1
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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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2
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Ledderose JMT, Zolnik TA, Toumazou M, Trimbuch T, Rosenmund C, Eickholt BJ, Jaeger D, Larkum ME, Sachdev RNS. Layer 1 of somatosensory cortex: an important site for input to a tiny cortical compartment. Cereb Cortex 2023; 33:11354-11372. [PMID: 37851709 PMCID: PMC10690867 DOI: 10.1093/cercor/bhad371] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 09/17/2023] [Indexed: 10/20/2023] Open
Abstract
Neocortical layer 1 has been proposed to be at the center for top-down and bottom-up integration. It is a locus for interactions between long-range inputs, layer 1 interneurons, and apical tuft dendrites of pyramidal neurons. While input to layer 1 has been studied intensively, the level and effect of input to this layer has still not been completely characterized. Here we examined the input to layer 1 of mouse somatosensory cortex with retrograde tracing and optogenetics. Our assays reveal that local input to layer 1 is predominantly from layers 2/3 and 5 pyramidal neurons and interneurons, and that subtypes of local layers 5 and 6b neurons project to layer 1 with different probabilities. Long-range input from sensory-motor cortices to layer 1 of somatosensory cortex arose predominantly from layers 2/3 neurons. Our optogenetic experiments showed that intra-telencephalic layer 5 pyramidal neurons drive layer 1 interneurons but have no effect locally on layer 5 apical tuft dendrites. Dual retrograde tracing revealed that a fraction of local and long-range neurons was both presynaptic to layer 5 neurons and projected to layer 1. Our work highlights the prominent role of local inputs to layer 1 and shows the potential for complex interactions between long-range and local inputs, which are both in position to modify the output of somatosensory cortex.
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Affiliation(s)
- Julia M T Ledderose
- Institute of Biology, Humboldt Universität zu Berlin, Charitéplatz 1, Virchowweg 6, 10117 Berlin, Germany
- Institute of Molecular Biology and Biochemistry, Charité—Universitätsmedizin Berlin, Charitéplatz 1, Virchowweg 6, 10117 Berlin, Germany
| | - Timothy A Zolnik
- Institute of Biology, Humboldt Universität zu Berlin, Charitéplatz 1, Virchowweg 6, 10117 Berlin, Germany
- Institute of Molecular Biology and Biochemistry, Charité—Universitätsmedizin Berlin, Charitéplatz 1, Virchowweg 6, 10117 Berlin, Germany
| | - Maria Toumazou
- Institute of Biology, Humboldt Universität zu Berlin, Charitéplatz 1, Virchowweg 6, 10117 Berlin, Germany
| | - Thorsten Trimbuch
- Institute of Neurophysiology, Charité—Universitätsmedizin Berlin, Charitéplatz 1, Virchowweg 6, 10117 Berlin, Germany
| | - Christian Rosenmund
- Institute of Neurophysiology, Charité—Universitätsmedizin Berlin, Charitéplatz 1, Virchowweg 6, 10117 Berlin, Germany
- Neurocure Centre for Excellence Charité—Universitätsmedizin Berlin Charitéplatz 1, Virchowweg 6, 10117 Berlin, Germany
| | | | - Dieter Jaeger
- Department of Biology, Emory University, Atlanta, GA 30322, USA
| | - Matthew E Larkum
- Institute of Biology, Humboldt Universität zu Berlin, Charitéplatz 1, Virchowweg 6, 10117 Berlin, Germany
- Neurocure Centre for Excellence Charité—Universitätsmedizin Berlin Charitéplatz 1, Virchowweg 6, 10117 Berlin, Germany
| | - Robert N S Sachdev
- Institute of Biology, Humboldt Universität zu Berlin, Charitéplatz 1, Virchowweg 6, 10117 Berlin, Germany
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3
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Sorensen SA, Gouwens NW, Wang Y, Mallory M, Budzillo A, Dalley R, Lee B, Gliko O, Kuo HC, Kuang X, Mann R, Ahmadinia L, Alfiler L, Baftizadeh F, Baker K, Bannick S, Bertagnolli D, Bickley K, Bohn P, Brown D, Bomben J, Brouner K, Chen C, Chen K, Chvilicek M, Collman F, Daigle T, Dawes T, de Frates R, Dee N, DePartee M, Egdorf T, El-Hifnawi L, Enstrom R, Esposito L, Farrell C, Gala R, Glomb A, Gamlin C, Gary A, Goldy J, Gu H, Hadley K, Hawrylycz M, Henry A, Hill D, Hirokawa KE, Huang Z, Johnson K, Juneau Z, Kebede S, Kim L, Lee C, Lesnar P, Li A, Glomb A, Li Y, Liang E, Link K, Maxwell M, McGraw M, McMillen DA, Mukora A, Ng L, Ochoa T, Oldre A, Park D, Pom CA, Popovich Z, Potekhina L, Rajanbabu R, Ransford S, Reding M, Ruiz A, Sandman D, Siverts L, Smith KA, Stoecklin M, Sulc J, Tieu M, Ting J, Trinh J, Vargas S, Vumbaco D, Walker M, Wang M, Wanner A, Waters J, Williams G, Wilson J, Xiong W, Lein E, Berg J, Kalmbach B, Yao S, Gong H, Luo Q, Ng L, Sümbül U, Jarsky T, Yao Z, Tasic B, Zeng H. Connecting single-cell transcriptomes to projectomes in mouse visual cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.25.568393. [PMID: 38168270 PMCID: PMC10760188 DOI: 10.1101/2023.11.25.568393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The mammalian brain is composed of diverse neuron types that play different functional roles. Recent single-cell RNA sequencing approaches have led to a whole brain taxonomy of transcriptomically-defined cell types, yet cell type definitions that include multiple cellular properties can offer additional insights into a neuron's role in brain circuits. While the Patch-seq method can investigate how transcriptomic properties relate to the local morphological and electrophysiological properties of cell types, linking transcriptomic identities to long-range projections is a major unresolved challenge. To address this, we collected coordinated Patch-seq and whole brain morphology data sets of excitatory neurons in mouse visual cortex. From the Patch-seq data, we defined 16 integrated morpho-electric-transcriptomic (MET)-types; in parallel, we reconstructed the complete morphologies of 300 neurons. We unified the two data sets with a multi-step classifier, to integrate cell type assignments and interrogate cross-modality relationships. We find that transcriptomic variations within and across MET-types correspond with morphological and electrophysiological phenotypes. In addition, this variation, along with the anatomical location of the cell, can be used to predict the projection targets of individual neurons. We also shed new light on infragranular cell types and circuits, including cell-type-specific, interhemispheric projections. With this approach, we establish a comprehensive, integrated taxonomy of excitatory neuron types in mouse visual cortex and create a system for integrated, high-dimensional cell type classification that can be extended to the whole brain and potentially across species.
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Affiliation(s)
| | | | - Yun Wang
- Allen Institute for Brain Science
| | | | | | | | | | | | | | - Xiuli Kuang
- School of Optometry and Ophthalmology, Wenzhou Medical University, Wenzhou, China
| | | | | | | | | | | | | | | | | | | | | | | | | | - Chao Chen
- School of Optometry and Ophthalmology, Wenzhou Medical University, Wenzhou, China
| | - Kai Chen
- School of Optometry and Ophthalmology, Wenzhou Medical University, Wenzhou, China
| | | | | | | | | | | | - Nick Dee
- Allen Institute for Brain Science
| | | | | | | | | | | | | | | | | | | | | | | | - Hong Gu
- Allen Institute for Brain Science
| | | | | | | | | | | | - Zili Huang
- School of Optometry and Ophthalmology, Wenzhou Medical University, Wenzhou, China
| | | | | | | | - Lisa Kim
- Allen Institute for Brain Science
| | | | | | - Anan Li
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan, China
- HUST-Suzhou Institute for Brainsmatics, JITRI Institute for Brainsmatics, Suzhou, China
| | | | - Yaoyao Li
- School of Optometry and Ophthalmology, Wenzhou Medical University, Wenzhou, China
| | | | | | | | | | | | | | | | | | | | | | | | - Zoran Popovich
- University of Washington, Dept. of Computer Science and Engineering
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Wei Xiong
- School of Optometry and Ophthalmology, Wenzhou Medical University, Wenzhou, China
| | - Ed Lein
- Allen Institute for Brain Science
| | - Jim Berg
- Allen Institute for Brain Science
| | | | | | - Hui Gong
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, Wuhan, China
- HUST-Suzhou Institute for Brainsmatics, JITRI Institute for Brainsmatics, Suzhou, China
| | - Qingming Luo
- State Key Laboratory of Digital Medical Engineering, School of Biomedical Engineering, Hainan University, Haikou, China
| | - Lydia Ng
- Allen Institute for Brain Science
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4
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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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5
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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: 0] [Impact Index Per Article: 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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6
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Yang D, Qi G, Ding C, Feldmeyer D. Layer 6A Pyramidal Cell Subtypes Form Synaptic Microcircuits with Distinct Functional and Structural Properties. Cereb Cortex 2021; 32:2095-2111. [PMID: 34628499 PMCID: PMC9113278 DOI: 10.1093/cercor/bhab340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/03/2021] [Accepted: 08/25/2021] [Indexed: 11/27/2022] Open
Abstract
Neocortical layer 6 plays a crucial role in sensorimotor co-ordination and integration through functionally segregated circuits linking intracortical and subcortical areas. We performed whole-cell recordings combined with morphological reconstructions to identify morpho-electric types of layer 6A pyramidal cells (PCs) in rat barrel cortex. Cortico-thalamic (CT), cortico-cortical (CC), and cortico-claustral (CCla) PCs were classified based on their distinct morphologies and have been shown to exhibit different electrophysiological properties. We demonstrate that these three types of layer 6A PCs innervate neighboring excitatory neurons with distinct synaptic properties: CT PCs establish weak facilitating synapses onto other L6A PCs; CC PCs form synapses of moderate efficacy, while synapses made by putative CCla PCs display the highest release probability and a marked short-term depression. For excitatory-inhibitory synaptic connections in layer 6, both the presynaptic PC type and the postsynaptic interneuron type govern the dynamic properties of the respective synaptic connections. We have identified a functional division of local layer 6A excitatory microcircuits which may be responsible for the differential temporal engagement of layer 6 feed-forward and feedback networks. Our results provide a basis for further investigations on the long-range CC, CT, and CCla pathways.
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Affiliation(s)
- Danqing Yang
- Research Center Juelich, Institute of Neuroscience and Medicine 10, 52425 Juelich, Germany
| | - Guanxiao Qi
- Research Center Juelich, Institute of Neuroscience and Medicine 10, 52425 Juelich, Germany
| | - Chao Ding
- Research Center Juelich, Institute of Neuroscience and Medicine 10, 52425 Juelich, Germany
| | - Dirk Feldmeyer
- Research Center Juelich, Institute of Neuroscience and Medicine 10, 52425 Juelich, Germany.,RWTH Aachen University Hospital, Dept of Psychiatry, Psychotherapy, and Psychosomatics, 52074 Aachen, Germany.,Jülich-Aachen Research Alliance, Translational Brain Medicine (JARA Brain), Aachen, Germany
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7
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Schmuhl-Giesen S, Rollenhagen A, Walkenfort B, Yakoubi R, Sätzler K, Miller D, von Lehe M, Hasenberg M, Lübke JHR. Sublamina-Specific Dynamics and Ultrastructural Heterogeneity of Layer 6 Excitatory Synaptic Boutons in the Adult Human Temporal Lobe Neocortex. Cereb Cortex 2021; 32:1840-1865. [PMID: 34530440 PMCID: PMC9070345 DOI: 10.1093/cercor/bhab315] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Synapses “govern” the computational properties of any given network in the brain. However, their detailed quantitative morphology is still rather unknown, particularly in humans. Quantitative 3D-models of synaptic boutons (SBs) in layer (L)6a and L6b of the temporal lobe neocortex (TLN) were generated from biopsy samples after epilepsy surgery using fine-scale transmission electron microscopy, 3D-volume reconstructions and electron microscopic tomography. Beside the overall geometry of SBs, the size of active zones (AZs) and that of the three pools of synaptic vesicles (SVs) were quantified. SBs in L6 of the TLN were middle-sized (~5 μm2), the majority contained only a single but comparatively large AZ (~0.20 μm2). SBs had a total pool of ~1100 SVs with comparatively large readily releasable (RRP, ~10 SVs L6a), (RRP, ~15 SVs L6b), recycling (RP, ~150 SVs), and resting (~900 SVs) pools. All pools showed a remarkably large variability suggesting a strong modulation of short-term synaptic plasticity. In conclusion, L6 SBs are highly reliable in synaptic transmission within the L6 network in the TLN and may act as “amplifiers,” “integrators” but also as “discriminators” for columnar specific, long-range extracortical and cortico-thalamic signals from the sensory periphery.
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Affiliation(s)
| | - Astrid Rollenhagen
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, 52425, Jülich, Germany
| | - Bernd Walkenfort
- Imaging Center Essen (IMCES), Electron Microscopy Unit (EMU), Medical Faculty of the University of Duisburg-Essen, 45147, Essen, Germany
| | - Rachida Yakoubi
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, 52425, Jülich, Germany
| | - Kurt Sätzler
- School of Biomedical Sciences, University of Ulster, Londonderry, BT52 1SA, UK
| | - Dorothea Miller
- University Hospital/Knappschaftskrankenhaus Bochum, 44892, Bochum, Germany
| | - Marec von Lehe
- Department of Neurosurgery, Brandenburg Medical School, Ruppiner Clinics, 16816, Neuruppin, Germany
| | - Mike Hasenberg
- Imaging Center Essen (IMCES), Electron Microscopy Unit (EMU), Medical Faculty of the University of Duisburg-Essen, 45147, Essen, Germany
| | - Joachim H R Lübke
- Address correspondence to Joachim Lübke, Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, 52425 Jülich, Germany.
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8
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Call CL, Bergles DE. Cortical neurons exhibit diverse myelination patterns that scale between mouse brain regions and regenerate after demyelination. Nat Commun 2021; 12:4767. [PMID: 34362912 PMCID: PMC8346564 DOI: 10.1038/s41467-021-25035-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/16/2021] [Indexed: 12/04/2022] Open
Abstract
Axons in the cerebral cortex show a broad range of myelin coverage. Oligodendrocytes establish this pattern by selecting a cohort of axons for myelination; however, the distribution of myelin on distinct neurons and extent of internode replacement after demyelination remain to be defined. Here we show that myelination patterns of seven distinct neuron subtypes in somatosensory cortex are influenced by both axon diameter and neuronal identity. Preference for myelination of parvalbumin interneurons was preserved between cortical areas with varying myelin density, suggesting that regional differences in myelin abundance arises through local control of oligodendrogenesis. By imaging loss and regeneration of myelin sheaths in vivo we show that myelin distribution on individual axons was altered but overall myelin content on distinct neuron subtypes was restored. Our findings suggest that local changes in myelination are tolerated, allowing regenerated oligodendrocytes to restore myelin content on distinct neurons through opportunistic selection of axons. Myelination patterns of different neurons in grey matter have not been fully defined. Here, the authors show that axon diameter and neuronal identity influence myelination patterns in the intact mouse somatosensory cortex. In vivo imaging revealed that remyelination altered myelin patterns but restored overall myelin content on distinct neuron subtypes.
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Affiliation(s)
- Cody L Call
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Dwight E Bergles
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA. .,Johns Hopkins University, Kavli Neuroscience Discovery Institute, Baltimore, MD, USA.
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9
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Hirata T, Tohsato Y, Itoga H, Shioi G, Kiyonari H, Oka S, Fujimori T, Onami S. NeuroGT: A brain atlas of neurogenic tagging CreER drivers for birthdate-based classification and manipulation of mouse neurons. CELL REPORTS METHODS 2021; 1:100012. [PMID: 35474959 PMCID: PMC9017123 DOI: 10.1016/j.crmeth.2021.100012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/02/2021] [Accepted: 04/23/2021] [Indexed: 11/30/2022]
Abstract
Neuronal birthdate is one of the major determinants of neuronal phenotypes. However, most birthdating methods are retrospective in nature, allowing very little experimental access to the classified neuronal subsets. Here, we introduce four neurogenic tagging mouse lines, which can assign CreER-loxP recombination to neuron subsets that share the same differentiation timing in living animals and enable various experimental manipulations of the classified subsets. We constructed a brain atlas of the neurogenic tagging mouse lines (NeuroGT), which includes holistic image data of the loxP-recombined neurons and their processes across the entire brain that were tagged on each single day during the neurodevelopmental period. This image database, which is open to the public, offers investigators the opportunity to find specific neurogenic tagging driver lines and the stages of tagging appropriate for their own research purposes.
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Affiliation(s)
- Tatsumi Hirata
- Brain Function Laboratory, National Institute of Genetics, 1111 Yata, Mishima 411-8540, Japan
- The Graduate University for Advanced Studies, SOKENDAI, Hayama, Japan
| | - Yukako Tohsato
- Computational Biology Laboratory, Faculty of Information Science and Engineering, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan
- Laboratory for Developmental Dynamics, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Hiroya Itoga
- Laboratory for Developmental Dynamics, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Go Shioi
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Hiroshi Kiyonari
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Sanae Oka
- Division of Embryology, National Institute for Basic Biology, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Toshihiko Fujimori
- The Graduate University for Advanced Studies, SOKENDAI, Hayama, Japan
- Division of Embryology, National Institute for Basic Biology, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Shuichi Onami
- Laboratory for Developmental Dynamics, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
- Life Science Data Sharing Unit, RIKEN Information R&D and Strategy Headquarters, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
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10
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Development of Auditory Cortex Circuits. J Assoc Res Otolaryngol 2021; 22:237-259. [PMID: 33909161 DOI: 10.1007/s10162-021-00794-3] [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: 09/21/2020] [Accepted: 03/03/2021] [Indexed: 02/03/2023] Open
Abstract
The ability to process and perceive sensory stimuli is an essential function for animals. Among the sensory modalities, audition is crucial for communication, pleasure, care for the young, and perceiving threats. The auditory cortex (ACtx) is a key sound processing region that combines ascending signals from the auditory periphery and inputs from other sensory and non-sensory regions. The development of ACtx is a protracted process starting prenatally and requires the complex interplay of molecular programs, spontaneous activity, and sensory experience. Here, we review the development of thalamic and cortical auditory circuits during pre- and early post-natal periods.
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11
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Burns TF, Rajan R. Sensing and processing whisker deflections in rodents. PeerJ 2021; 9:e10730. [PMID: 33665005 PMCID: PMC7906041 DOI: 10.7717/peerj.10730] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/17/2020] [Indexed: 11/20/2022] Open
Abstract
The classical view of sensory information mainly flowing into barrel cortex at layer IV, moving up for complex feature processing and lateral interactions in layers II and III, then down to layers V and VI for output and corticothalamic feedback is becoming increasingly undermined by new evidence. We review the neurophysiology of sensing and processing whisker deflections, emphasizing the general processing and organisational principles present along the entire sensory pathway—from the site of physical deflection at the whiskers to the encoding of deflections in the barrel cortex. Many of these principles support the classical view. However, we also highlight the growing number of exceptions to these general principles, which complexify the system and which investigators should be mindful of when interpreting their results. We identify gaps in the literature for experimentalists and theorists to investigate, not just to better understand whisker sensation but also to better understand sensory and cortical processing.
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Affiliation(s)
- Thomas F Burns
- Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
| | - Ramesh Rajan
- Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
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12
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White Matter Interstitial Neurons in the Adult Human Brain: 3% of Cortical Neurons in Quest for Recognition. Cells 2021; 10:cells10010190. [PMID: 33477896 PMCID: PMC7833373 DOI: 10.3390/cells10010190] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 02/03/2023] Open
Abstract
White matter interstitial neurons (WMIN) are a subset of cortical neurons located in the subcortical white matter. Although they were fist described over 150 years ago, they are still largely unexplored and often considered a small, functionally insignificant neuronal population. WMIN are adult remnants of neurons located in the transient fetal subplate zone (SP). Following development, some of the SP neurons undergo apoptosis, and the remaining neurons are incorporated in the adult white matter as WMIN. In the adult human brain, WMIN are quite a large population of neurons comprising at least 3% of all cortical neurons (between 600 and 1100 million neurons). They include many of the morphological neuronal types that can be found in the overlying cerebral cortex. Furthermore, the phenotypic and molecular diversity of WMIN is similar to that of the overlying cortical neurons, expressing many glutamatergic and GABAergic biomarkers. WMIN are often considered a functionally unimportant subset of neurons. However, upon closer inspection of the scientific literature, it has been shown that WMIN are integrated in the cortical circuitry and that they exhibit diverse electrophysiological properties, send and receive axons from the cortex, and have active synaptic contacts. Based on these data, we are able to enumerate some of the potential WMIN roles, such as the control of the cerebral blood flow, sleep regulation, and the control of information flow through the cerebral cortex. Also, there is a number of studies indicating the involvement of WMIN in the pathophysiology of many brain disorders such as epilepsy, schizophrenia, Alzheimer’s disease, etc. All of these data indicate that WMIN are a large population with an important function in the adult brain. Further investigation of WMIN could provide us with novel data crucial for an improved elucidation of the pathophysiology of many brain disorders. In this review, we provide an overview of the current WMIN literature, with an emphasis on studies conducted on the human brain.
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13
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Kostović I. The enigmatic fetal subplate compartment forms an early tangential cortical nexus and provides the framework for construction of cortical connectivity. Prog Neurobiol 2020; 194:101883. [PMID: 32659318 DOI: 10.1016/j.pneurobio.2020.101883] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 06/05/2020] [Accepted: 07/06/2020] [Indexed: 12/19/2022]
Abstract
The most prominent transient compartment of the primate fetal cortex is the deep, cell-sparse, synapse-containing subplate compartment (SPC). The developmental role of the SPC and its extraordinary size in humans remain enigmatic. This paper evaluates evidence on the development and connectivity of the SPC and discusses its role in the pathogenesis of neurodevelopmental disorders. A synthesis of data shows that the subplate becomes a prominent compartment by its expansion from the deep cortical plate (CP), appearing well-delineated on MR scans and forming a tangential nexus across the hemisphere, consisting of an extracellular matrix, randomly distributed postmigratory neurons, multiple branches of thalamic and long corticocortical axons. The SPC generates early spontaneous non-synaptic and synaptic activity and mediates cortical response upon thalamic stimulation. The subplate nexus provides large-scale interareal connectivity possibly underlying fMR resting-state activity, before corticocortical pathways are established. In late fetal phase, when synapses appear within the CP, transient the SPC coexists with permanent circuitry. The histogenetic role of the SPC is to provide interactive milieu and capacity for guidance, sorting, "waiting" and target selection of thalamocortical and corticocortical pathways. The new evolutionary role of the SPC and its remnant white matter neurons is linked to the increasing number of associative pathways in the human neocortex. These roles attributed to the SPC are regulated using a spatiotemporal gene expression during critical periods, when pathogenic factors may disturb vulnerable circuitry of the SPC, causing neurodevelopmental cognitive circuitry disorders.
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Affiliation(s)
- Ivica Kostović
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Scientific Centre of Excellence for Basic, Clinical and Translational Neuroscience, Salata 12, 10000 Zagreb, Croatia.
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14
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Ohtaka-Maruyama C. Subplate Neurons as an Organizer of Mammalian Neocortical Development. Front Neuroanat 2020; 14:8. [PMID: 32265668 PMCID: PMC7103628 DOI: 10.3389/fnana.2020.00008] [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: 10/02/2019] [Accepted: 02/20/2020] [Indexed: 12/30/2022] Open
Abstract
Subplate neurons (SpNs) are one of the earliest born and matured neurons in the developing cerebral cortex and play an important role in the early development of the neocortex. It has been known that SpNs have an essential role in thalamocortical axon (TCA) pathfinding and the establishment of the first neural circuit from the thalamus towards cortical layer IV. In addition to this function, it has recently been revealed in mouse corticogenesis that SpNs play an important role in the regulation of radial neuronal migration during the mid-embryonic stage. Moreover, accumulating studies throw light on the possible roles of SpNs in adult brain functions and also their involvement in psychiatric or other neurological disorders. As SpNs are unique to mammals, they may have contributed to the evolution of the mammalian neocortex by efficiently organizing cortical formation during the limited embryonic period of corticogenesis. By increasing our knowledge of the functions of SpNs, we will clarify how SpNs act as an organizer of mammalian neocortical formation.
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Affiliation(s)
- Chiaki Ohtaka-Maruyama
- Neural Network Project, Department of Brain Development and Neural Regeneration, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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15
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Layer 6b Is Driven by Intracortical Long-Range Projection Neurons. Cell Rep 2020; 30:3492-3505.e5. [DOI: 10.1016/j.celrep.2020.02.044] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 09/20/2019] [Accepted: 02/10/2020] [Indexed: 01/03/2023] Open
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16
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Case L, Broberger C. Neurotensin Broadly Recruits Inhibition via White Matter Neurons in the Mouse Cerebral Cortex: Synaptic Mechanisms for Decorrelation. Cereb Cortex 2019; 28:2711-2724. [PMID: 28981614 DOI: 10.1093/cercor/bhx149] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Indexed: 12/30/2022] Open
Abstract
The neuropeptide, neurotensin (NT), inhibits UP state generation in the cerebral cortex and temporally restricts the response to thalamic input, likely by a generalized increase in inhibition. To investigate the cellular and circuit substrate(s) for how a neuropeptide can shift the balance between cortical excitation and inhibition, we performed whole-cell recordings on slice preparations from mice expressing enhanced green fluorescent protein under control of the promoter for the homeobox gene, lhx6 (lhx6-EGFP mice). These mice identify the 2 largest classes of cortical interneurons; FS and low-threshold-spiking inhibitory neurons. In the presence of NT, both types of lhx6-EGFP neurons were excited through a direct, Na+-dependent depolarization, and through an increase in synaptic excitation. Paired recordings identified cortical white matter (WM) neurons as a source of this excitatory input, which was strengthened in the presence of NT. NT-driven increased synaptic input caused a functional decorrelation of gap junction transmission between lhx6-EGFP neuron pairs. Finally, the synaptic transmission between pyramidal cells and lhx6-EGFP neurons was modulated by addition of NT in favor of stronger inhibition and weaker excitation. These findings demonstrate the existence and functional consequences of an intracortical WM neuron projection, and suggest mechanisms underlying NT-induced promotion of wakefulness.
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Affiliation(s)
- Lovisa Case
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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17
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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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18
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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] [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
| | - Rongkang Deng
- Department of Biology, University of Maryland, College Park, MD, United States
| | - Xiangying Meng
- Department of Biology, University of Maryland, College Park, MD, United States
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19
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Luhmann HJ, Kirischuk S, Kilb W. The Superior Function of the Subplate in Early Neocortical Development. Front Neuroanat 2018; 12:97. [PMID: 30487739 PMCID: PMC6246655 DOI: 10.3389/fnana.2018.00097] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/29/2018] [Indexed: 12/25/2022] Open
Abstract
During early development the structure and function of the cerebral cortex is critically organized by subplate neurons (SPNs), a mostly transient population of glutamatergic and GABAergic neurons located below the cortical plate. At the molecular and morphological level SPNs represent a rather diverse population of cells expressing a variety of genetic markers and revealing different axonal-dendritic morphologies. Electrophysiologically SPNs are characterized by their rather mature intrinsic membrane properties and firing patterns. They are connected via electrical and chemical synapses to local and remote neurons, e.g., thalamic relay neurons forming the first thalamocortical input to the cerebral cortex. Therefore SPNs are robustly activated at pre- and perinatal stages by the sensory periphery. Although SPNs play pivotal roles in early neocortical activity, development and plasticity, they mostly disappear by programmed cell death during further maturation. On the one hand, SPNs may be selectively vulnerable to hypoxia-ischemia contributing to brain damage, on the other hand there is some evidence that enhanced survival rates or alterations in SPN distribution may contribute to the etiology of neurological or psychiatric disorders. This review aims to give a comprehensive and up-to-date overview on the many functions of SPNs during early physiological and pathophysiological development of the cerebral cortex.
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Affiliation(s)
- Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Sergei Kirischuk
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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20
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Viswanathan S, Sheikh A, Looger LL, Kanold PO. Molecularly Defined Subplate Neurons Project Both to Thalamocortical Recipient Layers and Thalamus. Cereb Cortex 2018; 27:4759-4768. [PMID: 27655928 DOI: 10.1093/cercor/bhw271] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 08/09/2016] [Indexed: 12/12/2022] Open
Abstract
In mammals, subplate neurons (SPNs) are among the first generated cortical neurons. While most SPNs exist only transiently during development, a number of SPNs persist among adult Layer 6b (L6b). During development, SPNs receive thalamic and intra-cortical input, and primarily project to Layer 4 (L4). SPNs are critical for the anatomical and functional development of thalamocortical connections and also pioneer corticothalamic projections. Since SPNs are heterogeneous, SPN subpopulations might serve different roles. Here, we investigate the connectivity of one subpopulation, complexin-3 (Cplx3)-positive SPNs (Cplx3-SPNs), in mouse whisker somatosensory (barrel) cortex (S1). We find that many Cplx3-SPNs survive into adulthood and become a subpopulation of L6b. Cplx3-SPNs axons project to thalamorecipient layers, that is, L4, 5a, and 1. The L4 projections are biased towards the septal regions between barrels in the second postnatal week. Thus, S1 Cplx3-SPN targets co-localize with the eventual projections of the medial posterior thalamic nucleus (POm). In addition to their cortical targets, Cplx3-SPNs also extend long-range axons to several thalamic nuclei, including POm. Thus, Cplx3-SPN/L6b neurons are associated with paralemniscal pathways and can potentially directly link thalamocortical and corticothalamic circuits. This suggests an additional key role for SPNs in the establishment and maintenance of thalamocortical processing.
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Affiliation(s)
- Sarada Viswanathan
- Department of Biology, University of Maryland, College Park, MD 20742, USA.,Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Aminah Sheikh
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Loren L Looger
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Patrick O Kanold
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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21
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Sundberg SC, Granseth B. Cre-expressing neurons in the cortical white matter of Ntsr1-Cre GN220 mice. Neurosci Lett 2018; 675:36-40. [PMID: 29580883 DOI: 10.1016/j.neulet.2018.03.053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 03/21/2018] [Accepted: 03/22/2018] [Indexed: 12/13/2022]
Abstract
Genetically modified mouse strains that express Cre-recombinase in specific neuronal sub-populations have become widely used tools for investigating neuronal function. The Ntsr1-Cre GN220 mouse expresses this enzyme in corticothalamic neurons in layer 6 of cerebral cortex. We observed that about 7% of Cre-expressing cells in the primary visual cortex are found within the white matter bordering layer 6. By using the immunohistochemical marker for layer 6 neurons, Forkhead box protein 2 (FoxP2), and fluorescently conjugated latex beads injected into the dorsal lateral geniculate nucleus, we show that about half of these cells are similar to and could belong to the layer 6 corticothalamic neuron population. The other half seems to be a distinct white matter (WM) neuron sub-population that we estimate to constitute 2-4% of the total cortical Cre-expressing population. Staining for the neuronal marker Neuronal nuclei (NeuN) revealed that about 15-40% of WM neurons are Cre-expressing. Thus, the potential contribution from WM neurons needs to be considered when interpreting the results from experiments using the Ntsr1-Cre GN220 mouse for investigating corticothalamic neuronal function.
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Affiliation(s)
- Sofie C Sundberg
- Department of Clinical and Experimental Medicine, Linköping University, Sweden
| | - Björn Granseth
- Department of Clinical and Experimental Medicine, Linköping University, Sweden.
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22
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Marx M, Qi G, Hanganu-Opatz IL, Kilb W, Luhmann HJ, Feldmeyer D. Neocortical Layer 6B as a Remnant of the Subplate - A Morphological Comparison. Cereb Cortex 2018; 27:1011-1026. [PMID: 26637449 DOI: 10.1093/cercor/bhv279] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The fate of the subplate (SP) is still a matter of debate. The SP and layer 6 (which is ontogenetically the oldest and innermost neocortical lamina) develop coincidentally. Yet, the function of sublamina 6B is largely unknown. It has been suggested that it consists partly of neurons from the transient SP, however, experimental evidence for this hypothesis is still missing. To obtain first insights into the neuronal complement of layer 6B in the somatosensory rat barrel cortex, we used biocytin stainings of SP neurons (aged 0-4 postnatal days, PND) and layer 6B neurons (PND 11-35) obtained during in vitro whole-cell patch-clamp recordings. Neurons were reconstructed for a quantitative characterization of their axonal and dendritic morphology. An unsupervised cluster analysis revealed that the SP and layer 6B consist of heterogeneous but comparable neuronal cell populations. Both contain 5 distinct spine-bearing cell types whose relative fractions change with increasing age. Pyramidal cells were more prominent in layer 6B, whereas non-pyramidal neurons were less frequent. Because of the high morphological similarity of SP and layer 6B neurons, we suggest that layer 6B consists of persistent non-pyramidal neurons from the SP and cortical L6B pyramidal neurons.
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Affiliation(s)
- Manuel Marx
- Institute of Neuroscience and Medicine, INM-2, Research Centre Jülich, D-52428 Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, D-52074 Aachen, Germany
| | - Guanxiao Qi
- Institute of Neuroscience and Medicine, INM-2, Research Centre Jülich, D-52428 Jülich, Germany
| | - Ileana L Hanganu-Opatz
- Developmental Neurophysiology, Institute of Neuroanatomy, Centre for Molecular Neurobiology Hamburg (ZMNH), D-20251 Hamburg, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Centre of the Johannes Gutenberg-University Mainz, D-55128 Mainz, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Centre of the Johannes Gutenberg-University Mainz, D-55128 Mainz, Germany
| | - Dirk Feldmeyer
- Institute of Neuroscience and Medicine, INM-2, Research Centre Jülich, D-52428 Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, D-52074 Aachen, Germany.,Jülich Aachen Research Alliance, Translational Brain Medicine (JARA Brain), D-52074 Aachen, Germany
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23
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Radnikow G, Feldmeyer D. Layer- and Cell Type-Specific Modulation of Excitatory Neuronal Activity in the Neocortex. Front Neuroanat 2018; 12:1. [PMID: 29440997 PMCID: PMC5797542 DOI: 10.3389/fnana.2018.00001] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 01/04/2018] [Indexed: 01/08/2023] Open
Abstract
From an anatomical point of view the neocortex is subdivided into up to six layers depending on the cortical area. This subdivision has been described already by Meynert and Brodmann in the late 19/early 20. century and is mainly based on cytoarchitectonic features such as the size and location of the pyramidal cell bodies. Hence, cortical lamination is originally an anatomical concept based on the distribution of excitatory neuron. However, it has become apparent in recent years that apart from the layer-specific differences in morphological features, many functional properties of neurons are also dependent on cortical layer or cell type. Such functional differences include changes in neuronal excitability and synaptic activity by neuromodulatory transmitters. Many of these neuromodulators are released from axonal afferents from subcortical brain regions while others are released intrinsically. In this review we aim to describe layer- and cell-type specific differences in the effects of neuromodulator receptors in excitatory neurons in layers 2–6 of different cortical areas. We will focus on the neuromodulator systems using adenosine, acetylcholine, dopamine, and orexin/hypocretin as examples because these neuromodulator systems show important differences in receptor type and distribution, mode of release and functional mechanisms and effects. We try to summarize how layer- and cell type-specific neuromodulation may affect synaptic signaling in cortical microcircuits.
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Affiliation(s)
- Gabriele Radnikow
- Research Centre Jülich, Institute of Neuroscience and Medicine, INM-10, Jülich, Germany
| | - Dirk Feldmeyer
- Research Centre Jülich, Institute of Neuroscience and Medicine, INM-10, Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, Medical School, RWTH Aachen University, Aachen, Germany.,Jülich-Aachen Research Alliance - Translational Brain Medicine, Jülich, Germany
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24
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Case L, Lyons DJ, Broberger C. Desynchronization of the Rat Cortical Network and Excitation of White Matter Neurons by Neurotensin. Cereb Cortex 2017; 27:2671-2685. [PMID: 27095826 DOI: 10.1093/cercor/bhw100] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cortical network activity correlates with vigilance state: Deep sleep is characterized by slow, synchronized oscillations, whereas desynchronized, stochastic discharge is typical of the waking state. Neuropeptides, such as orexin and substance P but also neurotensin (NT), promote arousal. Relatively little is known about if NT can directly affect the cortical network, and if so, through which mechanisms and cellular targets. Here, we addressed these issues using rat in vitro cortex preparations. Following NT application specifically to deeper layers, slow oscillation activity was attenuated with a significant reduction in UP state frequency. The cortical response to thalamic stimulation exhibited enhanced temporal precision in the presence of NT, consistent with the transition in vivo from sleep to wakefulness. These changes were associated with a relative shift toward inhibition in the excitation/inhibition balance. Whole-cell recordings from layer 6 revealed presynaptically driven NT-induced inhibition of pyramidal neurons and excitation of fast-spiking interneurons. Deeper in the cortex, neurons within the white matter (WM) were strongly depolarized by NT application. The colocalization of NT and tyrosine hydroxylase immunoreactivities in deep layer fibers throughout the cortical mantle indicates mediation via dopaminergic systems. These data suggest a cortical mechanism for NT-induced wakefulness and support a role for WM neurons in state control.
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Affiliation(s)
- Lovisa Case
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - David J Lyons
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Current address: Rowett Institute of Nutrition and Health, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, UK
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25
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Ramos RL, Toia AR, Pasternack DM, Dotzler TP, Cuoco JA, Esposito AW, Le MM, Parker AK, Goodman JH, Sarkisian MR. Neuroanatomical characterization of the cellular and axonal architecture of subcortical band heterotopia in the BXD29-Tlr4 lps-2J/J mouse cortex. Neuroscience 2016; 337:48-65. [PMID: 27595889 DOI: 10.1016/j.neuroscience.2016.08.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 08/24/2016] [Accepted: 08/28/2016] [Indexed: 10/21/2022]
Abstract
Subcortical band heterotopia (SBH) are malformations of the human cerebral cortex typically associated with epilepsy and cognitive delay/disability. Rodent models of SBH have demonstrated strong face validity as they are accompanied by both cognitive deficits and spontaneous seizures or reduced seizure threshold. BXD29-Tlr4lps-2J/J recombinant inbred mice display striking bilateral SBH, partial callosal agenesis, morphological changes in subcortical structures of the auditory pathway, and display sensory deficits in behavioral tests (Rosen et al., 2013; Truong et al., 2013, 2015). Surprisingly, these mice show no cognitive deficits and have a higher seizure threshold to chemi-convulsive treatment (Gabel et al., 2013) making them different than other rodent SBH models described previously. In the present report, we perform a detailed characterization of the cellular and axonal constituents of SBH in BXD29-Tlr4lps-2J/J mice and demonstrate that various types of interneurons and glia as well as cortical and subcortical projections are found in SBH. In addition, the length of neuronal cilia was reduced in SBH compared to neurons in the overlying and adjacent normotopic cortex. Finally, we describe additional and novel malformations of the hippocampus and neocortex present in BXD29-Tlr4lps-2J/J mice. Together, our findings in BXD29-Tlr4lps-2J/J mice are discussed in the context of the known neuroanatomy and phenotype of other SBH rodent models.
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Affiliation(s)
- Raddy L Ramos
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, USA.
| | - Alyssa R Toia
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, USA
| | - Daniel M Pasternack
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, USA
| | - Timothy P Dotzler
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, USA
| | - Joshua A Cuoco
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, USA
| | - Anthony W Esposito
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, USA
| | - Megan M Le
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32610-0244, USA
| | - Alexander K Parker
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32610-0244, USA
| | - Jeffrey H Goodman
- Department of Developmental Neurobiology, NY State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA; Department of Physiology & Pharmacology and Department of Neurology, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Matthew R Sarkisian
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32610-0244, USA.
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Wenger Combremont AL, Bayer L, Dupré A, Mühlethaler M, Serafin M. Effects of Hypocretin/Orexin and Major Transmitters of Arousal on Fast Spiking Neurons in Mouse Cortical Layer 6B. Cereb Cortex 2016; 26:3553-62. [PMID: 27235100 PMCID: PMC4961029 DOI: 10.1093/cercor/bhw158] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Fast spiking (FS) GABAergic neurons are thought to be involved in the generation of high-frequency cortical rhythms during the waking state. We previously showed that cortical layer 6b (L6b) was a specific target for the wake-promoting transmitter, hypocretin/orexin (hcrt/orx). Here, we have investigated whether L6b FS cells were sensitive to hcrt/orx and other transmitters associated with cortical activation. Recordings were thus made from L6b FS cells in either wild-type mice or in transgenic mice in which GFP-positive GABAergic cells are parvalbumin positive. Whereas in a control condition hcrt/orx induced a strong increase in the frequency, but not amplitude, of spontaneous synaptic currents, in the presence of TTX, it had no effect at all on miniature synaptic currents. Hcrt/orx effect was thus presynaptic although not by an action on glutamatergic terminals but rather on neighboring cells. In contrast, noradrenaline and acetylcholine depolarized and excited these cells through a direct postsynaptic action. Neurotensin, which is colocalized in hcrt/orx neurons, also depolarized and excited these cells but the effect was indirect. Morphologically, these cells exhibited basket-like features. These results suggest that hcrt/orx, noradrenaline, acetylcholine, and neurotensin could contribute to high-frequency cortical activity through an action on L6b GABAergic FS cells.
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Affiliation(s)
| | - Laurence Bayer
- Département des Neurosciences Fondamentales, Centre Médical Universitaire, Genève, Suisse Centre de Médecine du Sommeil, Hôpitaux Universitaires de Genève, Genève, Suisse
| | - Anouk Dupré
- Département des Neurosciences Fondamentales, Centre Médical Universitaire, Genève, Suisse
| | - Michel Mühlethaler
- Département des Neurosciences Fondamentales, Centre Médical Universitaire, Genève, Suisse
| | - Mauro Serafin
- Département des Neurosciences Fondamentales, Centre Médical Universitaire, Genève, Suisse
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27
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Postnatal development of GABAergic interneurons in the neocortical subplate of mice. Neuroscience 2016; 322:78-93. [PMID: 26892297 DOI: 10.1016/j.neuroscience.2016.02.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/28/2016] [Accepted: 02/10/2016] [Indexed: 11/22/2022]
Abstract
The subplate (SP) plays important roles in developmental and functional events in the neocortex, such as thalamocortical and corticofugal projection, cortical oscillation generation and corticocortical connectivity. Although accumulated evidence indicates that SP interneurons are crucial for SP function, the molecular composition of SP interneurons as well as their developmental profile and distribution remain largely unclear. In this study, we systematically investigated dynamic development of SP thickness and chemical marker expression in SP interneurons in distinct cortical regions during the first postnatal month. We found that, although the relative area of the SP in the cerebral cortex significantly declined with postnatal development, the absolute thickness did not change markedly. We also found that somatostatin (SOM), the ionotropic serotonin receptor 3A (5HT3AR), and parvalbumin (PV) reliably identify three distinct non-overlapping subpopulations of SP interneurons. The SOM group, which represents ~30% of total SP interneurons, expresses neuronal nitric oxide synthase (nNOS) and calbindin (CB) and colocalizes entirely with neuropeptide Y (NPY). The 5HT3AR group, which accounts for ~60% of the total interneuronal population, expresses calretinin (CR) and GABA-A receptor subunit delta (GABAARδ). The PV group accounts for ~10% of total SP interneurons and coexpressed GABAARδ. Moreover, distinct interneuron subtypes show characteristic temporal and spatial distribution in the SP. nNOS(+) interneurons in the SP increase from the anterior motor cortex to posterior visual cortex, while CR(+) and CB(+) interneurons the opposite. Interestedly, the majority of GABAARδ(+) neurons in SP are non-GABAergic neurons in contrast to other cortical layers. These findings clarify and extend our understanding of SP interneurons in the developing cerebral cortex and will underpin further study of SP function.
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Hu B, Yang N, Qiao QC, Hu ZA, Zhang J. Roles of the orexin system in central motor control. Neurosci Biobehav Rev 2014; 49:43-54. [PMID: 25511388 DOI: 10.1016/j.neubiorev.2014.12.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 11/10/2014] [Accepted: 12/03/2014] [Indexed: 12/15/2022]
Abstract
The neuropeptides orexin-A and orexin-B are produced by one group of neurons located in the lateral hypothalamic/perifornical area. However, the orexins are widely released in entire brain including various central motor control structures. Especially, the loss of orexins has been demonstrated to associate with several motor deficits. Here, we first summarize the present knowledge that describes the anatomical and morphological connections between the orexin system and various central motor control structures. In the next section, the direct influence of orexins on related central motor control structures is reviewed at molecular, cellular, circuitry, and motor activity levels. After the summarization, the characteristic and functional relevance of the orexin system's direct influence on central motor control function are demonstrated and discussed. We also propose a hypothesis as to how the orexin system orchestrates central motor control in a homeostatic regulation manner. Besides, the importance of the orexin system's phasic modulation on related central motor control structures is highlighted in this regulation manner. Finally, a scheme combining the homeostatic regulation of orexin system on central motor control and its effects on other brain functions is presented to discuss the role of orexin system beyond the pure motor activity level, but at the complex behavioral level.
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Affiliation(s)
- Bo Hu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China
| | - Nian Yang
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China
| | - Qi-Cheng Qiao
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China
| | - Zhi-An Hu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China.
| | - Jun Zhang
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China.
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29
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Hay YA, Andjelic S, Badr S, Lambolez B. Orexin-dependent activation of layer VIb enhances cortical network activity and integration of non-specific thalamocortical inputs. Brain Struct Funct 2014; 220:3497-512. [PMID: 25108310 DOI: 10.1007/s00429-014-0869-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 07/31/2014] [Indexed: 10/24/2022]
Abstract
Neocortical layer VI is critically involved in thalamocortical activity changes during the sleep/wake cycle. It receives dense projections from thalamic nuclei sensitive to the wake-promoting neuropeptides orexins, and its deepest part, layer VIb, is the only cortical lamina reactive to orexins. This convergence of wake-promoting inputs prompted us to investigate how layer VIb can modulate cortical arousal, using patch-clamp recordings and optogenetics in rat brain slices. We found that the majority of layer VIb neurons were excited by nicotinic agonists and orexin through the activation of nicotinic receptors containing α4-α5-β2 subunits and OX2 receptor, respectively. Specific effects of orexin on layer VIb neurons were potentiated by low nicotine concentrations and we used this paradigm to explore their intracortical projections. Co-application of nicotine and orexin increased the frequency of excitatory post-synaptic currents in the ipsilateral cortex, with maximal effect in infragranular layers and minimal effect in layer IV, as well as in the contralateral cortex. The ability of layer VIb to relay thalamocortical inputs was tested using photostimulation of channelrhodopsin-expressing fibers from the orexin-sensitive rhomboid nucleus in the parietal cortex. Photostimulation induced robust excitatory currents in layer VIa neurons that were not pre-synaptically modulated by orexin, but exhibited a delayed, orexin-dependent, component. Activation of layer VIb by orexin enhanced the reliability and spike-timing precision of layer VIa responses to rhomboid inputs. These results indicate that layer VIb acts as an orexin-gated excitatory feedforward loop that potentiates thalamocortical arousal.
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Affiliation(s)
- Y Audrey Hay
- UM CR 18, Neuroscience Paris Seine, Sorbonne Universités, UPMC Univ Paris 06, 75005, Paris, France.
- UMR 8246, Centre National de la Recherche Scientifique (CNRS), Paris, France.
- UMR-S 1130, Institut national de la Santé et de la Recherche Médicale (INSERM), Paris, France.
| | - Sofija Andjelic
- UM CR 18, Neuroscience Paris Seine, Sorbonne Universités, UPMC Univ Paris 06, 75005, Paris, France
- UMR 8246, Centre National de la Recherche Scientifique (CNRS), Paris, France
- UMR-S 1130, Institut national de la Santé et de la Recherche Médicale (INSERM), Paris, France
| | - Sammy Badr
- UM CR 18, Neuroscience Paris Seine, Sorbonne Universités, UPMC Univ Paris 06, 75005, Paris, France
- UMR 8246, Centre National de la Recherche Scientifique (CNRS), Paris, France
- UMR-S 1130, Institut national de la Santé et de la Recherche Médicale (INSERM), Paris, France
| | - Bertrand Lambolez
- UM CR 18, Neuroscience Paris Seine, Sorbonne Universités, UPMC Univ Paris 06, 75005, Paris, France.
- UMR 8246, Centre National de la Recherche Scientifique (CNRS), Paris, France.
- UMR-S 1130, Institut national de la Santé et de la Recherche Médicale (INSERM), Paris, France.
- UMR 8246, Neuroscience Paris Seine, Université Pierre et Marie Curie, 9 quai St Bernard case 16, 75005, Paris, France.
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Aracri P, Banfi D, Pasini ME, Amadeo A, Becchetti A. Hypocretin (orexin) regulates glutamate input to fast-spiking interneurons in layer V of the Fr2 region of the murine prefrontal cortex. Cereb Cortex 2013; 25:1330-47. [PMID: 24297328 PMCID: PMC4397574 DOI: 10.1093/cercor/bht326] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We studied the effect of hypocretin 1 (orexin A) in the frontal area 2 (Fr2) of the murine neocortex, implicated in the motivation-dependent goal-directed tasks. In layer V, hypocretin stimulated the spontaneous excitatory postsynaptic currents (EPSCs) on fast-spiking (FS) interneurons. The effect was accompanied by increased frequency of miniature EPSCs, indicating that hypocretin can target the glutamatergic terminals. Moreover, hypocretin stimulated the spontaneous inhibitory postsynaptic currents (IPSCs) on pyramidal neurons, with no effect on miniature IPSCs. This action was prevented by blocking 1) the ionotropic glutamatergic receptors; 2) the hypocretin receptor type 1 (HCRTR-1), with SB-334867. Finally, hypocretin increased the firing frequency in FS cells, and the effect was blocked when the ionotropic glutamate transmission was inhibited. Immunolocalization confirmed that HCRTR-1 is highly expressed in Fr2, particularly in layer V-VI. Conspicuous labeling was observed in pyramidal neuron somata and in VGLUT1+ glutamatergic terminals, but not in VGLUT2+ fibers (mainly thalamocortical afferents). The expression of HCRTR-1 in GABAergic structures was scarce. We conclude that 1) hypocretin regulates glutamate release in Fr2; 2) the effect presents a presynaptic component; 3) the peptide control of FS cells is indirect, and probably mediated by the regulation of glutamatergic input onto these cells.
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Affiliation(s)
- Patrizia Aracri
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan 20126, Italy
| | - Daniele Banfi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan 20126, Italy
| | - Maria Enrica Pasini
- Department of Biomolecular Sciences and Biotechnology, University of Milano, Milan 20128, Italy
| | - Alida Amadeo
- Department of Biomolecular Sciences and Biotechnology, University of Milano, Milan 20128, Italy
| | - Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan 20126, Italy
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31
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Ramos-Moreno T, Clascá F. Quantitative mapping of the local and extrinsic sources of GABA and Reelin to the layer Ia neuropil in the adult rat neocortex. Brain Struct Funct 2013; 219:1639-57. [PMID: 23817670 DOI: 10.1007/s00429-013-0591-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 05/31/2013] [Indexed: 12/23/2022]
Abstract
Inputs to apical dendritic tufts have been considered to be crucial for associative learning, attention and similar ''feedback'' interactions and are located in neocortical layer Ia. Excitatory thalamic projections to apical tufts in layer Ia have been well characterized and their role in the cortical circuit has been emphasized. In addition, the neuropil and the extracellular matrix surrounding apical tufts are highly reactive to GABA and to the glycoprotein Reelin, respectively. Recently it has been shown that the GABA inhibition on apical dendrites can reduce the output of pyramidal cells in layer V, however, the origin of 89% of the symmetric synapses in layer I still remains unknown. In the present study we have systematically analyzed the origin of the GABAergic neuropil in neocortical layer Ia in a qualitative and quantitative manner, and investigated the possible extrinsic origin of the rich extracellular Reelin content of the same layer. We show that the inhibitory inputs in a given spot in layer I come from cortical projections and arise mainly from Martinotti cells located directly under that same spot. Double bouquet and bipolar cells may also project to layer Ia although to a lesser extent and the external globus pallidus and zona incerta provide the remaining inhibitory inputs. Finally, our results suggest that Martinotti cells are also the main source of Reelin in layer Ia. The present data will help in the understanding of the cortical circuit and why it changes in pathological conditions.
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Affiliation(s)
- Tania Ramos-Moreno
- Department of Anatomy and Neuroscience, School of Medicine, Autonoma University, 28029, Madrid, Spain,
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32
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Watakabe A, Hirokawa J, Ichinohe N, Ohsawa S, Kaneko T, Rockland KS, Yamamori T. Area-specific substratification of deep layer neurons in the rat cortex. J Comp Neurol 2013; 520:3553-73. [PMID: 22678985 DOI: 10.1002/cne.23160] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Gene markers are useful tools to identify cell types for fine mapping of neuronal circuits. Here we report area-specific sublamina structure of the rat cerebral cortex using cholecystokinin (cck) and purkinje cell protein4 (pcp4) mRNAs as the markers for excitatory neuron subtypes in layers 5 and 6. We found a segregated expression, especially pronounced in layer 6, where corticothalamic and corticocortical projecting neurons reside. To examine the relationship between gene expression and projection target, we injected retrograde tracers into several thalamic subnuclei, ventral posterior (VP), posterior (PO), mediodorsal (MD), medial and lateral geniculate nuclei (MGN and LGN); as well as into two cortical areas (M1 and V1). This combination of tracer-in situ hybridization (ISH) experiments revealed that corticocortical neurons predominantly express cck and corticothalamic neurons predominantly express pcp4 mRNAs in all areas tested. In general, cck(+) and pcp4(+) cells occupied the upper and lower compartment of layer 6a, respectively. However, the sublaminar distribution and the relative abundance of cck(+) and pcp4(+) cells were quite distinctive across areas. For example, layer 6 of the prelimbic cortex was almost devoid of cck(+) neurons, and was occupied instead by corticothalamic pcp4(+) neurons. In the lateral areas, such as S2, there was an additional layer of cck(+) cells positioned below the pcp4(+) compartment. The claustrum, which has a tight relationship with the cortex, mostly consisted of cck(+)/pcp4(-) cells. In summary, the combination of gene markers and retrograde tracers revealed a distinct sublaminar organization, with conspicuous cross-area variation in the arrangement and relative density of corticothalamic connections.
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Affiliation(s)
- Akiya Watakabe
- Division of Brain Biology, National Institute for Basic Biology, Graduate University for Advanced Studies, Okazaki, Japan.
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Marx M, Feldmeyer D. Morphology and physiology of excitatory neurons in layer 6b of the somatosensory rat barrel cortex. ACTA ACUST UNITED AC 2012; 23:2803-17. [PMID: 22944531 PMCID: PMC3827708 DOI: 10.1093/cercor/bhs254] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Neocortical lamina 6B (L6B) is a largely unexplored layer with a very heterogeneous cellular composition. To date, only little is known about L6B neurons on a systematic and quantitative basis. We investigated the morphological and electrophysiological properties of excitatory L6B neurons in the rat somatosensory barrel cortex using whole-cell patch-clamp recordings and simultaneous biocytin fillings. Subsequent histological processing and computer-assisted 3D reconstructions provided the basis for a classification of excitatory L6B neurons according to their structural and functional characteristics. Three distinct clusters of excitatory L6B neurons were identified: (C1) pyramidal neurons with an apical dendrite pointing towards the pial surface, (C2) neurons with a prominent, “apical”-like dendrite not oriented towards the pia, and (C3) multipolar spiny neurons without any preferential dendritic orientation. The second group could be further subdivided into three categories termed inverted, “tangentially” oriented and “horizontally” oriented neurons. Furthermore, based on the axonal domain two subcategories of L6B pyramidal cells were identified that had either a more barrel-column confined or an extended axonal field. The classification of excitatory L6B neurons provided here may serve as a basis for future studies on the structure, function, and synaptic connectivity of L6B neurons.
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Affiliation(s)
- Manuel Marx
- Research Center Jülich, Institute of Neuroscience and Medicine (INM-2), D-52425 Jülich, Germany,
| | - Dirk Feldmeyer
- Research Center Jülich, Institute of Neuroscience and Medicine (INM-2), D-52425 Jülich, Germany,
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical School, RWTH Aachen University, D-52074 Aachen, Germany and
- Jülich Aachen Research Alliance, Translational Brain Medicine (JARA Brain), D-52074 Aachen, Germany
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34
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Perrenoud Q, Rossier J, Geoffroy H, Vitalis T, Gallopin T. Diversity of GABAergic interneurons in layer VIa and VIb of mouse barrel cortex. Cereb Cortex 2012; 23:423-41. [PMID: 22357664 DOI: 10.1093/cercor/bhs032] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Neocortical layer VI modulates the thalamocortical transfer of information and has a significant impact on sensory processing. This function implicates local γ-aminobutyric acidergic (GABAergic) interneurons that have only been partly described at the present time. Here, we characterized 85 layer VI GABAergic interneurons in acute slices of mouse somatosensory barrel cortex, using whole-cell current-clamp recordings, single-cell reverse transcription-polymerase chain reaction, and biocytin labeling followed by Neurolucida reconstructions. Unsupervised clustering based on electrophysiological molecular and morphological properties disclosed 4 types of interneurons. The 2 major classes were fast-spiking cells transcribing parvalbumin (PV) (51%) and adapting interneurons transcribing somatostatin (SOM) (26%). The third population (18%) transcribed neuropeptide Y (NPY) and appeared very similar to neurogliaform cells. The last class (5%) was constituted by well-segregated GABAergic interneurons transcribing vasoactive intestinal peptide (VIP). Using transgenic mice expressing GFP under the control of the glutamic acid decarboxylase 67k (GAD67) promoter, we investigated the densities of GABAergic cells immunolabeled against PV, SOM, VIP, and NPY through the depth of layer VI. This analysis revealed that PV and NPY translating interneurons concentrate in the upper and lower parts of layer VI, respectively. This study provides an extensive characterization of the properties of layer VI interneurons.
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Affiliation(s)
- Quentin Perrenoud
- Laboratoire de Neurobiologie et Diversité Cellulaire, CNRS UMR7637, Ecole Supérieure de Physique et de Chimie Industrielles, 75005 Paris, France
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35
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Liao CC, Lee LJ. Evidence for structural and functional changes of subplate neurons in developing rat barrel cortex. Brain Struct Funct 2011; 217:275-92. [PMID: 22002739 DOI: 10.1007/s00429-011-0354-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 09/26/2011] [Indexed: 01/24/2023]
Abstract
In the developing sensory cortex, the subplate could serve as a transient relay station between the thalamus and cortical plate and assists the formation of thalamocortical projection. While the thalamus-layer IV connection is formed, the thalamic activation of subplate is diminished. In the present study, we aimed to explore the mechanism which may attribute to the decline of subplate activity. To resolve this issue, the developmental changes of subplate neurons (SPns) in rat somatosensory cortex were examined during the first two postnatal weeks which covers the stages prior and subsequent to the establishment of thalamocortical connection. During development, more SPns exhibited regular-spiking firing pattern and the membrane properties of SPns displayed a continual trend of maturation. In the meantime, the excitability of SPns decreased as revealed by increasing rheobase and rightwardly shifted frequency-current curves. On the other hand, increasing paired-pulse ratio and slowing MK-801 blocking rate were noted during development, implying the reduction of presynaptic transmitter release. Morphologically, the size of SPn soma increased with age while the shape became flat. The total length, branching nodes and segments of dendrites increased significantly during the first week. However, after peaking around day 10, these values decreased, implying a pruning process. Our findings here propose that the reduction of neuronal excitability, synaptic transmission and dendritic complexity may attribute to the decline of functional connectivity between thalamus and subplate and reduction of subplate activity while the thalamocortical pathway is established.
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Affiliation(s)
- Chun-Chieh Liao
- Graduate Institute of Anatomy and Cell Biology, College of Medicine, National Taiwan University, No. 1, Ren-Ai Rd, Section 1, Taipei, 100, Taiwan
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36
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García-Marín V, Blazquez-Llorca L, Rodriguez JR, Gonzalez-Soriano J, DeFelipe J. Differential distribution of neurons in the gyral white matter of the human cerebral cortex. J Comp Neurol 2011; 518:4740-59. [PMID: 20963826 DOI: 10.1002/cne.22485] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The neurons in the cortical white matter (WM neurons) originate from the first set of postmitotic neurons that migrates from the ventricular zone. In particular, they arise in the subplate that contains the earliest cells generated in the telencephalon, prior to the appearance of neurons in gray matter cortical layers. These cortical WM neurons are very numerous during development, when they are thought to participate in transient synaptic networks, although many of these cells later die, and relatively few cells survive as WM neurons in the adult. We used light and electron microscopy to analyze the distribution and density of WM neurons in various areas of the adult human cerebral cortex. Furthermore, we examined the perisomatic innervation of these neurons and estimated the density of synapses in the white matter. Finally, we examined the distribution and neurochemical nature of interneurons that putatively innervate the somata of WM neurons. From the data obtained, we can draw three main conclusions: first, the density of WM neurons varies depending on the cortical areas; second, calretinin-immunoreactive neurons represent the major subpopulation of GABAergic WM neurons; and, third, the somata of WM neurons are surrounded by both glutamatergic and GABAergic axon terminals, although only symmetric axosomatic synapses were found. By contrast, both symmetric and asymmetric axodendritic synapses were observed in the neuropil. We discuss the possible functional implications of these findings in terms of cortical circuits.
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Affiliation(s)
- V García-Marín
- Laboratorio de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain.
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Abstract
The developing mammalian cerebral cortex contains a distinct class of cells, subplate neurons (SPns), that play an important role during early development. SPns are the first neurons to be generated in the cerebral cortex, they reside in the cortical white matter, and they are the first to mature physiologically. SPns receive thalamic and neuromodulatory inputs and project into the developing cortical plate, mostly to layer 4. Thus SPns form one of the first functional cortical circuits and are required to relay early oscillatory activity into the developing cortical plate. Pathophysiological impairment or removal of SPns profoundly affects functional cortical development. SPn removal in visual cortex prevents the maturation of thalamocortical synapses, the maturation of inhibition in layer 4, the development of orientation selective responses and the formation of ocular dominance columns. SPn removal also alters ocular dominance plasticity during the critical period. Therefore, SPns are a key regulator of cortical development and plasticity. SPns are vulnerable to injury during prenatal stages and might provide a crucial link between brain injury in development and later cognitive malfunction.
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Affiliation(s)
- Patrick O Kanold
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA.
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38
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Judaš M, Sedmak G, Pletikos M. Early history of subplate and interstitial neurons: from Theodor Meynert (1867) to the discovery of the subplate zone (1974). J Anat 2010; 217:344-67. [PMID: 20979585 PMCID: PMC2992413 DOI: 10.1111/j.1469-7580.2010.01283.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2010] [Indexed: 12/29/2022] Open
Abstract
In this historical review, we trace the early history of research on the fetal subplate zone, subplate neurons and interstitial neurons in the white matter of the adult nervous system. We arrive at several general conclusions. First, a century of research clearly testifies that interstitial neurons, subplate neurons and the subplate zone were first observed and variously described in the human brain - or, in more general terms, in large brains of gyrencephalic mammals, characterized by an abundant white matter and slow and protracted prenatal and postnatal development. Secondly, the subplate zone cannot be meaningfully defined using a single criterion - be it a specific population of cells, fibres or a specific molecular or genetic marker. The subplate zone is a highly dynamic architectonic compartment and its size and cellular composition do not remain constant during development. Thirdly, it is important to make a clear distinction between the subplate zone and the subplate (and interstitial) neurons. The transient existence of the subplate zone (as a specific architectonic compartment of the fetal telencephalic wall) should not be equated with the putative transient existence of subplate neurons. It is clear that in rodents, and to an even greater extent in humans and monkeys, a significant number of subplate cells survive and remain functional throughout life.
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Affiliation(s)
- Miloš Judaš
- University of Zagreb School of Medicine, Croatian Institute for Brain Research, Salata 12, Zagreb, Croatia.
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39
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Chung L, Moore SD, Cox CL. Cholecystokinin action on layer 6b neurons in somatosensory cortex. Brain Res 2009; 1282:10-9. [PMID: 19497313 DOI: 10.1016/j.brainres.2009.05.061] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 05/09/2009] [Accepted: 05/11/2009] [Indexed: 11/30/2022]
Abstract
Layer 6b in neocortex is a distinct sublamina at the ventral portion of layer 6. Corticothalamic projections arise from 6b neurons, but few studies have examined the functional properties of these cells. In the present study we examined the actions of cholecystokinin (CCK) on layer 6b neocortical neurons using whole-cell patch clamp recording techniques. We found that the general CCK receptor agonist CCK8S (sulfated CCK octapeptide) strongly depolarized the neurons, and this action persisted in the presence of tetrodotoxin, suggesting a postsynaptic site of action. The excitatory actions of CCK8S were mimicked by the selective CCK(B) receptor agonist CCK4, and attenuated by the selective CCK(B) receptor antagonist L365260, indicating a role for CCK(B) receptors. Voltage-clamp recordings revealed that CCK8S produced a slow inward current associated with a decreased conductance with a reversal potential near the K(+) equilibrium potential. In addition, intracellular cesium also blocked the inward current, suggesting the involvement of a K(+) conductance, likely K(leak). Our data indicate that CCK, acting via CCK(B) receptors, produces a long-lasting excitation of layer 6b neocortical neurons, and this action may play a critical role in modulation of corticothalamic circuit activity.
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Affiliation(s)
- Leeyup Chung
- Neuroscience Program, Beckman Institute, University of Illinois, Urbana, IL 61801, USA
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40
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Tomioka R, Rockland KS. Long-distance corticocortical GABAergic neurons in the adult monkey white and gray matter. J Comp Neurol 2008; 505:526-38. [PMID: 17924571 DOI: 10.1002/cne.21504] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A subgroup of GABAergic neurons has been reported to project over long distances in several species. Here we demonstrate that long-distance cortically projecting nonpyramidal neurons occur in monkeys in both white and gray matter. Nonpyramidal neurons were first identified morphologically. Visualization of Golgi-like details was achieved by retrograde infection from injections of an adenovirus vector, producing enhanced green fluorescent protein (EGFP) under control of a neuron-specific promoter. Injections in areas V1, V4, TEO, and posterior TE resulted in EGFP-expressing nonpyramidal neurons up to 1.5 cm distant from the injections, mainly in the white matter. Some neurons occurred in the gray matter, mainly in layer 3, but also in layers 5 and 6, and, very occasionally, layer 1. As control, we injected cholera toxin subunit B, a standard retrograde tracer, in V4, and observed a similarly wide distribution of neurons in the white matter. Second, the GABAergic identity of EGFP-expressing nonpyramidal neurons was established by colabeling for EGFP and GAD67 in selected tissue sections. Most neurons positive for EGFP and GAD67 were positive for somatostatin (SS; 90%). Of those neurons positive for EGFP and SS, almost all were also positive for neuronal nitric oxide synthase or m2 muscarinic receptor, but only 23% were also positive for calretinin. None were positive for parvalbumin. We conclude that long-distance projecting GABAergic neurons 1) are phylogenetically conserved, although in monkeys most gray matter neurons are in the upper layers, and 2) are heterogeneous in terms of their neurochemistry, location, and potentially function.
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Affiliation(s)
- Ryohei Tomioka
- Laboratory for Cortical Organization and Systematics, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan.
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41
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Friedlander MJ. Lifespan longitudinal multitasking by cortical neurons. FUTURE NEUROLOGY 2008. [DOI: 10.2217/14796708.3.2.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The large number of neurons (1011) and synapses (1014) in the mammalian brain provides a rich anatomical substrate for information processing. Many neurons perform very specialized functions, such as detecting or processing sensory stimuli, relaying or amplifying attributes of an afferent input to another brain area or making decisions to convert inputs into action. Some cell types, including the early-generated subplate cells of the developing cerebral cortex, play a special role during a restricted period of early brain development, acting transiently as scaffolds for the formation of thalamocortical and corticothalamic connections. However, many of these neurons (10–20%) survive elimination and become functionally integrated into the mature cortical circuitry. Thus, a single neuron type can perform different functions in the brain at different periods of life, potentially increasing the combinatorial capacity of the functional cellular architecture of the brain over the lifespan.
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Affiliation(s)
- Michael J Friedlander
- Baylor College of Medicine, Department of Neuroscience, Director of Neuroscience Initiatives, One Baylor Plaza, Suite S740A, Houston, TX 77030, USA
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42
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Stress blunts serotonin- and hypocretin-evoked EPSCs in prefrontal cortex: role of corticosterone-mediated apical dendritic atrophy. Proc Natl Acad Sci U S A 2008; 105:359-64. [PMID: 18172209 DOI: 10.1073/pnas.0706679105] [Citation(s) in RCA: 255] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Morphological studies show that repeated restraint stress leads to selective atrophy in the apical dendritic field of pyramidal cells in the medial prefrontal cortex (mPFC). However, the functional consequence of this selectivity remains unclear. The apical dendrite of layer V pyramidal neurons in the mPFC is a selective locus for the generation of increased excitatory postsynaptic currents (EPSCs) by serotonin (5-HT) and hypocretin (orexin). On that basis, we hypothesized that apical dendritic atrophy might result in a blunting of 5-HT- and hypocretin-induced excitatory responses. Using a combination of whole-cell recording and two-photon imaging in rat mPFC slices, we were able to correlate electrophysiological and morphological changes in the same layer V pyramidal neurons. Repeated mild restraint stress produced a decrement in both 5-HT- and hypocretin-induced EPSCs, an effect that was correlated with a decrease in apical tuft dendritic branch length and spine density in the distal tuft branches. Chronic treatment with the stress hormone corticosterone, while reducing 5-HT responses and generally mimicking the morphological effects of stress, failed to produce a significant decrease in hypocretin-induced EPSCs. Accentuating this difference, pretreatment of stressed animals with the glucocorticoid receptor antagonist RU486 blocked reductions in 5-HT-induced EPSCs but not hypocretin-induced EPSCs. We conclude: (i) stress-induced apical dendritic atrophy results in diminished responses to apically targeted excitatory inputs and (ii) corticosterone plays a greater role in stress-induced reductions in EPSCs evoked by 5-HT as compared with hypocretin, possibly reflecting the different pathways activated by the two transmitters.
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43
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Galazo MJ, Martinez-Cerdeño V, Porrero C, Clascá F. Embryonic and Postnatal Development of the Layer I–Directed (“Matrix”) Thalamocortical System in the Rat. Cereb Cortex 2007; 18:344-63. [PMID: 17517678 DOI: 10.1093/cercor/bhm059] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Inputs to the layer I apical dendritic tufts of pyramidal cells are crucial in "top-down" interactions in the cerebral cortex. A large population of thalamocortical cells, the "matrix" (M-type) cells, provides a direct robust input to layer I that is anatomically and functionally different from the thalamocortical input to layer VI. The developmental timecourse of M-type axons is examined here in rats aged E (embryonic day) 16 to P (postnatal day) 30. Anterograde techniques were used to label axons arising from 2 thalamic nuclei mainly made up of M-type cells, the Posterior and the Ventromedial. The primary growth cones of M-type axons rapidly reached the subplate of dorsally situated cortical areas. After this, interstitial branches would sprout from these axons under more lateral cortical regions to invade the overlying cortical plate forming secondary arbors. Moreover, retrograde labeling of M-type cell somata in the thalamus after tracer deposits confined to layer I revealed that large numbers of axons from multiple thalamic nuclei had already converged in a given spot of layer I by P3. Because of early ingrowth in such large numbers, interactions of M-type axons may significantly influence the early development of cortical circuits.
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Affiliation(s)
- Maria J Galazo
- Department of Anatomy & Neuroscience, School of Medicine, Autónoma University, E-28871 Madrid, Spain
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44
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Watakabe A, Ohsawa S, Hashikawa T, Yamamori T. Binding and complementary expression patterns of semaphorin 3E and plexin D1 in the mature neocortices of mice and monkeys. J Comp Neurol 2006; 499:258-73. [PMID: 16977617 DOI: 10.1002/cne.21106] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Although axon guidance molecules play critical roles in neural circuit formation during development, their roles in the adult circuit are not well understood. In this study we examined the expression patterns of Semaphorin 3E (Sema3E), a member of the semaphorin family, in the mature neocortices of monkeys and mice by in situ hybridization (ISH). We found that Sema3E mRNA is highly specific to layer VI throughout the macaque monkey neocortex. We further examined the ratio of Sema3E+ cells among the layer VI excitatory neurons in areas M1, S1, TE, and V1 by fluorescence double ISH, using the vesicular glutamate transporter 1 (VGluT1) gene as a specific marker for excitatory neurons. Among these areas, 34-63% of the VGluT1+ neurons expressed Sema3E mRNA. In the mouse cortex, two significant differences were observed in the pattern of Sema3E mRNA distribution. 1) Sema3E mRNA was expressed in layer Vb, in addition to layer VI in mice. 2) A subset of GABAergic interneurons expressed Sema3E mRNA in mice. By an in vitro binding experiment, we provide evidence that Plexin D1 is the specific receptor for Sema3E. Plexin D1 mRNA was preferentially expressed in layers II-V in both monkey and mouse cortices. The detailed lamina analysis by double ISH, however, revealed that Plexin D1 mRNA is expressed in layers II-Va, but not in layer Vb in the mouse cortex. Thus, the Plexin D1 and Sema3E mRNAs exhibit conserved complementary lamina patterns in mice and monkeys, despite the species differences in the pattern of each gene.
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Affiliation(s)
- Akiya Watakabe
- Division of Brain Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
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45
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Watakabe A, Ichinohe N, Ohsawa S, Hashikawa T, Komatsu Y, Rockland KS, Yamamori T. Comparative analysis of layer-specific genes in Mammalian neocortex. ACTA ACUST UNITED AC 2006; 17:1918-33. [PMID: 17065549 DOI: 10.1093/cercor/bhl102] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We examined the expression patterns of 4 layer-specific genes in monkey and mouse cortices by fluorescence double in situ hybridization. Based on their coexpression profiles, we were able to distinguish several subpopulations of deep layer neurons. One group was characterized by the expression of ER81 and the lack of Nurr1 mRNAs and mainly localized to layer 5. In monkeys, this neuronal group was further subdivided by 5-HT2C receptor mRNA expression. The 5-HT2C(+)/ER81(+) neurons were located in layer 5B in most cortical areas, but they intruded layer 6 in the primary visual area (V1). Another group of neurons, in monkey layer 6, was characterized by Nurr1 mRNA expression and was further subdivided as Nurr1(+)/connective tissue growth factor (CTGF)(-) and Nurr1(+)/CTGF(+) neurons in layers 6A and 6B, respectively. The Nurr1(+)/CTGF(+) neurons coexpressed ER81 mRNA in monkeys but not in mice. On the basis of tracer injections in 3 monkeys, we found that the Nurr1(+) neurons in layer 6A send some corticocortical, but not corticopulvinar, projections. Although the Nurr1(+)/CTGF(-) neurons were restricted to lateral regions in the mouse cortex, they were present throughout the monkey cortex. Thus, an architectonic heterogeneity across areas and species was revealed for the neuronal subpopulations with distinct gene expression profiles.
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Affiliation(s)
- Akiya Watakabe
- Division of Brain Biology, National Institute for Basic Biology, 38 Nishigonaka Myodaiji, Okazaki 444-8585, Japan
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46
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Sizonenko SV, Kiss JZ, Inder T, Gluckman PD, Williams CE. Distinctive neuropathologic alterations in the deep layers of the parietal cortex after moderate ischemic-hypoxic injury in the P3 immature rat brain. Pediatr Res 2005; 57:865-72. [PMID: 15774844 DOI: 10.1203/01.pdr.0000157673.36848.67] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Moderate focal brain hypoxic-ischemic (HI) injury in the immature P3 rat leads to loss of cortical volume and disruptions of cortical myelination. In this study, we characterized the time course and pattern of cellular degeneration, axonal disruption, astrogliosis, and microglia activation. After moderate transient unilateral hypoxia-ischemia, brains were collected at set time points and positive staining was assessed. Cellular degeneration stained with Fluoro-Jade B (FJ-B) was distributed in a columnar pattern, primarily within the deep cortical layers V-VII extending up to layer IV of the parietal cortex (pCx). FJ-B staining increased in the ipsilateral pCx 12 and 24 h (p < 0.05) after the injury. Beta-amyloid precursor protein immunoreactivity indicating axonal disruption increased at 24 h (p < 0.05) and showed the same distribution as FJ-B. Glial fibrillary acidic protein-positive astrocytes increased dramatically within the ipsilateral pCx from 24 h (p < 0.05) to 18 d (p < 0.001) after HI injury and displayed a columnar pattern extending from the deep cortical layers to layers IV. Isolectin-B4 and ED1-labeled microglia were also increased within the ipsilateral deep pCx and underlying white matter between 12 and 24 h (p < 0.01), and increased Isolectin-B4 lasted up to 7 d after injury. These observations are consistent with the hypothesis that neuronal loss, astrogliosis, and microglia activation precede the subsequent disruption of cortical growth and myelination. This model offers new possibilities for investigating the cellular and molecular mechanisms of damage and repair after neonatal HI injury.
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Affiliation(s)
- Stéphane V Sizonenko
- Unité de Dévelopment, Department of Pediatrics, University of Geneva, 1211 Geneva, Switzerland.
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47
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Bai W, Ishida M, Okabe M, Arimatsu Y. Role of the Protomap and Target-derived Signals in the Development of Intrahemispheric Connections. Cereb Cortex 2005; 16:124-35. [PMID: 15843629 DOI: 10.1093/cercor/bhi092] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mechanisms intrinsic to the early cerebral cortex have been implicated in the establishment of cortical area identity. However, the extent to which the cortical protomap contributes to the formation of highly complex intrahemispheric connections remains obscure. Mechanisms by which postmitotic neurons establish correct corticocortical connections later in corticogenesis also remain to be elucidated. Here, we used a new transplantation method, employing donor tissue harvested from enhanced green fluorescent protein-expressing rats, to show that cortical progenitors are regionally specified for connectional potential and that this controls the development of specific intrahemispheric projections. The acquisition of connectional capacity relies on positional cues within the cortical primordium, but is independent of thalamic inputs. In addition, since cortical neurons developing in organotypic slice culture extended axons more prominently into their normal cortical target tissues than into non-target tissues, we suggest that cortical neurons respond to specific signals derived from their cortical targets.
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Affiliation(s)
- Wanzhu Bai
- Mitsubishi Kagaku Institute of Life Sciences, 11 Minamiooya, Machida, Tokyo 194-8511, Japan
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48
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Bai WZ, Ishida M, Arimatsu Y. Chemically defined feedback connections from infragranular layers of sensory association cortices in the rat. Neuroscience 2004; 123:257-67. [PMID: 14667460 DOI: 10.1016/j.neuroscience.2003.08.056] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The primary visual (V1), auditory (AI), and somatosensory (SI) cortices are reciprocally connected with their respective sensory association cortices. In the rat, we have previously demonstrated that some of the connections arising from the secondary somatosensory (SII) and parietal insular (PA) cortices and terminating in the SI, are characterized by the expression of latexin, a candidate protein of carboxypeptidase A inhibitor. Here, by using retrograde tracing and latexin-immunohistochemistry, we show that latexin-expressing neurons in other association cortices of different sensory modalities also contribute to the feedback projections to the corresponding primary sensory cortices. These are the lateral part of the secondary visual cortex (V2L), temporal association cortex, and the dorsal and ventral (AIIv) parts of the secondary auditory belt cortex. Within sublayer VIa of the V2L, AIIv and SII, the majority of the V1-, AI- and SI-projecting neurons respectively, are latexin-immunopositive. In contrast to feedback connections, far fewer latexin-expressing neurons participate in callosal or intrahemispheric feedforward connections. The latexin-expressing neurons constitute a virtually completely different population from corticothalamic neurons within the infragranular layers. Given that latexin might participate in the modulation of neuronal activity by controlling the protease activity, latexin-expressing feedback pathways would play a unique role in the modulation of sensory perception.
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Affiliation(s)
- W-Z Bai
- Mitsubishi Kagaku Institute of Life Sciences, 11 Minamiooya, Machida-shi, 194-8511, Tokyo, Japan
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49
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Arimatsu Y, Ishida M, Kaneko T, Ichinose S, Omori A. Organization and development of corticocortical associative neurons expressing the orphan nuclear receptor Nurr1. J Comp Neurol 2003; 466:180-96. [PMID: 14528447 DOI: 10.1002/cne.10875] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The developmental mechanism that contributes to the highly organized axonal connections within the cerebral cortex is not well understood. This is partly due to the lack of molecular markers specifically expressed in corticocortical associative neurons during the period of circuit formation. We have shown previously that latexin, a carboxypeptidase A inhibitor, is expressed in intrahemispheric corticocortical neurons from the second postnatal week in the rat (Arimatsu et al. [1999] Cereb. Cortex 9:569-576). In the present study, we first demonstrate in the adult rat that the orphan nuclear receptor Nurr1 is coexpressed in latexin-expressing neurons located in layer V, sublayer VIa, and the white matter of the lateral sector of the neocortex, and also in latexin-negative early born neurons in sublayer VIb of the entire neocortex. Virtually all Nurr1-expressing neurons exhibit immunoreactivity for phosphate-activated glutaminase but not for gamma-aminobutyric acid, suggesting that they are glutamatergic-excitatory neurons. By combining Nurr1 immunohistochemistry and 5-bromo-2'-deoxyuridine-birthdating, we then show that Nurr1 is expressed in (early born) subplate neurons and (later born) presumptive latexin-expressing neurons from embryonic day 18 onward. Finally, by combination of Nurr1 immunohistochemistry and retrograde tracing, we show that Nurr1-expressing neurons, including those in sublayer VIb, contribute predominantly to long-range intrahemispheric corticocortical projections. These results raise the possibility that Nurr1 plays a role in the establishment and maintenance of normal corticocortical circuitry and function.
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Affiliation(s)
- Yasuyoshi Arimatsu
- Cortical Circuits Research Unit, Mitsubishi Kagaku Institute of Life Sciences (MITILS), Tokyo 194-8511, Japan.
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50
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Heuer H, Christ S, Friedrichsen S, Brauer D, Winckler M, Bauer K, Raivich G. Connective tissue growth factor: a novel marker of layer VII neurons in the rat cerebral cortex. Neuroscience 2003; 119:43-52. [PMID: 12763067 DOI: 10.1016/s0306-4522(03)00100-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Connective tissue growth factor (CTGF) belongs to a family of secreted, extracellular matrix-associated proteins that are involved in the regulation of cellular functions such as adhesion, migration, mitogenesis, differentiation and survival. Recent studies have also suggested the up-regulation of CTGF in response to trauma, scar formation and excitotoxicity in the CNS. To further elucidate the localization and regulation of this molecule in the rat brain we performed in situ hybridization experiments and found a very strong and selective expression of CTGF messenger ribonucleic acid (mRNA) on the band of layer VII neurons throughout the adult cerebral cortex. Similarly strong neuronal expression was also present in the dorsal endopiriform nucleus, extending rostrally from the ventrocaudal cortical layer VII, and in the deep layers of the olfactory glomeruli and the accessory olfactory nucleus. Double in situ hybridization confirmed selective CTGF mRNA expression on a subpopulation (approximately 35%) of microtubule-associated protein 2 mRNA-positive neurons in the cortical layer VII and the dorsal endopiriform nucleus. The nucleus of lateral olfactory tract showed moderate signal intensity; other parts of the forebrain, mesencephalon and brain stem only revealed a very weak level of CTGF mRNA expression. Non-neuronal expression was rare, considerably weaker than on cortical layer VII neurons, and normally associated with blood vessels. Developmental analysis of CTGF mRNA expression in embryonic and postnatal mouse also showed a moderately late onset at embryonic day 16-18, and confirmed the presence of CTGF mRNA in cortical layer VII in a second rodent species. Interestingly, injury experiments using direct cerebral trauma or injection of excitotoxic kainic acid into rat brain failed to up-regulate CTGF mRNA after injury and during the ensuing period of neuronal cell death, gliosis and neural scar tissue formation. Altogether, the current data suggest a constitutive role of CTGF, particularly in the adult cerebral cortex. In view of the strong ascending projections of subplate neurons into cortical layer 1, this molecule may be involved in the modulation of synaptic input to apical dendrites of pyramidal neurons.
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Affiliation(s)
- H Heuer
- Max-Planck Institute for Experimental Endocrinology, Feodor-Lynen-Str. 7, D-30625 Hannover, Germany
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