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Kast RJ, Levitt P. Precision in the development of neocortical architecture: From progenitors to cortical networks. Prog Neurobiol 2019; 175:77-95. [PMID: 30677429 PMCID: PMC6402587 DOI: 10.1016/j.pneurobio.2019.01.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 01/02/2019] [Accepted: 01/21/2019] [Indexed: 02/07/2023]
Abstract
Of all brain regions, the 6-layered neocortex has undergone the most dramatic changes in size and complexity during mammalian brain evolution. These changes, occurring in the context of a conserved set of organizational features that emerge through stereotypical developmental processes, are considered responsible for the cognitive capacities and sensory specializations represented within the mammalian clade. The modern experimental era of developmental neurobiology, spanning 6 decades, has deciphered a number of mechanisms responsible for producing the diversity of cortical neuron types, their precise connectivity and the role of gene by environment interactions. Here, experiments providing insight into the development of cortical projection neuron differentiation and connectivity are reviewed. This current perspective integrates discussion of classic studies and new findings, based on recent technical advances, to highlight an improved understanding of the neuronal complexity and precise connectivity of cortical circuitry. These descriptive advances bring new opportunities for studies related to the developmental origins of cortical circuits that will, in turn, improve the prospects of identifying pathogenic targets of neurodevelopmental disorders.
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Affiliation(s)
- Ryan J Kast
- Department of Pediatrics and Program in Developmental Neuroscience and Developmental Neurogenetics, The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90027, USA
| | - Pat Levitt
- Department of Pediatrics and Program in Developmental Neuroscience and Developmental Neurogenetics, The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90027, USA.
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202
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Casas-Torremocha D, Porrero C, Rodriguez-Moreno J, García-Amado M, Lübke JHR, Núñez Á, Clascá F. Posterior thalamic nucleus axon terminals have different structure and functional impact in the motor and somatosensory vibrissal cortices. Brain Struct Funct 2019; 224:1627-1645. [PMID: 30919051 PMCID: PMC6509070 DOI: 10.1007/s00429-019-01862-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Accepted: 03/13/2019] [Indexed: 12/20/2022]
Abstract
Rodents extract information about nearby objects from the movement of their whiskers through dynamic computations that are carried out by a network of forebrain structures that includes the thalamus and the primary sensory (S1BF) and motor (M1wk) whisker cortices. The posterior nucleus (Po), a higher order thalamic nucleus, is a key hub of this network, receiving cortical and brainstem sensory inputs and innervating both motor and sensory whisker-related cortical areas. In a recent study in rats, we showed that Po inputs differently impact sensory processing in S1BF and M1wk. Here, in C57BL/6 mice, we measured Po synaptic bouton layer distribution and size, compared cortical unit response latencies to "in vivo" Po activation, and pharmacologically examined the glutamatergic receptor mechanisms involved. We found that, in S1BF, a large majority (56%) of Po axon varicosities are located in layer (L)5a and only 12% in L2-L4, whereas in M1wk this proportion is inverted to 18% and 55%, respectively. Light and electron microscopic measurements showed that Po synaptic boutons in M1wk layers 3-4 are significantly larger (~ 50%) than those in S1BF L5a. Electrical Po stimulation elicits different area-specific response patterns. In S1BF, responses show weak or no facilitation, and involve both ionotropic and metabotropic glutamate receptors, whereas in M1wk, unit responses exhibit facilitation to repetitive stimulation and involve ionotropic NMDA glutamate receptors. Because of the different laminar distribution of axon terminals, synaptic bouton size and receptor mechanisms, the impact of Po signals on M1wk and S1BF, although simultaneous, is likely to be markedly different.
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Affiliation(s)
- Diana Casas-Torremocha
- Department of Anatomy and Graduate Program in Neuroscience, School of Medicine, Autónoma de Madrid University, Calle Arzobispo Morcillo 4, 28029, Madrid, Spain
| | - César Porrero
- Department of Anatomy and Graduate Program in Neuroscience, School of Medicine, Autónoma de Madrid University, Calle Arzobispo Morcillo 4, 28029, Madrid, Spain
| | - Javier Rodriguez-Moreno
- Department of Anatomy and Graduate Program in Neuroscience, School of Medicine, Autónoma de Madrid University, Calle Arzobispo Morcillo 4, 28029, Madrid, Spain
| | - María García-Amado
- Department of Anatomy and Graduate Program in Neuroscience, School of Medicine, Autónoma de Madrid University, Calle Arzobispo Morcillo 4, 28029, Madrid, Spain
| | - Joachim H R Lübke
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, 52425, Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany.,JARA-Brain Medicine, Aachen, Germany
| | - Ángel Núñez
- Department of Anatomy and Graduate Program in Neuroscience, School of Medicine, Autónoma de Madrid University, Calle Arzobispo Morcillo 4, 28029, Madrid, Spain
| | - Francisco Clascá
- Department of Anatomy and Graduate Program in Neuroscience, School of Medicine, Autónoma de Madrid University, Calle Arzobispo Morcillo 4, 28029, Madrid, Spain.
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203
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Shepherd GM, Marenco L, Hines ML, Migliore M, McDougal RA, Carnevale NT, Newton AJH, Surles-Zeigler M, Ascoli GA. Neuron Names: A Gene- and Property-Based Name Format, With Special Reference to Cortical Neurons. Front Neuroanat 2019; 13:25. [PMID: 30949034 DOI: 10.3389/fnana.2019.00025/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/07/2019] [Indexed: 05/25/2023] Open
Abstract
Precision in neuron names is increasingly needed. We are entering a new era in which classical anatomical criteria are only the beginning toward defining the identity of a neuron as carried in its name. New criteria include patterns of gene expression, membrane properties of channels and receptors, pharmacology of neurotransmitters and neuropeptides, physiological properties of impulse firing, and state-dependent variations in expression of characteristic genes and proteins. These gene and functional properties are increasingly defining neuron types and subtypes. Clarity will therefore be enhanced by conveying as much as possible the genes and properties in the neuron name. Using a tested format of parent-child relations for the region and subregion for naming a neuron, we show how the format can be extended so that these additional properties can become an explicit part of a neuron's identity and name, or archived in a linked properties database. Based on the mouse, examples are provided for neurons in several brain regions as proof of principle, with extension to the complexities of neuron names in the cerebral cortex. The format has dual advantages, of ensuring order in archiving the hundreds of neuron types across all brain regions, as well as facilitating investigation of a given neuron type or given gene or property in the context of all its properties. In particular, we show how the format is extensible to the variety of neuron types and subtypes being revealed by RNA-seq and optogenetics. As current research reveals increasingly complex properties, the proposed approach can facilitate a consensus that goes beyond traditional neuron types.
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Affiliation(s)
- Gordon M Shepherd
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Luis Marenco
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Michael L Hines
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
| | - Michele Migliore
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Robert A McDougal
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Nicholas T Carnevale
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
| | - Adam J H Newton
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, Brooklyn, NY, United States
| | - Monique Surles-Zeigler
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Giorgio A Ascoli
- Bioengineering Department and Center for Neural Informatics, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, United States
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204
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Shepherd GM, Marenco L, Hines ML, Migliore M, McDougal RA, Carnevale NT, Newton AJH, Surles-Zeigler M, Ascoli GA. Neuron Names: A Gene- and Property-Based Name Format, With Special Reference to Cortical Neurons. Front Neuroanat 2019; 13:25. [PMID: 30949034 PMCID: PMC6437103 DOI: 10.3389/fnana.2019.00025] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/07/2019] [Indexed: 12/15/2022] Open
Abstract
Precision in neuron names is increasingly needed. We are entering a new era in which classical anatomical criteria are only the beginning toward defining the identity of a neuron as carried in its name. New criteria include patterns of gene expression, membrane properties of channels and receptors, pharmacology of neurotransmitters and neuropeptides, physiological properties of impulse firing, and state-dependent variations in expression of characteristic genes and proteins. These gene and functional properties are increasingly defining neuron types and subtypes. Clarity will therefore be enhanced by conveying as much as possible the genes and properties in the neuron name. Using a tested format of parent-child relations for the region and subregion for naming a neuron, we show how the format can be extended so that these additional properties can become an explicit part of a neuron's identity and name, or archived in a linked properties database. Based on the mouse, examples are provided for neurons in several brain regions as proof of principle, with extension to the complexities of neuron names in the cerebral cortex. The format has dual advantages, of ensuring order in archiving the hundreds of neuron types across all brain regions, as well as facilitating investigation of a given neuron type or given gene or property in the context of all its properties. In particular, we show how the format is extensible to the variety of neuron types and subtypes being revealed by RNA-seq and optogenetics. As current research reveals increasingly complex properties, the proposed approach can facilitate a consensus that goes beyond traditional neuron types.
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Affiliation(s)
- Gordon M. Shepherd
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Luis Marenco
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Michael L. Hines
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
| | - Michele Migliore
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Robert A. McDougal
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | | | - Adam J. H. Newton
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, Brooklyn, NY, United States
| | - Monique Surles-Zeigler
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Giorgio A. Ascoli
- Bioengineering Department and Center for Neural Informatics, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, United States
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205
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Economo MN, Winnubst J, Bas E, Ferreira TA, Chandrashekar J. Single‐neuron axonal reconstruction: The search for a wiring diagram of the brain. J Comp Neurol 2019; 527:2190-2199. [DOI: 10.1002/cne.24674] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 02/19/2019] [Accepted: 02/19/2019] [Indexed: 12/16/2022]
Affiliation(s)
| | - Johan Winnubst
- Janelia Research CampusHoward Hughes Medical Institute Ashburn Virginia
| | - Erhan Bas
- Janelia Research CampusHoward Hughes Medical Institute Ashburn Virginia
| | - Tiago A. Ferreira
- Janelia Research CampusHoward Hughes Medical Institute Ashburn Virginia
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206
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Tasic B, Yao Z, Graybuck LT, Smith KA, Nguyen TN, Bertagnolli D, Goldy J, Garren E, Economo MN, Viswanathan S, Penn O, Bakken T, Menon V, Miller J, Fong O, Hirokawa KE, Lathia K, Rimorin C, Tieu M, Larsen R, Casper T, Barkan E, Kroll M, Parry S, Shapovalova NV, Hirschstein D, Pendergraft J, Sullivan HA, Kim TK, Szafer A, Dee N, Groblewski P, Wickersham I, Cetin A, Harris JA, Levi BP, Sunkin SM, Madisen L, Daigle TL, Looger L, Bernard A, Phillips J, Lein E, Hawrylycz M, Svoboda K, Jones AR, Koch C, Zeng H. Shared and distinct transcriptomic cell types across neocortical areas. Nature 2018; 563:72-78. [PMID: 30382198 DOI: 10.1038/s41586-018-0654-5] [Citation(s) in RCA: 968] [Impact Index Per Article: 161.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 09/24/2018] [Indexed: 12/11/2022]
Abstract
The neocortex contains a multitude of cell types that are segregated into layers and functionally distinct areas. To investigate the diversity of cell types across the mouse neocortex, here we analysed 23,822 cells from two areas at distant poles of the mouse neocortex: the primary visual cortex and the anterior lateral motor cortex. We define 133 transcriptomic cell types by deep, single-cell RNA sequencing. Nearly all types of GABA (γ-aminobutyric acid)-containing neurons are shared across both areas, whereas most types of glutamatergic neurons were found in one of the two areas. By combining single-cell RNA sequencing and retrograde labelling, we match transcriptomic types of glutamatergic neurons to their long-range projection specificity. Our study establishes a combined transcriptomic and projectional taxonomy of cortical cell types from functionally distinct areas of the adult mouse cortex.
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Affiliation(s)
| | - Zizhen Yao
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | | | | | - Jeff Goldy
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Emma Garren
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Michael N Economo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Sarada Viswanathan
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Osnat Penn
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Vilas Menon
- Allen Institute for Brain Science, Seattle, WA, USA.,Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | | | - Olivia Fong
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Kanan Lathia
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Michael Tieu
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | - Eliza Barkan
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Sheana Parry
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | | | | | | | - Aaron Szafer
- Allen Institute for Brain Science, Seattle, WA, USA
| | - Nick Dee
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Ian Wickersham
- Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ali Cetin
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Boaz P Levi
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | | | | | - Loren Looger
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Amy Bernard
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Ed Lein
- Allen Institute for Brain Science, Seattle, WA, USA
| | | | - Karel Svoboda
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | | | | | - Hongkui Zeng
- Allen Institute for Brain Science, Seattle, WA, USA
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207
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208
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Anterolateral Motor Cortex Connects with a Medial Subdivision of Ventromedial Thalamus through Cell Type-Specific Circuits, Forming an Excitatory Thalamo-Cortico-Thalamic Loop via Layer 1 Apical Tuft Dendrites of Layer 5B Pyramidal Tract Type Neurons. J Neurosci 2018; 38:8787-8797. [PMID: 30143573 DOI: 10.1523/jneurosci.1333-18.2018] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/03/2018] [Accepted: 08/09/2018] [Indexed: 01/18/2023] Open
Abstract
The anterolateral motor cortex (ALM) and ventral medial (VM) thalamus are functionally linked to support persistent activity during motor planning. We analyzed the underlying synaptic interconnections using optogenetics and electrophysiology in mice (female/male). In cortex, thalamocortical (TC) axons from VM thalamus excited VM-projecting pyramidal tract (PT) neurons in layer 5B of ALM. These axons also strongly excited layer 2/3 neurons (which strongly excite PT neurons, as previously shown) but not VM-projecting corticothalamic (CT) neurons in layer 6. The strongest connections in the VM → PT circuit were localized to apical tuft dendrites of PT neurons, in layer 1. These tuft inputs were selectively augmented after blocking hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. In thalamus, axons from ALM PT neurons excited ALM-projecting VM neurons, located medially in VM. These axons provided weak input to neurons in mediodorsal nucleus, and little or no input either to neurons in the GABAergic reticular thalamic nucleus or to neurons in VM projecting to primary motor cortex (M1). Conversely, M1 PT axons excited M1- but not ALM-projecting VM neurons. Our findings indicate, first, a set of cell type-specific connections forming an excitatory thalamo-cortico-thalamic loop for ALM ↔ VM communication and a circuit-level substrate for supporting reverberant activity in this system. Second, a key feature of this loop is the prominent involvement of layer 1 synapses onto apical dendrites, a subcellular compartment with distinct signaling properties, including HCN-mediated gain control. Third, the segregation of the ALM ↔ VM loop from M1-related circuits of VM adds cellular-level support for the concept of parallel pathway organization in the motor system.SIGNIFICANCE STATEMENT Anterolateral motor cortex (ALM), a higher-order motor area in the mouse, and ventromedial (VM) thalamus are anatomically and functionally linked, but their synaptic interconnections at the cellular level are unknown. Our results show that ALM pyramidal tract neurons monosynaptically excite ALM-projecting thalamocortical neurons in a medial subdivision of VM thalamus, and vice versa. The thalamo-cortico-thalamic loop formed by these recurrent connections constitutes a circuit-level substrate for supporting reverberant activity in this system.
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