MWM, reversal MWM, and cdMWM tasks, and assessed their learning, navigational search strategies, and memory. Mice exposed to 5 Gy performed successfully in the spatial and reversal MWM tasks; however, in the cdMWM task 6 or 8 weeks (but not 3 weeks) after irradiation, they demonstrated transient learning deficit, decreased use of efficient spatially precise search strategies during learning, and, 6 weeks after irradiation, memory deficit. We also observed impaired neurogenesis after irradiation and selective activation of 12-week-old newborn neurons by specific components of cdMWM training paradigm. Thus, our new behavioral paradigm reveals the effects of γ-radiation on cognitive flexibility and indicates an extended timeframe for the functional maturation of new hippocampal neurons.SIGNIFICANCE STATEMENT Exposure to radiation can affect cognitive performance and cognitive flexibility - the ability to adapt to changed circumstances and demands. The full range of consequences of irradiation on cognitive flexibility is unknown, partly because of a lack of suitable models. Here, we developed a new behavioral task requiring mice to combine various types of cues and strategies to find a correct solution. We show that animals exposed to γ-radiation, despite being able to successfully solve standard problems, show delayed learning, deficient memory, and diminished use of efficient navigation patterns in circumstances requiring adjustments of previously used search strategies. This new task could be applied in other settings for assessing the cognitive changes induced by aging, trauma, or disease.
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Affiliation(s)
- Evgeny M Amelchenko
- Center for Developmental Genetics
- Department of Anesthesiology, Stony Brook University, Stony Brook, New York 11794
| | - Dmitri V Bezriadnov
- P.K. Anokhin Research Institute of Normal Physiology, Moscow, 125315, Russian Federation
| | - Olga A Chekhov
- Center for Developmental Genetics
- Department of Anesthesiology, Stony Brook University, Stony Brook, New York 11794
| | - Anna A Ivanova
- Institute of Higher Nervous Activity and Neurophysiology RAS, Moscow, 117485, Russian Federation
- Institute for Advanced Brain Studies, Lomonosov Moscow State University, Moscow, 119234, Russian Federation
| | - Alexander V Kedrov
- P.K. Anokhin Research Institute of Normal Physiology, Moscow, 125315, Russian Federation
| | - Konstantin V Anokhin
- P.K. Anokhin Research Institute of Normal Physiology, Moscow, 125315, Russian Federation
- Institute for Advanced Brain Studies, Lomonosov Moscow State University, Moscow, 119234, Russian Federation
| | - Alexander A Lazutkin
- Center for Developmental Genetics
- Department of Anesthesiology, Stony Brook University, Stony Brook, New York 11794
- Institute of Higher Nervous Activity and Neurophysiology RAS, Moscow, 117485, Russian Federation
| | - Grigori Enikolopov
- Center for Developmental Genetics
- Department of Anesthesiology, Stony Brook University, Stony Brook, New York 11794
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Gutiérrez-Menéndez A, Méndez M, Arias JL. Learning and metabolic brain differences between juvenile male and female rats in the execution of different training regimes of a spatial memory task. Physiol Behav 2023; 267:114203. [PMID: 37086830 DOI: 10.1016/j.physbeh.2023.114203] [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: 02/14/2023] [Revised: 04/17/2023] [Accepted: 04/19/2023] [Indexed: 04/24/2023]
Abstract
Spatial memory is responsible for encoding spatial information to form a path, storing this mental representation, and evaluating and recovering spatial configurations to find a target location in the environment. It is mainly supported by the hippocampus and its interaction with other structures, such as the prefrontal cortex, and emerges in rodents around postnatal day (PND) 20. Sex differences in spatial tasks have been found in adults, with a supposedly better performance in males. However, few studies have examined sex differences in orientation throughout postnatal development. This study aimed to analyse the performance of juvenile (PND 23) male (n=18) and female (n=21) Wistar rats in a spatial reference memory task in the Morris water maze (MWM) with two different training regimes in the acquisition phase, and their subjacent metabolic brain activity. Based on sex, subjects were assigned to two different groups: one that performed four learning trials per day (n=9 males and n=8 females) and the other that was submitted to two trials per day (n=9 males and n=13 females). After the behavioural protocols, metabolic activity was evaluated using cytochrome c oxidase histochemistry. Results showed no metabolic brain or behavioural differences in the four-trial protocol performance, in which both sexes reached the learning criterion on the fourth day. By contrast, the two-trial protocol revealed an advantage for females, who reached the learning criterion on day four, whereas males needed more training and succeeded on day six. The female group showed lower metabolic activity than the male group in the cingulate and prelimbic cortex. These results suggest a faster consolidation process in the female group than the male group. Further research is needed to understand sex differences in spatial memory at early stages.
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Affiliation(s)
- Alba Gutiérrez-Menéndez
- Laboratory of Neuroscience, Department of Psychology, University of Oviedo, Plaza Feijóo, s/n, E-33003, Oviedo, Spain; Instituto de Neurociencias del Principado de Asturias (INEUROPA), Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain.
| | - Marta Méndez
- Laboratory of Neuroscience, Department of Psychology, University of Oviedo, Plaza Feijóo, s/n, E-33003, Oviedo, Spain; Instituto de Neurociencias del Principado de Asturias (INEUROPA), Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Jorge L Arias
- Laboratory of Neuroscience, Department of Psychology, University of Oviedo, Plaza Feijóo, s/n, E-33003, Oviedo, Spain; Instituto de Neurociencias del Principado de Asturias (INEUROPA), Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
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3
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Sun D, Mei L, Xiong WC. Dorsal Dentate Gyrus, a Key Regulator for Mood and Psychiatric Disorders. Biol Psychiatry 2023:S0006-3223(23)00009-4. [PMID: 36894487 DOI: 10.1016/j.biopsych.2023.01.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 12/06/2022] [Accepted: 01/09/2023] [Indexed: 01/18/2023]
Abstract
The dentate gyrus, a "gate" that controls the flow of information into the hippocampus, is critical for learning, memory, spatial navigation, and mood regulation. Several lines of evidence have demonstrated that deficits in dentate granule cells (DGCs) (e.g., loss of DGCs or genetic mutations in DGCs) contribute to the development of various psychiatric disorders, such as depression and anxiety disorders. Whereas ventral DGCs are believed to be critical for mood regulation, the functions of dorsal DGCs in this regard remain elusive. Here, we review the role of DGCs, in particular the dorsal DGCs, in the regulation of mood, their functional relationships with DGC development, and the contributions of dysfunctional DGCs to mental disorders.
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Affiliation(s)
- Dong Sun
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio; National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun, Jilin, China
| | - Lin Mei
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Wen-Cheng Xiong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio.
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4
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Lods M, Mortessagne P, Pacary E, Terral G, Farrugia F, Mazier W, Masachs N, Charrier V, Cota D, Ferreira G, Abrous DN, Tronel S. Chemogenetic stimulation of adult neurogenesis, and not neonatal neurogenesis, is sufficient to improve long-term memory accuracy. Prog Neurobiol 2022; 219:102364. [DOI: 10.1016/j.pneurobio.2022.102364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 09/21/2022] [Accepted: 10/06/2022] [Indexed: 12/05/2022]
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5
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Pathological Nuclear Hallmarks in Dentate Granule Cells of Alzheimer’s Patients: A Biphasic Regulation of Neurogenesis. Int J Mol Sci 2022; 23:ijms232112873. [PMID: 36361662 PMCID: PMC9654738 DOI: 10.3390/ijms232112873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 10/14/2022] [Accepted: 10/18/2022] [Indexed: 11/29/2022] Open
Abstract
The dentate gyrus (DG) of the human hippocampus is a complex and dynamic structure harboring mature and immature granular neurons in diverse proliferative states. While most mammals show persistent neurogenesis through adulthood, human neurogenesis is still under debate. We found nuclear alterations in granular cells in autopsied human brains, detected by immunohistochemistry. These alterations differ from those reported in pyramidal neurons of the hippocampal circuit. Aging and early AD chromatin were clearly differentiated by the increased epigenetic markers H3K9me3 (heterochromatin suppressive mark) and H3K4me3 (transcriptional euchromatin mark). At early AD stages, lamin B2 was redistributed to the nucleoplasm, indicating cell-cycle reactivation, probably induced by hippocampal nuclear pathology. At intermediate and late AD stages, higher lamin B2 immunopositivity in the perinucleus suggests fewer immature neurons, less neurogenesis, and fewer adaptation resources to environmental factors. In addition, senile samples showed increased nuclear Tau interacting with aged chromatin, likely favoring DNA repair and maintaining genomic stability. However, at late AD stages, the progressive disappearance of phosphorylated Tau forms in the nucleus, increased chromatin disorganization, and increased nuclear autophagy support a model of biphasic neurogenesis in AD. Therefore, designing therapies to alleviate the neuronal nuclear pathology might be the only pathway to a true rejuvenation of brain circuits.
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6
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Shridhar S, Mishra P, Narayanan R. Dominant role of adult neurogenesis-induced structural heterogeneities in driving plasticity heterogeneity in dentate gyrus granule cells. Hippocampus 2022; 32:488-516. [PMID: 35561083 PMCID: PMC9322436 DOI: 10.1002/hipo.23422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 04/21/2022] [Accepted: 04/28/2022] [Indexed: 02/02/2023]
Abstract
Neurons and synapses manifest pronounced variability in the amount of plasticity induced by identical activity patterns. The mechanisms underlying such plasticity heterogeneity, which have been implicated in context‐specific resource allocation during encoding, have remained unexplored. Here, we employed a systematic physiologically constrained parametric search to identify the cellular mechanisms behind plasticity heterogeneity in dentate gyrus granule cells. We used heterogeneous model populations to ensure that our conclusions were not biased by parametric choices in a single hand‐tuned model. We found that each of intrinsic, synaptic, and structural heterogeneities independently yielded heterogeneities in synaptic plasticity profiles obtained with two different induction protocols. However, among the disparate forms of neural‐circuit heterogeneities, our analyses demonstrated the dominance of neurogenesis‐induced structural heterogeneities in driving plasticity heterogeneity in granule cells. We found that strong relationships between neuronal intrinsic excitability and plasticity emerged only when adult neurogenesis‐induced heterogeneities in neural structure were accounted for. Importantly, our analyses showed that it was not imperative that the manifestation of neural‐circuit heterogeneities must translate to heterogeneities in plasticity profiles. Specifically, despite the expression of heterogeneities in structural, synaptic, and intrinsic neuronal properties, similar plasticity profiles were attainable across all models through synergistic interactions among these heterogeneities. We assessed the parametric combinations required for the manifestation of such degeneracy in the expression of plasticity profiles. We found that immature cells showed physiological plasticity profiles despite receiving afferent inputs with weak synaptic strengths. Thus, the high intrinsic excitability of immature granule cells was sufficient to counterbalance their low excitatory drive in the expression of plasticity profile degeneracy. Together, our analyses demonstrate that disparate forms of neural‐circuit heterogeneities could mechanistically drive plasticity heterogeneity, but also caution against treating neural‐circuit heterogeneities as proxies for plasticity heterogeneity. Our study emphasizes the need for quantitatively characterizing the relationship between neural‐circuit and plasticity heterogeneities across brain regions.
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Affiliation(s)
- Sameera Shridhar
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Poonam Mishra
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Rishikesh Narayanan
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
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7
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Adult hippocampal neurogenesis shapes adaptation and improves stress response: a mechanistic and integrative perspective. Mol Psychiatry 2022; 27:403-421. [PMID: 33990771 PMCID: PMC8960391 DOI: 10.1038/s41380-021-01136-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 04/09/2021] [Accepted: 04/19/2021] [Indexed: 02/03/2023]
Abstract
Adult hippocampal neurogenesis (AHN) represents a remarkable form of neuroplasticity that has increasingly been linked to the stress response in recent years. However, the hippocampus does not itself support the expression of the different dimensions of the stress response. Moreover, the main hippocampal functions are essentially preserved under AHN depletion and adult-born immature neurons (abGNs) have no extrahippocampal projections, which questions the mechanisms by which abGNs influence functions supported by brain areas far from the hippocampus. Within this framework, we propose that through its computational influences AHN is pivotal in shaping adaption to environmental demands, underlying its role in stress response. The hippocampus with its high input convergence and output divergence represents a computational hub, ideally positioned in the brain (1) to detect cues and contexts linked to past, current and predicted stressful experiences, and (2) to supervise the expression of the stress response at the cognitive, affective, behavioral, and physiological levels. AHN appears to bias hippocampal computations toward enhanced conjunctive encoding and pattern separation, promoting contextual discrimination and cognitive flexibility, reducing proactive interference and generalization of stressful experiences to safe contexts. These effects result in gating downstream brain areas with more accurate and contextualized information, enabling the different dimensions of the stress response to be more appropriately set with specific contexts. Here, we first provide an integrative perspective of the functional involvement of AHN in the hippocampus and a phenomenological overview of the stress response. We then examine the mechanistic underpinning of the role of AHN in the stress response and describe its potential implications in the different dimensions accompanying this response.
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8
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Abrous DN, Koehl M, Lemoine M. A Baldwin interpretation of adult hippocampal neurogenesis: from functional relevance to physiopathology. Mol Psychiatry 2022; 27:383-402. [PMID: 34103674 PMCID: PMC8960398 DOI: 10.1038/s41380-021-01172-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 05/03/2021] [Accepted: 05/12/2021] [Indexed: 02/05/2023]
Abstract
Hippocampal adult neurogenesis has been associated to many cognitive, emotional, and behavioral functions and dysfunctions, and its status as a selected effect or an "appendix of the brain" has been debated. In this review, we propose to understand hippocampal neurogenesis as the process underlying the "Baldwin effect", a particular situation in evolution where fitness does not rely on the natural selection of genetic traits, but on "ontogenetic adaptation" to a changing environment. This supports the view that a strong distinction between developmental and adult hippocampal neurogenesis is made. We propose that their functions are the constitution and the lifelong adaptation, respectively, of a basic repertoire of cognitive and emotional behaviors. This lifelong adaptation occurs through new forms of binding, i.e., association or dissociation of more basic elements. This distinction further suggests that a difference is made between developmental vulnerability (or resilience), stemming from dysfunctional (or highly functional) developmental hippocampal neurogenesis, and adult vulnerability (or resilience), stemming from dysfunctional (or highly functional) adult hippocampal neurogenesis. According to this hypothesis, developmental and adult vulnerability are distinct risk factors for various mental disorders in adults. This framework suggests new avenues for research on hippocampal neurogenesis and its implication in mental disorders.
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Affiliation(s)
- Djoher Nora Abrous
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, Neurogenesis and Pathophysiology group, F-33000, Bordeaux, France.
| | - Muriel Koehl
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, Neurogenesis and Pathophysiology group, F-33000 Bordeaux, France
| | - Maël Lemoine
- grid.412041.20000 0001 2106 639XUniversity Bordeaux, CNRS, ImmunoConcEpT, UMR 5164, Bordeaux, France
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9
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Loureiro-Campos E, Mateus-Pinheiro A, Patrício P, Soares-Cunha C, Silva J, Sardinha VM, Mendes-Pinheiro B, Silveira-Rosa T, Domingues AV, Rodrigues AJ, Oliveira J, Sousa N, Alves ND, Pinto L. Constitutive deficiency of the neurogenic hippocampal modulator AP2γ promotes anxiety-like behavior and cumulative memory deficits in mice from juvenile to adult periods. eLife 2021; 10:70685. [PMID: 34859784 PMCID: PMC8709574 DOI: 10.7554/elife.70685] [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: 05/26/2021] [Accepted: 12/02/2021] [Indexed: 11/23/2022] Open
Abstract
The transcription factor activating protein two gamma (AP2γ) is an important regulator of neurogenesis both during embryonic development as well as in the postnatal brain, but its role for neurophysiology and behavior at distinct postnatal periods is still unclear. In this work, we explored the neurogenic, behavioral, and functional impact of a constitutive and heterozygous AP2γ deletion in mice from early postnatal development until adulthood. AP2γ deficiency promotes downregulation of hippocampal glutamatergic neurogenesis, altering the ontogeny of emotional and memory behaviors associated with hippocampus formation. The impairments induced by AP2γ constitutive deletion since early development leads to an anxious-like phenotype and memory impairments as early as the juvenile phase. These behavioral impairments either persist from the juvenile phase to adulthood or emerge in adult mice with deficits in behavioral flexibility and object location recognition. Collectively, we observed a progressive and cumulative impact of constitutive AP2γ deficiency on the hippocampal glutamatergic neurogenic process, as well as alterations on limbic-cortical connectivity, together with functional behavioral impairments. The results herein presented demonstrate the modulatory role exerted by the AP2γ transcription factor and the relevance of hippocampal neurogenesis in the development of emotional states and memory processes.
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Affiliation(s)
- Eduardo Loureiro-Campos
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal
| | - António Mateus-Pinheiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal
| | - Patrícia Patrício
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal
| | - Carina Soares-Cunha
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal
| | - Joana Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal
| | - Vanessa Morais Sardinha
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal
| | - Bárbara Mendes-Pinheiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal
| | - Tiago Silveira-Rosa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal
| | - Ana Verónica Domingues
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal
| | - Ana João Rodrigues
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
| | - João Oliveira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal.,IPCA-EST-2Ai, Polytechnic Institute of Cávado and Ave, Applied Artificial Intelligence Laboratory, Campus of IPCA, Barcelos, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal
| | - Nuno Dinis Alves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal
| | - Luísa Pinto
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's -PT Government Associate Laboratory, Guimarães, Portugal
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10
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Hippocampal neurogenesis promotes preference for future rewards. Mol Psychiatry 2021; 26:6317-6335. [PMID: 34021262 DOI: 10.1038/s41380-021-01165-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/29/2021] [Accepted: 05/06/2021] [Indexed: 02/04/2023]
Abstract
Adult hippocampal neurogenesis has been implicated in a number of disorders where reward processing is disrupted but whether new neurons regulate specific aspects of reward-related decision making remains unclear. Given the role of the hippocampus in future-oriented cognition, here we tested whether adult neurogenesis regulates preference for future, advantageous rewards in a delay discounting paradigm for rats. Indeed, blocking neurogenesis caused a profound aversion for delayed rewards, and biased choice behavior toward immediately available, but smaller, rewards. Consistent with a role for the ventral hippocampus in impulsive decision making and future-thinking, neurogenesis-deficient animals displayed reduced activity in the ventral hippocampus. In intact animals, delay-based decision making restructured dendrites and spines in adult-born neurons and specifically activated adult-born neurons in the ventral dentate gyrus, relative to dorsal activation in rats that chose between immediately-available rewards. Putative developmentally-born cells, located in the superficial granule cell layer, did not display task-specific activity. These findings identify a novel and specific role for neurogenesis in decisions about future rewards, thereby implicating newborn neurons in disorders where short-sighted gains are preferred at the expense of long-term health.
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11
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Damphousse CC, Medeiros J, Marrone DF. Functional Integration of Adult-Generated Neurons in Diabetic Goto-Kakizaki Rats. Front Behav Neurosci 2021; 15:734359. [PMID: 34675787 PMCID: PMC8523851 DOI: 10.3389/fnbeh.2021.734359] [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: 07/01/2021] [Accepted: 08/31/2021] [Indexed: 11/30/2022] Open
Abstract
Adult-born neurons in the dentate gyrus (DG) make important contributions to learning as they integrate into neuronal networks. Neurogenesis is dramatically reduced by a number of conditions associated with cognitive impairment, including type 2 diabetes mellitus (T2DM). Increasing neurogenesis may thus provide a therapeutic target for ameliorating diabetes-associated cognitive impairments, but only if new neurons remain capable of normal function. To address the capacity for adult-generated neurons to incorporate into functional circuits in the hyperglycemic DG, we measured Egr1 expression in granule cells (GCs), BrdU labeled four weeks prior, in Goto-Kakizaki (GK) rats, an established model of T2DM, and age-matched Wistars. The results indicate that while fewer GCs are generated in the DG of GK rats, GCs that survive readily express Egr1 in response to spatial information. These data demonstrate that adult-generated GCs in the hyperglycemic DG remain functionally competent and support neurogenesis as a viable therapeutic target.
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Affiliation(s)
| | - Jaclyn Medeiros
- Department of Psychology, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Diano F Marrone
- Department of Psychology, Wilfrid Laurier University, Waterloo, ON, Canada
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12
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Lods M, Pacary E, Mazier W, Farrugia F, Mortessagne P, Masachs N, Charrier V, Massa F, Cota D, Ferreira G, Abrous DN, Tronel S. Adult-born neurons immature during learning are necessary for remote memory reconsolidation in rats. Nat Commun 2021; 12:1778. [PMID: 33741954 PMCID: PMC7979763 DOI: 10.1038/s41467-021-22069-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 02/25/2021] [Indexed: 01/09/2023] Open
Abstract
Memory reconsolidation, the process by which memories are again stabilized after being reactivated, has strengthened the idea that memory stabilization is a highly plastic process. To date, the molecular and cellular bases of reconsolidation have been extensively investigated particularly within the hippocampus. However, the role of adult neurogenesis in memory reconsolidation is unclear. Here, we combined functional imaging, retroviral and chemogenetic approaches in rats to tag and manipulate different populations of rat adult-born neurons. We find that both mature and immature adult-born neurons are activated by remote memory retrieval. However, only specific silencing of the adult-born neurons immature during learning impairs remote memory retrieval-induced reconsolidation. Hence, our findings show that adult-born neurons immature during learning are required for the maintenance and update of remote memory reconsolidation.
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Affiliation(s)
- Marie Lods
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Emilie Pacary
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Wilfrid Mazier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Fanny Farrugia
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Pierre Mortessagne
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Nuria Masachs
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Vanessa Charrier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Federico Massa
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Daniela Cota
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Guillaume Ferreira
- INRA, Bordeaux INP, Nutrition and Integrative Neurobiology, UMR 1286, Bordeaux Cedex, France
| | - Djoher Nora Abrous
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France.
| | - Sophie Tronel
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France.
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13
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Sun D, Milibari L, Pan JX, Ren X, Yao LL, Zhao Y, Shen C, Chen WB, Tang FL, Lee D, Zhang JS, Mei L, Xiong WC. Critical Roles of Embryonic Born Dorsal Dentate Granule Neurons for Activity-Dependent Increases in BDNF, Adult Hippocampal Neurogenesis, and Antianxiety-like Behaviors. Biol Psychiatry 2021; 89:600-614. [PMID: 33183762 PMCID: PMC7889658 DOI: 10.1016/j.biopsych.2020.08.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 08/11/2020] [Accepted: 08/31/2020] [Indexed: 11/18/2022]
Abstract
BACKGROUND Dentate gyrus (DG), a "gate" that controls information flow into the hippocampus, plays important roles in regulating both cognitive (e.g., spatial learning and memory) and mood behaviors. Deficits in DG neurons contribute to the pathogenesis of not only neurological, but also psychiatric, disorders, such as anxiety disorder. Whereas DG's function in spatial learning and memory has been extensively investigated, its role in regulating anxiety remains elusive. METHODS Using c-Fos to mark DG neuron activation, we identified a group of embryonic born dorsal DG (dDG) neurons, which were activated by anxiogenic stimuli and specifically express osteocalcin (Ocn)-Cre. We further investigated their functions in regulating anxiety and the underlying mechanisms by using a combination of chemogenetic, electrophysiological, and RNA-sequencing methods. RESULTS The Ocn-Cre+ dDG neurons were highly active in response to anxiogenic environment but had lower excitability and fewer presynaptic inputs than those of Ocn-Cre- or adult born dDG neurons. Activating Ocn-Cre+ dDG neurons suppressed anxiety-like behaviors and increased adult DG neurogenesis, whereas ablating or chronically inhibiting Ocn-Cre+ dDG neurons exacerbated anxiety-like behaviors, impaired adult DG neurogenesis, and abolished activity (e.g., voluntary wheel running)-induced anxiolytic effect and adult DG neurogenesis. RNA-sequencing screening for factors induced by activation of Ocn-Cre+ dDG neurons identified BDNF, which was required for Ocn-Cre+ dDG neurons mediated antianxiety-like behaviors and adult DG neurogenesis. CONCLUSIONS These results demonstrate critical functions of Ocn-Cre+ dDG neurons in suppressing anxiety-like behaviors but promoting adult DG neurogenesis, and both functions are likely through activation of BDNF.
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Affiliation(s)
- Dong Sun
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Leena Milibari
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Jin-Xiu Pan
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Xiao Ren
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Ling-Ling Yao
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Yang Zhao
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Chen Shen
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Wen-Bing Chen
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Fu-Lei Tang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Daehoon Lee
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Jun-Shi Zhang
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Lin Mei
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio; Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio; Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Wen-Cheng Xiong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio; Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio; Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia.
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14
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Huckleberry KA, Shansky RM. The unique plasticity of hippocampal adult-born neurons: Contributing to a heterogeneous dentate. Hippocampus 2021; 31:543-556. [PMID: 33638581 DOI: 10.1002/hipo.23318] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/15/2021] [Accepted: 02/09/2021] [Indexed: 12/14/2022]
Abstract
The dentate gyrus (DG) of the hippocampus is evolutionarily conserved as one of the few sites of adult neurogenesis in mammals. Although there is clear evidence that neurogenesis is necessary for healthy hippocampal function, whether adult-born neurons are simply integrated into existing hippocampal networks to serve a similar purpose to that of developmentally born neurons or whether they represent a discrete cell population with unique functions remains less clear. In this review, we consider evidence for discrete cellular, synaptic, and structural features of adult-born DG neurons, suggesting that neurogenesis contributes to the formation of a heterogeneous DG. We therefore propose that hippocampal neurogenesis creates a specialized neuronal subpopulation that may play a key role in hippocampal functions like episodic memory. We note critical gaps in this extensive body of work, including a general failure to include female animals in relevant research and a need for more precise consideration of intrahippocampal neuroanatomy.
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Affiliation(s)
- Kylie A Huckleberry
- Behavioral Neuroscience Program, Department of Psychology, Northeastern University, Boston, Massachusetts, USA
| | - Rebecca M Shansky
- Behavioral Neuroscience Program, Department of Psychology, Northeastern University, Boston, Massachusetts, USA
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15
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Kerloch T, Farrugia F, Bouit L, Maître M, Terral G, Koehl M, Mortessagne P, Heng JIT, Blanchard M, Doat H, Leste-Lasserre T, Goron A, Gonzales D, Perrais D, Guillemot F, Abrous DN, Pacary E. The atypical Rho GTPase Rnd2 is critical for dentate granule neuron development and anxiety-like behavior during adult but not neonatal neurogenesis. Mol Psychiatry 2021; 26:7280-7295. [PMID: 34561615 PMCID: PMC8872985 DOI: 10.1038/s41380-021-01301-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/06/2021] [Accepted: 09/08/2021] [Indexed: 02/08/2023]
Abstract
Despite the central role of Rho GTPases in neuronal development, their functions in adult hippocampal neurogenesis remain poorly explored. Here, by using a retrovirus-based loss-of-function approach in vivo, we show that the atypical Rho GTPase Rnd2 is crucial for survival, positioning, somatodendritic morphogenesis, and functional maturation of adult-born dentate granule neurons. Interestingly, most of these functions are specific to granule neurons generated during adulthood since the deletion of Rnd2 in neonatally-born granule neurons only affects dendritogenesis. In addition, suppression of Rnd2 in adult-born dentate granule neurons increases anxiety-like behavior whereas its deletion in pups has no such effect, a finding supporting the adult neurogenesis hypothesis of anxiety disorders. Thus, our results are in line with the view that adult neurogenesis is not a simple continuation of earlier processes from development, and establish a causal relationship between Rnd2 expression and anxiety.
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Affiliation(s)
- Thomas Kerloch
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Fanny Farrugia
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Lou Bouit
- grid.462202.00000 0004 0382 7329Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000 Bordeaux, France
| | - Marlène Maître
- grid.412041.20000 0001 2106 639XLaser microdissection Facility, Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Geoffrey Terral
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Muriel Koehl
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Pierre Mortessagne
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Julian Ik-Tsen Heng
- grid.1032.00000 0004 0375 4078Curtin Health Innovation Research Institute, Curtin University, 6102 Bentley, WA Australia
| | - Mylène Blanchard
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Hélène Doat
- grid.412041.20000 0001 2106 639XLaser microdissection Facility, Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France ,grid.412041.20000 0001 2106 639XTranscriptome Facility, Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Thierry Leste-Lasserre
- grid.412041.20000 0001 2106 639XTranscriptome Facility, Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Adeline Goron
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Delphine Gonzales
- grid.412041.20000 0001 2106 639XGenotyping Facility, Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - David Perrais
- grid.462202.00000 0004 0382 7329Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000 Bordeaux, France
| | - François Guillemot
- grid.451388.30000 0004 1795 1830The Francis Crick Institute, 1 Midland Road, London, NW1 1AT UK
| | - Djoher Nora Abrous
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Emilie Pacary
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300, Bordeaux, France.
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16
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Masachs N, Charrier V, Farrugia F, Lemaire V, Blin N, Mazier W, Tronel S, Montaron MF, Ge S, Marsicano G, Cota D, Deroche-Gamonet V, Herry C, Abrous DN. The temporal origin of dentate granule neurons dictates their role in spatial memory. Mol Psychiatry 2021; 26:7130-7140. [PMID: 34526669 PMCID: PMC8873024 DOI: 10.1038/s41380-021-01276-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 07/20/2021] [Indexed: 11/27/2022]
Abstract
The dentate gyrus is one of the only brain regions that continues its development after birth in rodents. Adolescence is a very sensitive period during which cognitive competences are programmed. We investigated the role of dentate granule neurons (DGNs) born during adolescence in spatial memory and compared them with those generated earlier in life (in embryos or neonates) or during adulthood by combining functional imaging, retroviral and optogenetic tools to tag and silence DGNs. By imaging DGNs expressing Zif268, a proxy for neuronal activity, we found that neurons generated in adolescent rats (and not embryos or neonates) are transiently involved in spatial memory processing. In contrast, adult-generated DGNs are recruited at a later time point when animals are older. A causal relationship between the temporal origin of DGNs and spatial memory was confirmed by silencing DGNs in behaving animals. Our results demonstrate that the emergence of spatial memory depends on neurons born during adolescence, a function later assumed by neurons generated during adulthood.
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Affiliation(s)
- Nuria Masachs
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Vanessa Charrier
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Fanny Farrugia
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Valerie Lemaire
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Nicolas Blin
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Wilfrid Mazier
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Energy Balance and Obesity Group, U1215, F-33000 Bordeaux, France
| | - Sophie Tronel
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Marie-Françoise Montaron
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Shaoyu Ge
- grid.36425.360000 0001 2216 9681Program in Neuroscience, SUNY at Stony Brook, Stony Brook, New York, NY USA
| | - Giovanni Marsicano
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Endocannabinoids and Neuroadaptation Group, U1215, F-33000 Bordeaux, France
| | - Daniela Cota
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Energy Balance and Obesity Group, U1215, F-33000 Bordeaux, France
| | - Véronique Deroche-Gamonet
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Psychobiology of Drug Addiction Group, U1215, F-33000 Bordeaux, France
| | - Cyril Herry
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neuronal Circuits of Associative Learning Group, U1215, F-33000 Bordeaux, France
| | - Djoher Nora Abrous
- Univ. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000, Bordeaux, France.
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17
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Montaron M, Charrier V, Blin N, Garcia P, Abrous DN. Responsiveness of dentate neurons generated throughout adult life is associated with resilience to cognitive aging. Aging Cell 2020; 19:e13161. [PMID: 32599664 PMCID: PMC7431828 DOI: 10.1111/acel.13161] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/09/2020] [Accepted: 04/21/2020] [Indexed: 01/10/2023] Open
Abstract
During aging, some individuals are resilient to the decline of cognitive functions whereas others are vulnerable. These inter-individual differences in memory abilities have been associated with differences in the rate of hippocampal neurogenesis measured in elderlies. Whether the maintenance of the functionality of neurons generated throughout adult life is linked to resilience to cognitive aging remains completely unexplored. Using the immediate early gene Zif268, we analyzed the activation of dentate granule neurons born in adult (3-month-old), middle-aged (12-month-old), or senescent (18-month-old) rats (n = 96) in response to learning when animals reached 21 months of age. The activation of neurons born during the developmental period was also examined. We show that adult-born neurons can survive up to 19 months and that neurons generated 4, 10, or 19 months before learning, but not developmentally born neurons, are activated in senescent rats with good learning abilities. In contrast, aged rats with bad learning abilities do not exhibit activity-dependent regulation of newborn cells, whatever their birthdate. In conclusion, we propose that resilience to cognitive aging is associated with responsiveness of neurons born during adult life. These data add to our current knowledge by showing that the aging of memory abilities stems not only from the number but also from the responsiveness of adult-born neurons.
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Affiliation(s)
- Marie‐Françoise Montaron
- INSERM UMR 1215, Magendie Neurocenter Neurogenesis and Pathophysiology Group Bordeaux France
- Université de Bordeaux Bordeaux France
| | - Vanessa Charrier
- INSERM UMR 1215, Magendie Neurocenter Neurogenesis and Pathophysiology Group Bordeaux France
- Université de Bordeaux Bordeaux France
| | - Nicolas Blin
- INSERM UMR 1215, Magendie Neurocenter Neurogenesis and Pathophysiology Group Bordeaux France
- Université de Bordeaux Bordeaux France
| | - Pierre Garcia
- INSERM UMR 1215, Magendie Neurocenter Neurogenesis and Pathophysiology Group Bordeaux France
- Université de Bordeaux Bordeaux France
| | - Djoher Nora Abrous
- INSERM UMR 1215, Magendie Neurocenter Neurogenesis and Pathophysiology Group Bordeaux France
- Université de Bordeaux Bordeaux France
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18
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Kerloch T, Clavreul S, Goron A, Abrous DN, Pacary E. Dentate Granule Neurons Generated During Perinatal Life Display Distinct Morphological Features Compared With Later-Born Neurons in the Mouse Hippocampus. Cereb Cortex 2020; 29:3527-3539. [PMID: 30215686 DOI: 10.1093/cercor/bhy224] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 08/06/2018] [Indexed: 02/07/2023] Open
Abstract
In nonhuman mammals and in particular in rodents, most granule neurons of the dentate gyrus (DG) are generated during development and yet little is known about their properties compared with adult-born neurons. Although it is generally admitted that these populations are morphologically indistinguishable once mature, a detailed analysis of developmentally born neurons is lacking. Here, we used in vivo electroporation to label dentate granule cells (DGCs) generated in mouse embryos (E14.5) or in neonates (P0) and followed their morphological development up to 6 months after birth. By comparison with mature retrovirus-labeled DGCs born at weaning (P21) or young adult (P84) stages, we provide the evidence that perinatally born neurons, especially embryonically born cells, are morphologically distinct from later-born neurons and are thus easily distinguishable. In addition, our data indicate that semilunar and hilar GCs, 2 populations in ectopic location, are generated during the embryonic and the neonatal periods, respectively. Thus, our findings provide new insights into the development of the different populations of GCs in the DG and open new questions regarding their function in the brain.
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Affiliation(s)
- Thomas Kerloch
- INSERM U1215, Neurocentre Magendie, Bordeaux, France.,Université de Bordeaux, Bordeaux, France
| | - Solène Clavreul
- INSERM U1215, Neurocentre Magendie, Bordeaux, France.,Université de Bordeaux, Bordeaux, France
| | - Adeline Goron
- INSERM U1215, Neurocentre Magendie, Bordeaux, France.,Université de Bordeaux, Bordeaux, France
| | - Djoher Nora Abrous
- INSERM U1215, Neurocentre Magendie, Bordeaux, France.,Université de Bordeaux, Bordeaux, France
| | - Emilie Pacary
- INSERM U1215, Neurocentre Magendie, Bordeaux, France.,Université de Bordeaux, Bordeaux, France
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19
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Adult-Born Hippocampal Neurons Undergo Extended Development and Are Morphologically Distinct from Neonatally-Born Neurons. J Neurosci 2020; 40:5740-5756. [PMID: 32571837 DOI: 10.1523/jneurosci.1665-19.2020] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 02/28/2020] [Accepted: 05/04/2020] [Indexed: 11/21/2022] Open
Abstract
During immature stages, adult-born neurons pass through critical periods for survival and plasticity. It is generally assumed that by 2 months of age adult-born neurons are mature and equivalent to the broader neuronal population, raising questions of how they might contribute to hippocampal function in old age when neurogenesis has declined. However, few have examined adult-born neurons beyond the critical period or directly compared them to neurons born in infancy. Here, we used a retrovirus to visualize functionally relevant morphological features of 2- to 24-week-old adult-born neurons in male rats. From 2 to 7 weeks, neurons grew and attained a relatively mature phenotype. However, several features of 7-week-old neurons suggested a later wave of growth: these neurons had larger nuclei, thicker dendrites, and more dendritic filopodia than all other groups. Indeed, between 7 and 24 weeks, adult-born neurons gained additional dendritic branches, formed a second primary dendrite, acquired more mushroom spines, and had enlarged mossy fiber presynaptic terminals. Compared with neonatal-born neurons, old adult-born neurons had greater spine density, larger presynaptic terminals, and more putative efferent filopodial contacts onto inhibitory neurons. By integrating rates of cell birth and growth across the life span, we estimate that adult neurogenesis ultimately produces half of the cells and the majority of spines in the dentate gyrus. Critically, protracted development contributes to the plasticity of the hippocampus through to the end of life, even after cell production declines. Persistent differences from neonatal-born neurons may additionally endow adult-born neurons with unique functions even after they have matured.SIGNIFICANCE STATEMENT Neurogenesis occurs in the hippocampus throughout adult life and contributes to memory and emotion. It is generally assumed that new neurons have the greatest impact on behavior when they are immature and plastic. However, since neurogenesis declines dramatically with age, it is unclear how they might contribute to behavior later in life when cell proliferation has slowed. Here we find that newborn neurons mature over many months in rats and may end up with distinct morphological features compared with neurons born in infancy. Using a mathematical model, we estimate that a large fraction of neurons is added in adulthood. Moreover, their extended growth produces a reserve of plasticity that persists even after neurogenesis has declined to low rates.
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20
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Li C, Li R, Zhou C. Memory Traces Diminished by Exercise Affect New Learning as Proactive Facilitation. Front Neurosci 2020; 14:189. [PMID: 32210755 PMCID: PMC7076129 DOI: 10.3389/fnins.2020.00189] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/21/2020] [Indexed: 12/21/2022] Open
Abstract
Exercise enhances cognitive function through increased neurogenesis but can also cause neurogenesis-induced forgetting. It remains unclear whether the diminished memory traces are completely forgotten. Our goals were to determine whether spatial memory is diminished by exercise, and if so, whether the memory is completely gone or whether only the local details disappear but not the acquired strategy. Two-month-old male C57BL/6J mice were trained on a spatial memory task using the Morris water maze and tested to determine that they had learned the platform location. Another mouse group received no training. Half the mice in each group then exercised on a running wheel, while the other half remained sedentary in home cages. After 4 weeks of this, previously trained mice were tested for their retention of the platform location. All mice were then subjected to the task, but the platform was located in a different position (reversal learning for previously trained mice). We found that exercise significantly facilitated the forgetting of the first platform location (i.e., diminished spatial memory) but also significantly enhanced reversal learning. Compared with mice that received no pre-exercise training, mice that had been previously trained, even those in the exercise group that had decreased recall, showed significantly better performance in the reversal learning test. Activation of new adult-born neurons was also examined. Although newborn neuron activation between groups that had or had not received prior task training was not different, activation was significantly higher in exercise groups than in sedentary groups after the probe test for reversal learning. These results indicated that the experience of pre-exercise training equally facilitated new learning in the sedentary and exercise groups, even though significantly lower memory retention was found in the exercise group, suggesting rule-based learning in mice. Furthermore, newborn neurons equally participated in similar and novel memory acquisition.
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Affiliation(s)
- Cuicui Li
- Department of Sport Psychology, School of Sport Science, Shanghai University of Sport, Shanghai, China
| | - Rena Li
- Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China.,Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Chenglin Zhou
- Department of Sport Psychology, School of Sport Science, Shanghai University of Sport, Shanghai, China
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21
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Gustus K, Lozano E, Newville J, Li L, Valenzuela CF, Cunningham LA. Resistance of Postnatal Hippocampal Neurogenesis to Alcohol Toxicity in a Third Trimester-Equivalent Mouse Model of Gestational Alcohol Exposure. Alcohol Clin Exp Res 2019; 43:2504-2513. [PMID: 31573091 DOI: 10.1111/acer.14207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/22/2019] [Indexed: 12/14/2022]
Abstract
BACKGROUND The adult hippocampal dentate is comprised of both developmentally generated dentate granule cells (dDGCs) and adult-generated dentate granule cells (aDGCs), which play distinct roles in hippocampal information processing and network function. EtOH exposure throughout gestation in mouse impairs the neurogenic response to enriched environment (EE) in adulthood, although the basal rate of adult neurogenesis under standard housing (SH) is unaffected. Here, we tested whether the production and/or survival of either dDGCs or aDGCs are selectively impaired following exposure of mice to EtOH vapors during early postnatal development (human third trimester-equivalent), and whether this exposure paradigm leads to impairment of EE-mediated dentate neurogenesis in adulthood. METHODS All experiments were performed using NestinCreERT2 :tdTomato bitransgenic mice, which harbor a tamoxifen-inducible tdTomato (tdTom) reporter for indelible labeling of newborn hippocampal DGCs. We exposed all mice to EtOH vapor or room air (Control) for 4 h/d from postnatal day (PND) 3 through PND 15. This paradigm resulted in a mean daily postexposure blood EtOH concentration of ~160 mg/dl. One cohort of neonatal mice received a single injection of tamoxifen at PND 2 and was sacrificed at either PND 16 or PND 50 to assess the impact of EtOH exposure on the production and long-term survival of dDGCs born during the early postnatal period. A second cohort of mice received daily injections of tamoxifen at PND 35 to 39 to label aDGCs and was exposed to SH or EE for 6 weeks prior to sacrifice. RESULTS Early postnatal EtOH exposure had no statistically significant effect on the production or survival of tdTom+ dDGCs, as assessed at PND 16 or PND 50. Early postnatal EtOH exposure also had no effect on the number of tdTom+ aDGCs under SH conditions. Furthermore, early postnatal EtOH exposure had no significant impact on the adult neurogenic response to EE. CONCLUSIONS Both early postnatal dentate neurogenesis and adult dentate neurogenesis, as well as the adult neurogenic response to EE, are surprisingly resistant to early postnatal EtOH vapor exposure in mice.
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Affiliation(s)
- Kymberly Gustus
- Department of Neuroscience, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Evelyn Lozano
- Department of Neuroscience, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Jessie Newville
- Department of Neuroscience, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Lu Li
- Department of Neuroscience, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | | | - Lee Anna Cunningham
- Department of Neuroscience, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
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22
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Miller SM, Sahay A. Functions of adult-born neurons in hippocampal memory interference and indexing. Nat Neurosci 2019; 22:1565-1575. [PMID: 31477897 DOI: 10.1038/s41593-019-0484-2] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 07/30/2019] [Indexed: 12/22/2022]
Abstract
The dentate gyrus-CA3 circuit of the hippocampus is continuously modified by the integration of adult-born dentate granule cells (abDGCs). All abDGCs undergo a prolonged period of maturation, during which they exhibit heightened synaptic plasticity and refinement of electrophysiological properties and connectivity. Consistent with theoretical models and the known functions of the dentate gyrus-CA3 circuit, acute or chronic manipulations of abDGCs support a role for abDGCs in the regulation of memory interference. In this Review, we integrate insights from studies that examine the maturation of abDGCs and their integration into the circuit with network mechanisms that support memory discrimination, consolidation and clearance. We propose that adult hippocampal neurogenesis enables the generation of a library of experiences, each registered in mature abDGC physiology and connectivity. Mature abDGCs recruit inhibitory microcircuits to support pattern separation and memory indexing.
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Affiliation(s)
- Samara M Miller
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA.,Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Amar Sahay
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA. .,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA. .,Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA. .,BROAD Institute of Harvard and MIT, Cambridge, Massachusetts, USA.
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23
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Cahill SP, Martinovic A, Cole JD, Seib DR, Snyder JS. A combination of running and memantine increases neurogenesis and reduces activation of developmentally-born dentate granule neurons in rats. Behav Brain Res 2019; 372:112005. [PMID: 31167109 DOI: 10.1016/j.bbr.2019.112005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 05/16/2019] [Accepted: 05/31/2019] [Indexed: 11/19/2022]
Abstract
During hippocampal-dependent memory formation, sensory signals from the neocortex converge in the dentate gyrus. It is generally believed that the dentate gyrus decorrelates inputs in order to minimize interference between codes for similar experiences, often referred to as pattern separation. The proportion of dentate neurons that are activated by experience is therefore likely to impact how memories are stored and separated. Emerging evidence from mouse models suggests that adult-born neurons can both increase and decrease activity levels in the dentate gyrus. However, the conditions that determine the direction of this modulation, and whether it occurs in other species, remains unclear. Furthermore, since the dentate gyrus is composed of a heterogeneous population of cells that are born throughout life, newborn neurons may not modulate all cells equally. We aimed to investigate whether adult neurogenesis in rats regulates activity in dentate gyrus neurons that are born at the peak of early postnatal development. Adult neurogenesis was increased by subjecting rats to an alternating running and memantine treatment schedule, and it was decreased with a transgenic GFAP-TK rat model. Activity was measured by Fos expression in BrdU+ cells after rats explored a novel environment. Running+memantine treatment increased adult neurogenesis by only 17%, but completely blocked experience-dependent Fos expression. In contrast, GFAP-TK rats had a 68% reduction in adult neurogenesis but normal experience-dependent Fos expression. The inconsistent relationship between neurogenesis and Fos expression suggests that neurogenesis does not regulate DG activity during exploration of a novel environment. Nonetheless, running and memantine may benefit disorders where there is elevated activity in the dentate gyrus, such as anxiety and age-related memory impairments.
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Affiliation(s)
- Shaina P Cahill
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia, V6T 2B5, Canada
| | - Angela Martinovic
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia, V6T 2B5, Canada
| | - John Darby Cole
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia, V6T 2B5, Canada
| | - Desiree R Seib
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia, V6T 2B5, Canada
| | - Jason S Snyder
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia, V6T 2B5, Canada.
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24
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Recalibrating the Relevance of Adult Neurogenesis. Trends Neurosci 2019; 42:164-178. [PMID: 30686490 DOI: 10.1016/j.tins.2018.12.001] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/28/2018] [Accepted: 12/10/2018] [Indexed: 10/27/2022]
Abstract
Conflicting reports about whether adult hippocampal neurogenesis occurs in humans raise questions about its significance for human health and the relevance of animal models. Drawing upon published data, I review species' neurogenesis rates across the lifespan and propose that accelerated neurodevelopmental timing is consistent with lower rates of neurogenesis in adult primates and humans. Nonetheless, protracted neurogenesis may produce populations of neurons that retain plastic properties for long intervals, and have distinct functions depending on when in the lifespan they were born. With some conceptual recalibration we may therefore be able to reconcile seemingly disparate findings and continue to ask how adult neurogenesis, as studied in animals, is relevant for human health.
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25
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de Melo MFFT, Pereira DE, Moura RDL, da Silva EB, de Melo FALT, Dias CDCQ, Silva MDCA, de Oliveira MEG, Viera VB, Pintado MME, Dos Santos SG, Soares JKB. Maternal Supplementation With Avocado ( Persea americana Mill.) Pulp and Oil Alters Reflex Maturation, Physical Development, and Offspring Memory in Rats. Front Neurosci 2019; 13:9. [PMID: 30728763 PMCID: PMC6351466 DOI: 10.3389/fnins.2019.00009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/07/2019] [Indexed: 12/13/2022] Open
Abstract
Avocado (Persea americana Mill.) is an oleaginous fruit source of fatty acids with high levels of neuroprotective phytocomplexes. The objective of this study was to evaluate the development of reflex and somatic maturation, fatty acid profiles in the brain, and memory in different stages of life in the offspring of dams supplemented with avocado pulp and oil during gestation and lactation. The dams were randomly divided into three groups (n = 15 pups/group), and recieved by gavage supplementation: control group (CG)-distilled water; Avocado Oil (AO)-3,000 mg avocado oil/kg animal weight, and Avocado Pulp (AP)-3,000 mg avocado pulp/kg animal weight. We performed the following tests: Analysis of Somatic Development and Ontogeny of Postnatal Reflex (T0 to T21), the Open Field Habituation Test and the Object Recognition Test (ORT) in the adolescent (T45) and adult (T90) phases. The cerebral fatty acids content was evaluated at times T0, T21, T45, and T90. The results were analyzed using the statistical program GraphPad Prism and significant statistics were considered when p < 0.05. Acceleration of reflex maturation and reflex ontogeny was observed in the offspring of AO and AP fed dams, with the results being more pronounced in the pulp fed group (p < 0.05). All groups presented a decrease in the ambulation parameter in the second exposure to the Open Field Habituation Test, at T45 and T90 (p < 0.05). In the ORT, the AO and AP offspring presented memory improvements in the short and long term in the adult and adolescent phases (p < 0.05). The results of the brain fatty acid profiles presented higher polyunsaturated fatty acids (PUFA) content in the AO and AP groups at T21, T45, and T90. The docosahexaenoic fatty acid (DHA) content was higher at T21 (AO and AP), at T45 (AO and AP), and at T90 (AP) (p < 0.05). The arachidonic acid (ARA) content was higher at T45 (AO and AP), and at T90 (AO) (p < 0.05). Maternal supplementation with avocado oil and pulp anticipates reflex maturation and somatic postnatal development, and improves memory during the adolescent and adult phases.
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Affiliation(s)
- Marilia Ferreira Frazão Tavares de Melo
- Program of Food Science and Tecnology, Universidade Federal da Paraíba, João Pessoa, Brazil.,Laboratory of Experimental Nutrition, Department of Nutrition, Universidade Federal de Campina Grande, Cuité, Brazil
| | - Diego Elias Pereira
- Program of Food Science and Tecnology, Universidade Federal da Paraíba, João Pessoa, Brazil.,Laboratory of Experimental Nutrition, Department of Nutrition, Universidade Federal de Campina Grande, Cuité, Brazil
| | - Renally de Lima Moura
- Laboratory of Experimental Nutrition, Department of Nutrition, Universidade Federal de Campina Grande, Cuité, Brazil
| | - Elisiane Beatriz da Silva
- Laboratory of Experimental Nutrition, Department of Nutrition, Universidade Federal de Campina Grande, Cuité, Brazil
| | | | - Celina de Castro Querino Dias
- Program of Food Science and Tecnology, Universidade Federal da Paraíba, João Pessoa, Brazil.,Laboratory of Experimental Nutrition, Department of Nutrition, Universidade Federal de Campina Grande, Cuité, Brazil
| | - Maciel da Costa Alves Silva
- Laboratory of Experimental Nutrition, Department of Nutrition, Universidade Federal de Campina Grande, Cuité, Brazil
| | - Maria Elieidy Gomes de Oliveira
- Program of Food Science and Tecnology, Universidade Federal da Paraíba, João Pessoa, Brazil.,Laboratory of Bromatology, Department of Nutrition, Universidade Federal da Paraíba, João Pessoa, Brazil
| | - Vanessa Bordin Viera
- Laboratory of Bromatology, Department of Nutrition, Universidade Federal de Campina Grande, Cuité, Brazil
| | | | | | - Juliana Késsia Barbosa Soares
- Program of Food Science and Tecnology, Universidade Federal da Paraíba, João Pessoa, Brazil.,Laboratory of Experimental Nutrition, Department of Nutrition, Universidade Federal de Campina Grande, Cuité, Brazil
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26
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Ohline SM, Wake KL, Hawkridge MV, Dinnunhan MF, Hegemann RU, Wilson A, Schoderboeck L, Logan BJ, Jungenitz T, Schwarzacher SW, Hughes SM, Abraham WC. Adult-born dentate granule cell excitability depends on the interaction of neuron age, ontogenetic age and experience. Brain Struct Funct 2018; 223:3213-3228. [PMID: 29796923 DOI: 10.1007/s00429-018-1685-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 05/15/2018] [Indexed: 12/11/2022]
Abstract
Early during their maturation, adult-born dentate granule cells (aDGCs) are particularly excitable, but eventually develop the electrophysiologically quiet properties of mature cells. However, the stability versus plasticity of this quiet state across time and experience remains unresolved. By birthdating two populations of aDGCs across different animal ages, we found for 10-month-old rats the expected reduction in excitability across cells aged 4-12 weeks, as determined by Egr1 immunoreactivity. Unexpectedly, cells 35 weeks old (after genesis at an animal age of 2 months) were as excitable as 4-week-old cells, in the dorsal hippocampus. This high level of excitability at maturity was specific for cells born in animals 2 months of age, as cells born later in life did not show this effect. Importantly, excitability states were not fixed once maturity was gained, but were enhanced by enriched environment exposure or LTP induction, indicating that any maturational decrease in excitability can be compensated by experience. These data reveal the importance of the animal's age for aDGC excitability, and emphasize their prolonged capability for plasticity during adulthood.
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Affiliation(s)
- S M Ohline
- Department of Psychology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.,Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - K L Wake
- Department of Psychology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.,Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - M-V Hawkridge
- Institute of Clinical Neuroanatomy, Goethe-University of Frankfurt, Frankfurt am Main, Germany
| | - M F Dinnunhan
- Department of Psychology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.,Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - R U Hegemann
- Department of Psychology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.,Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - A Wilson
- Department of Psychology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.,Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - L Schoderboeck
- Department of Psychology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.,Department of Biochemistry, University of Otago, Dunedin, New Zealand.,Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - B J Logan
- Department of Psychology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.,Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - T Jungenitz
- Institute of Clinical Neuroanatomy, Goethe-University of Frankfurt, Frankfurt am Main, Germany
| | - S W Schwarzacher
- Institute of Clinical Neuroanatomy, Goethe-University of Frankfurt, Frankfurt am Main, Germany
| | - S M Hughes
- Department of Biochemistry, University of Otago, Dunedin, New Zealand.,Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand
| | - W C Abraham
- Department of Psychology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand. .,Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin, New Zealand.
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27
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Kanzari A, Bourcier-Lucas C, Freyssin A, Abrous DN, Haddjeri N, Lucas G. Inducing a long-term potentiation in the dentate gyrus is sufficient to produce rapid antidepressant-like effects. Mol Psychiatry 2018; 23:587-596. [PMID: 28485406 DOI: 10.1038/mp.2017.94] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 03/10/2017] [Accepted: 03/16/2017] [Indexed: 12/19/2022]
Abstract
Recent hypotheses propose that one prerequisite to obtain a rapid antidepressant (AD) effect would reside in processes of synaptic reinforcement occurring within the dentate gyrus (DG) of the hippocampus independently from neurogenesis. However, to date no relationship has been established between an increased DG synaptic plasticity, and rapid AD-like action. To the best of our knowledge, this study shows for the first time that inducing a long-term potentiation (LTP) within the DG by stimulating the perforant pathway (PP) is sufficient to induce such effects. Thus, Sprague-Dawley rats having undergone a successful LTP displayed a significant reduction of immobility when passed acutely 3 days thereafter in the forced swimming test (FST). Further, in a longitudinal paradigm using the pseudo-depressed Wistar-Kyoto rat strain, LTP elicited a decrease of FST immobility after only 2 days, whereas the AD desipramine was not effective before 16 days. In both models, the influence of LTP was transient, as it was no more observed after 8-9 days. No effects were observed on the locomotor activity or on anxiety-related behavior. Theta-burst stimulation of a brain region anatomically adjacent to the PP remained ineffective in the FST. Immunoreactivity of DG cells for phosphorylated histone H3 and doublecortin were not modified three days after LTP, indicating a lack of effect on both cell proliferation and neurogenesis. Finally, depleting brain serotonin contents reduced the success rate of LTP but did not affect its subsequent AD-like effects. These results confirm the 'plastic DG' theory of rapid AD efficacy. Beyond, they point out stimulations of the entorhinal cortex, from which the PP originates, as putative new approaches in AD research.
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Affiliation(s)
- A Kanzari
- INSERM and Université Claude Bernard Lyon 1, Institut Cellule Souche et Cerveau U846, Lyon, France.,Department of Biology, Université de Tunis El Manar, Tunis, Tunisia
| | - C Bourcier-Lucas
- INSERM and Université de Bordeaux, Neurocentre Magendie U1215, Bordeaux, France
| | - A Freyssin
- INSERM and Université Claude Bernard Lyon 1, Institut Cellule Souche et Cerveau U846, Lyon, France
| | - D N Abrous
- INSERM and Université de Bordeaux, Neurocentre Magendie U1215, Bordeaux, France
| | - N Haddjeri
- INSERM and Université Claude Bernard Lyon 1, Institut Cellule Souche et Cerveau U846, Lyon, France
| | - G Lucas
- INSERM and Université Claude Bernard Lyon 1, Institut Cellule Souche et Cerveau U846, Lyon, France.,INSERM and Université de Bordeaux, Neurocentre Magendie U1215, Bordeaux, France
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28
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Cahill SP, Yu RQ, Green D, Todorova EV, Snyder JS. Early survival and delayed death of developmentally-born dentate gyrus neurons. Hippocampus 2017; 27:1155-1167. [PMID: 28686814 DOI: 10.1002/hipo.22760] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 06/23/2017] [Accepted: 06/27/2017] [Indexed: 01/20/2023]
Abstract
The storage and persistence of memories depends on plasticity in the hippocampus. Adult neurogenesis produces new neurons that mature through critical periods for plasticity and cellular survival, which determine their contributions to learning and memory. However, most granule neurons are generated prior to adulthood; the maturational timecourse of these neurons is poorly understood compared to adult-born neurons but is essential to identify how the dentate gyrus (DG), as a whole, contributes to behavior. To characterize neurons born in the early postnatal period, we labeled DG neurons born on postnatal day 6 (P6) with BrdU and quantified maturation and survival across early (1 hr to 8 weeks old) and late (2-6 months old) cell ages. We find that the dynamics of developmentally-born neuron survival is essentially the opposite of neurons born in adulthood: P6-born neurons did not go through a period of cell death during their immature stages (from 1 to 8 weeks). In contrast, 17% of P6-born neurons died after reaching maturity, between 2 and 6 months of age. Delayed death was evident from the loss of BrdU+ cells as well as pyknotic BrdU+ caspase3+ neurons within the superficial granule cell layer. Patterns of DCX, NeuN, and activity-dependent Fos expression indicate that developmentally-born neurons mature over several weeks and a sharp peak in zif268 expression at 2 weeks suggests that developmentally-born neurons mature faster than adult-born neurons (which peak at 3 weeks). Collectively, our findings are relevant for understanding how developmentally-born DG neurons contribute to memory and disorders throughout the lifespan. High levels of early survival and zif268 expression may promote learning, while also rendering neurons sensitive to insults at defined stages. Late neuronal death in young adulthood may result in the loss of hundreds of thousands of DG neurons, which could impact memory persistence and contribute to hippocampal/DG atrophy in disorders such as depression.
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Affiliation(s)
- Shaina P Cahill
- Department of Psychology & Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ru Qi Yu
- Department of Psychology & Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Dylan Green
- Department of Psychology & Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Evgenia V Todorova
- Department of Psychology & Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jason S Snyder
- Department of Psychology & Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
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29
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Abstract
Adult hippocampal neurogenesis (AHN) occurs in humans and every other mammalian species examined. Evidence that AHN is stimulated by a variety of treatments and behaviors with anxiolytic properties has sparked interest in harnessing AHN to treat anxiety disorders. However, relatively little is known about the mechanisms through which AHN modulates fear and anxiety. In this review, we consider evidence that AHN modulates fear and anxiety by altering the processing of and memory for traumatic experiences. Based on studies of the role of AHN in Pavlovian fear conditioning, we conclude that AHN modulates the consequences of aversive experience by influencing 1) the efficiency of hippocampus-dependent memory acquisition; 2) generalization of hippocampal fear memories; 3) long-term retention of hippocampal aversive memories; and 4) the nonassociative effects of acute aversive experience. The preclinical literature suggests that stimulation of AHN is likely to have therapeutically relevant consequences, including reduced generalization and long-term retention of aversive memories. However, the literature also identifies four caveats that must be addressed if AHN-based therapies are to achieve therapeutic benefits without significant side effects.
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Affiliation(s)
- Michael R Drew
- Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Austin, TX, USA.
| | - Kylie A Huckleberry
- Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Austin, TX, USA
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30
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Beining M, Jungenitz T, Radic T, Deller T, Cuntz H, Jedlicka P, Schwarzacher SW. Adult-born dentate granule cells show a critical period of dendritic reorganization and are distinct from developmentally born cells. Brain Struct Funct 2016; 222:1427-1446. [PMID: 27514866 DOI: 10.1007/s00429-016-1285-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/02/2016] [Indexed: 02/05/2023]
Abstract
Adult-born dentate granule cells (abGCs) exhibit a critical developmental phase during function integration. The time window of this phase is debated and whether abGCs become indistinguishable from developmentally born mature granule cells (mGCs) is uncertain. We analyzed complete dendritic reconstructions from abGCs and mGCs using viral labeling. AbGCs from 21-77 days post intrahippocampal injection (dpi) exhibited comparable dendritic arbors, suggesting that structural maturation precedes functional integration. In contrast, significant structural differences were found compared to mGCs: AbGCs had more curved dendrites, more short terminal segments, a different branching pattern, and more proximal terminal branches. Morphological modeling attributed these differences to developmental dendritic pruning and postnatal growth of the dentate gyrus. We further correlated GC morphologies with the responsiveness to unilateral medial perforant path stimulation using the immediate-early gene Arc as a marker of synaptic activation. Only abGCs at 28 and 35 dpi but neither old abGCs nor mGCs responded to stimulation with a remodeling of their dendritic arbor. Summarized, abGCs stay distinct from mGCs and their dendritic arbor can be shaped by afferent activity during a narrow critical time window.
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Affiliation(s)
- Marcel Beining
- Institute of Clinical Neuroanatomy, Goethe University, 60528, Frankfurt am Main, Germany. .,Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Deutschordenstr. 46, 60528, Frankfurt am Main, Germany. .,Frankfurt Institute for Advanced Studies (FIAS), 60438, Frankfurt am Main, Germany.
| | - Tassilo Jungenitz
- Institute of Clinical Neuroanatomy, Goethe University, 60528, Frankfurt am Main, Germany
| | - Tijana Radic
- Institute of Clinical Neuroanatomy, Goethe University, 60528, Frankfurt am Main, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Goethe University, 60528, Frankfurt am Main, Germany
| | - Hermann Cuntz
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Deutschordenstr. 46, 60528, Frankfurt am Main, Germany.,Frankfurt Institute for Advanced Studies (FIAS), 60438, Frankfurt am Main, Germany
| | - Peter Jedlicka
- Institute of Clinical Neuroanatomy, Goethe University, 60528, Frankfurt am Main, Germany
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31
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Reichelt AC, Morris MJ, Westbrook RF. Daily access to sucrose impairs aspects of spatial memory tasks reliant on pattern separation and neural proliferation in rats. ACTA ACUST UNITED AC 2016; 23:386-90. [PMID: 27317199 PMCID: PMC4918785 DOI: 10.1101/lm.042416.116] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 04/27/2016] [Indexed: 11/24/2022]
Abstract
High sugar diets reduce hippocampal neurogenesis, which is required for minimizing interference between memories, a process that involves “pattern separation.” We provided rats with 2 h daily access to a sucrose solution for 28 d and assessed their performance on a spatial memory task. Sucrose consuming rats discriminated between objects in novel and familiar locations when there was a large spatial separation between the objects, but not when the separation was smaller. Neuroproliferation markers in the dentate gyrus of the sucrose-consuming rats were reduced relative to controls. Thus, sucrose consumption impaired aspects of spatial memory and reduced hippocampal neuroproliferation.
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Affiliation(s)
- Amy C Reichelt
- School of Psychology, UNSW Australia, UNSW Sydney, New South Wales 2052, Australia
| | - Margaret J Morris
- School of Medical Sciences, UNSW Australia, UNSW Sydney, New South Wales 2052, Australia
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32
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Dinel AL, Rey C, Bonhomme C, Le Ruyet P, Joffre C, Layé S. Dairy fat blend improves brain DHA and neuroplasticity and regulates corticosterone in mice. Prostaglandins Leukot Essent Fatty Acids 2016; 109:29-38. [PMID: 27269711 DOI: 10.1016/j.plefa.2016.03.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/22/2016] [Accepted: 03/24/2016] [Indexed: 12/31/2022]
Abstract
Mimicking the breast milk lipid composition appears to be necessary for infant formula to cover the brain's needs in n-3 PUFA. In this study, we evaluated the impact of partial replacement of vegetable oil (VL) in infant formula by dairy fat (DL) on docosahexaenoic acid (DHA) brain level, neuroplasticity and corticosterone in mice. Mice were fed with balanced VL or balanced DL diets enriched or not in DHA and arachidonic acid (ARA) from the first day of gestation. Brain DHA level, microglia number, neurogenesis, corticosterone and glucocorticoid receptor expression were measured in the offsprings. DL diet increased DHA and neuroplasticity in the brain of mice at postnatal day (PND) 14 and at adulthood compared to VL. At PND14, ARA and DHA supplementation increased DHA in VL but not in DL mice brain. Importantly, DHA and ARA supplementation further improved neurogenesis and decreased corticosterone level in DL mice at adulthood. In conclusion, dairy lipids improve brain DHA level and neuroplasticity.
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Affiliation(s)
- A L Dinel
- Nutrition et Neurobiologie Intégrée, INRA UMR 1286, 33076 Bordeaux, France; University of Bordeaux, Bordeaux, France
| | - C Rey
- Nutrition et Neurobiologie Intégrée, INRA UMR 1286, 33076 Bordeaux, France; University of Bordeaux, Bordeaux, France; ITERG, Institut des Corps Gras, 33600 Pessac, France
| | - C Bonhomme
- Lactalis Nutrition Europe, Torce F-35370, France
| | | | - C Joffre
- Nutrition et Neurobiologie Intégrée, INRA UMR 1286, 33076 Bordeaux, France; University of Bordeaux, Bordeaux, France
| | - S Layé
- Nutrition et Neurobiologie Intégrée, INRA UMR 1286, 33076 Bordeaux, France; University of Bordeaux, Bordeaux, France
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33
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Lopez-Rojas J, Kreutz MR. Mature granule cells of the dentate gyrus--Passive bystanders or principal performers in hippocampal function? Neurosci Biobehav Rev 2016; 64:167-74. [PMID: 26949226 DOI: 10.1016/j.neubiorev.2016.02.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 01/18/2016] [Accepted: 02/27/2016] [Indexed: 10/22/2022]
Abstract
The dentate gyrus is the main entrance of highly processed information to the hippocampus which derives from associative cortices and it is one of the few privileged areas in the brain where adult neurogenesis occurs. This creates the unique situation that neurons of diverse maturation stages are part of one neuronal network at any given point in life. While recently adult-born cells have a low induction threshold for long-term potentiation several studies suggest that following maturation granule cells are poorly excitable and they exhibit reduced Hebbian synaptic plasticity to an extent that it was even suggested that they functionally retire. Here, we review the functional properties of mature granule cells and discuss how plasticity of intrinsic excitability and alterations in excitation-inhibition balance might impact on their role in hippocampal information processing.
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Affiliation(s)
- Jeffrey Lopez-Rojas
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Brenneckestrasse 6, D-39118 Magdeburg, Germany.
| | - Michael R Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Brenneckestrasse 6, D-39118 Magdeburg, Germany; Leibniz Group 'Dendritic Organelles and Synaptic Function', University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology, ZMNH, 20251 Hamburg, Germany
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Expression Profiles of Long Noncoding RNAs and Messenger RNAs in Mn-Exposed Hippocampal Neurons of Sprague-Dawley Rats Ascertained by Microarray: Implications for Mn-Induced Neurotoxicity. PLoS One 2016; 11:e0145856. [PMID: 26745496 PMCID: PMC4706437 DOI: 10.1371/journal.pone.0145856] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 12/09/2015] [Indexed: 12/12/2022] Open
Abstract
Manganese (Mn) is an essential trace element, while excessive expose may induce neurotoxicity. Recently, lncRNAs have been extensively studied and it has been confirmed that lncRNAs participate in neural functions and aberrantly expressed lncRNAs are involved in neurological diseases. However, the pathological effects of lncRNAs on Mn-induced neurotoxicity remain unclear. In this study, the expression profiles of lncRNAs and messenger RNAs (mRNAs) were identified in Mn-treated hippocampal neurons and control neurons via microarray. Bioinformatic methods and intersection analysis were also employed. Results indicated that 566, 1161, and 1474 lncRNAs meanwhile 1848, 3228, and 4022 mRNAs were aberrantly expressed in low, intermediate, and high Mn-exposed groups compared with the control group, respectively. Go analysis determined that differentially expressed mRNAs were targeted to biological processes, cellular components, and molecular functions. Pathway analysis indicated that these mRNAs were enriched in insulin secretion, cell cycle, and DNA replication. Intersection analysis denominated that 135 lncRNAs and 373 mRNAs were consistently up-regulated while 150 lncRNAs and 560 mRNAs were consistently down-regulated. Meanwhile, lncRNA BC079195 was significantly up-regulated while lncRNAs uc.229- and BC089928 were significantly down-regulated in three comparison groups. The relative expression levels of 3 lncRNAs and 4 mRNAs were validated through qRT-PCR. To the best of our knowledge, this study is the first to identify the expression patterns of lncRNAs and mRNAs in hippocampal neurons of Sprague-Dawley rats. The results may provide evidence on underlying mechanisms of Mn-induced neurotoxicity, and aberrantly expressed lncRNAs/mRNAs may be useful in further investigations to detect early symptoms of Mn-induced neuropsychiatric disorders in the central nervous system.
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Hersman S, Rodriguez Barrera V, Fanselow M. Assigning Function to Adult-Born Neurons: A Theoretical Framework for Characterizing Neural Manipulation of Learning. Front Syst Neurosci 2016; 9:182. [PMID: 26778981 PMCID: PMC4700131 DOI: 10.3389/fnsys.2015.00182] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 12/07/2015] [Indexed: 12/26/2022] Open
Abstract
Neuroscientists are concerned with neural processes or computations, but these may not be directly observable. In the field of learning, a behavioral procedure is observed to lead to performance outcomes, but differing inferences on underlying internal processes can lead to difficulties in interpreting conflicting results. An example of this challenge is how many functions have been attributed to adult-born granule cells in the dentate gyrus. Some of these functions were suggested by computational models of the properties of these neurons, while others were hypothesized after manipulations of adult-born neurons resulted in changes to behavioral metrics. This review seeks to provide a framework, based in learning theory classification of behavioral procedures, of the processes that may be underlying behavioral results after manipulating procedure and observing performance. We propose that this framework can serve to clarify experimental findings on adult-born neurons as well as other classes of neural manipulations and their effects on behavior.
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Affiliation(s)
- Sarah Hersman
- Department of Psychology, University of California, Los AngelesLos Angeles, CA, USA
| | | | - Michael Fanselow
- Department of Psychology, University of California, Los AngelesLos Angeles, CA, USA
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los AngelesLos Angeles, CA, USA
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36
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McAvoy K, Besnard A, Sahay A. Adult hippocampal neurogenesis and pattern separation in DG: a role for feedback inhibition in modulating sparseness to govern population-based coding. Front Syst Neurosci 2015; 9:120. [PMID: 26347621 PMCID: PMC4542503 DOI: 10.3389/fnsys.2015.00120] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 08/07/2015] [Indexed: 12/17/2022] Open
Abstract
The dentate gyrus (DG) of mammals harbors neural stem cells that generate new dentate granule cells (DGCs) throughout life. Behavioral studies using the contextual fear discrimination paradigm have found that selectively augmenting or blocking adult hippocampal neurogenesis enhances or impairs discrimination under conditions of high, but not low, interference suggestive of a role in pattern separation. Although contextual discrimination engages population-based coding mechanisms underlying pattern separation such as global remapping in the DG and CA3, how adult hippocampal neurogenesis modulates pattern separation in the DG is poorly understood. Here, we propose a role for adult-born DGCs in re-activation coupled modulation of sparseness through feed-back inhibition to govern global remapping in the DG.
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Affiliation(s)
- Kathleen McAvoy
- Center for Regenerative Medicine, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA
| | - Antoine Besnard
- Center for Regenerative Medicine, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA
| | - Amar Sahay
- Center for Regenerative Medicine, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA ; Harvard Stem Cell Institute, Harvard University Cambridge, MA, USA ; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA
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37
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Abrous DN, Wojtowicz JM. Interaction between Neurogenesis and Hippocampal Memory System: New Vistas. Cold Spring Harb Perspect Biol 2015; 7:7/6/a018952. [PMID: 26032718 DOI: 10.1101/cshperspect.a018952] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
During the last decade, the questions on the functionality of adult neurogenesis have changed their emphasis from if to how the adult-born neurons participate in a variety of memory processes. The emerging answers are complex because we are overwhelmed by a variety of behavioral tasks that apparently require new neurons to be performed optimally. With few exceptions, the hippocampal memory system seems to use the newly generated neurons for multiple roles. Adult neurogenesis has given the dentate gyrus new capabilities not previously thought possible within the scope of traditional synaptic plasticity. Looking at these new developments from the perspective of past discoveries, the science of adult neurogenesis has emerged from its initial phase of being, first, a surprising oddity and, later, exciting possibility, to the present state of being an integral part of mainstream neuroscience. The answers to many remaining questions regarding adult neurogenesis will come along only with our growing understanding of the functionality of the brain as a whole. This, in turn, will require integration of multiple levels of organization from molecules and cells to circuits and systems, ultimately resulting in comprehension of behavioral outcomes.
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Affiliation(s)
- Djoher Nora Abrous
- Inserm U862, Bordeaux-F33077, France Université de Bordeaux, Bordeaux-F33077, France
| | - Jan Martin Wojtowicz
- Department of Physiology, University of Toronto, Medical Sciences Building, Toronto, Ontario M5S 1A8, Canada
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38
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Tronel S, Charrier V, Sage C, Maitre M, Leste-Lasserre T, Abrous DN. Adult-born dentate neurons are recruited in both spatial memory encoding and retrieval. Hippocampus 2015; 25:1472-9. [PMID: 25913775 DOI: 10.1002/hipo.22468] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2015] [Indexed: 11/08/2022]
Abstract
Adult neurogenesis occurs in the dentate gyrus (DG) of the hippocampus, which is a key structure in learning and memory. Adult-generated granule cells have been shown to play a role in spatial memory processes such as acquisition or retrieval, in particular during an immature stage when they exhibit a period of increased plasticity. Here, we demonstrate that immature and mature neurons born in the DG of adult rats are similarly activated in spatial memory processes. By imaging the activation of these two different neuron generations in the same rat and by using the immediate early gene Zif268, we show that these neurons are involved in both spatial memory acquisition and retrieval. These results demonstrate that adult-generated granule cells are involved in memory beyond their immaturity stage.
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Affiliation(s)
- Sophie Tronel
- Neurocentre MagendiePhysiopathologie De La Plasticité NeuronaleUnité 862, Institut National De La Santé Et De La Recherche Médicale, Inserm U862, Bordeaux-F33077, Paris, France.,Université Bordeaux, Bordeaux-F33000, France
| | - Vanessa Charrier
- Neurocentre MagendiePhysiopathologie De La Plasticité NeuronaleUnité 862, Institut National De La Santé Et De La Recherche Médicale, Inserm U862, Bordeaux-F33077, Paris, France.,Université Bordeaux, Bordeaux-F33000, France
| | - Cyrille Sage
- Neurocentre MagendiePhysiopathologie De La Plasticité NeuronaleUnité 862, Institut National De La Santé Et De La Recherche Médicale, Inserm U862, Bordeaux-F33077, Paris, France.,Université Bordeaux, Bordeaux-F33000, France
| | - Marlene Maitre
- Neurocentre MagendiePhysiopathologie De La Plasticité NeuronaleUnité 862, Institut National De La Santé Et De La Recherche Médicale, Inserm U862, Bordeaux-F33077, Paris, France.,Université Bordeaux, Bordeaux-F33000, France
| | - Thierry Leste-Lasserre
- Neurocentre MagendiePhysiopathologie De La Plasticité NeuronaleUnité 862, Institut National De La Santé Et De La Recherche Médicale, Inserm U862, Bordeaux-F33077, Paris, France.,Université Bordeaux, Bordeaux-F33000, France
| | - Djoher N Abrous
- Neurocentre MagendiePhysiopathologie De La Plasticité NeuronaleUnité 862, Institut National De La Santé Et De La Recherche Médicale, Inserm U862, Bordeaux-F33077, Paris, France.,Université Bordeaux, Bordeaux-F33000, France
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39
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Seib DR, Martin-Villalba A. Neurogenesis in the Normal Ageing Hippocampus: A Mini-Review. Gerontology 2014; 61:327-35. [DOI: 10.1159/000368575] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 09/22/2014] [Indexed: 11/19/2022] Open
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