1
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Fischer M, Kukley M. Hidden in the white matter: Current views on interstitial white matter neurons. Neuroscientist 2024:10738584241282969. [PMID: 39365761 DOI: 10.1177/10738584241282969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2024]
Abstract
The mammalian brain comprises two structurally and functionally distinct compartments: the gray matter (GM) and the white matter (WM). In humans, the WM constitutes approximately half of the brain volume, yet it remains significantly less investigated than the GM. The major cellular elements of the WM are neuronal axons and glial cells. However, the WM also contains cell bodies of the interstitial neurons, estimated to number 10 to 28 million in the adult bat brain, 67 million in Lar gibbon brain, and 450 to 670 million in the adult human brain, representing as much as 1.3%, 2.25%, and 3.5% of all neurons in the cerebral cortex, respectively. Many studies investigated the interstitial WM neurons (IWMNs) using immunohistochemistry, and some information is available regarding their electrophysiological properties. However, the functional role of IWMNs in physiologic and pathologic conditions largely remains unknown. This review aims to provide a concise update regarding the distribution and properties of interstitial WM neurons, highlight possible functions of these cells as debated in the literature, and speculate about other possible functions of the IWMNs and their interactions with glial cells. We hope that our review will inspire new research on IWMNs, which represent an intriguing cell population in the brain.
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Affiliation(s)
- Maximilian Fischer
- Institut de Neurociències and Departamento Bioquímica i Biología Molecular, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - Maria Kukley
- Achucarro Basque Centre for Neuroscience, Leioa, Spain
- IKERBASQUE Basque Foundation for Science, Bilbao, Spain
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2
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Zolnik TA, Bronec A, Ross A, Staab M, Sachdev RNS, Molnár Z, Eickholt BJ, Larkum ME. Layer 6b controls brain state via apical dendrites and the higher-order thalamocortical system. Neuron 2024; 112:805-820.e4. [PMID: 38101395 DOI: 10.1016/j.neuron.2023.11.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 09/11/2023] [Accepted: 11/18/2023] [Indexed: 12/17/2023]
Abstract
The deepest layer of the cortex (layer 6b [L6b]) contains relatively few neurons, but it is the only cortical layer responsive to the potent wake-promoting neuropeptide orexin/hypocretin. Can these few neurons significantly influence brain state? Here, we show that L6b-photoactivation causes a surprisingly robust enhancement of attention-associated high-gamma oscillations and population spiking while abolishing slow waves in sleep-deprived mice. To explain this powerful impact on brain state, we investigated L6b's synaptic output using optogenetics, electrophysiology, and monoCaTChR ex vivo. We found powerful output in the higher-order thalamus and apical dendrites of L5 pyramidal neurons, via L1a and L5a, as well as in superior colliculus and L6 interneurons. L6b subpopulations with distinct morphologies and short- and long-term plasticities project to these diverse targets. The L1a-targeting subpopulation triggered powerful NMDA-receptor-dependent spikes that elicited burst firing in L5. We conclude that orexin/hypocretin-activated cortical neurons form a multifaceted, fine-tuned circuit for the sustained control of the higher-order thalamocortical system.
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Affiliation(s)
- Timothy Adam Zolnik
- Department of Biochemistry, Charité Universitätsmedizin Berlin, Berlin 10117, Germany; Department of Biology, Humboldt Universität zu Berlin, Berlin 10117, Germany.
| | - Anna Bronec
- Department of Biology, Humboldt Universität zu Berlin, Berlin 10117, Germany
| | - Annemarie Ross
- Department of Biology, Humboldt Universität zu Berlin, Berlin 10117, Germany
| | - Marcel Staab
- Department of Biology, Humboldt Universität zu Berlin, Berlin 10117, Germany
| | - Robert N S Sachdev
- Department of Biology, Humboldt Universität zu Berlin, Berlin 10117, Germany
| | - Zoltán Molnár
- Department of Biochemistry, Charité Universitätsmedizin Berlin, Berlin 10117, Germany; Department of Physiology, Anatomy, and Genetics, University of Oxford, Parks Road, Sherrington Building, Oxford OX1 3PT, UK
| | | | - Matthew Evan Larkum
- Department of Biology, Humboldt Universität zu Berlin, Berlin 10117, Germany.
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3
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Feldmeyer D. Structure and function of neocortical layer 6b. Front Cell Neurosci 2023; 17:1257803. [PMID: 37744882 PMCID: PMC10516558 DOI: 10.3389/fncel.2023.1257803] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 08/14/2023] [Indexed: 09/26/2023] Open
Abstract
Cortical layer 6b is considered by many to be a remnant of the subplate that forms during early stages of neocortical development, but its role in the adult is not well understood. Its neuronal complement has only recently become the subject of systematic studies, and its axonal projections and synaptic input structures have remained largely unexplored despite decades of research into neocortical function. In recent years, however, layer 6b (L6b) has attracted increasing attention and its functional role is beginning to be elucidated. In this review, I will attempt to provide an overview of what is currently known about the excitatory and inhibitory neurons in this layer, their pre- and postsynaptic connectivity, and their functional implications. Similarities and differences between different cortical areas will be highlighted. Finally, layer 6b neurons are highly responsive to several neuropeptides such as orexin/hypocretin, neurotensin and cholecystokinin, in some cases exclusively. They are also strongly controlled by neurotransmitters such as acetylcholine and norepinephrine. The interaction of these neuromodulators with L6b microcircuitry and its functional consequences will also be discussed.
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Affiliation(s)
- Dirk Feldmeyer
- Research Centre Jülich, Institute of Neuroscience and Medicine 10 (INM-10), Jülich, Germany
- Department of Psychiatry, Psychotherapy, and Psychosomatics, RWTH Aachen University Hospital, Aachen, Germany
- Jülich-Aachen Research Alliance, Translational Brain Medicine (JARA Brain), Aachen, Germany
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4
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Pinotsis DA, Fridman G, Miller EK. Cytoelectric Coupling: Electric fields sculpt neural activity and "tune" the brain's infrastructure. Prog Neurobiol 2023; 226:102465. [PMID: 37210066 DOI: 10.1016/j.pneurobio.2023.102465] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/09/2023] [Accepted: 05/17/2023] [Indexed: 05/22/2023]
Abstract
We propose and present converging evidence for the Cytoelectric Coupling Hypothesis: Electric fields generated by neurons are causal down to the level of the cytoskeleton. This could be achieved via electrodiffusion and mechanotransduction and exchanges between electrical, potential and chemical energy. Ephaptic coupling organizes neural activity, forming neural ensembles at the macroscale level. This information propagates to the neuron level, affecting spiking, and down to molecular level to stabilize the cytoskeleton, "tuning" it to process information more efficiently.
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Affiliation(s)
- Dimitris A Pinotsis
- Centre for Mathematical Neuroscience and Psychology and Department of Psychology, City -University of London, London EC1V 0HB, United Kingdom; The Picower Institute for Learning & Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Gene Fridman
- Departments of Otolaryngology, Biomedical Engineering, and Electrical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Earl K Miller
- The Picower Institute for Learning & Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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5
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Akcay G, Luttge R. Microenvironments Matter: Advances in Brain-on-Chip. BIOSENSORS 2023; 13:551. [PMID: 37232912 PMCID: PMC10216565 DOI: 10.3390/bios13050551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/04/2023] [Accepted: 05/12/2023] [Indexed: 05/27/2023]
Abstract
To highlight the particular needs with respect to modeling the unique and complex organization of the human brain structure, we reviewed the state-of-the-art in devising brain models with engineered instructive microenvironments. To acquire a better perspective on the brain's working mechanisms, we first summarize the importance of regional stiffness gradients in brain tissue, varying per layer and the cellular diversities of the layers. Through this, one can acquire an understanding of the essential parameters in emulating the brain in vitro. In addition to the brain's organizational architecture, we addressed also how the mechanical properties have an impact on neuronal cell responses. In this respect, advanced in vitro platforms emerged and profoundly changed the methods of brain modeling efforts from the past, mainly focusing on animal or cell line research. The main challenges in imitating features of the brain in a dish are with regard to composition and functionality. In neurobiological research, there are now methods that aim to cope with such challenges by the self-assembly of human-derived pluripotent stem cells (hPSCs), i.e., brainoids. Alternatively, these brainoids can be used stand-alone or in conjunction with Brain-on-Chip (BoC) platform technology, 3D-printed gels, and other types of engineered guidance features. Currently, advanced in vitro methods have made a giant leap forward regarding cost-effectiveness, ease-of-use, and availability. We bring these recent developments together into one review. We believe our conclusions will give a novel perspective towards advancing instructive microenvironments for BoCs and the understanding of the brain's cellular functions either in modeling healthy or diseased states of the brain.
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Affiliation(s)
- Gulden Akcay
- Neuro-Nanoscale Engineering, Department of Mechanical Engineering/Microsystems, Institute of Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands;
| | - Regina Luttge
- Neuro-Nanoscale Engineering, Department of Mechanical Engineering/Microsystems, Institute of Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands;
- Eindhoven Artificial Intelligence Systems Institute, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
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6
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McLeod F, Dimtsi A, Marshall AC, Lewis-Smith D, Thomas R, Clowry GJ, Trevelyan AJ. Altered synaptic connectivity in an in vitro human model of STXBP1 encephalopathy. Brain 2023; 146:850-857. [PMID: 36315647 PMCID: PMC9976961 DOI: 10.1093/brain/awac396] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 08/05/2022] [Accepted: 10/01/2022] [Indexed: 01/14/2023] Open
Abstract
Early infantile developmental and epileptic encephalopathies are devastating conditions, generally of genetic origin, but the pathological mechanisms often remain obscure. A major obstacle in this field of research is the difficulty of studying cortical brain development in humans, at the relevant time period in utero. To address this, we established an in vitro assay to study the impact of gene variants on the developing human brain by using living organotypic cultures of the human subplate and neighbouring cortical regions, prepared from ethically sourced, 14-17 post-conception week brain tissue (www.hdbr.org). We were able to maintain cultures for several months, during which time the gross anatomical structures of the cortical plate, subplate and marginal zone persisted, while neurons continued to develop morphologically and form new synaptic networks. This preparation thus permits the study of genetic manipulations and their downstream effects on an intact developing human cortical network. We focused on STXBP1 haploinsufficiency, which is among the most common genetic causes of developmental and epileptic encephalopathy. This was induced using shRNA interference, leading to impaired synaptic function and a reduced density of glutamatergic synapses. We thereby provide a critical proof-of-principle for how to study the impact of any gene of interest on the development of the human cortex.
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Affiliation(s)
- Faye McLeod
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Anna Dimtsi
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Amy C Marshall
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - David Lewis-Smith
- Newcastle University Translational and Clinical Research Institute, Newcastle upon Tyne NE2 4HH, UK
- Department of Clinical Neurosciences, Royal Victoria Infirmary, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE1 4LP, UK
| | - Rhys Thomas
- Newcastle University Translational and Clinical Research Institute, Newcastle upon Tyne NE2 4HH, UK
- Department of Clinical Neurosciences, Royal Victoria Infirmary, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE1 4LP, UK
| | - Gavin J Clowry
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Andrew J Trevelyan
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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Junaković A, Kopić J, Duque A, Rakic P, Krsnik Ž, Kostović I. Laminar dynamics of deep projection neurons and mode of subplate formation are hallmarks of histogenetic subdivisions of the human cingulate cortex before onset of arealization. Brain Struct Funct 2023; 228:613-633. [PMID: 36592215 PMCID: PMC9944618 DOI: 10.1007/s00429-022-02606-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/23/2022] [Indexed: 01/03/2023]
Abstract
The cingulate gyrus, as a prominent part of the human limbic lobe, is involved in the integration and regulation of complex emotional, executive, motivational, and cognitive functions, attributed to several functional regions along the anteroposterior axis. In contrast to increasing knowledge of cingulate function in the adult brain, our knowledge of cingulate development is based primarily on classical neuroembryological studies. We aimed to reveal the laminar and cellular development of the various cingulate regions during the critical period from 7.5 to 15 postconceptional weeks (PCW) before the formation of Brodmann type arealization, employing diverse molecular markers on serial histological sections of postmortem human fetal brains. The study was performed by analysis of: (1) deep projection neuron (DPN) markers laminar dynamics, (2) all transient laminar compartments, and (3) characteristic subplate (SP) formation-expansion phase. We found that DPN markers labeling an incipient cortical plate (CP) were the first sign of regional differentiation of the dorsal isocortical and ventral mesocortical belt. Remarkably, increased width of the fibrillar marginal zone (MZ) towards the limbus, in parallel with the narrowing of CP containing DPN, as well as the diminishment of subventricular zone (SVZ) were reliable landmarks of early mesocortical differentiation. Finally, the SP formation pattern was shown to be a crucial event in the isocortical cingulate portion, given that the mesocortical belt is characterized by an incomplete CP delamination and absence of SP expansion. In conclusion, laminar DPN markers dynamics, together with the SVZ size and mode of SP formation indicate regional belt-like cingulate cortex differentiation before the corpus callosum expansion and several months before Brodmann type arealization.
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Affiliation(s)
- Alisa Junaković
- School of Medicine, Croatian Institute for Brain Research, University of Zagreb, Zagreb, Croatia
| | - Janja Kopić
- School of Medicine, Croatian Institute for Brain Research, University of Zagreb, Zagreb, Croatia
| | - Alvaro Duque
- School of Medicine, Yale University, New Haven, CT, 06510, USA
| | - Pasko Rakic
- School of Medicine, Yale University, New Haven, CT, 06510, USA
| | - Željka Krsnik
- School of Medicine, Croatian Institute for Brain Research, University of Zagreb, Zagreb, Croatia
| | - Ivica Kostović
- School of Medicine, Croatian Institute for Brain Research, University of Zagreb, Zagreb, Croatia.
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8
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Luhmann HJ. Malformations-related neocortical circuits in focal seizures. Neurobiol Dis 2023; 178:106018. [PMID: 36706927 DOI: 10.1016/j.nbd.2023.106018] [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: 11/25/2022] [Revised: 01/18/2023] [Accepted: 01/23/2023] [Indexed: 01/25/2023] Open
Abstract
This review article gives an overview on the molecular, cellular and network mechanisms underlying focal seizures in neocortical networks with developmental malformations. Neocortical malformations comprise a large variety of structural abnormalities associated with epilepsy and other neurological and psychiatric disorders. Genetic or acquired disorders of neocortical cell proliferation, neuronal migration and/or programmed cell death may cause pathologies ranging from the expression of dysmorphic neurons and heterotopic cell clusters to abnormal layering and cortical misfolding. After providing a brief overview on the pathogenesis and structure of neocortical malformations in humans, animal models are discussed and how they contributed to our understanding on the mechanisms of neocortical hyperexcitability associated with developmental disorders. State-of-the-art molecular biological and electrophysiological techniques have been also used in humans and on resectioned neocortical tissue of epileptic patients and provide deep insights into the subcellular, cellular and network mechanisms contributing to focal seizures. Finally, a brief outlook is given how novel models and methods can shape translational research in the near future.
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Affiliation(s)
- Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz, Germany.
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9
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Gellért L, Luhmann HJ, Kilb W. Axonal connections between S1 barrel, M1, and S2 cortex in the newborn mouse. Front Neuroanat 2023; 17:1105998. [PMID: 36760662 PMCID: PMC9905141 DOI: 10.3389/fnana.2023.1105998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 01/09/2023] [Indexed: 01/26/2023] Open
Abstract
The development of functionally interconnected networks between primary (S1), secondary somatosensory (S2), and motor (M1) cortical areas requires coherent neuronal activity via corticocortical projections. However, the anatomical substrate of functional connections between S1 and M1 or S2 during early development remains elusive. In the present study, we used ex vivo carbocyanine dye (DiI) tracing in paraformaldehyde-fixed newborn mouse brain to investigate axonal projections of neurons in different layers of S1 barrel field (S1Bf), M1, and S2 toward the subplate (SP), a hub layer for sensory information transfer in the immature cortex. In addition, we performed extracellular recordings in neocortical slices to unravel the functional connectivity between these areas. Our experiments demonstrate that already at P0 neurons from the cortical plate (CP), layer 5/6 (L5/6), and the SP of both M1 and S2 send projections through the SP of S1Bf. Reciprocally, neurons from CP to SP of S1Bf send projections through the SP of M1 and S2. Electrophysiological recordings with multi-electrode arrays in cortical slices revealed weak, but functional synaptic connections between SP and L5/6 within and between S1 and M1. An even lower functional connectivity was observed between S1 and S2. In summary, our findings demonstrate that functional connections between SP and upper cortical layers are not confined to the same cortical area, but corticocortical connection between adjacent cortical areas exist already at the day of birth. Hereby, SP can integrate early cortical activity of M1, S1, and S2 and shape the development of sensorimotor integration at an early stage.
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10
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Venkatesan S, Chen T, Liu Y, Turner EE, Tripathy SJ, Lambe EK. Chrna5 and lynx prototoxins identify acetylcholine super-responder subplate neurons. iScience 2023; 26:105992. [PMID: 36798433 PMCID: PMC9926215 DOI: 10.1016/j.isci.2023.105992] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 11/22/2022] [Accepted: 01/12/2023] [Indexed: 01/15/2023] Open
Abstract
Attention depends on cholinergic excitation of prefrontal neurons but is sensitive to perturbation of α5-containing nicotinic receptors encoded by Chrna5. However, Chrna5-expressing (Chrna5+) neurons remain enigmatic, despite their potential as a target to improve attention. Here, we generate complex transgenic mice to probe Chrna5+ neurons and their sensitivity to endogenous acetylcholine. Through opto-physiological experiments, we discover that Chrna5+ neurons contain a distinct population of acetylcholine super-responders. Leveraging single-cell transcriptomics, we discover molecular markers conferring subplate identity on this subset. We determine that Chrna5+ super-responders express a unique complement of GPI-anchored lynx prototoxin genes (Lypd1, Ly6g6e, and Lypd6b), predicting distinct nicotinic receptor regulation. To manipulate lynx regulation of endogenous nicotinic responses, we developed a pharmacological strategy guided by transcriptomic predictions. Overall, we reveal Chrna5-Cre mice as a transgenic tool to target the diversity of subplate neurons in adulthood, yielding new molecular strategies to manipulate their cholinergic activation relevant to attention disorders.
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Affiliation(s)
- Sridevi Venkatesan
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King’s College Circle, Toronto, ON, Canada
| | - Tianhui Chen
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King’s College Circle, Toronto, ON, Canada
| | - Yupeng Liu
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King’s College Circle, Toronto, ON, Canada
| | - Eric E. Turner
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Shreejoy J. Tripathy
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King’s College Circle, Toronto, ON, Canada,Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada,Department of Psychiatry, University of Toronto, Toronto, ON, Canada,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Evelyn K. Lambe
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King’s College Circle, Toronto, ON, Canada,Department of Psychiatry, University of Toronto, Toronto, ON, Canada,Department of Obstetrics and Gynecology, University of Toronto, Toronto, ON, Canada,Corresponding author
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11
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Mukherjee D, Kanold PO. Changing subplate circuits: Early activity dependent circuit plasticity. Front Cell Neurosci 2023; 16:1067365. [PMID: 36713777 PMCID: PMC9874351 DOI: 10.3389/fncel.2022.1067365] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 12/16/2022] [Indexed: 01/12/2023] Open
Abstract
Early neural activity in the developing sensory system comprises spontaneous bursts of patterned activity, which is fundamental for sculpting and refinement of immature cortical connections. The crude early connections that are initially refined by spontaneous activity, are further elaborated by sensory-driven activity from the periphery such that orderly and mature connections are established for the proper functioning of the cortices. Subplate neurons (SPNs) are one of the first-born mature neurons that are transiently present during early development, the period of heightened activity-dependent plasticity. SPNs are well integrated within the developing sensory cortices. Their structural and functional properties such as relative mature intrinsic membrane properties, heightened connectivity via chemical and electrical synapses, robust activation by neuromodulatory inputs-place them in an ideal position to serve as crucial elements in monitoring and regulating spontaneous endogenous network activity. Moreover, SPNs are the earliest substrates to receive early sensory-driven activity from the periphery and are involved in its modulation, amplification, and transmission before the maturation of the direct adult-like thalamocortical connectivity. Consequently, SPNs are vulnerable to sensory manipulations in the periphery. A broad range of early sensory deprivations alters SPN circuit organization and functions that might be associated with long term neurodevelopmental and psychiatric disorders. Here we provide a comprehensive overview of SPN function in activity-dependent development during early life and integrate recent findings on the impact of early sensory deprivation on SPNs that could eventually lead to neurodevelopmental disorders.
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Affiliation(s)
- Didhiti Mukherjee
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Patrick O. Kanold
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States,Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, United States,*Correspondence: Patrick O. Kanold ✉
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12
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Neubauer A, Menegaux A, Wendt J, Li HB, Schmitz-Koep B, Ruzok T, Thalhammer M, Schinz D, Bartmann P, Wolke D, Priller J, Zimmer C, Rueckert D, Hedderich DM, Sorg C. Aberrant claustrum structure in preterm-born neonates: an MRI study. Neuroimage Clin 2023; 37:103286. [PMID: 36516730 PMCID: PMC9755238 DOI: 10.1016/j.nicl.2022.103286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/18/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Abstract
The human claustrum is a gray matter structure in the white matter between insula and striatum. Previous analysis found altered claustrum microstructure in very preterm-born adults associated with lower cognitive performance. As the claustrum development is related to hypoxia-ischemia sensitive transient cell populations being at-risk in premature birth, we hypothesized that claustrum structure is already altered in preterm-born neonates. We studied anatomical and diffusion-weighted MRIs of 83 preterm- and 83 term-born neonates at term-equivalent age. Additionally, claustrum development was analyzed both in a spectrum of 377 term-born neonates and longitudinally in 53 preterm-born subjects. Data was provided by the developing Human Connectome Project. Claustrum development showed increasing volume, increasing fractional anisotropy (FA), and decreasing mean diffusivity (MD) around term both across term- and preterm-born neonates. Relative to term-born ones, preterm-born neonates had (i) increased absolute and relative claustrum volumes, both indicating increased cellular and/or extracellular matter and being in contrast to other subcortical gray matter regions of decreased volumes such as thalamus; (ii) lower claustrum FA and higher claustrum MD, pointing at increased extracellular matrix and impaired axonal integrity; and (iii) aberrant covariance between claustrum FA and MD, respectively, and that of distributed gray matter regions, hinting at relatively altered claustrum microstructure. Results together demonstrate specifically aberrant claustrum structure in preterm-born neonates, suggesting altered claustrum development in prematurity, potentially relevant for later cognitive performance.
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Affiliation(s)
- Antonia Neubauer
- Department of Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Germany; School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Germany.
| | - Aurore Menegaux
- Department of Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Germany; School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Jil Wendt
- Department of Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Germany; School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Hongwei Bran Li
- Department of Informatics, Technical University of Munich, Germany; Department of Quantitative Biomedicine, University of Zurich, Switzerland
| | - Benita Schmitz-Koep
- Department of Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Germany; School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Tobias Ruzok
- Department of Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Germany; School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Melissa Thalhammer
- Department of Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Germany; School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - David Schinz
- Department of Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Germany; School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Peter Bartmann
- Department of Neonatology and Pediatric Intensive Care, University Hospital Bonn, Germany
| | - Dieter Wolke
- Department of Psychology, University of Warwick, Coventry, UK; Warwick Medical School, University of Warwick, Coventry, UK
| | - Josef Priller
- Department of Psychiatry and Psychotherapy, Klinikum Rechts der Isar, Technical University of Munich, Germany; Neuropsychiatry, Charité - Universitätsmedizin Berlin and DZNE, Berlin, Germany; University of Edinburgh and UK DRI, Edinburgh, UK
| | - Claus Zimmer
- Department of Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Germany; School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Daniel Rueckert
- School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Germany; Department of Informatics, Technical University of Munich, Germany; Department of Computing, Imperial College London, UK
| | - Dennis M Hedderich
- Department of Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Germany; School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Germany
| | - Christian Sorg
- Department of Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Germany; School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Germany; Department of Psychiatry and Psychotherapy, Klinikum Rechts der Isar, Technical University of Munich, Germany
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13
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Linke AC, Chen B, Olson L, Ibarra C, Fong C, Reynolds S, Apostol M, Kinnear M, Müller RA, Fishman I. Sleep Problems in Preschoolers With Autism Spectrum Disorder Are Associated With Sensory Sensitivities and Thalamocortical Overconnectivity. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2023; 8:21-31. [PMID: 34343726 PMCID: PMC9826645 DOI: 10.1016/j.bpsc.2021.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 07/08/2021] [Accepted: 07/21/2021] [Indexed: 01/18/2023]
Abstract
BACKGROUND Projections between the thalamus and sensory cortices are established early in development and play an important role in regulating sleep as well as in relaying sensory information to the cortex. Atypical thalamocortical functional connectivity frequently observed in children with autism spectrum disorder (ASD) might therefore be linked to sensory and sleep problems common in ASD. METHODS Here, we investigated the relationship between auditory-thalamic functional connectivity measured during natural sleep functional magnetic resonance imaging, sleep problems, and sound sensitivities in 70 toddlers and preschoolers (1.5-5 years old) with ASD compared with a matched group of 46 typically developing children. RESULTS In children with ASD, sleep problems and sensory sensitivities were positively correlated, and increased sleep latency was associated with overconnectivity between the thalamus and auditory cortex in a subsample with high-quality magnetic resonance imaging data (n = 29). In addition, auditory cortex blood oxygen level-dependent signal amplitude was elevated in children with ASD, potentially reflecting reduced sensory gating or a lack of auditory habituation during natural sleep. CONCLUSIONS These findings indicate that atypical thalamocortical functional connectivity can be detected early in development and may play a crucial role in sleep problems and sensory sensitivities in ASD.
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Affiliation(s)
- Annika Carola Linke
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California.
| | - Bosi Chen
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California; San Diego State University/University of California San Diego Joint Doctoral Program in Clinical Psychology, San Diego, California
| | - Lindsay Olson
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California; San Diego State University/University of California San Diego Joint Doctoral Program in Clinical Psychology, San Diego, California
| | - Cynthia Ibarra
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
| | - Chris Fong
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California; San Diego State University/University of California San Diego Joint Doctoral Program in Clinical Psychology, San Diego, California
| | - Sarah Reynolds
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
| | - Michael Apostol
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
| | - Mikaela Kinnear
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
| | - Ralph-Axel Müller
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California; San Diego State University/University of California San Diego Joint Doctoral Program in Clinical Psychology, San Diego, California; SDSU Center for Autism and Developmental Disorders, San Diego, California
| | - Inna Fishman
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California; San Diego State University/University of California San Diego Joint Doctoral Program in Clinical Psychology, San Diego, California; SDSU Center for Autism and Developmental Disorders, San Diego, California
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14
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Petanjek Z, Banovac I, Sedmak D, Hladnik A. Dendritic Spines: Synaptogenesis and Synaptic Pruning for the Developmental Organization of Brain Circuits. ADVANCES IN NEUROBIOLOGY 2023; 34:143-221. [PMID: 37962796 DOI: 10.1007/978-3-031-36159-3_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Synaptic overproduction and elimination is a regular developmental event in the mammalian brain. In the cerebral cortex, synaptic overproduction is almost exclusively correlated with glutamatergic synapses located on dendritic spines. Therefore, analysis of changes in spine density on different parts of the dendritic tree in identified classes of principal neurons could provide insight into developmental reorganization of specific microcircuits.The activity-dependent stabilization and selective elimination of the initially overproduced synapses is a major mechanism for generating diversity of neural connections beyond their genetic determination. The largest number of overproduced synapses was found in the monkey and human cerebral cortex. The highest (exceeding adult values by two- to threefold) and most protracted overproduction (up to third decade of life) was described for associative layer IIIC pyramidal neurons in the human dorsolateral prefrontal cortex.Therefore, the highest proportion and extraordinarily extended phase of synaptic spine overproduction is a hallmark of neural circuitry in human higher-order associative areas. This indicates that microcircuits processing the most complex human cognitive functions have the highest level of developmental plasticity. This finding is the backbone for understanding the effect of environmental impact on the development of the most complex, human-specific cognitive and emotional capacities, and on the late onset of human-specific neuropsychiatric disorders, such as autism and schizophrenia.
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Affiliation(s)
- Zdravko Petanjek
- Department of Anatomy and Clinical Anatomy, School of Medicine, University of Zagreb, Zagreb, Croatia.
- Department of Neuroscience, Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia.
- Center of Excellence for Basic, Clinical and Translational Neuroscience, School of Medicine, University of Zagreb, Zagreb, Croatia.
| | - Ivan Banovac
- Department of Anatomy and Clinical Anatomy, School of Medicine, University of Zagreb, Zagreb, Croatia
- Department of Neuroscience, Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
- Center of Excellence for Basic, Clinical and Translational Neuroscience, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Dora Sedmak
- Department of Anatomy and Clinical Anatomy, School of Medicine, University of Zagreb, Zagreb, Croatia
- Department of Neuroscience, Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
- Center of Excellence for Basic, Clinical and Translational Neuroscience, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Ana Hladnik
- Department of Anatomy and Clinical Anatomy, School of Medicine, University of Zagreb, Zagreb, Croatia
- Department of Neuroscience, Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
- Center of Excellence for Basic, Clinical and Translational Neuroscience, School of Medicine, University of Zagreb, Zagreb, Croatia
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15
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Thill B. The fetal pain paradox. FRONTIERS IN PAIN RESEARCH 2023; 4:1128530. [PMID: 37025166 PMCID: PMC10072285 DOI: 10.3389/fpain.2023.1128530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 02/21/2023] [Indexed: 04/08/2023] Open
Abstract
Controversy exists as to when conscious pain perception in the fetus may begin. According to the hypothesis of cortical necessity, thalamocortical connections, which do not form until after 24-28 weeks gestation, are necessary for conscious pain perception. However, anesthesiologists and neonatologists treat age-matched neonates as both conscious and pain-capable due to observable and measurable behavioral, hormonal, and physiologic indicators of pain. In preterm infants, these multimodal indicators of pain are uncontroversial, and their presence, despite occurring prior to functional thalamocortical connections, has guided the use of analgesics in neonatology and fetal surgery for decades. However, some medical groups state that below 24 weeks gestation, there is no pain capacity. Thus, a paradox exists in the disparate acknowledgment of pain capability in overlapping patient populations. Brain networks vary by age. During the first and second trimesters, the cortical subplate, a unique structure that is present only during fetal and early neonatal development, forms the first cortical network. In the third trimester, the cortical plate assumes this function. According to the subplate modulation hypothesis, a network of connections to the subplate and subcortical structures is sufficient to facilitate conscious pain perception in the fetus and the preterm neonate prior to 24 weeks gestation. Therefore, similar to other fetal and neonatal systems that have a transitional phase (i.e., circulatory system), there is now strong evidence for transitional developmental phases of fetal and neonatal pain circuitry.
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16
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Beopoulos A, Géa M, Fasano A, Iris F. Autism spectrum disorders pathogenesis: Toward a comprehensive model based on neuroanatomic and neurodevelopment considerations. Front Neurosci 2022; 16:988735. [PMID: 36408388 PMCID: PMC9671112 DOI: 10.3389/fnins.2022.988735] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 10/10/2022] [Indexed: 11/26/2023] Open
Abstract
Autism spectrum disorder (ASD) involves alterations in neural connectivity affecting cortical network organization and excitation to inhibition ratio. It is characterized by an early increase in brain volume mediated by abnormal cortical overgrowth patterns and by increases in size, spine density, and neuron population in the amygdala and surrounding nuclei. Neuronal expansion is followed by a rapid decline from adolescence to middle age. Since no known neurobiological mechanism in human postnatal life is capable of generating large excesses of frontocortical neurons, this likely occurs due to a dysregulation of layer formation and layer-specific neuronal migration during key early stages of prenatal cerebral cortex development. This leads to the dysregulation of post-natal synaptic pruning and results in a huge variety of forms and degrees of signal-over-noise discrimination losses, accounting for ASD clinical heterogeneities, including autonomic nervous system abnormalities and comorbidities. We postulate that sudden changes in environmental conditions linked to serotonin/kynurenine supply to the developing fetus, throughout the critical GW7 - GW20 (Gestational Week) developmental window, are likely to promote ASD pathogenesis during fetal brain development. This appears to be driven by discrete alterations in differentiation and patterning mechanisms arising from in utero RNA editing, favoring vulnerability outcomes over plasticity outcomes. This paper attempts to provide a comprehensive model of the pathogenesis and progression of ASD neurodevelopmental disorders.
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Affiliation(s)
| | | | - Alessio Fasano
- Division of Pediatric Gastroenterology and Nutrition, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital for Children, Boston, MA, United States
- Division of Pediatric Gastroenterology and Nutrition, Center for Celiac Research and Treatment, Massachusetts General Hospital for Children, Boston, MA, United States
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17
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Hadders‐Algra M. Emerging signs of autism spectrum disorder in infancy: Putative neural substrate. Dev Med Child Neurol 2022; 64:1344-1350. [PMID: 35801808 PMCID: PMC9796067 DOI: 10.1111/dmcn.15333] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 12/30/2022]
Abstract
Autism spectrum disorder (ASD) is characterized by altered development of the social brain with prominent atypical features in the fronto-temporo-parietal cortex and cerebellum. Early signs of ASD emerge between 6 and 12 months: reduced social communication, slightly less advanced motor development, and repetitive behaviour. The fronto-temporo-parietal cortex and cerebellum play a prominent role in the development of social communication, whereas fronto-parietal-cerebellar networks are involved in the planning of movements, that is, movement selection. Atypical sensory responsivity, a core feature of ASD, may result in impaired development of social communication and motor skills and/or selection of atypical repetitive behaviour. In the first postnatal year, the brain areas involved are characterized by gradual dissolution of temporary structures: the fronto-temporo-parietal cortical subplate and cerebellar external granular layer. It is hypothesized that altered dissolution of the transient structures opens the window for the expression of early signs of ASD arising in the impaired developing permanent networks. WHAT THIS PAPER ADDS: The early social and motor signs of autism spectrum disorder emerge between the ages of 6 and 12 months. Altered dissolution of transient brain structures in the fronto-temporo-parietal cortex and cerebellum may underlie the emergence of these early signs.
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Affiliation(s)
- Mijna Hadders‐Algra
- University of Groningen, University Medical Center GroningenDepartment of Paediatrics, Section of Developmental NeurologyGroningenthe Netherlands,University of Groningen, Faculty of Theology and Religious StudiesGroningenthe Netherlands
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18
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Polese D, Riccio ML, Fagioli M, Mazzetta A, Fagioli F, Parisi P, Fagioli M. The Newborn's Reaction to Light as the Determinant of the Brain's Activation at Human Birth. Front Integr Neurosci 2022; 16:933426. [PMID: 36118115 PMCID: PMC9478760 DOI: 10.3389/fnint.2022.933426] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 06/16/2022] [Indexed: 11/13/2022] Open
Abstract
Developmental neuroscience research has not yet fully unveiled the dynamics involved in human birth. The trigger of the first breath, often assumed to be the marker of human life, has not been characterized nor has the process entailing brain modification and activation at birth been clarified yet. To date, few researchers only have investigated the impact of the extrauterine environment, with its strong stimuli, on birth. This ‘hypothesis and theory' article assumes the role of a specific stimulus activating the central nervous system (CNS) at human birth. This stimulus must have specific features though, such as novelty, efficacy, ubiquity, and immediacy. We propose light as a robust candidate for the CNS activation via the retina. Available data on fetal and neonatal neurodevelopment, in particular with reference to retinal light-responsive pathways, will be examined together with the GABA functional switch, and the subplate disappearance, which, at an experimental level, differentiate the neonatal brain from the fetal brain. In this study, we assume how a very rapid activation of retinal photoreceptors at birth initiates a sudden brain shift from the prenatal pattern of functions to the neonatal setup. Our assumption implies the presence of a photoreceptor capable of capturing and transducing light/photon stimulus, transforming it into an effective signal for the activation of new brain functions at birth. Opsin photoreception or, more specifically, melanopsin-dependent photoreception, which is provided by intrinsically photosensitive retinal ganglion cells (ipRGCs), is considered as a valid candidate. Although what is assumed herein cannot be verified in humans based on knowledge available so far, proposing an important and novel function can trigger a broad range of diversified research in different domains, from neurophysiology to neurology and psychiatry.
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Affiliation(s)
- Daniela Polese
- PhD Program on Sensorineural Plasticity, Department of Neuroscience, Mental Health and Sensory Organs NESMOS, Sant'Andrea Hospital, Sapienza University of Rome, Rome, Italy
- *Correspondence: Daniela Polese
| | | | - Marcella Fagioli
- Department of Mental Health, National Health System ASL Rome 1, Rome, Italy
| | - Alessandro Mazzetta
- PhD Program on Neuroscience, Department of Systems Medicine, Tor Vergata University, Rome, Italy
| | - Francesca Fagioli
- Department of Mental Health, National Health System ASL Rome 1, Rome, Italy
| | - Pasquale Parisi
- Chair of Pediatrics, Department of Neuroscience, Mental Health and Sensory Organs NESMOS, Sant'Andrea Hospital, Sapienza University of Rome, Rome, Italy
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19
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Ben-Simon Y, Kaefer K, Velicky P, Csicsvari J, Danzl JG, Jonas P. A direct excitatory projection from entorhinal layer 6b neurons to the hippocampus contributes to spatial coding and memory. Nat Commun 2022; 13:4826. [PMID: 35974109 PMCID: PMC9381769 DOI: 10.1038/s41467-022-32559-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 08/03/2022] [Indexed: 11/08/2022] Open
Abstract
The mammalian hippocampal formation (HF) plays a key role in several higher brain functions, such as spatial coding, learning and memory. Its simple circuit architecture is often viewed as a trisynaptic loop, processing input originating from the superficial layers of the entorhinal cortex (EC) and sending it back to its deeper layers. Here, we show that excitatory neurons in layer 6b of the mouse EC project to all sub-regions comprising the HF and receive input from the CA1, thalamus and claustrum. Furthermore, their output is characterized by unique slow-decaying excitatory postsynaptic currents capable of driving plateau-like potentials in their postsynaptic targets. Optogenetic inhibition of the EC-6b pathway affects spatial coding in CA1 pyramidal neurons, while cell ablation impairs not only acquisition of new spatial memories, but also degradation of previously acquired ones. Our results provide evidence of a functional role for cortical layer 6b neurons in the adult brain.
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Affiliation(s)
- Yoav Ben-Simon
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria.
- Department of Neurophysiology and Pharmacology, Vienna Medical University, Vienna, Austria.
| | - Karola Kaefer
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
- Department of Neuroinformatics, Radboud University, Nijmegen, The Netherlands
| | - Philipp Velicky
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Jozsef Csicsvari
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Johann G Danzl
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Peter Jonas
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
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20
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Genescu I, Aníbal-Martínez M, Kouskoff V, Chenouard N, Mailhes-Hamon C, Cartonnet H, Lokmane L, Rijli FM, López-Bendito G, Gambino F, Garel S. Dynamic interplay between thalamic activity and Cajal-Retzius cells regulates the wiring of cortical layer 1. Cell Rep 2022; 39:110667. [PMID: 35417707 PMCID: PMC9035679 DOI: 10.1016/j.celrep.2022.110667] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/17/2022] [Accepted: 03/18/2022] [Indexed: 11/30/2022] Open
Abstract
Cortical wiring relies on guidepost cells and activity-dependent processes that are thought to act sequentially. Here, we show that the construction of layer 1 (L1), a main site of top-down integration, is regulated by crosstalk between transient Cajal-Retzius cells (CRc) and spontaneous activity of the thalamus, a main driver of bottom-up information. While activity was known to regulate CRc migration and elimination, we found that prenatal spontaneous thalamic activity and NMDA receptors selectively control CRc early density, without affecting their demise. CRc density, in turn, regulates the distribution of upper layer interneurons and excitatory synapses, thereby drastically impairing the apical dendrite activity of output pyramidal neurons. In contrast, postnatal sensory-evoked activity had a limited impact on L1 and selectively perturbed basal dendrites synaptogenesis. Collectively, our study highlights a remarkable interplay between thalamic activity and CRc in L1 functional wiring, with major implications for our understanding of cortical development. Prenatal thalamic waves of activity regulate CRc density in L1 Prenatal and postnatal CRc manipulations alter specific interneuron populations Postnatal CRc shape L5 apical dendrite structural and functional properties Early sensory activity selectively regulates L5 basal dendrite spine formation
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Affiliation(s)
- Ioana Genescu
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Mar Aníbal-Martínez
- Instituto de Neurosciencias de Alicante, Universidad Miguel Hernandez, Sant Joan d'Alacant, Spain
| | - Vladimir Kouskoff
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS UMR 5297, 33000 Bordeaux, France
| | - Nicolas Chenouard
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS UMR 5297, 33000 Bordeaux, France
| | - Caroline Mailhes-Hamon
- Acute Transgenesis Facility, Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Université Paris, 75005 Paris, France
| | - Hugues Cartonnet
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Ludmilla Lokmane
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Filippo M Rijli
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; University of Basel, 4056 Basel, Switzerland
| | | | - Frédéric Gambino
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS UMR 5297, 33000 Bordeaux, France
| | - Sonia Garel
- Institut de Biologie de l'École Normale Supérieure (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France; Collège de France, 75005 Paris, France.
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21
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Lee KG, Rajakumar N. Partial ablation of frontal cortical subplate leads to developmental abnormalities in KCC2 in the prefrontal cortex. Mol Cell Neurosci 2022; 120:103733. [DOI: 10.1016/j.mcn.2022.103733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 04/20/2022] [Accepted: 04/23/2022] [Indexed: 10/18/2022] Open
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22
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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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23
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Hedderich DM, Menegaux A, Li H, Schmitz-Koep B, Stämpfli P, Bäuml JG, Berndt MT, Bäuerlein FJB, Grothe MJ, Dyrba M, Avram M, Boecker H, Daamen M, Zimmer C, Bartmann P, Wolke D, Sorg C. Aberrant Claustrum Microstructure in Humans after Premature Birth. Cereb Cortex 2021; 31:5549-5559. [PMID: 34171095 DOI: 10.1093/cercor/bhab178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 04/28/2021] [Accepted: 05/19/2021] [Indexed: 01/01/2023] Open
Abstract
Several observations suggest an impact of prematurity on the claustrum. First, the claustrum's development appears to depend on transient subplate neurons of intra-uterine brain development, which are affected by prematurity. Second, the claustrum is the most densely connected region of the mammalian forebrain relative to its volume; due to its effect on pre-oligodendrocytes, prematurity impacts white matter connections and thereby the development of sources and targets of such connections, potentially including the claustrum. Third, due to its high connection degree, the claustrum contributes to general cognitive functioning (e.g., selective attention and task switching/maintaining); general cognitive functioning, however, is at risk in prematurity. Thus, we hypothesized altered claustrum structure after premature birth, with these alterations being associated with impaired general cognitive performance in premature born persons. Using T1-weighted and diffusion-weighted magnetic resonance imaging in 70 very preterm/very low-birth-weight (VP/VLBW) born adults and 87 term-born adults, we found specifically increased mean diffusivity in the claustrum of VP/VLBW adults, associated both with low birth weight and at-trend with reduced IQ. This result demonstrates altered claustrum microstructure after premature birth. Data suggest aberrant claustrum development, which is potentially related with aberrant subplate neuron and forebrain connection development of prematurity.
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Affiliation(s)
- Dennis M Hedderich
- Department of Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
| | - Aurore Menegaux
- Department of Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
| | - Hongwei Li
- Department of Informatics, Technical University of Munich, 85748 Garching, Germany
| | - Benita Schmitz-Koep
- Department of Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
| | - Philipp Stämpfli
- MR-Center of the Psychiatric Hospital and the Department of Child and Adolescent Psychiatry, University of Zurich, 8032 Zurich, Switzerland
| | - Josef G Bäuml
- Department of Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
| | - Maria T Berndt
- Department of Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
| | - Felix J B Bäuerlein
- Max Planck Institute of Biochemistry, Department of Molecular Structural Biology, 82152 Martinsried, Germany
| | - Michel J Grothe
- German Center for Neurodegenerative Diseases (DZNE), Site Rostock/Greifswald, 18147 Rostock, Germany.,Unidad de Trastornos del Movimiento, Servicio de Neurología y Neurofisiología Clínica, Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain
| | - Martin Dyrba
- German Center for Neurodegenerative Diseases (DZNE), Site Rostock/Greifswald, 18147 Rostock, Germany
| | - Mihai Avram
- Department of Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany.,Department of Psychiatry, Psychosomatics and Psychotherapy, Schleswig Holstein University Hospital, University Lübeck, 23538 Lübeck, Germany
| | - Henning Boecker
- Functional Neuroimaging Group, Department of Diagnostic and Interventional Radiology, University Hospital Bonn, 53127 Bonn, Germany
| | - Marcel Daamen
- Functional Neuroimaging Group, Department of Diagnostic and Interventional Radiology, University Hospital Bonn, 53127 Bonn, Germany.,Department of Neonatology, University Hospital Bonn, 53127 Bonn, Germany
| | - Claus Zimmer
- Department of Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
| | - Peter Bartmann
- Department of Neonatology, University Hospital Bonn, 53127 Bonn, Germany
| | - Dieter Wolke
- Department of Psychology, University of Warwick, CV4 7AL, Coventry, UK.,Warwick Medical School, University of Warwick, CV4 7AL, Coventry, UK
| | - Christian Sorg
- Department of Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany.,Department of Psychiatry, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
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Xing W, de Lima AD, Voigt T. The Structural E/I Balance Constrains the Early Development of Cortical Network Activity. Front Cell Neurosci 2021; 15:687306. [PMID: 34349623 PMCID: PMC8326976 DOI: 10.3389/fncel.2021.687306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/17/2021] [Indexed: 01/03/2023] Open
Abstract
Neocortical networks have a characteristic constant ratio in the number of glutamatergic projection neurons (PN) and GABAergic interneurons (IN), and deviations in this ratio are often associated with developmental neuropathologies. Cultured networks with defined cellular content allowed us to ask if initial PN/IN ratios change the developmental population dynamics, and how different ratios impact the physiological excitatory/inhibitory (E/I) balance and the network activity development. During the first week in vitro, the IN content modulated PN numbers, increasing their proliferation in networks with higher IN proportions. The proportion of INs in each network set remained similar to the initial plating ratio during the 4 weeks cultivation period. Results from additional networks generated with more diverse cellular composition, including early-born GABA neurons, suggest that a GABA-dependent mechanism may decrease the survival of additional INs. A large variation of the PN/IN ratio did not change the balance between isolated spontaneous glutamatergic and GABAergic postsynaptic currents charge transfer (E/I balance) measured in PNs or INs. In contrast, the E/I balance of multisynaptic bursts reflected differences in IN content. Additionally, the spontaneous activity recorded by calcium imaging showed that higher IN ratios were associated with increased frequency of network bursts combined with a decrease of participating neurons per event. In the 4th week in vitro, bursting activity was stereotypically synchronized in networks with very few INs but was more desynchronized in networks with higher IN proportions. These results suggest that the E/I balance of isolated postsynaptic currents in single cells may be regulated independently of PN/IN proportions, but the network bursts E/I balance and the maturation of spontaneous network activity critically depends upon the structural PN/IN ratio.
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Affiliation(s)
- Wenxi Xing
- Medizinische Fakultät, Institut für Physiologie, Otto-von-Guericke Universität, Magdeburg, Germany
| | - Ana Dolabela de Lima
- Medizinische Fakultät, Institut für Physiologie, Otto-von-Guericke Universität, Magdeburg, Germany
| | - Thomas Voigt
- Medizinische Fakultät, Institut für Physiologie, Otto-von-Guericke Universität, Magdeburg, Germany
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Abstract
By evaluating children with a malformed cerebral cortex, we identified an ATPase pump (ATP1A3) with an early role in brain development. The ATP1A3 pump maintains the physiological concentration of sodium and potassium ions in cells, a process critical for osmotic equilibrium and membrane potential across several developing cell populations. We employed single-cell sequencing approaches to identify key enrichments for ATP1A3 expression during human cortex development. Unravelling this early cell-type–specific pathophysiology in the developing brain offers a potential basis for the treatment of ATP1A3-related diseases affecting prenatal and early childhood development. Osmotic equilibrium and membrane potential in animal cells depend on concentration gradients of sodium (Na+) and potassium (K+) ions across the plasma membrane, a function catalyzed by the Na+,K+-ATPase α-subunit. Here, we describe ATP1A3 variants encoding dysfunctional α3-subunits in children affected by polymicrogyria, a developmental malformation of the cerebral cortex characterized by abnormal folding and laminar organization. To gain cell-biological insights into the spatiotemporal dynamics of prenatal ATP1A3 expression, we built an ATP1A3 transcriptional atlas of fetal cortical development using mRNA in situ hybridization and transcriptomic profiling of ∼125,000 individual cells with single-cell RNA sequencing (Drop-seq) from 11 areas of the midgestational human neocortex. We found that fetal expression of ATP1A3 is most abundant to a subset of excitatory neurons carrying transcriptional signatures of the developing subplate, yet also maintains expression in nonneuronal cell populations. Moving forward a year in human development, we profiled ∼52,000 nuclei from four areas of an infant neocortex and show that ATP1A3 expression persists throughout early postnatal development, most predominantly in inhibitory neurons, including parvalbumin interneurons in the frontal cortex. Finally, we discovered the heteromeric Na+,K+-ATPase pump complex may form nonredundant cell-type–specific α-β isoform combinations, including α3-β1 in excitatory neurons and α3-β2 in inhibitory neurons. Together, the developmental malformation phenotype of affected individuals and single-cell ATP1A3 expression patterns point to a key role for α3 in human cortex development, as well as a cell-type basis for pre- and postnatal ATP1A3-associated diseases.
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Supernumerary neurons within the cerebral cortical subplate in autism spectrum disorders. Brain Res 2021; 1760:147350. [PMID: 33607045 DOI: 10.1016/j.brainres.2021.147350] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 12/11/2022]
Abstract
Autism spectrum disorders (ASDs) involve alterations to cortical connectivity that manifest as reduced coordinated activity between cortical regions. The neurons of the cortical subplate are a major contributor to establishing thalamocortical, corticothalamic and corticocortical long-range connections and only a subset of this cell population survives into adulthood. Previous reports of an indistinct gray-white matter boundary in subjects with ASD suggest that the adjacent subplate may also show organizational abnormalities. Frozen human postmortem tissue samples from the parietal lobe (BA7) were used to evaluate white-matter neuron densities adjacent to layer VI with an antibody to NeuN. In addition, fixed postmortem tissue samples from frontal (BA9), parietal (BA7) and temporal lobe (BA21) locations, were stained with a Golgi-Kopsch procedure, and used to examine the morphology of these neuronal profiles. Relative to control cases, ASD subjects showed a large average density increase of NeuN-positive profiles of 44.7 percent. The morphologies of these neurons were consistent with subplate cells of the fusiform, polymorphic and pyramidal cell types. Lower ratios of fusiform to other cell types are found early in development and although adult ASD subjects showed consistently lower ratios, these differences were not significant. The increased number of retained subplate profiles, along with cell type ratios redolent of earlier developmental stages, suggests either an abnormal initial population or a partial failure of the apoptosis seen in neurotypical development. These results indicate abnormalities within a neuron population that plays multiple roles in the developing and mature cerebral cortex, including the establishment of long-range cortical connections.
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Tsai SH, Tsao CY, Lee LJ. Altered White Matter and Layer VIb Neurons in Heterozygous Disc1 Mutant, a Mouse Model of Schizophrenia. Front Neuroanat 2020; 14:605029. [PMID: 33384588 PMCID: PMC7769951 DOI: 10.3389/fnana.2020.605029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/24/2020] [Indexed: 11/13/2022] Open
Abstract
Increased white matter neuron density has been associated with neuropsychiatric disorders including schizophrenia. However, the pathogenic features of these neurons are still largely unknown. Subplate neurons, the earliest generated neurons in the developing cortex have also been associated with schizophrenia and autism. The link between these neurons and mental disorders is also not well established. Since cortical layer VIb neurons are believed to be the remnant of subplate neurons in the adult rodent brain, in this study, we aimed to examine the cytoarchitecture of neurons in cortical layer VIb and the underlying white matter in heterozygous Disc1 mutant (Het) mice, a mouse model of schizophrenia. In the white matter, the number of NeuN-positive neurons was quite low in the external capsule; however, the density of these cells was found increased (54%) in Het mice compared with wildtype (WT) littermates. The density of PV-positive neurons was unchanged in the mutants. In the cortical layer VIb, the density of CTGF-positive neurons increased (21.5%) in Het mice, whereas the number of Cplx3-positive cells reduced (16.1%) in these mutants, compared with WT mice. Layer VIb neurons can be classified by their morphological characters. The morphology of Type I pyramidal neurons was comparable between genotypes while the dendritic length and complexity of Type II multipolar neurons were significantly reduced in Het mice. White matter neurons and layer VIb neurons receive synaptic inputs and modulate the process of sensory information and sleep/arousal pattern. Aberrances of these neurons in Disc1 mutants implies altered brain functions in these mice.
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Affiliation(s)
- Shin-Hwa Tsai
- School of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chih-Yu Tsao
- Graduate Institute of Anatomy and Cell Biology, National Taiwan University, Taipei, Taiwan
| | - Li-Jen Lee
- School of Medicine, National Taiwan University, Taipei, Taiwan
- Graduate Institute of Anatomy and Cell Biology, National Taiwan University, Taipei, Taiwan
- Institute of Brain and Mind Sciences, National Taiwan University, Taipei, Taiwan
- Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan
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Abstract
Brain structures change shape dramatically during development. Elucidating the mechanisms of morphogenesis provides insights relevant to understanding brain function in health and disease. The tension-based morphogenesis (TBM) hypothesis posits that mechanical tension along axons, dendrites, and glial processes contributes to many aspects of central nervous system morphogenesis. Since TBM was proposed in 1997, extensive evidence supports a role for tension in diverse cellular phenomena, but tension’s role in cortical folding has been controversial. An extensively revised version of the TBM model for cerebral cortex addresses limitations of the original model, incorporates new features, and can be tested by many experimental approaches. For cerebellar cortex, a revised model accounts for many aspects of its development and adult architecture. Mechanical tension along the length of axons, dendrites, and glial processes has been proposed as a major contributor to morphogenesis throughout the nervous system [D. C. Van Essen, Nature 385, 313–318 (1997)]. Tension-based morphogenesis (TBM) is a conceptually simple and general hypothesis based on physical forces that help shape all living things. Moreover, if each axon and dendrite strive to shorten while preserving connectivity, aggregate wiring length would remain low. TBM can explain key aspects of how the cerebral and cerebellar cortices remain thin, expand in surface area, and acquire their distinctive folds. This article reviews progress since 1997 relevant to TBM and other candidate morphogenetic mechanisms. At a cellular level, studies of diverse cell types in vitro and in vivo demonstrate that tension plays a major role in many developmental events. At a tissue level, I propose a differential expansion sandwich plus (DES+) revision to the original TBM model for cerebral cortical expansion and folding. It invokes tangential tension and “sulcal zipping” forces along the outer cortical margin as well as tension in the white matter core, together competing against radially biased tension in the cortical gray matter. Evidence for and against the DES+ model is discussed, and experiments are proposed to address key tenets of the DES+ model. For cerebellar cortex, a cerebellar multilayer sandwich (CMS) model is proposed that can account for many distinctive features, including its unique, accordion-like folding in the adult, and experiments are proposed to address its specific tenets.
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Genescu I, Garel S. Being superficial: a developmental viewpoint on cortical layer 1 wiring. Curr Opin Neurobiol 2020; 66:125-134. [PMID: 33186879 DOI: 10.1016/j.conb.2020.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/03/2020] [Accepted: 10/04/2020] [Indexed: 01/01/2023]
Abstract
Functioning of the neocortex relies on a complex architecture of circuits, as illustrated by the causal link between neocortical excitation/inhibition imbalance and the etiology of several neurodevelopmental disorders. An important entry point to cortical circuits is located in the superficial layer 1 (L1), which contains mostly local and long-range inputs and sparse inhibitory interneurons that collectively regulate cerebral functions. While increasing evidence indicates that L1 has important physiological roles, our understanding of how it wires up during development remains limited. Here, we provide an integrated overview of L1 anatomy, function and development, with a focus on transient early born Cajal-Retzius neurons, and highlight open questions key for progressing our understanding of this essential yet understudied layer of the cerebral cortex.
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Affiliation(s)
- Ioana Genescu
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, 75005 Paris, France
| | - Sonia Garel
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, 75005 Paris, France; Collège de France, Paris, France.
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30
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Wallois F, Routier L, Heberlé C, Mahmoudzadeh M, Bourel-Ponchel E, Moghimi S. Back to basics: the neuronal substrates and mechanisms that underlie the electroencephalogram in premature neonates. Neurophysiol Clin 2020; 51:5-33. [PMID: 33162287 DOI: 10.1016/j.neucli.2020.10.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/05/2020] [Accepted: 10/05/2020] [Indexed: 02/06/2023] Open
Abstract
Electroencephalography is the only clinically available technique that can address the premature neonate normal and pathological functional development week after week. The changes in the electroencephalogram (EEG) result from gradual structural and functional modifications that arise during the last trimester of pregnancy. Here, we review the structural changes over time that underlie the establishment of functional immature neural networks, the impact of certain anatomical specificities (fontanelles, connectivity, etc.) on the EEG, limitations in EEG interpretation, and the utility of high-resolution EEG (HR-EEG) in premature newborns (a promising technique with a high degree of spatiotemporal resolution). In particular, we classify EEG features according to whether they are manifestations of endogenous generators (i.e. theta activities that coalesce with a slow wave or delta brushes) or come from a broader network. Furthermore, we review publications on EEG in premature animals because the data provide a better understanding of what is happening in premature newborns. We then discuss the results and limitations of functional connectivity analyses in premature newborns. Lastly, we report on the magnetoelectroencephalographic studies of brain activity in the fetus. A better understanding of complex interactions at various structural and functional levels during normal neurodevelopment (as assessed using electroencephalography as a benchmark method) might lead to better clinical care and monitoring for premature neonates.
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Affiliation(s)
- Fabrice Wallois
- INSERM U1105, Research Group on Multimodal Analysis of Brain Function, Jules Verne University of Picardie, Amiens, France; Service d'Explorations Fonctionnelles du Système Nerveux Pédiatrique, Amiens-Picardie Medical Center, Amiens, France.
| | - Laura Routier
- INSERM U1105, Research Group on Multimodal Analysis of Brain Function, Jules Verne University of Picardie, Amiens, France; Service d'Explorations Fonctionnelles du Système Nerveux Pédiatrique, Amiens-Picardie Medical Center, Amiens, France
| | - Claire Heberlé
- INSERM U1105, Research Group on Multimodal Analysis of Brain Function, Jules Verne University of Picardie, Amiens, France; Service d'Explorations Fonctionnelles du Système Nerveux Pédiatrique, Amiens-Picardie Medical Center, Amiens, France
| | - Mahdi Mahmoudzadeh
- INSERM U1105, Research Group on Multimodal Analysis of Brain Function, Jules Verne University of Picardie, Amiens, France; Service d'Explorations Fonctionnelles du Système Nerveux Pédiatrique, Amiens-Picardie Medical Center, Amiens, France
| | - Emilie Bourel-Ponchel
- INSERM U1105, Research Group on Multimodal Analysis of Brain Function, Jules Verne University of Picardie, Amiens, France; Service d'Explorations Fonctionnelles du Système Nerveux Pédiatrique, Amiens-Picardie Medical Center, Amiens, France
| | - Sahar Moghimi
- INSERM U1105, Research Group on Multimodal Analysis of Brain Function, Jules Verne University of Picardie, Amiens, France; Service d'Explorations Fonctionnelles du Système Nerveux Pédiatrique, Amiens-Picardie Medical Center, Amiens, France
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31
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Luhmann HJ, Fukuda A. Can we understand human brain development from experimental studies in rodents? Pediatr Int 2020; 62:1139-1144. [PMID: 32531857 DOI: 10.1111/ped.14339] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/05/2020] [Accepted: 05/22/2020] [Indexed: 12/12/2022]
Abstract
Animal models are needed to gain an understanding of the genetic, molecular, cellular, and network mechanisms of human brain development. In rodents, a large spectrum of in vitro and in vivo approaches allows detailed analyses and specific experimental manipulations for studying the sequence of developmental steps in corticogenesis. Neurogenesis, neuronal migration, cellular differentiation, programmed cell death, synaptogenesis, and myelination are surprisingly similar in the rodent cortex and the human cortex. Spontaneous EEG activity in the pre- and early postnatal human cortex resembles the activity patterns recorded with intracortical multi-electrode arrays in newborn rodents. This early activity is generated by thalamic activation of a subplate-driven local network coupled via gap junctions, which controls the development of cortical columns and the spatio-temporal pattern of apoptosis. Disturbances of this activity may induce disturbances in cortical structure and function leading to neurological and psychiatric disorders.
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Affiliation(s)
- Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Atsuo Fukuda
- Department of Physiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
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Medvedeva VP, Pierani A. How Do Electric Fields Coordinate Neuronal Migration and Maturation in the Developing Cortex? Front Cell Dev Biol 2020; 8:580657. [PMID: 33102486 PMCID: PMC7546860 DOI: 10.3389/fcell.2020.580657] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/04/2020] [Indexed: 12/13/2022] Open
Abstract
During development the vast majority of cells that will later compose the mature cerebral cortex undergo extensive migration to reach their final position. In addition to intrinsically distinct migratory behaviors, cells encounter and respond to vastly different microenvironments. These range from axonal tracts to cell-dense matrices, electrically active regions and extracellular matrix components, which may all change overtime. Furthermore, migrating neurons themselves not only adapt to their microenvironment but also modify the local niche through cell-cell contacts, secreted factors and ions. In the radial dimension, the developing cortex is roughly divided into dense progenitor and cortical plate territories, and a less crowded intermediate zone. The cortical plate is bordered by the subplate and the marginal zone, which are populated by neurons with high electrical activity and characterized by sophisticated neuritic ramifications. Neuronal migration is influenced by these boundaries resulting in dramatic changes in migratory behaviors as well as morphology and electrical activity. Modifications in the levels of any of these parameters can lead to alterations and even arrest of migration. Recent work indicates that morphology and electrical activity of migrating neuron are interconnected and the aim of this review is to explore the extent of this connection. We will discuss on one hand how the response of migrating neurons is altered upon modification of their intrinsic electrical properties and whether, on the other hand, the electrical properties of the cellular environment can modify the morphology and electrical activity of migrating cortical neurons.
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Affiliation(s)
- Vera P Medvedeva
- Imagine Institute of Genetic Diseases, Université de Paris, Paris, France.,Institute of Psychiatry and Neuroscience of Paris, INSERM U1266, Université de Paris, Paris, France
| | - Alessandra Pierani
- Imagine Institute of Genetic Diseases, Université de Paris, Paris, France.,Institute of Psychiatry and Neuroscience of Paris, INSERM U1266, Université de Paris, Paris, France
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Family nurture intervention alters relationships between preterm infant EEG delta brush characteristics and term age EEG power. Clin Neurophysiol 2020; 131:1909-1916. [PMID: 32599274 DOI: 10.1016/j.clinph.2020.05.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 04/21/2020] [Accepted: 05/01/2020] [Indexed: 01/21/2023]
Abstract
OBJECTIVE Family Nurture Intervention (FNI) facilitates mother/infant emotional connection, improves neurodevelopmental outcomes and increases electroencephalogram (EEG) power at term age. Here we explored whether delta brushes (DB), early EEG bursts that shape brain development, are altered by FNI and mediate later effects of FNI on EEG. METHODS We assessed DB characteristics in EEG data from a randomized controlled trial comparing infants with standard care (SC, n = 31) versus SC + FNI (n = 33) at ~35 and ~40 weeks GA. RESULTS Compared to SC infants, FNI infant DB amplitude increased more from ~35 to ~40 weeks, and FNI infants had longer duration DBs. DB parameters (rate, amplitude, brush frequency) at ~35 weeks were correlated with power at ~40 weeks, but only in SC infants. FNI effects on DB parameters do not mediate FNI effects on EEG power or coherence at term. CONCLUSIONS DBs are related to subsequent brain activity and FNI alters DB parameters. However, FNI's effects on electrocortical activity at term age are not dependent on its earlier effects on DBs. SIGNIFICANCE While early DBs can have important effects on later brain activity in preterm infants, facilitating emotional connection with FNI may allow brain maturation to be less dependent on early bursts.
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Prodromidou K, Vlachos IS, Gaitanou M, Kouroupi G, Hatzigeorgiou AG, Matsas R. MicroRNA-934 is a novel primate-specific small non-coding RNA with neurogenic function during early development. eLife 2020; 9:e50561. [PMID: 32459171 PMCID: PMC7295570 DOI: 10.7554/elife.50561] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 05/21/2020] [Indexed: 12/12/2022] Open
Abstract
Integrating differential RNA and miRNA expression during neuronal lineage induction of human embryonic stem cells we identified miR-934, a primate-specific miRNA that displays a stage-specific expression pattern during progenitor expansion and early neuron generation. We demonstrate the biological relevance of this finding by comparison with data from early to mid-gestation human cortical tissue. Further we find that miR-934 directly controls progenitor to neuroblast transition and impacts on neurite growth of newborn neurons. In agreement, miR-934 targets are involved in progenitor proliferation and neuronal differentiation whilst miR-934 inhibition results in profound global transcriptome changes associated with neurogenesis, axonogenesis, neuronal migration and neurotransmission. Interestingly, miR-934 inhibition affects the expression of genes associated with the subplate zone, a transient compartment most prominent in primates that emerges during early corticogenesis. Our data suggest that mir-934 is a novel regulator of early human neurogenesis with potential implications for a species-specific evolutionary role in brain function.
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Affiliation(s)
- Kanella Prodromidou
- Laboratory of Cellular and Molecular Neurobiology-Stem Cells, Department of Neurobiology, Hellenic Pasteur InstituteAthensGreece
| | - Ioannis S Vlachos
- Department of Pathology, Beth Israel Deaconess Medical CenterBostonUnited States
- DIANA-Lab, Hellenic Pasteur InstituteAthensGreece
- Harvard Medical SchoolBostonUnited States
- Broad Institute of MIT and HarvardCambridgeUnited States
| | - Maria Gaitanou
- Laboratory of Cellular and Molecular Neurobiology-Stem Cells, Department of Neurobiology, Hellenic Pasteur InstituteAthensGreece
| | - Georgia Kouroupi
- Laboratory of Cellular and Molecular Neurobiology-Stem Cells, Department of Neurobiology, Hellenic Pasteur InstituteAthensGreece
| | | | - Rebecca Matsas
- Laboratory of Cellular and Molecular Neurobiology-Stem Cells, Department of Neurobiology, Hellenic Pasteur InstituteAthensGreece
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Kocovic DM, Limaye PV, Colburn LCH, Singh MB, Milosevic MM, Tadic J, Petronijevic M, Vrzic-Petronijevic S, Andjus PR, Antic SD. Cadmium versus Lanthanum Effects on Spontaneous Electrical Activity and Expression of Connexin Isoforms Cx26, Cx36, and Cx45 in the Human Fetal Cortex. Cereb Cortex 2020; 30:1244-1259. [PMID: 31408166 PMCID: PMC7132928 DOI: 10.1093/cercor/bhz163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/25/2019] [Accepted: 06/25/2019] [Indexed: 12/29/2022] Open
Abstract
Electrical activity is important for brain development. In brain slices, human subplate neurons exhibit spontaneous electrical activity that is highly sensitive to lanthanum. Based on the results of pharmacological experiments in human fetal tissue, we hypothesized that hemichannel-forming connexin (Cx) isoforms 26, 36, and 45 would be expressed on neurons in the subplate (SP) zone. RNA sequencing of dissected human cortical mantles at ages of 17-23 gestational weeks revealed that Cx45 has the highest expression, followed by Cx36 and Cx26. The levels of Cx and pannexin expression between male and female fetal cortices were not significantly different. Immunohistochemical analysis detected Cx45- and Cx26-expressing neurons in the upper segment of the SP zone. Cx45 was present on the cell bodies of human SP neurons, while Cx26 was found on both cell bodies and dendrites. Cx45, Cx36, and Cx26 were strongly expressed in the cortical plate, where newborn migrating neurons line up to form cortical layers. New information about the expression of 3 "neuronal" Cx isoforms in each cortical layer/zone (e.g., SP, cortical plate) and pharmacological data with cadmium and lanthanum may improve our understanding of the cellular mechanisms underlying neuronal development in human fetuses and potential vulnerabilities.
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Affiliation(s)
- Dusica M Kocovic
- Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
| | - Pallavi V Limaye
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Lauren C H Colburn
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Mandakini B Singh
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Milena M Milosevic
- Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Jasmina Tadic
- Faculty of Medicine, University of Belgrade, Belgrade 11000, Serbia
| | | | | | - Pavle R Andjus
- Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
| | - Srdjan D Antic
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
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Wallois F, Routier L, Bourel-Ponchel E. Impact of prematurity on neurodevelopment. HANDBOOK OF CLINICAL NEUROLOGY 2020; 173:341-375. [PMID: 32958184 DOI: 10.1016/b978-0-444-64150-2.00026-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The consequences of prematurity on brain functional development are numerous and diverse, and impact all brain functions at different levels. Prematurity occurs between 22 and 36 weeks of gestation. This period is marked by extreme dynamics in the physiologic maturation, structural, and functional processes. These different processes appear sequentially or simultaneously. They are dependent on genetic and/or environmental factors. Disturbance of these processes or of the fine-tuning between them, when caring for premature children, is likely to induce disturbances in the structural and functional development of the immature neural networks. These will appear as impairments in learning skills progress and are likely to have a lasting impact on the development of children born prematurely. The level of severity depends on the initial alteration, whether structural or functional. In this chapter, after having briefly reviewed the neurodevelopmental, structural, and functional processes, we describe, in a nonexhaustive manner, the impact of prematurity on the different brain, motor, sensory, and cognitive functions.
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Affiliation(s)
- Fabrice Wallois
- Research Group on Multimodal Analysis of Brain Function, Jules Verne Picardie University, Amiens, France; Department of Pediatric Functional Exploration of the Nervous System, University Hospital, Picardie, Amiens, France.
| | - Laura Routier
- Research Group on Multimodal Analysis of Brain Function, Jules Verne Picardie University, Amiens, France; Department of Pediatric Functional Exploration of the Nervous System, University Hospital, Picardie, Amiens, France
| | - Emilie Bourel-Ponchel
- Research Group on Multimodal Analysis of Brain Function, Jules Verne Picardie University, Amiens, France; Department of Pediatric Functional Exploration of the Nervous System, University Hospital, Picardie, Amiens, France
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Martínez-Méndez R, Pérez-Torres D, Gómez-Chavarín M, Padilla-Cortés P, Fiordelisio T, Gutiérrez-Ospina G. Bilateral enucleation at birth modifies calcium spike amplitude, but not frequency, in neurons of the somatosensory thalamus and cortex: Implications for developmental cross-modal plasticity. IBRO Rep 2019; 7:108-116. [PMID: 31799470 PMCID: PMC6881598 DOI: 10.1016/j.ibror.2019.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Accepted: 11/07/2019] [Indexed: 11/17/2022] Open
Abstract
Bilateral eye enucleation at birth (BE) leads to an expansion of the primary somatosensory cortex (S1) in rat pups. Although increased growth of the somatosensory thalamo-cortical afferents (STCAs) in part explains S1 expansion, timing mechanisms governing S1 formation are also involved. In this work, we begin the search of a developmental clock by intending to document the existence of putative clock neurons in the somatosensory thalamus (VPM) and S1 based upon changes of spontaneous spike amplitude; a biophysical property sensitive to circadian regulation; the latter known to be shifted by enucleation. In addition, we also evaluated whether STCAs growth rate and segregation timing were modified, as parameters the clock might time. We found that spontaneous spike amplitude transiently, but significantly, increased or decreased in VPM and S1 neurons of BE rat pups, respectively, as compared to their control counterparts. The growth rate and segregation timing of STCAs was, however, unaffected by BE. These results support the existence of a developmental clock that ticks differently in the VPM and S1 after BE. This observation, together with the fact that STCAs growth rate and segregation timing is unchanged, suggests that S1 expansion in BE rats may in part be controlled at the cortical level.
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Key Words
- ACSF, artificial cerebrospinal fluid
- AChE, acetylcholinesterase
- BE, birth-enucleated
- Barrel formation
- Blind
- CP, cortical plate
- DAPI, 4′,6-diamidino-2-phenylindole
- Developmental clock
- Developmental timing
- DiI, 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine Perchlorate
- PD, postnatal day
- S, sighted
- S1, primary somatosensory cortex
- SEM, standard error of the mean
- STCAs, somatosensory thalamo-cortical afferents
- Somatosensory cortex specification
- Spontaneous activity
- VPM, ventral posteromedial nucleus
- τd, decay time constant
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Affiliation(s)
- Raquel Martínez-Méndez
- Laboratorio de Biología de Sistemas, Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, 04510, Mexico
| | - Daniel Pérez-Torres
- Laboratorio de Biología de Sistemas, Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, 04510, Mexico
| | - Margarita Gómez-Chavarín
- Laboratorio de Biología de Sistemas, Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, 04510, Mexico
| | - Patricia Padilla-Cortés
- Unidad de Cromatografía de Alta Resolución, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, 04510, Mexico
| | - Tatiana Fiordelisio
- Laboratorio de Neuroendocrinología, Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad de México, 04510, Mexico
| | - Gabriel Gutiérrez-Ospina
- Laboratorio de Biología de Sistemas, Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, 04510, Mexico
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Leikos S, Tokariev A, Koolen N, Nevalainen P, Vanhatalo S. Cortical responses to tactile stimuli in preterm infants. Eur J Neurosci 2019; 51:1059-1073. [PMID: 31679163 DOI: 10.1111/ejn.14613] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 10/07/2019] [Accepted: 10/22/2019] [Indexed: 12/22/2022]
Abstract
The conventional assessment of preterm somatosensory functions using averaged cortical responses to electrical stimulation ignores the characteristic components of preterm somatosensory evoked responses (SERs). Our study aimed to systematically evaluate the occurrence and development of SERs after tactile stimulus in preterm infants. We analysed SERs performed during 45 electroencephalograms (EEGs) from 29 infants at the mean post-menstrual age of 30.7 weeks. Altogether 2,087 SERs were identified visually at single-trial level from unfiltered signals capturing also their slowest components. We observed salient SERs with a high-amplitude slow component at a high success rate after hand (95%) and foot (83%) stimuli. There was a clear developmental change in both the slow wave and the higher-frequency components of the SERs. Infants with intraventricular haemorrhage (IVH; eleven infants) had initially normal SERs, but those with bilateral IVH later showed a developmental decrease in the ipsilateral SER occurrence after 30 weeks of post-menstrual age. Our study shows that tactile stimulus applied at bedside elicits salient SERs with a large slow component and an overriding fast oscillation, which are specific to the preterm period. Prior experimental research indicates that such SERs allow studying both subplate and cortical functions. Our present findings further suggest that they might offer a window to the emergence of neurodevelopmental sequelae after major structural brain lesions and, hence, an additional tool for both research and clinical neurophysiological evaluation of infants before term age.
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Affiliation(s)
- Susanna Leikos
- Children's Clinical Neurophysiology, BABA Center, Children's Hospital, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Anton Tokariev
- Children's Clinical Neurophysiology, BABA Center, Children's Hospital, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Ninah Koolen
- Children's Clinical Neurophysiology, BABA Center, Children's Hospital, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Päivi Nevalainen
- Children's Clinical Neurophysiology, BABA Center, Children's Hospital, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Sampsa Vanhatalo
- Children's Clinical Neurophysiology, BABA Center, Children's Hospital, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
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Hedrich J, Angamo EA, Conrad A, Lutz B, Luhmann HJ. Cell type specific impact of cannabinoid receptor signaling in somatosensory barrel map formation in mice. J Comp Neurol 2019; 528:3-13. [PMID: 31226222 DOI: 10.1002/cne.24733] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 06/11/2019] [Accepted: 06/11/2019] [Indexed: 12/15/2022]
Abstract
Endocannabinoids and their receptors are highly abundant in the developing cerebral cortex and play major roles in early developmental processes, for example, neuronal proliferation, migration, and axonal guidance as well as postnatal plasticity. To investigate the role of the cannabinoid type 1 receptor (CB1) in the formation of sensory maps in the cerebral cortex, the topographic representation of the whiskers in the primary somatosensory cortex (barrel field) of adult mice with different cell type specific genetic deletion of CB1 was studied. A constitutive absence of CB1 (CB1-KO) significantly decreased the total area of the somatosensory cortical map, affecting barrel, and septal areas. Cell specific CB1 deletion in dorsal telencephalic glutamatergic neurons only (Glu-CB1-KO) or in both glutamatergic and forebrain GABAergic neurons (Glu/GABA-CB1-KO) resulted in an increased septa area in the barrel field map. No significant modifications in area parameters could be observed in GABA-CB1-KO mice. These data demonstrate that CB1 signaling especially in cortical glutamatergic neurons is essential for the development of topographic maps in the cerebral cortex.
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Affiliation(s)
- Jana Hedrich
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Eskedar A Angamo
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Andrea Conrad
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Beat Lutz
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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Tiong SYX, Oka Y, Sasaki T, Taniguchi M, Doi M, Akiyama H, Sato M. Kcnab1 Is Expressed in Subplate Neurons With Unilateral Long-Range Inter-Areal Projections. Front Neuroanat 2019; 13:39. [PMID: 31130851 PMCID: PMC6509479 DOI: 10.3389/fnana.2019.00039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/20/2019] [Indexed: 12/20/2022] Open
Abstract
Subplate (SP) neurons are among the earliest-born neurons in the cerebral cortex and heterogeneous in terms of gene expression. SP neurons consist mainly of projection neurons, which begin to extend their axons to specific target areas very early during development. However, the relationships between axon projection and gene expression patterns of the SP neurons, and their remnant layer 6b (L6b) neurons, are largely unknown. In this study, we analyzed the corticocortical projections of L6b/SP neurons in the mouse cortex and searched for a marker gene expressed in L6b/SP neurons that have ipsilateral inter-areal projections. Retrograde tracing experiments demonstrated that L6b/SP neurons in the primary somatosensory cortex (S1) projected to the primary motor cortex (M1) within the same cortical hemisphere at postnatal day (PD) 2 but did not show any callosal projection. This unilateral projection pattern persisted into adulthood. Our microarray analysis identified the gene encoding a β subunit of voltage-gated potassium channel (Kcnab1) as being expressed in L6b/SP. Double labeling with retrograde tracing and in situ hybridization demonstrated that Kcnab1 was expressed in the unilaterally-projecting neurons in L6b/SP. Embryonic expression was specifically detected in the SP as early as embryonic day (E) 14.5, shortly after the emergence of SP. Double immunostaining experiments revealed different degrees of co-expression of the protein product Kvβ1 with L6b/SP markers Ctgf (88%), Cplx3 (79%), and Nurr1 (58%), suggesting molecular subdivision of unilaterally-projecting L6b/SP neurons. In addition to expression in L6b/SP, scattered expression of Kcnab1 was observed during postnatal stages without layer specificity. Among splicing variants with three alternative first exons, the variant 1.1 explained all the cortical expression mentioned in this study. Together, our data suggest that L6b/SP neurons have corticocortical projections and Kcnab1 expression defines a subpopulation of L6b/SP neurons with a unilateral inter-areal projection.
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Affiliation(s)
- Sheena Yin Xin Tiong
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan.,Division of Developmental Neuroscience, Department of Child Development, United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Osaka, Japan.,Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Yuichiro Oka
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan.,Division of Developmental Neuroscience, Department of Child Development, United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Osaka, Japan.,Division of Cell Biology and Neuroscience, Department of Morphological and Physiological Sciences, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.,Research Center for Child Mental Development, University of Fukui, Fukui, Japan
| | - Tatsuya Sasaki
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Manabu Taniguchi
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Miyuki Doi
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Hisanori Akiyama
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Makoto Sato
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan.,Division of Developmental Neuroscience, Department of Child Development, United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Osaka, Japan.,Division of Cell Biology and Neuroscience, Department of Morphological and Physiological Sciences, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.,Research Center for Child Mental Development, University of Fukui, Fukui, Japan
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Kanold PO, Deng R, Meng X. The Integrative Function of Silent Synapses on Subplate Neurons in Cortical Development and Dysfunction. Front Neuroanat 2019; 13:41. [PMID: 31040772 PMCID: PMC6476909 DOI: 10.3389/fnana.2019.00041] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 03/26/2019] [Indexed: 12/20/2022] Open
Abstract
The thalamocortical circuit is of central importance in relaying information to the cortex. In development, subplate neurons (SPNs) form an integral part of the thalamocortical pathway. These early born cortical neurons are the first neurons to receive thalamic inputs and excite neurons in the cortical plate. This feed-forward circuit topology of SPNs supports the role of SPNs in shaping the formation and plasticity of thalamocortical connections. Recently it has been shown that SPNs also receive inputs from the developing cortical plate and project to the thalamus. The cortical inputs to SPNs in early ages are mediated by N-methyl-D-aspartate (NMDA)-receptor only containing synapses while at later ages α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-receptors are present. Thus, SPNs perform a changing integrative function over development. NMDA-receptor only synapses are crucially influenced by the resting potential and thus insults to the developing brain that causes depolarizations, e.g., hypoxia, can influence the integrative function of SPNs. Since such insults in humans cause symptoms of neurodevelopmental disorders, NMDA-receptor only synapses on SPNs might provide a crucial link between early injuries and later circuit dysfunction. We thus here review subplate associated circuits, their changing functions, and discuss possible roles in development and disease.
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Affiliation(s)
- Patrick O. Kanold
- Department of Biology, University of Maryland, College Park, MD, United States
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