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Gao M, Wang K, Zhao H. GABAergic neurons maturation is regulated by a delicate network. Int J Dev Neurosci 2023; 83:3-15. [PMID: 36401305 DOI: 10.1002/jdn.10242] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 10/25/2022] [Accepted: 11/13/2022] [Indexed: 11/21/2022] Open
Abstract
Gamma-aminobutyric acid-expressing (GABAergic) neurons are implicated in a variety of neuropsychiatric disorders, such as epilepsy, anxiety, autism, and other pathological processes, including cerebral ischemia injury and drug addiction. Therefore, GABAergic neuronal processes warrant further research. The development of GABAergic neurons is a tightly controlled process involving the activity of multiple transcription and growth factors. Here, we focus on the gene expression pathways and the molecular modulatory networks that are engaged during the development of GABAergic neurons with the goal of exploring regulatory mechanisms that influence GABAergic neuron fate (i.e., maturation). Overall, we hope to provide a basis for clarifying the pathogenesis of neurodegenerative disorders.
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Affiliation(s)
- Mingxing Gao
- Department of Histology and Embryology, School of Basic Medical Science, Jilin University, Changchun, Jilin, China
| | - Kaizhong Wang
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Hui Zhao
- Department of Histology and Embryology, School of Basic Medical Science, Jilin University, Changchun, Jilin, China
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2
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Pae EK, Chung MK, Harper RM. Intermittent Hypoxia Interferes with Autocrine Effects of GABA on Insulin Secretion in Postnatal Rodents—Implications for Pediatric Obstructive Sleep Apnea. CHILDREN 2022; 9:children9091305. [PMID: 36138614 PMCID: PMC9497165 DOI: 10.3390/children9091305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/20/2022] [Accepted: 08/24/2022] [Indexed: 11/25/2022]
Abstract
Gamma-amino butyric acid (GABA) is well known to help elevate pancreatic β cell vitality and insulin levels in blood. GABA works via a coupling with GABA receptors; thus, the concentration of GABAA receptors on the plasma membrane of β cells appears to be critical for insulin regulation. Various medical conditions, such as pediatric and adult obstructive sleep apnea (OSA), show high levels of Type 2 diabetes; such patients also are exposed to intermittent hypoxia (IH), which modifies the GABA levels. To evaluate the potential therapeutic roles of GABA for diabetic patients with OSA, we studied the interactions of IH with GABA and GABAA receptors in young rats. Using rat pups and primary pancreatic islets, we evaluated the roles of GABA in insulin secretion. We show that GABA effectively increased the insulin secretion of pancreatic islets under normal ambient oxygen levels, as well as in culture medium with a glucose level of 2 mM. GABA also increased islet insulin secretion conditioned under IH in a 16 mM glucose medium. When islets were IH-treated, insulin secretion decreased due to lower intracellular chloride levels in accordance with the increased KCC2 levels. The results show that IH challenges down-regulate the GABAA receptor levels in pancreatic islets, which decreases GABA–GABAA receptor coupling action, as well as membrane depolarization for insulin secretion. The findings have the potential to suggest novel interventions for insulin regulation during IH of disordered breathing, including OSA.
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Affiliation(s)
- Eung-Kwon Pae
- School of Dentistry, University of Maryland, Baltimore, MD 21201, USA
- Correspondence:
| | - Man-Kyo Chung
- Department of Neural and Pain Sciences, School of Dentistry, Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD 21201, USA
| | - Ronald M. Harper
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, CA 90095, USA
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3
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Abed Zadeh A, Turner BD, Calakos N, Brunel N. Non-monotonic effects of GABAergic synaptic inputs on neuronal firing. PLoS Comput Biol 2022; 18:e1010226. [PMID: 35666719 PMCID: PMC9203025 DOI: 10.1371/journal.pcbi.1010226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 06/16/2022] [Accepted: 05/19/2022] [Indexed: 11/26/2022] Open
Abstract
GABA is generally known as the principal inhibitory neurotransmitter in the nervous system, usually acting by hyperpolarizing membrane potential. However, GABAergic currents sometimes exhibit non-inhibitory effects, depending on the brain region, developmental stage or pathological condition. Here, we investigate the diverse effects of GABA on the firing rate of several single neuron models, using both analytical calculations and numerical simulations. We find that GABAergic synaptic conductance and output firing rate exhibit three qualitatively different regimes as a function of GABA reversal potential, EGABA: monotonically decreasing for sufficiently low EGABA (inhibitory), monotonically increasing for EGABA above firing threshold (excitatory); and a non-monotonic region for intermediate values of EGABA. In the non-monotonic regime, small GABA conductances have an excitatory effect while large GABA conductances show an inhibitory effect. We provide a phase diagram of different GABAergic effects as a function of GABA reversal potential and glutamate conductance. We find that noisy inputs increase the range of EGABA for which the non-monotonic effect can be observed. We also construct a micro-circuit model of striatum to explain observed effects of GABAergic fast spiking interneurons on spiny projection neurons, including non-monotonicity, as well as the heterogeneity of the effects. Our work provides a mechanistic explanation of paradoxical effects of GABAergic synaptic inputs, with implications for understanding the effects of GABA in neural computation and development.
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Affiliation(s)
- Aghil Abed Zadeh
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Brandon D. Turner
- Department of Neurology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Nicole Calakos
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Neurology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Institute for Brain Sciences, Duke University, Durham, North Carolina, United States of America
| | - Nicolas Brunel
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Institute for Brain Sciences, Duke University, Durham, North Carolina, United States of America
- Department of Physics, Duke University, Durham, North Carolina, United States of America
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4
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Wilson C, Moyano AL, Cáceres A. Perspectives on Mechanisms Supporting Neuronal Polarity From Small Animals to Humans. Front Cell Dev Biol 2022; 10:878142. [PMID: 35517494 PMCID: PMC9062071 DOI: 10.3389/fcell.2022.878142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 04/04/2022] [Indexed: 11/23/2022] Open
Abstract
Axon-dendrite formation is a crucial milestone in the life history of neurons. During this process, historically referred as “the establishment of polarity,” newborn neurons undergo biochemical, morphological and functional transformations to generate the axonal and dendritic domains, which are the basis of neuronal wiring and connectivity. Since the implementation of primary cultures of rat hippocampal neurons by Gary Banker and Max Cowan in 1977, the community of neurobiologists has made significant achievements in decoding signals that trigger axo-dendritic specification. External and internal cues able to switch on/off signaling pathways controlling gene expression, protein stability, the assembly of the polarity complex (i.e., PAR3-PAR6-aPKC), cytoskeleton remodeling and vesicle trafficking contribute to shape the morphology of neurons. Currently, the culture of hippocampal neurons coexists with alternative model systems to study neuronal polarization in several species, from single-cell to whole-organisms. For instance, in vivo approaches using C. elegans and D. melanogaster, as well as in situ imaging in rodents, have refined our knowledge by incorporating new variables in the polarity equation, such as the influence of the tissue, glia-neuron interactions and three-dimensional development. Nowadays, we have the unique opportunity of studying neurons differentiated from human induced pluripotent stem cells (hiPSCs), and test hypotheses previously originated in small animals and propose new ones perhaps specific for humans. Thus, this article will attempt to review critical mechanisms controlling polarization compiled over decades, highlighting points to be considered in new experimental systems, such as hiPSC neurons and human brain organoids.
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5
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Chen X, Zheng X, Cai J, Yang X, Lin Y, Wu M, Deng X, Peng YG. Effect of Anesthetics on Functional Connectivity of Developing Brain. Front Hum Neurosci 2022; 16:853816. [PMID: 35360283 PMCID: PMC8963106 DOI: 10.3389/fnhum.2022.853816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/21/2022] [Indexed: 11/27/2022] Open
Abstract
The potential anesthetic neurotoxicity on the neonate is an important focus of research investigation in the field of pediatric anesthesiology. It is essential to understand how these anesthetics may affect the development and growth of neonatal immature and vulnerable brains. Functional magnetic resonance imaging (fMRI) has suggested that using anesthetics result in reduced functional connectivity may consider as core sequence for the neurotoxicity and neurodegenerative changes in the developed brain. Anesthetics either directly impact the primary structures and functions of the brain or indirectly alter the hemodynamic parameters that contribute to cerebral blood flow (CBF) in neonatal patients. We hypothesis that anesthetic agents may either decrease the brain functional connectivity in neonatal patients or animals, which was observed by fMRI. This review will summarize the effect and mechanism of anesthesia on the rapid growth and development infant and neonate brain with fMRI through functional connectivity. It is possible to provide the new mechanism of neuronal injury induced by anesthetics and objective imaging evidence in animal developing brain.
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Affiliation(s)
- Xu Chen
- Department of Pharmacy, Chengdu Women’s and Children’s Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Xuemei Zheng
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Jianghui Cai
- Department of Pharmacy, Chengdu Women’s and Children’s Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Xiao Yang
- Department of Obstetrics, Chengdu Women’s and Children’s Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yonghong Lin
- Department of Gynecology, Chengdu Women’s and Children’s Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Mengjun Wu
- Department of Anesthesiology, Chengdu Women’s and Children’s Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- *Correspondence: Mengjun Wu,
| | - Xiaofan Deng
- Center of Organ Transplantation, Sichuan Provincial People’s Hospital, Sichuan Academy of Medical Sciences, Chengdu, China
| | - Yong G. Peng
- Department of Anesthesiology, College of Medicine, University of Florida, Gainesville, FL, United States
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Luhmann HJ. Neurophysiology of the Developing Cerebral Cortex: What We Have Learned and What We Need to Know. Front Cell Neurosci 2022; 15:814012. [PMID: 35046777 PMCID: PMC8761895 DOI: 10.3389/fncel.2021.814012] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 12/09/2021] [Indexed: 11/15/2022] Open
Abstract
This review article aims to give a brief summary on the novel technologies, the challenges, our current understanding, and the open questions in the field of the neurophysiology of the developing cerebral cortex in rodents. In the past, in vitro electrophysiological and calcium imaging studies on single neurons provided important insights into the function of cellular and subcellular mechanism during early postnatal development. In the past decade, neuronal activity in large cortical networks was recorded in pre- and neonatal rodents in vivo by the use of novel high-density multi-electrode arrays and genetically encoded calcium indicators. These studies demonstrated a surprisingly rich repertoire of spontaneous cortical and subcortical activity patterns, which are currently not completely understood in their functional roles in early development and their impact on cortical maturation. Technological progress in targeted genetic manipulations, optogenetics, and chemogenetics now allow the experimental manipulation of specific neuronal cell types to elucidate the function of early (transient) cortical circuits and their role in the generation of spontaneous and sensory evoked cortical activity patterns. Large-scale interactions between different cortical areas and subcortical regions, characterization of developmental shifts from synchronized to desynchronized activity patterns, identification of transient circuits and hub neurons, role of electrical activity in the control of glial cell differentiation and function are future key tasks to gain further insights into the neurophysiology of the developing cerebral cortex.
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Affiliation(s)
- Heiko J. Luhmann
- Institute of Physiology, University Medical Center Mainz, Mainz, Germany
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Lekchand Dasriya V, Samtiya M, Dhewa T, Puniya M, Kumar S, Ranveer S, Chaudhary V, Vij S, Behare P, Singh N, Aluko RE, Puniya AK. Etiology and management of Alzheimer's disease: Potential role of gut microbiota modulation with probiotics supplementation. J Food Biochem 2021; 46:e14043. [PMID: 34927261 DOI: 10.1111/jfbc.14043] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 11/11/2021] [Accepted: 12/13/2021] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD) is the leading type of dementia in aging people and is a progressive condition that causes neurodegeneration, resulting in confusion, memory loss, and deterioration of mental functions. AD happens because of abnormal twisting of the microtubule tau protein in neurons into a tangled neurofibrillary structure. Different factors responsible for AD pathogenesis include heavy metals, aging, cardiovascular disease, and environmental and genetic factors. Market available drugs for AD have several side effects that include hepato-toxicity, accelerated cognitive decline, worsened neuropsychiatric symptoms, and triggered suicidal ideation. Therefore, an emerging alternative therapeutic approach is probiotics, which can improve AD by modulating the gut-brain axis. Probiotics modulate different neurochemical pathways by regulating the signalling pathways associated with inflammation, histone deacetylation, and microglial cell activation and maturation. In addition, probiotics-derived metabolites (i.e., short-chain fatty acid, neurotransmitters, and antioxidants) have shown ameliorative effects against AD. Probiotics also modulate gut microbiota, with a beneficial impact on neural signalling and cognitive activity, which can attenuate AD progression. Therefore, the current review describes the etiology and mechanism of AD progression as well as various treatment options with a focus on the use of probiotics. PRACTICAL APPLICATIONS: In an aging population, dementia concerns are quite prevalent globally. AD is one of the most commonly occurring cognition disorders, which is linked to diminished brain functions. Scientific evidence supports the findings that probiotics and gut microbiota can regulate/modulate brain functions, one of the finest strategies to alleviate such disorders through the gut-brain axis. Thus, gut microbiota modulation, especially through probiotic supplementation, could become an effective solution to ameliorate AD.
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Affiliation(s)
| | - Mrinal Samtiya
- Department of Nutrition Biology, Central University of Haryana, Mahendergarh, India
| | - Tejpal Dhewa
- Department of Nutrition Biology, Central University of Haryana, Mahendergarh, India
| | - Monica Puniya
- Food Safety and Standards Authority of India, FDA Bhawan, New Delhi, India
| | - Sanjeev Kumar
- Department of Life Science and Bioinformatics, Assam University, Silchar, India
| | - Soniya Ranveer
- Dairy Microbiology Division, ICAR-National Dairy Research Institute, Karnal, India
| | - Vishu Chaudhary
- Department of Microbiology, Punjab Agriculture University, Ludhiana, India
| | - Shilpa Vij
- Dairy Microbiology Division, ICAR-National Dairy Research Institute, Karnal, India
| | - Pradip Behare
- Dairy Microbiology Division, ICAR-National Dairy Research Institute, Karnal, India
| | - Namita Singh
- Department of Bio and Nano Technology, Guru Jambheshwar University of Science and Technology, Hisar, India
| | - Rotimi E Aluko
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Anil Kumar Puniya
- Dairy Microbiology Division, ICAR-National Dairy Research Institute, Karnal, India
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8
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Kilb W. When Are Depolarizing GABAergic Responses Excitatory? Front Mol Neurosci 2021; 14:747835. [PMID: 34899178 PMCID: PMC8651619 DOI: 10.3389/fnmol.2021.747835] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/28/2021] [Indexed: 11/13/2022] Open
Abstract
The membrane responses upon activation of GABA(A) receptors critically depend on the intracellular Cl− concentration ([Cl−]i), which is maintained by a set of transmembrane transporters for Cl−. During neuronal development, but also under several pathophysiological conditions, the prevailing expression of the Cl− loader NKCC1 and the low expression of the Cl− extruder KCC2 causes elevated [Cl−]i, which result in depolarizing GABAergic membrane responses. However, depolarizing GABAergic responses are not necessarily excitatory, as GABA(A) receptors also reduces the input resistance of neurons and thereby shunt excitatory inputs. To summarize our knowledge on the effect of depolarizing GABA responses on neuronal excitability, this review discusses theoretical considerations and experimental studies illustrating the relation between GABA conductances, GABA reversal potential and neuronal excitability. In addition, evidences for the complex spatiotemporal interaction between depolarizing GABAergic and glutamatergic inputs are described. Moreover, mechanisms that influence [Cl−]i beyond the expression of Cl− transporters are presented. And finally, several in vitro and in vivo studies that directly investigated whether GABA mediates excitation or inhibition during early developmental stages are summarized. In summary, these theoretical considerations and experimental evidences suggest that GABA can act as inhibitory neurotransmitter even under conditions that maintain substantial depolarizing membrane responses.
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Affiliation(s)
- Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
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Lombardi A, Luhmann HJ, Kilb W. Modelling the spatial and temporal constrains of the GABAergic influence on neuronal excitability. PLoS Comput Biol 2021; 17:e1009199. [PMID: 34767548 PMCID: PMC8612559 DOI: 10.1371/journal.pcbi.1009199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 11/24/2021] [Accepted: 10/24/2021] [Indexed: 11/21/2022] Open
Abstract
GABA (γ-amino butyric acid) is an inhibitory neurotransmitter in the adult brain that can mediate depolarizing responses during development or after neuropathological insults. Under which conditions GABAergic membrane depolarizations are sufficient to impose excitatory effects is hard to predict, as shunting inhibition and GABAergic effects on spatiotemporal filtering of excitatory inputs must be considered. To evaluate at which reversal potential a net excitatory effect was imposed by GABA (EGABAThr), we performed a detailed in-silico study using simple neuronal topologies and distinct spatiotemporal relations between GABAergic and glutamatergic inputs. These simulations revealed for GABAergic synapses located at the soma an EGABAThr close to action potential threshold (EAPThr), while with increasing dendritic distance EGABAThr shifted to positive values. The impact of GABA on AMPA-mediated inputs revealed a complex temporal and spatial dependency. EGABAThr depends on the temporal relation between GABA and AMPA inputs, with a striking negative shift in EGABAThr for AMPA inputs appearing after the GABA input. The spatial dependency between GABA and AMPA inputs revealed a complex profile, with EGABAThr being shifted to values negative to EAPThr for AMPA synapses located proximally to the GABA input, while for distally located AMPA synapses the dendritic distance had only a minor effect on EGABAThr. For tonic GABAergic conductances EGABAThr was negative to EAPThr over a wide range of gGABAtonic values. In summary, these results demonstrate that for several physiologically relevant situations EGABAThr is negative to EAPThr, suggesting that depolarizing GABAergic responses can mediate excitatory effects even if EGABA did not reach EAPThr. The neurotransmitter GABA mediates an inhibitory action in the mature brain, while it was found that GABA provokes depolarizations in the immature brain or after neurological insults. It is, however, not clear to which extend these GABAergic depolarizations can contribute to an excitatory effect. In the present manuscript we approached this question with a computational model of a simplified neurons to determine what amount of a GABAergic depolarizing effect, which we quantified by the so called GABA reversal potential (EGABA), was required to turn GABAergic inhibition to excitation. The results of our simulations revealed that if GABA was applied alone a GABAergic excitation was induced when EGABA was around the action potential threshold. When GABA was applied together with additional excitatory inputs, which is the physiological situation in the brain, only for spatially and temporally correlated inputs EGABA was close to the action potential threshold. For situations in which the additional excitatory inputs appear after the GABA input or are distant to the GABA input, an excitatory effect of GABA could be observed already at EGABA substantially negative to the action potential threshold. This results indicate that even slightly depolarizing GABA responses, which may be induced during or after neurological insults, can potentially turn GABAergic inhibition into GABAergic excitation.
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Affiliation(s)
- Aniello Lombardi
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Heiko J. Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
- * E-mail:
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10
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Abstract
In mammals, the selective transformation of transient experience into stored memory occurs in the hippocampus, which develops representations of specific events in the context in which they occur. In this review, we focus on the development of hippocampal circuits and the self-organized dynamics embedded within them since the latter critically support the role of the hippocampus in learning and memory. We first discuss evidence that adult hippocampal cells and circuits are sculpted by development as early as during embryonic neurogenesis. We argue that these primary developmental programs provide a scaffold onto which later experience of the external world can be grafted. Next, we review the different sequences in the development of hippocampal cells and circuits at anatomical and functional levels. We cover a period extending from neurogenesis and migration to the appearance of phenotypic diversity within hippocampal cells, and their wiring into functional networks. We describe the progressive emergence of network dynamics in the hippocampus, from sensorimotor-driven early sharp waves to sequences of place cells tracking relational information. We outline the critical turn points and discontinuities in that developmental journey, and close by formulating open questions. We propose that rewinding the process of hippocampal development helps understand the main organization principles of memory circuits.
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Affiliation(s)
- Rosa Cossart
- Inserm, INMED, Turing Center for Living Systems, Aix Marseille University, Marseille, France
| | - Rustem Khazipov
- Inserm, INMED, Turing Center for Living Systems, Aix Marseille University, Marseille, France.,Laboratory of Neurobiology, Kazan Federal University, Kazan Russia
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