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Parvalbumin-expressing interneurons can act solo while somatostatin-expressing interneurons act in chorus in most cases on cortical pyramidal cells. Sci Rep 2017; 7:12764. [PMID: 28986578 PMCID: PMC5630625 DOI: 10.1038/s41598-017-12958-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 09/13/2017] [Indexed: 11/24/2022] Open
Abstract
Neural circuits in the cerebral cortex consist primarily of excitatory pyramidal (Pyr) cells and inhibitory interneurons. Interneurons are divided into several subtypes, in which the two major groups are those expressing parvalbumin (PV) or somatostatin (SOM). These subtypes of interneurons are reported to play distinct roles in tuning and/or gain of visual response of pyramidal cells in the visual cortex. It remains unclear whether there is any quantitative and functional difference between the PV → Pyr and SOM → Pyr connections. We compared unitary inhibitory postsynaptic currents (uIPSCs) evoked by electrophysiological activation of single presynaptic interneurons with population IPSCs evoked by photo-activation of a mass of interneurons in vivo and in vitro in transgenic mice in which PV or SOM neurons expressed channelrhodopsin-2, and found that at least about 14 PV neurons made strong connections with a postsynaptic Pyr cell while a much larger number of SOM neurons made weak connections. Activation or suppression of single PV neurons modified visual responses of postsynaptic Pyr cells in 6 of 7 pairs whereas that of single SOM neurons showed no significant modification in 8 of 11 pairs, suggesting that PV neurons can act solo whereas most of SOM neurons may act in chorus on Pyr cells.
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102
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Abstract
Cortical networks are composed of glutamatergic excitatory projection neurons and local GABAergic inhibitory interneurons that gate signal flow and sculpt network dynamics. Although they represent a minority of the total neocortical neuronal population, GABAergic interneurons are highly heterogeneous, forming functional classes based on their morphological, electrophysiological, and molecular features, as well as connectivity and in vivo patterns of activity. Here we review our current understanding of neocortical interneuron diversity and the properties that distinguish cell types. We then discuss how the involvement of multiple cell types, each with a specific set of cellular properties, plays a crucial role in diversifying and increasing the computational power of a relatively small number of simple circuit motifs forming cortical networks. We illustrate how recent advances in the field have shed light onto the mechanisms by which GABAergic inhibition contributes to network operations.
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103
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Santuy A, Rodriguez JR, DeFelipe J, Merchan-Perez A. Volume electron microscopy of the distribution of synapses in the neuropil of the juvenile rat somatosensory cortex. Brain Struct Funct 2017; 223:77-90. [PMID: 28721455 PMCID: PMC5772167 DOI: 10.1007/s00429-017-1470-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 07/04/2017] [Indexed: 11/29/2022]
Abstract
Knowing the proportions of asymmetric (excitatory) and symmetric (inhibitory) synapses in the neuropil is critical for understanding the design of cortical circuits. We used focused ion beam milling and scanning electron microscopy (FIB/SEM) to obtain stacks of serial sections from the six layers of the juvenile rat (postnatal day 14) somatosensory cortex (hindlimb representation). We segmented in three-dimensions 6184 synaptic junctions and determined whether they were established on dendritic spines or dendritic shafts. Of all these synapses, 87–94% were asymmetric and 6–13% were symmetric. Asymmetric synapses were preferentially located on dendritic spines in all layers (80–91%) while symmetric synapses were mainly located on dendritic shafts (62–86%). Furthermore, we found that less than 6% of the dendritic spines establish more than one synapse. The vast majority of axospinous synapses were established on the spine head. Synapses on the spine neck were scarce, although they were more common when the dendritic spine established multiple synapses. This study provides a new large quantitative dataset that may contribute not only to the knowledge of the ultrastructure of the cortex, but also towards defining the connectivity patterns through all cortical layers.
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Affiliation(s)
- A Santuy
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223, Madrid, Spain.,CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Madrid, Spain
| | - J R Rodriguez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223, Madrid, Spain.,Instituto Cajal, Consejo Superior de Investigaciones Científicas, 28002, Madrid, Spain.,CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Madrid, Spain
| | - J DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223, Madrid, Spain.,Instituto Cajal, Consejo Superior de Investigaciones Científicas, 28002, Madrid, Spain.,CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Madrid, Spain
| | - A Merchan-Perez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223, Madrid, Spain. .,CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Madrid, Spain. .,Departamento de Arquitectura y Tecnología de sistemas Informáticos, Universidad Politécnica de Madrid, Boadilla del Monte, 28660, Madrid, Spain.
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104
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Vien TN, Moss SJ, Davies PA. Regulating the Efficacy of Inhibition Through Trafficking of γ-Aminobutyric Acid Type A Receptors. Anesth Analg 2017; 123:1220-1227. [PMID: 27285004 DOI: 10.1213/ane.0000000000001349] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Trafficking of anesthetic-sensitive receptors within the plasma membrane, or from one cellular component to another, occurs continuously. Changes in receptor trafficking have implications in altering anesthetic sensitivity. γ-Aminobutyric acid type A receptors (GABAARs) are anion-permeable ion channels and are the major class of receptor in the adult mammalian central nervous system that mediates inhibition. GABAergic signaling allows for precise synchronized firing of action potentials within brain circuits that is critical for cognition, behavior, and consciousness. This precision depends upon tightly controlled trafficking of GABAARs into the membrane. General anesthetics bind to and allosterically enhance GABAARs by prolonging the open state of the receptor and thereby altering neuronal and brain circuit activity. Subunit composition and GABAAR localization strongly influence anesthetic end points; therefore, changes in GABAAR trafficking could have significant consequences to anesthetic sensitivity. GABAARs are not static membrane structures but are in a constant state of flux between extrasynaptic and synaptic locations and are continually endocytosed and recycled from and to the membrane. Neuronal activity, posttranslational modifications, and some naturally occurring and synthetic compounds can influence the expression and trafficking of GABAARs. In this article, we review GABAARs, their trafficking, and how phosphorylation of GABAAR subunits can influence the surface expression and function of the receptor. Ultimately, alterations of GABAAR trafficking could modify anesthetic end points, both unintentionally through pathologic processes but potentially as a therapeutic target to adjust anesthetic-sensitive GABAARs.
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Affiliation(s)
- Thuy N Vien
- From the *Department of Neuroscience, Tufts University School of Medicine, Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts; and †Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts
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105
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Vascak M, Sun J, Baer M, Jacobs KM, Povlishock JT. Mild Traumatic Brain Injury Evokes Pyramidal Neuron Axon Initial Segment Plasticity and Diffuse Presynaptic Inhibitory Terminal Loss. Front Cell Neurosci 2017. [PMID: 28634442 PMCID: PMC5459898 DOI: 10.3389/fncel.2017.00157] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The axon initial segment (AIS) is the site of action potential (AP) initiation, thus a crucial regulator of neuronal activity. In excitatory pyramidal neurons, the high density of voltage-gated sodium channels (NaV1.6) at the distal AIS regulates AP initiation. A surrogate AIS marker, ankyrin-G (ankG) is a structural protein regulating neuronal functional via clustering voltage-gated ion channels. In neuronal circuits, changes in presynaptic input can alter postsynaptic output via AIS structural-functional plasticity. Recently, we showed experimental mild traumatic brain injury (mTBI) evokes neocortical circuit disruption via diffuse axonal injury (DAI) of excitatory and inhibitory neuronal systems. A key finding was that mTBI-induced neocortical electrophysiological changes involved non-DAI/ intact excitatory pyramidal neurons consistent with AIS-specific alterations. In the current study we employed Thy1-yellow fluorescent protein (YFP)-H mice to test if mTBI induces AIS structural and/or functional plasticity within intact pyramidal neurons 2 days after mTBI. We used confocal microscopy to assess intact YFP+ pyramidal neurons in layer 5 of primary somatosensory barrel field (S1BF), whose axons were continuous from the soma of origin to the subcortical white matter (SCWM). YFP+ axonal traces were superimposed on ankG and NaV1.6 immunofluorescent profiles to determine AIS position and length. We found that while mTBI had no effect on ankG start position, the length significantly decreased from the distal end, consistent with the site of AP initiation at the AIS. However, NaV1.6 structure did not change after mTBI, suggesting uncoupling from ankG. Parallel quantitative analysis of presynaptic inhibitory terminals along the postsynaptic perisomatic domain of these same intact YFP+ excitatory pyramidal neurons revealed a significant decrease in GABAergic bouton density. Also within this non-DAI population, patch-clamp recordings of intact YFP+ pyramidal neurons showed AP acceleration decreased 2 days post-mTBI, consistent with AIS functional plasticity. Simulations of realistic pyramidal neuron computational models using experimentally determined AIS lengths showed a subtle decrease is NaV1.6 density is sufficient to attenuate AP acceleration. Collectively, these findings highlight the complexity of mTBI-induced neocortical circuit disruption, involving changes in extrinsic/presynaptic inhibitory perisomatic input interfaced with intrinsic/postsynaptic intact excitatory neuron AIS output.
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Affiliation(s)
- Michal Vascak
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - Jianli Sun
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - Matthew Baer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - Kimberle M Jacobs
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
| | - John T Povlishock
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of MedicineRichmond, VA, United States
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106
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Thompson JL, Drysdale M, Baimel C, Kaur M, MacGowan T, Pitman KA, Borgland SL. Obesity-Induced Structural and Neuronal Plasticity in the Lateral Orbitofrontal Cortex. Neuropsychopharmacology 2017; 42:1480-1490. [PMID: 28042870 PMCID: PMC5398895 DOI: 10.1038/npp.2016.284] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/22/2016] [Accepted: 12/18/2016] [Indexed: 12/19/2022]
Abstract
The orbitofrontal cortex (OFC) integrates sensory information with the current value of foods and updates actions based on this information. Obese humans and rats fed a cafeteria diet have impaired devaluation of food rewards, implicating a potential obesity-induced dysfunction of the OFC. We hypothesized that obesity alters OFC pyramidal neuronal structure and function and reduces conditioned suppression of feeding. Rats were given restricted (1 h/day), extended (23 h/day) or no (chow only) access to a cafeteria diet and tested for a conditioned suppression of feeding. Golgi-cox impregnation and whole-cell patch clamp experiments were performed in lateral OFC pyramidal neurons of rats from the 3 feeding groups. Rats with 40 days of extended, but not restricted, access to a cafeteria diet became obese and continued to feed during foot shock-predicting cues. Access to a cafeteria diet induced morphological changes in basilar dendrites of lateral OFC pyramidal neurons. While there were no alterations in excitatory synaptic transmission underlying altered spine density, we observed a more depolarized resting membrane potential. This was accompanied by decreased inhibitory synaptic transmission onto lateral OFC pyramidal neurons due to decreased release probability at GABAergic inputs. These changes could underlie the inability of the OFC to encode changes in the motivation value of food that is observed in obese rodents and humans.
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Affiliation(s)
- Jennifer L Thompson
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Michael Drysdale
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Corey Baimel
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Manpreet Kaur
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Taigan MacGowan
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Kimberley A Pitman
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Stephanie L Borgland
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada,Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Dr NW Calgary, Alberta T2N 4N1, Canada, Tel: +1 403 220 6967, Fax: +4032832700, E-mail:
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107
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Differential excitatory control of 2 parallel basket cell networks in amygdala microcircuits. PLoS Biol 2017; 15:e2001421. [PMID: 28542195 PMCID: PMC5443504 DOI: 10.1371/journal.pbio.2001421] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 04/28/2017] [Indexed: 12/29/2022] Open
Abstract
Information processing in neural networks depends on the connectivity among excitatory and inhibitory neurons. The presence of parallel, distinctly controlled local circuits within a cortical network may ensure an effective and dynamic regulation of microcircuit function. By applying a combination of optogenetics, electrophysiological recordings, and high resolution microscopic techniques, we uncovered the organizing principles of synaptic communication between principal neurons and basket cells in the basal nucleus of the amygdala. In this cortical structure, known to be critical for emotional memory formation, we revealed the presence of 2 parallel basket cell networks expressing either parvalbumin or cholecystokinin. While the 2 basket cell types are mutually interconnected within their own category via synapses and gap junctions, they avoid innervating each other, but form synaptic contacts with axo-axonic cells. Importantly, both basket cell types have the similar potency to control principal neuron spiking, but they receive excitatory input from principal neurons with entirely diverse features. This distinct feedback synaptic excitation enables a markedly different recruitment of the 2 basket cell types upon the activation of local principal neurons. Our data suggest fundamentally different functions for the 2 parallel basket cell networks in circuit operations in the amygdala. The perisomatic region of neurons refers collectively to the membrane surface of the cell body or soma, proximal dendrites, and axon initial segment. This is a unique functional domain in which the activity of a neuron can be controlled in the most effective manner. In the cerebral cortex, the perisomatic region of excitatory principal cells is solely innervated by inhibitory interneurons, which can be divided into 3 functional groups: axo-axonic cells and 2 types of basket cells. The reason why 3 distinct types of inhibitory cells are specialized to control principal cell firing is still unknown. To reveal the possible differences in the role of the 3 interneuron types played in cortical operation, we have investigated the organizing principles of synaptic communication between principal cells and inhibitory cell types in the basal nucleus of the amygdala. In this cortical structure, known to be critical for affective behavior, we revealed that the 2 basket cell types avoid innervating each other but contact axo-axonic cells. Both basket cell types have a similar potency to control principal cell firing, but they receive excitatory input from principal cells with entirely distinct features. Our data suggest fundamentally different functions for the 2 parallel basket cell networks in amygdala operation.
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108
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Hildebrand DGC, Cicconet M, Torres RM, Choi W, Quan TM, Moon J, Wetzel AW, Scott Champion A, Graham BJ, Randlett O, Plummer GS, Portugues R, Bianco IH, Saalfeld S, Baden AD, Lillaney K, Burns R, Vogelstein JT, Schier AF, Lee WCA, Jeong WK, Lichtman JW, Engert F. Whole-brain serial-section electron microscopy in larval zebrafish. Nature 2017; 545:345-349. [PMID: 28489821 PMCID: PMC5594570 DOI: 10.1038/nature22356] [Citation(s) in RCA: 176] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/11/2017] [Indexed: 12/18/2022]
Abstract
High-resolution serial-section electron microscopy (ssEM) makes it possible to investigate the dense meshwork of axons, dendrites, and synapses that form neuronal circuits. However, the imaging scale required to comprehensively reconstruct these structures is more than ten orders of magnitude smaller than the spatial extents occupied by networks of interconnected neurons, some of which span nearly the entire brain. Difficulties in generating and handling data for large volumes at nanoscale resolution have thus restricted vertebrate studies to fragments of circuits. These efforts were recently transformed by advances in computing, sample handling, and imaging techniques, but high-resolution examination of entire brains remains a challenge. Here, we present ssEM data for the complete brain of a larval zebrafish (Danio rerio) at 5.5 days post-fertilization. Our approach utilizes multiple rounds of targeted imaging at different scales to reduce acquisition time and data management requirements. The resulting dataset can be analysed to reconstruct neuronal processes, permitting us to survey all myelinated axons (the projectome). These reconstructions enable precise investigations of neuronal morphology, which reveal remarkable bilateral symmetry in myelinated reticulospinal and lateral line afferent axons. We further set the stage for whole-brain structure-function comparisons by co-registering functional reference atlases and in vivo two-photon fluorescence microscopy data from the same specimen. All obtained images and reconstructions are provided as an open-access resource.
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Affiliation(s)
- David Grant Colburn Hildebrand
- Graduate Program in Neuroscience, Division of Medical Sciences, Graduate School of Arts and Sciences, Harvard University, Cambridge, Massachusetts, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
- Image and Data Analysis Core, Harvard Medical School, Boston, Massachusetts, USA
| | - Marcelo Cicconet
- Image and Data Analysis Core, Harvard Medical School, Boston, Massachusetts, USA
| | - Russel Miguel Torres
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Woohyuk Choi
- School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Tran Minh Quan
- School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Jungmin Moon
- School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Arthur Willis Wetzel
- Pittsburgh Supercomputing Center, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | | | - Brett Jesse Graham
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Owen Randlett
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - George Scott Plummer
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Ruben Portugues
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Isaac Henry Bianco
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Stephan Saalfeld
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | | | - Kunal Lillaney
- Department of Computer Science, Johns Hopkins University, Baltimore, Maryland, USA
| | - Randal Burns
- Department of Computer Science, Johns Hopkins University, Baltimore, Maryland, USA
| | - Joshua Tzvi Vogelstein
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Alexander Franz Schier
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
- Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA
- FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Wei-Chung Allen Lee
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Won-Ki Jeong
- School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Jeff William Lichtman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
| | - Florian Engert
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
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109
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Feldmeyer D, Qi G, Emmenegger V, Staiger JF. Inhibitory interneurons and their circuit motifs in the many layers of the barrel cortex. Neuroscience 2017; 368:132-151. [PMID: 28528964 DOI: 10.1016/j.neuroscience.2017.05.027] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 05/11/2017] [Accepted: 05/12/2017] [Indexed: 10/19/2022]
Abstract
Recent years have seen substantial progress in studying the structural and functional properties of GABAergic interneurons and their roles in the neuronal networks of barrel cortex. Although GABAergic interneurons represent only about 12% of the total number of neocortical neurons, they are extremely diverse with respect to their structural and functional properties. It has become clear that barrel cortex interneurons not only serve the maintenance of an appropriate excitation/inhibition balance but also are directly involved in sensory processing. In this review we present different interneuron types and their axonal projection pattern framework in the context of the laminar and columnar organization of the barrel cortex. The main focus is here on the most prominent interneuron types, i.e. basket cells, chandelier cells, Martinotti cells, bipolar/bitufted cells and neurogliaform cells, but interneurons with more unusual axonal domains will also be mentioned. We describe their developmental origin, their classification with respect to molecular, morphological and intrinsic membrane and synaptic properties. Most importantly, we will highlight the most prominent circuit motifs these interneurons are involved in and in which way they serve feed-forward inhibition, feedback inhibition and disinhibition. Finally, this will be put into context to their functional roles in sensory signal perception and processing in the whisker system and beyond.
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Affiliation(s)
- Dirk Feldmeyer
- Institute of Neuroscience and Medicine, INM-2, Research Center Jülich, D-52425 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.
| | - Guanxiao Qi
- Institute of Neuroscience and Medicine, INM-2, Research Center Jülich, D-52425 Jülich, Germany
| | - Vishalini Emmenegger
- Institute of Neuroscience and Medicine, INM-2, Research Center Jülich, D-52425 Jülich, Germany; Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, D-52074 Aachen, Germany
| | - Jochen F Staiger
- Institute for Neuroanatomy, University Medical Center Göttingen, Georg-August-University, Göttingen D-37075, Germany.
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110
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Krystal JH, Anticevic A, Yang GJ, Dragoi G, Driesen NR, Wang XJ, Murray JD. Impaired Tuning of Neural Ensembles and the Pathophysiology of Schizophrenia: A Translational and Computational Neuroscience Perspective. Biol Psychiatry 2017; 81:874-885. [PMID: 28434616 PMCID: PMC5407407 DOI: 10.1016/j.biopsych.2017.01.004] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 12/14/2016] [Accepted: 01/04/2017] [Indexed: 10/20/2022]
Abstract
The functional optimization of neural ensembles is central to human higher cognitive functions. When the functions through which neural activity is tuned fail to develop or break down, symptoms and cognitive impairments arise. This review considers ways in which disturbances in the balance of excitation and inhibition might develop and be expressed in cortical networks in association with schizophrenia. This presentation is framed within a developmental perspective that begins with disturbances in glutamate synaptic development in utero. It considers developmental correlates and consequences, including compensatory mechanisms that increase intrinsic excitability or reduce inhibitory tone. It also considers the possibility that these homeostatic increases in excitability have potential negative functional and structural consequences. These negative functional consequences of disinhibition may include reduced working memory-related cortical activity associated with the downslope of the "inverted-U" input-output curve, impaired spatial tuning of neural activity and impaired sparse coding of information, and deficits in the temporal tuning of neural activity and its implication for neural codes. The review concludes by considering the functional significance of noisy activity for neural network function. The presentation draws on computational neuroscience and pharmacologic and genetic studies in animals and humans, particularly those involving N-methyl-D-aspartate glutamate receptor antagonists, to illustrate principles of network regulation that give rise to features of neural dysfunction associated with schizophrenia. While this presentation focuses on schizophrenia, the general principles outlined in the review may have broad implications for considering disturbances in the regulation of neural ensembles in psychiatric disorders.
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Affiliation(s)
- John H. Krystal
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT USA,Department of Neuroscience, Yale University School of Medicine, New Haven, CT USA,Clinical Neuroscience Division, VA National Center for PTSD, VA Connecticut Healthcare System, West Haven, CT USA,Behavioral Health Services, Yale-New Haven Hospital, New Haven, CT USA
| | - Alan Anticevic
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT USA,Department of Psychology, Yale University
| | - Genevieve J. Yang
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT USA,Department of Neuroscience, Yale University School of Medicine, New Haven, CT USA
| | - George Dragoi
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT USA,Department of Neuroscience, Yale University School of Medicine, New Haven, CT USA
| | - Naomi R. Driesen
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT USA,Clinical Neuroscience Division, VA National Center for PTSD, VA Connecticut Healthcare System, West Haven, CT USA
| | | | - John D. Murray
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT USA
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111
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Tatti R, Haley MS, Swanson O, Tselha T, Maffei A. Neurophysiology and Regulation of the Balance Between Excitation and Inhibition in Neocortical Circuits. Biol Psychiatry 2017; 81:821-831. [PMID: 27865453 PMCID: PMC5374043 DOI: 10.1016/j.biopsych.2016.09.017] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 08/25/2016] [Accepted: 09/15/2016] [Indexed: 12/18/2022]
Abstract
Brain function relies on the ability of neural networks to maintain stable levels of activity, while experiences sculpt them. In the neocortex, the balance between activity and stability relies on the coregulation of excitatory and inhibitory inputs onto principal neurons. Shifts of excitation or inhibition result in altered excitability impaired processing of incoming information. In many neurodevelopmental and neuropsychiatric disorders, the excitability of local circuits is altered, suggesting that their pathophysiology may involve shifts in synaptic excitation, inhibition, or both. Most studies focused on identifying the cellular and molecular mechanisms controlling network excitability to assess whether they may be altered in animal models of disease. The impact of changes in excitation/inhibition balance on local circuit and network computations is not clear. Here we report findings on the integration of excitatory and inhibitory inputs in healthy cortical circuits and discuss how shifts in excitation/inhibition balance may relate to pathological phenotypes.
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Affiliation(s)
- Roberta Tatti
- Dept. of Neurobiology and Behavior, SUNY-Stony Brook, Stony Brook, NY 11794
| | - Melissa S. Haley
- Dept. of Neurobiology and Behavior, SUNY-Stony Brook, Stony Brook, NY 11794
| | - Olivia Swanson
- Dept. of Neurobiology and Behavior, SUNY-Stony Brook, Stony Brook, NY 11794
| | - Tenzin Tselha
- Dept. of Neurobiology and Behavior, SUNY-Stony Brook, Stony Brook, NY 11794
| | - Arianna Maffei
- Department of Neurobiology and Behavior, Stony Brook University, The State University of New York, Stony Brook, New York.
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112
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Neocortical Chandelier Cells Developmentally Shape Axonal Arbors through Reorganization but Establish Subcellular Synapse Specificity without Refinement. eNeuro 2017; 4:eN-NWR-0057-17. [PMID: 28584877 PMCID: PMC5458751 DOI: 10.1523/eneuro.0057-17.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 11/21/2022] Open
Abstract
Diverse types of cortical interneurons (INs) mediate various kinds of inhibitory control mechanisms to balance and shape network activity. Distinct IN subtypes develop uniquely organized axonal arbors that innervate different subcellular compartments of excitatory principal neurons (PNs), which critically contribute to determining their output properties. However, it remains poorly understood how they establish this peculiar axonal organization and synaptic connectivity during development. Here, taking advantage of genetic labeling of IN progenitors, we examined developmental processes of axonal arbors and synaptic connections formed by murine chandelier cells (ChCs), which innervate axon initial segments (AISs) of PNs and thus powerfully regulate their spike generation. Our quantitative analysis by light microscopy revealed that ChCs overgrow and subsequently refine axonal branches as well as varicosities. Interestingly, we found that although a significant number of axonal varicosities are formed off AISs in addition to on AISs, presynaptic markers are predominantly colocalized with those on AISs throughout development. Immunoelectron microscopic (IEM) analysis also demonstrated that only varicosities apposed to AISs contain presynaptic profiles. These results suggest that subcellular synapse specificity of ChCs is genetically predetermined while axonal geometry is shaped through remodeling. Molecular cues localized at AISs may regulate target recognition and synapse formation by ChCs.
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Albertson AJ, Bohannon AS, Hablitz JJ. HCN Channel Modulation of Synaptic Integration in GABAergic Interneurons in Malformed Rat Neocortex. Front Cell Neurosci 2017; 11:109. [PMID: 28469560 PMCID: PMC5396479 DOI: 10.3389/fncel.2017.00109] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/30/2017] [Indexed: 12/02/2022] Open
Abstract
Cortical malformations are often associated with pharmaco-resistant epilepsy. Alterations in hyperpolarization-activated, cyclic nucleotide-gated, non-specific cation (HCN) channels have been shown to contribute to malformation associated hyperexcitability. We have recently demonstrated that expression of HCN channels and Ih current amplitudes are reduced in layer (L) 5 pyramidal neurons of rats with freeze lesion induced malformations. These changes were associated with an increased EPSP temporal summation. Here, we examine the effects of HCN channel inhibition on synaptic responses in fast spiking, presumptive basket cells and accommodating, presumptive Martinotti, GABAergic interneurons in slices from freeze lesioned animals. In control animals, fast spiking cells showed small sag responses which were reduced by the HCN channel antagonist ZD7288. Fast spiking cells in lesioned animals showed absent or reduced sag responses. The amplitude of single evoked EPSPs in fast spiking cells in the control group was not affected by HCN channel inhibition with ZD7288. EPSP ratios during short stimulus trains at 25 Hz were not significantly different between control and lesion groups. ZD7288 produced an increase in EPSP ratios in the control but not lesion groups. Under voltage clamp conditions, ZD7288 did not affect EPSC ratios. In the control group, accommodating interneurons showed robust sag responses which were significantly reduced by ZD7288. HCN channel inhibition increased EPSP ratios and area in controls but not the lesioned group. The results indicate that HCN channels differentially modulate EPSPs in different classes of GABAergic interneurons and that this control is reduced in malformed rat neocortex.
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Affiliation(s)
- Asher J Albertson
- Department of Neurobiology, University of Alabama at BirminghamBirmingham, AL, USA
| | - Andrew S Bohannon
- Department of Neurobiology, University of Alabama at BirminghamBirmingham, AL, USA
| | - John J Hablitz
- Department of Neurobiology, University of Alabama at BirminghamBirmingham, AL, USA
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Distinct Physiological Maturation of Parvalbumin-Positive Neuron Subtypes in Mouse Prefrontal Cortex. J Neurosci 2017; 37:4883-4902. [PMID: 28408413 DOI: 10.1523/jneurosci.3325-16.2017] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 03/06/2017] [Accepted: 04/06/2017] [Indexed: 12/28/2022] Open
Abstract
Parvalbumin-positive (PV+) neurons control the timing of pyramidal cell output in cortical neuron networks. In the prefrontal cortex (PFC), PV+ neuron activity is involved in cognitive function, suggesting that PV+ neuron maturation is critical for cognitive development. The two major PV+ neuron subtypes found in the PFC, chandelier cells (ChCs) and basket cells (BCs), are thought to play different roles in cortical circuits, but the trajectories of their physiological maturation have not been compared. Using two separate mouse lines, we found that in the mature PFC, both ChCs and BCs are abundant in superficial layer 2, but only BCs are present in deeper laminar locations. This distinctive laminar distribution was observed by postnatal day 12 (P12), when we first identified ChCs by the presence of axon cartridges. Electrophysiology analysis of excitatory synapse development, starting at P12, showed that excitatory drive remains low throughout development in ChCs, but increases rapidly before puberty in BCs, with an earlier time course in deeper-layer BCs. Consistent with a role of excitatory synaptic drive in the maturation of PV+ neuron firing properties, the fast-spiking phenotype showed different maturation trajectories between ChCs and BCs, and between superficial versus deep-layer BCs. ChC and BC maturation was nearly completed, via different trajectories, before the onset of puberty. These findings suggest that ChC and BC maturation may contribute differentially to the emergence of cognitive function, primarily during prepubertal development.SIGNIFICANCE STATEMENT Parvalbumin-positive (PV+) neurons tightly control pyramidal cell output. Thus PV+ neuron maturation in the prefrontal cortex (PFC) is crucial for cognitive development. However, the relative physiological maturation of the two major subtypes of PV+ neurons, chandelier cells (ChCs) and basket cells (BCs), has not been determined. We assessed the maturation of ChCs and BCs in different layers of the mouse PFC, and found that, from early postnatal age, ChCs and BCs differ in laminar location. Excitatory synapses and fast-spiking properties matured before the onset of puberty in both cell types, but following cell type-specific developmental trajectories. Hence, the physiological maturation of ChCs and BCs may contribute to the emergence of cognitive function differentially, and predominantly during prepubertal development.
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115
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Rate and Temporal Coding Convey Multisensory Information in Primary Sensory Cortices. eNeuro 2017; 4:eN-NWR-0037-17. [PMID: 28374008 PMCID: PMC5362936 DOI: 10.1523/eneuro.0037-17.2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 02/10/2017] [Indexed: 11/21/2022] Open
Abstract
Optimal behavior and survival result from integration of information across sensory systems. Modulation of network activity at the level of primary sensory cortices has been identified as a mechanism of cross-modal integration, yet its cellular substrate is still poorly understood. Here, we uncover the mechanisms by which individual neurons in primary somatosensory (S1) and visual (V1) cortices encode visual-tactile stimuli. For this, simultaneous extracellular recordings were performed from all layers of the S1 barrel field and V1 in Brown Norway rats in vivo and units were clustered and assigned to pyramidal neurons (PYRs) and interneurons (INs). We show that visual-tactile stimulation modulates the firing rate of a relatively low fraction of neurons throughout all cortical layers. Generally, it augments the firing of INs and decreases the activity of PYRs. Moreover, bimodal stimulation shapes the timing of neuronal firing by strengthening the phase-coupling between neuronal discharge and theta–beta band network oscillations as well as by modulating spiking onset. Sparse direct axonal projections between neurons in S1 and V1 seem to time the spike trains between the two cortical areas and, thus, may act as a substrate of cross-modal modulation. These results indicate that few cortical neurons mediate multisensory effects in primary sensory areas by directly encoding cross-modal information by their rate and timing of firing.
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Farahmandfar M, Akbarabadi A, Bakhtazad A, Zarrindast MR. Recovery from ketamine-induced amnesia by blockade of GABA-A receptor in the medial prefrontal cortex of mice. Neuroscience 2017; 344:48-55. [DOI: 10.1016/j.neuroscience.2016.02.056] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 02/23/2016] [Accepted: 02/23/2016] [Indexed: 11/30/2022]
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Barsy B, Szabó GG, Andrási T, Vikór A, Hájos N. Different output properties of perisomatic region-targeting interneurons in the basal amygdala. Eur J Neurosci 2017; 45:548-558. [PMID: 27977063 DOI: 10.1111/ejn.13498] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/24/2016] [Accepted: 11/27/2016] [Indexed: 01/06/2023]
Abstract
The perisomatic region of principal neurons in cortical regions is innervated by three types of GABAergic interneuron, including parvalbumin-containing basket cells (PVBCs) and axo-axonic cells (AACs), as well as cholecystokinin and type 1 cannabinoid receptor-expressing basket cells (CCK/CB1BCs). These perisomatic inhibitory cell types can also be found in the basal nucleus of the amygdala, however, their output properties are largely unknown. Here, we performed whole-cell recordings in morphologically identified interneurons in slices prepared from transgenic mice, in which the GABAergic cells could be selectively targeted. Investigating the passive and active membrane properties of interneurons located within the basal amygdala revealed that the three interneuron types have distinct single-cell properties. For instance, the input resistance, spike rate, accommodation in discharge rate, or after-hyperpolarization width at the half maximal amplitude separated the three interneuron types. Furthermore, we performed paired recordings from interneurons and principal neurons to uncover the basic features of unitary inhibitory postsynaptic currents (uIPSCs). Although we found no difference in the magnitude of responses measured in the principal neurons, the uIPSCs originating from the distinct interneuron types differed in rise time, failure rate, latency, and short-term dynamics. Moreover, the asynchronous transmitter release induced by a train of action potentials was typical for the output synapses of CCK/CB1BCs. Our results suggest that, despite the similar uIPSC magnitudes originating from the three perisomatic inhibitory cell types, their distinct release properties together with the marked differences in their spiking characteristics may contribute to accomplish specific functions in amygdala network operation.
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Affiliation(s)
- Boglárka Barsy
- 'Lendület' Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, H-1450, Hungary
| | - Gergely G Szabó
- 'Lendület' Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, H-1450, Hungary
| | - Tibor Andrási
- 'Lendület' Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, H-1450, Hungary.,János Szentágothai School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Attila Vikór
- 'Lendület' Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, H-1450, Hungary
| | - Norbert Hájos
- 'Lendület' Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, H-1450, Hungary
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118
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Long-range projections coordinate distributed brain-wide neural activity with a specific spatiotemporal profile. Proc Natl Acad Sci U S A 2016; 113:E8306-E8315. [PMID: 27930323 DOI: 10.1073/pnas.1616361113] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One challenge in contemporary neuroscience is to achieve an integrated understanding of the large-scale brain-wide interactions, particularly the spatiotemporal patterns of neural activity that give rise to functions and behavior. At present, little is known about the spatiotemporal properties of long-range neuronal networks. We examined brain-wide neural activity patterns elicited by stimulating ventral posteromedial (VPM) thalamo-cortical excitatory neurons through combined optogenetic stimulation and functional MRI (fMRI). We detected robust optogenetically evoked fMRI activation bilaterally in primary visual, somatosensory, and auditory cortices at low (1 Hz) but not high frequencies (5-40 Hz). Subsequent electrophysiological recordings indicated interactions over long temporal windows across thalamo-cortical, cortico-cortical, and interhemispheric callosal projections at low frequencies. We further observed enhanced visually evoked fMRI activation during and after VPM stimulation in the superior colliculus, indicating that visual processing was subcortically modulated by low-frequency activity originating from VPM. Stimulating posteromedial complex thalamo-cortical excitatory neurons also evoked brain-wide blood-oxygenation-level-dependent activation, although with a distinct spatiotemporal profile. Our results directly demonstrate that low-frequency activity governs large-scale, brain-wide connectivity and interactions through long-range excitatory projections to coordinate the functional integration of remote brain regions. This low-frequency phenomenon contributes to the neural basis of long-range functional connectivity as measured by resting-state fMRI.
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119
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Fassini A, Resstel LBM, Corrêa FMA. Prelimbic cortex GABA A receptors are involved in the mediation of restraint stress-evoked cardiovascular responses. Stress 2016; 19:576-584. [PMID: 27582393 DOI: 10.1080/10253890.2016.1231177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Stress is a response of the organism to homeostasis-threatening stimuli and is coordinated by two main neural systems: the hypothalamic-pituitary-adrenal and the autonomic nervous system. Acute restraint stress (RS) is a model of unavoidable stress, which is characterized by autonomic responses including an increase in mean arterial pressure (MAP) and heart rate (HR), as well as a drop in tail temperature. The prelimbic cortex (PL) has been implicated in the modulation of functional responses caused by RS. The present study aimed to evaluate the role of PL GABAergic neurotransmission in the modulation of autonomic changes induced by RS. Bilateral microinjection of the GABAA receptor antagonist bicuculline methiodide into the PL reduced pressor and tachycardic responses evoked by RS, in a dose-dependent manner, without affecting the tail temperature drop evoked by RS. In order to investigate which peripheral autonomic effector modulated the reduction in RS-cardiovascular responses caused by the blockade of PL GABAA receptors, rats were intravenously pretreated with either atenolol or homatropine methylbromide. The blockade of the cardiac sympathetic nervous system with atenolol blunted the reducing effect of PL treatment with bicuculline methiodide on RS-evoked pressor and tachycardic responses. The blockade of the parasympathetic nervous system with homatropine methylbromide, regardless of affecting the beginning of the tachycardic response, did not impact on the reduction of RS-evoked tachycardic and pressor responses caused by the PL treatment with bicuculline methiodide. The present results indicate that both cardiac sympathetic and parasympathetic activities are involved in the reduction of RS-evoked cardiovascular responses evidenced after the blockade of PL GABAA receptors by bicuculline methiodide.
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Affiliation(s)
- Aline Fassini
- a Department of Pharmacology of the School of Medicine of Ribeirão Preto , University of São Paulo , Ribeirão Preto , São Paulo , Brazil
| | - Leonardo B M Resstel
- a Department of Pharmacology of the School of Medicine of Ribeirão Preto , University of São Paulo , Ribeirão Preto , São Paulo , Brazil
| | - Fernando M A Corrêa
- a Department of Pharmacology of the School of Medicine of Ribeirão Preto , University of São Paulo , Ribeirão Preto , São Paulo , Brazil
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Persistent Structural Plasticity Optimizes Sensory Information Processing in the Olfactory Bulb. Neuron 2016; 91:384-96. [PMID: 27373833 DOI: 10.1016/j.neuron.2016.06.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 04/14/2016] [Accepted: 05/19/2016] [Indexed: 11/23/2022]
Abstract
In the mammalian brain, the anatomical structure of neural circuits changes little during adulthood. As a result, adult learning and memory are thought to result from specific changes in synaptic strength. A possible exception is the olfactory bulb (OB), where activity guides interneuron turnover throughout adulthood. These adult-born granule cell (GC) interneurons form new GABAergic synapses that have little synaptic strength plasticity. In the face of persistent neuronal and synaptic turnover, how does the OB balance flexibility, as is required for adapting to changing sensory environments, with perceptual stability? Here we show that high dendritic spine turnover is a universal feature of GCs, regardless of their developmental origin and age. We find matching dynamics among postsynaptic sites on the principal neurons receiving the new synaptic inputs. We further demonstrate in silico that this coordinated structural plasticity is consistent with stable, yet flexible, decorrelated sensory representations. Together, our study reveals that persistent, coordinated synaptic structural plasticity between interneurons and principal neurons is a major mode of functional plasticity in the OB.
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121
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Lledo PM, Saghatelyan A, Lemasson M. Inhibitory Interneurons in the Olfactory Bulb: From Development to Function. Neuroscientist 2016; 10:292-303. [PMID: 15271257 DOI: 10.1177/1073858404263460] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Identifying and defining the characteristic features of the inhibitory neurons in the nervous system has become essential for achieving a cellular understanding of complex brain activities. For this, the olfactory bulb is ideally suited because it is readily accessible, it is a laminated structure where local interneurons can be easily distinguished from projecting neurons, and, more important, GABAergic interneurons are continuously replaced. How the newly generated neurons integrate into a preexisting neural network and how basic network functions are maintained when a large percentage of neurons are subjected to continuous renewal are important questions that have recently received new insights. Here, it is seen that the production of bulbar interneurons is specifically adapted to experience-dependent regulation of adult neural networks. In particular, the authors report the degree of sensitivity of the bulbar neurogenesis to the activity level of sensory inputs and, in turn, how the adult neurogenesis adjusts the neural network functioning to optimize information processing. By maintaining a constitutive neurogenesis sensitive to environmental cues, this neuronal recruitment leads to improving sensory abilities. This review brings together recently described properties and emerging principles of interneuron functions that may convey, into bulbar neuronal networks, a degree of circuit adaptation unmatched by synaptic plasticity alone.
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Affiliation(s)
- Pierre-Marie Lledo
- Laboratory of Perception and Memory, Centre National de la Recherche Scientifique, Pasteur Institute, Paris, France.
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122
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Carron SF, Alwis DS, Rajan R. Traumatic Brain Injury and Neuronal Functionality Changes in Sensory Cortex. Front Syst Neurosci 2016; 10:47. [PMID: 27313514 PMCID: PMC4889613 DOI: 10.3389/fnsys.2016.00047] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 05/19/2016] [Indexed: 01/21/2023] Open
Abstract
Traumatic brain injury (TBI), caused by direct blows to the head or inertial forces during relative head-brain movement, can result in long-lasting cognitive and motor deficits which can be particularly consequential when they occur in young people with a long life ahead. Much is known of the molecular and anatomical changes produced in TBI but much less is known of the consequences of these changes to neuronal functionality, especially in the cortex. Given that much of our interior and exterior lives are dependent on responsiveness to information from and about the world around us, we have hypothesized that a significant contributor to the cognitive and motor deficits seen after TBI could be changes in sensory processing. To explore this hypothesis, and to develop a model test system of the changes in neuronal functionality caused by TBI, we have examined neuronal encoding of simple and complex sensory input in the rat’s exploratory and discriminative tactile system, the large face macrovibrissae, which feeds to the so-called “barrel cortex” of somatosensory cortex. In this review we describe the short-term and long-term changes in the barrel cortex encoding of whisker motion modeling naturalistic whisker movement undertaken by rats engaged in a variety of tasks. We demonstrate that the most common form of TBI results in persistent neuronal hyperexcitation specifically in the upper cortical layers, likely due to changes in inhibition. We describe the types of cortical inhibitory neurons and their roles and how selective effects on some of these could produce the particular forms of neuronal encoding changes described in TBI, and then generalize to compare the effects on inhibition seen in other forms of brain injury. From these findings we make specific predictions as to how non-invasive extra-cranial electrophysiology can be used to provide the high-precision information needed to monitor and understand the temporal evolution of changes in neuronal functionality in humans suffering TBI. Such detailed understanding of the specific changes in an individual patient’s cortex can allow for treatment to be tailored to the neuronal changes in that particular patient’s brain in TBI, a precision that is currently unavailable with any technique.
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Affiliation(s)
- Simone F Carron
- Neuroscience Research Program, Biomedicine Discovery Institute, Department of Physiology, Monash University Monash, VIC, Australia
| | - Dasuni S Alwis
- Neuroscience Research Program, Biomedicine Discovery Institute, Department of Physiology, Monash University Monash, VIC, Australia
| | - Ramesh Rajan
- Neuroscience Research Program, Biomedicine Discovery Institute, Department of Physiology, Monash UniversityMonash, VIC, Australia; Ear Sciences Institute of AustraliaPerth, WA, Australia
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123
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Inui K, Nakagawa K, Nishihara M, Motomura E, Kakigi R. Inhibition in the Human Auditory Cortex. PLoS One 2016; 11:e0155972. [PMID: 27219470 PMCID: PMC4878756 DOI: 10.1371/journal.pone.0155972] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 05/06/2016] [Indexed: 02/06/2023] Open
Abstract
Despite their indispensable roles in sensory processing, little is known about inhibitory interneurons in humans. Inhibitory postsynaptic potentials cannot be recorded non-invasively, at least in a pure form, in humans. We herein sought to clarify whether prepulse inhibition (PPI) in the auditory cortex reflected inhibition via interneurons using magnetoencephalography. An abrupt increase in sound pressure by 10 dB in a continuous sound was used to evoke the test response, and PPI was observed by inserting a weak (5 dB increase for 1 ms) prepulse. The time course of the inhibition evaluated by prepulses presented at 10-800 ms before the test stimulus showed at least two temporally distinct inhibitions peaking at approximately 20-60 and 600 ms that presumably reflected IPSPs by fast spiking, parvalbumin-positive cells and somatostatin-positive, Martinotti cells, respectively. In another experiment, we confirmed that the degree of the inhibition depended on the strength of the prepulse, but not on the amplitude of the prepulse-evoked cortical response, indicating that the prepulse-evoked excitatory response and prepulse-evoked inhibition reflected activation in two different pathways. Although many diseases such as schizophrenia may involve deficits in the inhibitory system, we do not have appropriate methods to evaluate them; therefore, the easy and non-invasive method described herein may be clinically useful.
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Affiliation(s)
- Koji Inui
- Department of Integrative Physiology, National Institute for Physiological Sciences, Japan
- * E-mail:
| | - Kei Nakagawa
- Department of Integrative Physiology, National Institute for Physiological Sciences, Japan
| | | | - Eishi Motomura
- Department of Neuropsychiatry, Mie University Graduate School of Medicine, Japan
| | - Ryusuke Kakigi
- Department of Integrative Physiology, National Institute for Physiological Sciences, Japan
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Hamid K, Ng I, Tallapragada VJ, Váradi L, Hibbs DE, Hanrahan J, Groundwater PW. An Investigation of the Differential Effects of Ursane Triterpenoids fromCentella asiatica, and Their Semisynthetic Analogues, on GABAAReceptors. Chem Biol Drug Des 2016; 88:386-97. [DOI: 10.1111/cbdd.12766] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 02/29/2016] [Accepted: 03/28/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Kaiser Hamid
- Faculty of Pharmacy; The University of Sydney; Sydney NSW 2006 Australia
| | - Irene Ng
- Faculty of Pharmacy; The University of Sydney; Sydney NSW 2006 Australia
| | | | - Linda Váradi
- Faculty of Pharmacy; The University of Sydney; Sydney NSW 2006 Australia
| | - David E. Hibbs
- Faculty of Pharmacy; The University of Sydney; Sydney NSW 2006 Australia
| | - Jane Hanrahan
- Faculty of Pharmacy; The University of Sydney; Sydney NSW 2006 Australia
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Rock C, Zurita H, Wilson C, Apicella AJ. An inhibitory corticostriatal pathway. eLife 2016; 5. [PMID: 27159237 PMCID: PMC4905740 DOI: 10.7554/elife.15890] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/08/2016] [Indexed: 12/05/2022] Open
Abstract
Anatomical and physiological studies have led to the assumption that the dorsal striatum receives exclusively excitatory afferents from the cortex. Here we test the hypothesis that the dorsal striatum receives also GABAergic projections from the cortex. We addressed this fundamental question by taking advantage of optogenetics and directly examining the functional effects of cortical GABAergic inputs to spiny projection neurons (SPNs) of the mouse auditory and motor cortex. We found that the cortex, via corticostriatal somatostatin neurons (CS-SOM), has a direct inhibitory influence on the output of the striatum SPNs. Our results describe a corticostriatal long-range inhibitory circuit (CS-SOM inhibitory projections → striatal SPNs) underlying the control of spike timing/generation in SPNs and attributes a specific function to a genetically defined type of cortical interneuron in corticostriatal communication. DOI:http://dx.doi.org/10.7554/eLife.15890.001 The striatum is located beneath the cerebral cortex, where it contributes to processes including learning and movement. The Spanish anatomist Ramon y Cajal, working in the early 20th century, was the first to observe individual neurons extending from the cortex to the striatum. Cajal published drawings of these neurons in his now celebrated anatomical papers, but knew little about their properties. In the 1980s, advances in techniques for labeling individual cells made it possible to study these neurons in detail. The results suggested that the pathways are exclusively excitatory: that is, the cortical neurons always increase the activity of their partners in the striatum. However, this result made it difficult to explain why electrically stimulating the cortex can sometimes reduce or inhibit the activity of the striatum. To reconcile these facts, most people assumed that inhibition must occur when excitatory cortical neurons activate networks of inhibitory cells within the striatum itself. Rock et al. now challenge this view by providing anatomical and physiological evidence for the existence of long-range inhibitory pathways from the cortex to the striatum in the mouse brain. These inhibitory neurons project from the auditory and motor regions of the cortex, and contain a substance called somatostatin. These neurons form connections with a specific type of striatal neuron called medium spiny neurons, which in turn project to other brain regions outside the striatum. The inhibitory cortical neurons can alter the activity of the medium spiny neurons, and can therefore directly control the output of the striatum. The discovery that the striatum receives both excitatory and inhibitory inputs from cortex suggests that the timing and relative strength of these inputs can affect the activity of the striatum. Future experiments should examine whether this is a general mechanism by which sensory stimuli can influence the processes controlled by the striatum, such as movement. DOI:http://dx.doi.org/10.7554/eLife.15890.002
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Affiliation(s)
- Crystal Rock
- Department of Biology, Neurosciences Institute, University of Texas at San Antonio, San Antonio, United States
| | - Hector Zurita
- Department of Biology, Neurosciences Institute, University of Texas at San Antonio, San Antonio, United States
| | - Charles Wilson
- Department of Biology, Neurosciences Institute, University of Texas at San Antonio, San Antonio, United States
| | - Alfonso Junior Apicella
- Department of Biology, Neurosciences Institute, University of Texas at San Antonio, San Antonio, United States
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126
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Carron SF, Yan EB, Alwis DS, Rajan R. Differential susceptibility of cortical and subcortical inhibitory neurons and astrocytes in the long term following diffuse traumatic brain injury. J Comp Neurol 2016; 524:3530-3560. [PMID: 27072754 DOI: 10.1002/cne.24014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 04/01/2016] [Accepted: 04/04/2016] [Indexed: 02/02/2023]
Abstract
Long-term diffuse traumatic brain injury (dTBI) causes neuronal hyperexcitation in supragranular layers in sensory cortex, likely through reduced inhibition. Other forms of TBI affect inhibitory interneurons in subcortical areas but it is unknown if this occurs in cortex, or in any brain area in dTBI. We investigated dTBI effects on inhibitory neurons and astrocytes in somatosensory and motor cortex, and hippocampus, 8 weeks post-TBI. Brains were labeled with antibodies against calbindin (CB), parvalbumin (PV), calretinin (CR) and neuropeptide Y (NPY), and somatostatin (SOM) and glial fibrillary acidic protein (GFAP), a marker for astrogliosis during neurodegeneration. Despite persistent behavioral deficits in rotarod performance up to the time of brain extraction (TBI = 73.13 ± 5.23% mean ± SEM, Sham = 92.29 ± 5.56%, P < 0.01), motor cortex showed only a significant increase, in NPY neurons in supragranular layers (mean cells/mm2 ± SEM, Sham = 16 ± 0.971, TBI = 25 ± 1.51, P = 0.001). In somatosensory cortex, only CR+ neurons showed changes, being decreased in supragranular (TBI = 19 ± 1.18, Sham = 25 ± 1.10, P < 0.01) and increased in infragranular (TBI = 28 ± 1.35, Sham = 24 ± 1.07, P < 0.05) layers. Heterogeneous changes were seen in hippocampal staining: CB+ decreased in dentate gyrus (TBI = 2 ± 0.382, Sham = 4 ± 0.383, P < 0.01), PV+ increased in CA1 (TBI = 39 ± 1.26, Sham = 33 ± 1.69, P < 0.05) and CA2/3 (TBI = 26 ± 2.10, Sham = 20 ± 1.49, P < 0.05), and CR+ decreased in CA1 (TBI = 10 ± 1.02, Sham = 14 ± 1.14, P < 0.05). Astrogliosis significantly increased in corpus callosum (TBI = 6.7 ± 0.69, Sham = 2.5 ± 0.38; P = 0.007). While dTBI effects on inhibitory neurons appear region- and type-specific, a common feature in all cases of decrease was that changes occurred in dendrite targeting interneurons involved in neuronal integration. J. Comp. Neurol. 524:3530-3560, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Simone F Carron
- Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Edwin B Yan
- Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Dasuni S Alwis
- Department of Physiology, Monash University, Melbourne, VIC, Australia
| | - Ramesh Rajan
- Department of Physiology, Monash University, Melbourne, VIC, Australia.
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127
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Kubota Y, Karube F, Nomura M, Kawaguchi Y. The Diversity of Cortical Inhibitory Synapses. Front Neural Circuits 2016; 10:27. [PMID: 27199670 PMCID: PMC4842771 DOI: 10.3389/fncir.2016.00027] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 03/29/2016] [Indexed: 12/03/2022] Open
Abstract
The most typical and well known inhibitory action in the cortical microcircuit is a strong inhibition on the target neuron by axo-somatic synapses. However, it has become clear that synaptic inhibition in the cortex is much more diverse and complicated. Firstly, at least ten or more inhibitory non-pyramidal cell subtypes engage in diverse inhibitory functions to produce the elaborate activity characteristic of the different cortical states. Each distinct non-pyramidal cell subtype has its own independent inhibitory function. Secondly, the inhibitory synapses innervate different neuronal domains, such as axons, spines, dendrites and soma, and their inhibitory postsynaptic potential (IPSP) size is not uniform. Thus, cortical inhibition is highly complex, with a wide variety of anatomical and physiological modes. Moreover, the functional significance of the various inhibitory synapse innervation styles and their unique structural dynamic behaviors differ from those of excitatory synapses. In this review, we summarize our current understanding of the inhibitory mechanisms of the cortical microcircuit.
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Affiliation(s)
- Yoshiyuki Kubota
- Division of Cerebral Circuitry, National Institute for Physiological SciencesOkazaki, Japan; Department of Physiological Sciences, The Graduate University for Advanced Studies (SOKENDAI)Okazaki, Japan; Japan Science and Technology Agency, Core Research for Evolutional Science and TechnologyTokyo, Japan
| | - Fuyuki Karube
- Laboratory of Neural Circuitry, Graduate School of Brain Science, Doshisha University Kyoto, Japan
| | - Masaki Nomura
- Japan Science and Technology Agency, Core Research for Evolutional Science and TechnologyTokyo, Japan; Department of Mathematics, Kyoto UniversityKyoto, Japan
| | - Yasuo Kawaguchi
- Division of Cerebral Circuitry, National Institute for Physiological SciencesOkazaki, Japan; Department of Physiological Sciences, The Graduate University for Advanced Studies (SOKENDAI)Okazaki, Japan; Japan Science and Technology Agency, Core Research for Evolutional Science and TechnologyTokyo, Japan
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128
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Rufener KS, Oechslin MS, Zaehle T, Meyer M. Transcranial Alternating Current Stimulation (tACS) differentially modulates speech perception in young and older adults. Brain Stimul 2016; 9:560-5. [PMID: 27157057 DOI: 10.1016/j.brs.2016.04.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 03/24/2016] [Accepted: 04/01/2016] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Normal aging is accompanied by a functional decline in processing temporal features of spoken language, such as voice onset time (VOT). On an electrophysiological level, this finding is paralleled by altered patterns of gamma oscillations. OBJECTIVE Using 40 Hz transcranial alternating current stimulation (tACS) over the bilateral auditory cortex, this study aims to compare the effect of tACS to modulate VOT-processing in samples of healthy young and older adults. METHODS Twenty-five healthy young (age 20-35 years) and 20 older adults (age 60-75 years) participated in this study. Presented with an auditory phoneme categorization task participants received 40 Hz and 6 Hz tACS on two consecutive sessions. RESULTS While 40 Hz tACS diminished task accuracy in young adults, older adults benefitted from this stimulation resulting in a more precise phonetic categorization. CONCLUSION The results of the study are discussed with respect to the non-linear relationship between gamma oscillations in the vicinity of the auditory cortex and VOT-processing. The present findings are promising in the context of an intervention for subjects with impaired ability to process temporal acoustic features in the speech signal.
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Affiliation(s)
- Katharina S Rufener
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany; Research Unit for Neuroplasticity and Learning of the Healthy Aging Brain, University of Zurich, Switzerland.
| | - Mathias S Oechslin
- International Normal Aging and Plasticity Imaging Center, Zurich, Switzerland
| | - Tino Zaehle
- Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany
| | - Martin Meyer
- Research Unit for Neuroplasticity and Learning of the Healthy Aging Brain, University of Zurich, Switzerland; International Normal Aging and Plasticity Imaging Center, Zurich, Switzerland; University Research Priority Program "Dynamics of Healthy Aging", University of Zurich, Switzerland; Cognitive Psychology Unit (CPU), University of Klagenfurt, Klagenfurt am Wörthersee, Austria
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129
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Wischnewski M, Kowalski GM, Rink F, Belagaje SR, Haut MW, Hobbs G, Buetefisch CM. Demand on skillfulness modulates interhemispheric inhibition of motor cortices. J Neurophysiol 2016; 115:2803-13. [PMID: 26961108 DOI: 10.1152/jn.01076.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/08/2016] [Indexed: 11/22/2022] Open
Abstract
The role of primary motor cortex (M1) in the control of hand movements is still unclear. Functional magnetic resonance imaging (fMRI) studies of unimanual performance reported a relationship between level of precision of a motor task and additional ipsilateral M1 (iM1) activation. In the present study, we determined whether the demand on accuracy of a movement influences the magnitude of the inhibitory effect between primary motor cortices (IHI). We used transcranial magnetic stimulation (TMS) to measure active IHI (aIHI) of the iM1 on the contralateral M1 (cM1) in the premovement period of a left-hand motor task. Ten healthy participants manipulated a joystick to point to targets of two different sizes. For aIHI, the conditioning stimulus (CS) was applied to iM1, and the test stimulus (TS) to cM1, with an interstimulus interval of 10 ms. The amount of the inhibitory effect of the CS on the motor-evoked potential (MEP) of the subsequent TS was expressed as percentage of the mean MEP amplitude evoked by the single TS. Across different time points of aIHI measurements in the premovement period, there was a significant effect for target size on aIHI. Preparing to point to small targets was associated with weaker aIHI compared with pointing to large targets. The present findings suggest that, during the premovement period, aIHI from iM1 on cM1 is modulated by the demand on accuracy of the motor task. This is consistent with task fMRI findings showing bilateral M1 activation during high-precision movements but only unilateral M1 activity during low-precision movements.
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Affiliation(s)
| | | | | | - Samir R Belagaje
- Department of Neurology and Department of Rehabilitation Medicine, Emory University, Atlanta, Georgia
| | | | - Gerald Hobbs
- Department of Biostatistics, West Virginia University, Morgantown, West Virginia
| | - Cathrin M Buetefisch
- Department of Neurology and Department of Rehabilitation Medicine, Emory University, Atlanta, Georgia;
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130
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Vereczki VK, Veres JM, Müller K, Nagy GA, Rácz B, Barsy B, Hájos N. Synaptic Organization of Perisomatic GABAergic Inputs onto the Principal Cells of the Mouse Basolateral Amygdala. Front Neuroanat 2016; 10:20. [PMID: 27013983 PMCID: PMC4779893 DOI: 10.3389/fnana.2016.00020] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 02/18/2016] [Indexed: 12/27/2022] Open
Abstract
Spike generation is most effectively controlled by inhibitory inputs that target the perisomatic region of neurons. Despite the critical importance of this functional domain, very little is known about the organization of the GABAergic inputs contacting the perisomatic region of principal cells (PCs) in the basolateral amygdala. Using immunocytochemistry combined with in vitro single-cell labeling we determined the number and sources of GABAergic inputs of PCs at light and electron microscopic levels in mice. We found that the soma and proximal dendrites of PCs were innervated primarily by two neurochemically distinct basket cell types expressing parvalbumin (PVBC) or cholecystokinin and CB1 cannabinoid receptors (CCK/CB1BC). The innervation of the initial segment of PC axons was found to be parceled out by PVBCs and axo-axonic cells (AAC), as the majority of GABAergic inputs onto the region nearest to the soma (between 0 and 10 μm) originated from PVBCs, while the largest portion of the axon initial segment was innervated by AACs. Detailed morphological investigations revealed that the three perisomatic region-targeting interneuron types significantly differed in dendritic and axonal arborization properties. We found that, although individual PVBCs targeted PCs via more terminals than CCK/CB1BCs, similar numbers (15–17) of the two BC types converge onto single PCs, whereas fewer (6–7) AACs innervate the axon initial segment of single PCs. Furthermore, we estimated that a PVBC and a CCK/CB1BC may target 800–900 and 700–800 PCs, respectively, while an AAC can innervate 600–650 PCs. Thus, BCs and AACs innervate ~10 and 20% of PC population, respectively, within their axonal cloud. Our results collectively suggest, that these interneuron types may be differently affiliated within the local amygdalar microcircuits in order to fulfill specific functions in network operation during various brain states.
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Affiliation(s)
- Viktória K Vereczki
- Lendület' Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of SciencesBudapest, Hungary; Department of Anatomy, Histology and Embryology, Faculty of Medicine, Semmelweis UniversityBudapest, Hungary
| | - Judit M Veres
- Lendület' Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of SciencesBudapest, Hungary; János Szentágothai School of Neurosciences, Semmelweis UniversityBudapest, Hungary
| | - Kinga Müller
- Lendület' Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Gergö A Nagy
- Lendület' Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Bence Rácz
- Department of Anatomy and Histology, Szent István UniversityBudapest, Hungary; Electronmicroscopy Research Group, Faculty of Veterinary Science, Szent István UniversityBudapest, Hungary
| | - Boglárka Barsy
- Lendület' Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Norbert Hájos
- Lendület' Laboratory of Network Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
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131
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Tripp B, Eliasmith C. Function approximation in inhibitory networks. Neural Netw 2016; 77:95-106. [PMID: 26963256 DOI: 10.1016/j.neunet.2016.01.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Revised: 01/27/2016] [Accepted: 01/27/2016] [Indexed: 11/17/2022]
Abstract
In performance-optimized artificial neural networks, such as convolutional networks, each neuron makes excitatory connections with some of its targets and inhibitory connections with others. In contrast, physiological neurons are typically either excitatory or inhibitory, not both. This is a puzzle, because it seems to constrain computation, and because there are several counter-examples that suggest that it may not be a physiological necessity. Parisien et al. (2008) showed that any mixture of excitatory and inhibitory functional connections could be realized by a purely excitatory projection in parallel with a two-synapse projection through an inhibitory population. They showed that this works well with ratios of excitatory and inhibitory neurons that are realistic for the neocortex, suggesting that perhaps the cortex efficiently works around this apparent computational constraint. Extending this work, we show here that mixed excitatory and inhibitory functional connections can also be realized in networks that are dominated by inhibition, such as those of the basal ganglia. Further, we show that the function-approximation capacity of such connections is comparable to that of idealized mixed-weight connections. We also study whether such connections are viable in recurrent networks, and find that such recurrent networks can flexibly exhibit a wide range of dynamics. These results offer a new perspective on computation in the basal ganglia, and also perhaps on inhibitory networks within the cortex.
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Affiliation(s)
- Bryan Tripp
- Department of Systems Design Engineering, University of Waterloo, Canada; Centre for Theoretical Neuroscience, University of Waterloo, Canada.
| | - Chris Eliasmith
- Department of Systems Design Engineering, University of Waterloo, Canada; Centre for Theoretical Neuroscience, University of Waterloo, Canada; Department of Philosophy, University of Waterloo, Canada
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132
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Abstract
An accepted classification of GABAergic interneurons of the cerebral cortex is a major goal in neuroscience. A recently proposed taxonomy based on patterns of axonal arborization promises to be a pragmatic method for achieving this goal. It involves characterizing interneurons according to five axonal arborization features, called F1-F5, and classifying them into a set of predefined types, most of which are established in the literature. Unfortunately, there is little consensus among expert neuroscientists regarding the morphological definitions of some of the proposed types. While supervised classifiers were able to categorize the interneurons in accordance with experts' assignments, their accuracy was limited because they were trained with disputed labels. Thus, here we automatically classify interneuron subsets with different label reliability thresholds (i.e., such that every cell's label is backed by at least a certain (threshold) number of experts). We quantify the cells with parameters of axonal and dendritic morphologies and, in order to predict the type, also with axonal features F1-F4 provided by the experts. Using Bayesian network classifiers, we accurately characterize and classify the interneurons and identify useful predictor variables. In particular, we discriminate among reliable examples of common basket, horse-tail, large basket, and Martinotti cells with up to 89.52% accuracy, and single out the number of branches at 180 μm from the soma, the convex hull 2D area, and the axonal features F1-F4 as especially useful predictors for distinguishing among these types. These results open up new possibilities for an objective and pragmatic classification of interneurons.
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133
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Hettige NC, de Moraes GHF, Kennedy JL, De Luca V. Candidate gene analysis of pharmacodynamic targets for antipsychotic dosage. Pharmacogenomics 2016; 17:199-208. [DOI: 10.2217/pgs.15.171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: In order to administer antipsychotic medication with the most beneficial outcome, the appropriate drug and dose needs to be identified. Though often not considered in pharmacogenetic studies, dosage plays an important role in treatment outcome. This study set out to analyze the association between 109 SNPs and antipsychotic dosage among schizophrenia patients. In a previous study, we tested 134 SNPs in regards to antipsychotic dosage. In the current study, we tested additional markers in the same candidate genes that we investigated in the previous study to confirm our previous findings. Methods: We included 263 participants with schizophrenia spectrum disorders between the ages of 18–75. Each participant was assessed cross-sectionally to collect clinical and antipsychotic treatment information through a semi-structured interview. The antipsychotic dosage for each individual was standardized according to chlorpromazine equivalents (CPZe), defined daily dose, and the percentage of maximum dosage (PM%). For each participant, 109 SNPs from 29 candidate genes were imputed or genotyped using a Customized Illumina Chip. Results: Polymorphisms in the GABRB1 gene were significantly associated with higher antipsychotic dosage according to CPZe and PM% standardization. Conclusion: Our analysis suggests that variation in the GABRB1 gene may be significantly associated with antipsychotic dosage according to CPZe and PM% standardization. Antipsychotic dosage remains an integral measure for treatment response that warrants future pharmacogenetic testing and studies with larger sample sizes.
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Affiliation(s)
- Nuwan C Hettige
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Room 2374, Toronto, ON M5S 1A8, Canada
- EEG & Genetics Group, Centre for Addiction & Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
| | - Gustavo HF de Moraes
- EEG & Genetics Group, Centre for Addiction & Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
| | - James L Kennedy
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Room 2374, Toronto, ON M5S 1A8, Canada
- Department of Psychiatry, University of Toronto, 250 College Street, Toronto, ON, Canada
| | - Vincenzo De Luca
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Room 2374, Toronto, ON M5S 1A8, Canada
- EEG & Genetics Group, Centre for Addiction & Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
- Department of Psychiatry, University of Toronto, 250 College Street, Toronto, ON, Canada
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134
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Hu F, Ge MM, Chen WH. Effects of lead exposure on dendrite and spine development in hippocampal dentate gyrus areas of rats. Synapse 2016; 70:87-97. [DOI: 10.1002/syn.21873] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 10/27/2015] [Accepted: 11/02/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Fan Hu
- School of Biotechnology and Food Engineering; Hefei University of Technology; Hefei Anhui 230009 People's Republic of China
| | - Meng-Meng Ge
- School of Biotechnology and Food Engineering; Hefei University of Technology; Hefei Anhui 230009 People's Republic of China
| | - Wei-Heng Chen
- School of Life Sciences; University of Science and Technology of China; Hefei Anhui 230027 People's Republic of China
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135
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Calcagnotto ME. Interneurons: Role in Maintaining and Restoring Synaptic Plasticity. Front Psychiatry 2016; 7:86. [PMID: 27242556 PMCID: PMC4863890 DOI: 10.3389/fpsyt.2016.00086] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 05/02/2016] [Indexed: 01/09/2023] Open
Affiliation(s)
- Maria Elisa Calcagnotto
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Biochemistry Department, Universidade Federal do Rio Grande do Sul , Porto Alegre , Brazil
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136
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Clark R, Blizzard C, Dickson T. Inhibitory dysfunction in amyotrophic lateral sclerosis: future therapeutic opportunities. Neurodegener Dis Manag 2015; 5:511-25. [DOI: 10.2217/nmt.15.49] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In amyotrophic lateral sclerosis, motor neuron hyperexcitability and inhibitory dysfunction is emerging as a potential causative link in the dysfunction and degeneration of the motoneuronal circuitry that characterizes the disease. Interneurons, as key regulators of excitability, may mediate much of this imbalance, yet we know little about the way in which inhibitory deficits perturb excitability. In this review, we explore inhibitory control of excitability and the potential contribution of altered inhibition to amyotrophic lateral sclerosis disease processes and vulnerabilities, identifying important windows of therapeutic opportunity and potential interventions, specifically targeting inhibitory control at key disease stages.
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Affiliation(s)
- Rosemary Clark
- Menzies Institute for Medical Research, University of Tasmania, Hobart TAS 7000, Australia
| | - Catherine Blizzard
- Menzies Institute for Medical Research, University of Tasmania, Hobart TAS 7000, Australia
| | - Tracey Dickson
- Menzies Institute for Medical Research, University of Tasmania, Hobart TAS 7000, Australia
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137
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Bunzeck N, Thiel C. Neurochemical modulation of repetition suppression and novelty signals in the human brain. Cortex 2015; 80:161-73. [PMID: 26625882 DOI: 10.1016/j.cortex.2015.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 09/22/2015] [Accepted: 10/15/2015] [Indexed: 12/11/2022]
Abstract
The repeated processing of a sensory stimulus, such as a picture or sound, leads to a decrement in response in neurons that fired to the initial presentation. These effects are well known from single cell recordings in the inferior temporal cortex in monkeys, and functional neuroimaging in humans on large-scale neural activity could show similar effects in extrastriate, frontal and medial temporal lobe (MTL) regions. The role of specific neurotransmitters in repeated processing of information is, however, less clear. In the first part of this article, we will introduce the two concepts of repetition suppression and novelty signals, which is followed by a brief overview of pharmacological neuroimaging in humans. We will then summarize human studies suggesting that gamma-aminobutyric-acid (GABA) and acetylcholine (ACh) play an important role in modulating behavioral priming and associated repetition suppression in extrastriate and frontal brain regions. Finally, we review studies on neural novelty signals in the dopaminergic mesolimbic system, and conclude that dopamine (DA) regulates the temporal aspects of novelty processing and closely relates to long-term memory encoding rather than behavioral priming. As such, this review describes differential roles of GABA, ACh and DA in repeated stimulus processing, and further suggests that repetition suppression and neural novelty signals may not be two sides of the same coin but rather independent processes.
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Affiliation(s)
- Nico Bunzeck
- Department of Psychology, University of Lübeck, Lübeck, Germany; Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Christiane Thiel
- Biological Psychology, Department of Psychology, European Medical School, Carl von Ossietzky University Oldenburg, Oldenburg, Germany; Cluster of Excellence "Hearing4all" and Research Center Neurosensory Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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138
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Purves-Tyson TD, Allen K, Fung S, Rothmond D, Noble PL, Handelsman DJ, Shannon Weickert C. Adolescent testosterone influences BDNF and TrkB mRNA and neurotrophin-interneuron marker relationships in mammalian frontal cortex. Schizophr Res 2015; 168:661-70. [PMID: 26088421 DOI: 10.1016/j.schres.2015.05.040] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/11/2015] [Accepted: 05/28/2015] [Indexed: 11/24/2022]
Abstract
Late adolescence in males is a period of increased susceptibility for the onset of schizophrenia, coinciding with increased circulating testosterone. The cognitive deficits prevalent in schizophrenia may be related to unhealthy cortical interneurons, which are trophically dependent on brain derived neurotrophic factor. We investigated, under conditions of depleted (monkey and rat) and replaced (rat) testosterone over adolescence, changes in gene expression of cortical BDNF and TrkB transcripts and interneuron markers and the relationships between these mRNAs and circulating testosterone. Testosterone removal by gonadectomy reduced gene expression of some BDNF transcripts in monkey and rat frontal cortices and the BDNF mRNA reduction was prevented by testosterone replacement. In rat, testosterone replacement increased the potential for classical TrkB signalling by increasing the full length to truncated TrkB mRNA ratio, whereas in the monkey cortex, circulating testosterone was negatively correlated with the TrkB full length/truncated mRNA ratio. We did not identify changes in interneuron gene expression in monkey frontal cortex in response to gonadectomy, and in rat, we showed that only somatostatin mRNA was decreased by gonadectomy but not restored by testosterone replacement. We identified complex and possibly species-specific, relationships between BDNF/TrkB gene expression and interneuron marker gene expression that appear to be dependent on the presence of testosterone at adolescence in rat and monkey frontal cortices. Taken together, our findings suggest there are dynamic relationships between BDNF/TrkB and interneuron markers that are dependent on the presence of testosterone but that this may not be a straightforward increase in testosterone leading to changes in BDNF/TrkB that contributes to interneuron health.
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Affiliation(s)
- Tertia D Purves-Tyson
- Schizophrenia Research Institute, Sydney 2021, Australia; Neuroscience Research Australia, Sydney 2031, Australia; School of Medical Sciences, University of New South Wales, Sydney 2031, Australia
| | - Katherine Allen
- Schizophrenia Research Institute, Sydney 2021, Australia; Neuroscience Research Australia, Sydney 2031, Australia; School of Psychiatry, University of New South Wales, Sydney 2031, Australia
| | - Samantha Fung
- Schizophrenia Research Institute, Sydney 2021, Australia; Neuroscience Research Australia, Sydney 2031, Australia; School of Psychiatry, University of New South Wales, Sydney 2031, Australia
| | - Debora Rothmond
- Schizophrenia Research Institute, Sydney 2021, Australia; Neuroscience Research Australia, Sydney 2031, Australia
| | | | | | - Cynthia Shannon Weickert
- Schizophrenia Research Institute, Sydney 2021, Australia; Neuroscience Research Australia, Sydney 2031, Australia; School of Psychiatry, University of New South Wales, Sydney 2031, Australia
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139
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Ramaswamy S, Courcol JD, Abdellah M, Adaszewski SR, Antille N, Arsever S, Atenekeng G, Bilgili A, Brukau Y, Chalimourda A, Chindemi G, Delalondre F, Dumusc R, Eilemann S, Gevaert ME, Gleeson P, Graham JW, Hernando JB, Kanari L, Katkov Y, Keller D, King JG, Ranjan R, Reimann MW, Rössert C, Shi Y, Shillcock JC, Telefont M, Van Geit W, Diaz JV, Walker R, Wang Y, Zaninetta SM, DeFelipe J, Hill SL, Muller J, Segev I, Schürmann F, Muller EB, Markram H. The neocortical microcircuit collaboration portal: a resource for rat somatosensory cortex. Front Neural Circuits 2015; 9:44. [PMID: 26500503 PMCID: PMC4597797 DOI: 10.3389/fncir.2015.00044] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 08/13/2015] [Indexed: 11/13/2022] Open
Affiliation(s)
- Srikanth Ramaswamy
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Jean-Denis Courcol
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Marwan Abdellah
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Stanislaw R Adaszewski
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Nicolas Antille
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Selim Arsever
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Guy Atenekeng
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Ahmet Bilgili
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Yury Brukau
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Athanassia Chalimourda
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Giuseppe Chindemi
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Fabien Delalondre
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Raphael Dumusc
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Stefan Eilemann
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Michael Emiel Gevaert
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Padraig Gleeson
- Department of Neuroscience, Physiology and Pharmacology, University College London London, UK
| | - Joe W Graham
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Juan B Hernando
- CeSViMa, Centro de Supercomputación y Visualización de Madrid, Universidad Politécnica de Madrid Madrid, Spain
| | - Lida Kanari
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Yury Katkov
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Daniel Keller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - James G King
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Rajnish Ranjan
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland ; Laboratory of Neural Microcircuitry, Brain Mind Institute, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland
| | - Michael W Reimann
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Christian Rössert
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Ying Shi
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland ; Laboratory of Neural Microcircuitry, Brain Mind Institute, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland
| | - Julian C Shillcock
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Martin Telefont
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Werner Van Geit
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Jafet Villafranca Diaz
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Richard Walker
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Yun Wang
- Key Laboratory of Visual Science and National Ministry of Health, School of Optometry and Opthalmology, Wenzhou Medical College Wenzhou, China ; Caritas St. Elizabeth's Medical Center, Genesys Research Institute, Tufts University Boston, MA, USA
| | - Stefano M Zaninetta
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid Madrid, Spain ; Instituto Cajal (CSIC) and CIBERNED Madrid, Spain
| | - Sean L Hill
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Jeffrey Muller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Idan Segev
- Department of Neurobiology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem Jerusalem, Israel ; The Edmond and Lily Safra Centre for Brain Sciences, The Hebrew University of Jerusalem Jerusalem, Israel
| | - Felix Schürmann
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Eilif B Muller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Henry Markram
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland ; Laboratory of Neural Microcircuitry, Brain Mind Institute, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland
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140
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Reimann MW, King JG, Muller EB, Ramaswamy S, Markram H. An algorithm to predict the connectome of neural microcircuits. Front Comput Neurosci 2015; 9:120. [PMID: 26500529 PMCID: PMC4597796 DOI: 10.3389/fncom.2015.00120] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 05/22/2015] [Indexed: 11/18/2022] Open
Abstract
Experimentally mapping synaptic connections, in terms of the numbers and locations of their synapses and estimating connection probabilities, is still not a tractable task, even for small volumes of tissue. In fact, the six layers of the neocortex contain thousands of unique types of synaptic connections between the many different types of neurons, of which only a handful have been characterized experimentally. Here we present a theoretical framework and a data-driven algorithmic strategy to digitally reconstruct the complete synaptic connectivity between the different types of neurons in a small well-defined volume of tissue—the micro-scale connectome of a neural microcircuit. By enforcing a set of established principles of synaptic connectivity, and leveraging interdependencies between fundamental properties of neural microcircuits to constrain the reconstructed connectivity, the algorithm yields three parameters per connection type that predict the anatomy of all types of biologically viable synaptic connections. The predictions reproduce a spectrum of experimental data on synaptic connectivity not used by the algorithm. We conclude that an algorithmic approach to the connectome can serve as a tool to accelerate experimental mapping, indicating the minimal dataset required to make useful predictions, identifying the datasets required to improve their accuracy, testing the feasibility of experimental measurements, and making it possible to test hypotheses of synaptic connectivity.
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Affiliation(s)
- Michael W Reimann
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - James G King
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Eilif B Muller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Srikanth Ramaswamy
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
| | - Henry Markram
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL) Biotech Campus Geneva, Switzerland
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141
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Markram H, Muller E, Ramaswamy S, Reimann MW, Abdellah M, Sanchez CA, Ailamaki A, Alonso-Nanclares L, Antille N, Arsever S, Kahou GAA, Berger TK, Bilgili A, Buncic N, Chalimourda A, Chindemi G, Courcol JD, Delalondre F, Delattre V, Druckmann S, Dumusc R, Dynes J, Eilemann S, Gal E, Gevaert ME, Ghobril JP, Gidon A, Graham JW, Gupta A, Haenel V, Hay E, Heinis T, Hernando JB, Hines M, Kanari L, Keller D, Kenyon J, Khazen G, Kim Y, King JG, Kisvarday Z, Kumbhar P, Lasserre S, Le Bé JV, Magalhães BRC, Merchán-Pérez A, Meystre J, Morrice BR, Muller J, Muñoz-Céspedes A, Muralidhar S, Muthurasa K, Nachbaur D, Newton TH, Nolte M, Ovcharenko A, Palacios J, Pastor L, Perin R, Ranjan R, Riachi I, Rodríguez JR, Riquelme JL, Rössert C, Sfyrakis K, Shi Y, Shillcock JC, Silberberg G, Silva R, Tauheed F, Telefont M, Toledo-Rodriguez M, Tränkler T, Van Geit W, Díaz JV, Walker R, Wang Y, Zaninetta SM, DeFelipe J, Hill SL, Segev I, Schürmann F. Reconstruction and Simulation of Neocortical Microcircuitry. Cell 2015; 163:456-92. [PMID: 26451489 DOI: 10.1016/j.cell.2015.09.029] [Citation(s) in RCA: 772] [Impact Index Per Article: 85.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 05/04/2015] [Accepted: 09/11/2015] [Indexed: 02/03/2023]
Affiliation(s)
- Henry Markram
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland; Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland.
| | - Eilif Muller
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Srikanth Ramaswamy
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Michael W Reimann
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Marwan Abdellah
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Carlos Aguado Sanchez
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Anastasia Ailamaki
- Data-Intensive Applications and Systems Lab, EPFL, 1015 Lausanne, Switzerland
| | - Lidia Alonso-Nanclares
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain; Instituto Cajal (CSIC) and CIBERNED, 28002 Madrid, Spain
| | - Nicolas Antille
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Selim Arsever
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Guy Antoine Atenekeng Kahou
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Thomas K Berger
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Ahmet Bilgili
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Nenad Buncic
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Athanassia Chalimourda
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Giuseppe Chindemi
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Jean-Denis Courcol
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Fabien Delalondre
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Vincent Delattre
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Shaul Druckmann
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Raphael Dumusc
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - James Dynes
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Stefan Eilemann
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Eyal Gal
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Michael Emiel Gevaert
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Jean-Pierre Ghobril
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Albert Gidon
- Department of Neurobiology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Joe W Graham
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Anirudh Gupta
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Valentin Haenel
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Etay Hay
- Department of Neurobiology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Thomas Heinis
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland; Data-Intensive Applications and Systems Lab, EPFL, 1015 Lausanne, Switzerland; Imperial College London, London SW7 2AZ, UK
| | - Juan B Hernando
- CeSViMa, Centro de Supercomputación y Visualización de Madrid, Universidad Politécnica de Madrid, 28223 Madrid, Spain
| | - Michael Hines
- Department of Neurobiology, Yale University, New Haven, CT 06510 USA
| | - Lida Kanari
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Daniel Keller
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - John Kenyon
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Georges Khazen
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Yihwa Kim
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - James G King
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Zoltan Kisvarday
- MTA-Debreceni Egyetem, Neuroscience Research Group, 4032 Debrecen, Hungary
| | - Pramod Kumbhar
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Sébastien Lasserre
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland; Laboratoire d'informatique et de visualisation, EPFL, 1015 Lausanne, Switzerland
| | - Jean-Vincent Le Bé
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Bruno R C Magalhães
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Angel Merchán-Pérez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain; Instituto Cajal (CSIC) and CIBERNED, 28002 Madrid, Spain
| | - Julie Meystre
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Benjamin Roy Morrice
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Jeffrey Muller
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Alberto Muñoz-Céspedes
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain; Instituto Cajal (CSIC) and CIBERNED, 28002 Madrid, Spain
| | - Shruti Muralidhar
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Keerthan Muthurasa
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Daniel Nachbaur
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Taylor H Newton
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Max Nolte
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Aleksandr Ovcharenko
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Juan Palacios
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Luis Pastor
- Modeling and Virtual Reality Group, Universidad Rey Juan Carlos, 28933 Móstoles, Madrid, Spain
| | - Rodrigo Perin
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Rajnish Ranjan
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland; Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Imad Riachi
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - José-Rodrigo Rodríguez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain; Instituto Cajal (CSIC) and CIBERNED, 28002 Madrid, Spain
| | - Juan Luis Riquelme
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Christian Rössert
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Konstantinos Sfyrakis
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Ying Shi
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland; Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Julian C Shillcock
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Gilad Silberberg
- Department of Neuroscience, Karolinska Institutet, Stockholm 17177, Sweden
| | - Ricardo Silva
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Farhan Tauheed
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland; Data-Intensive Applications and Systems Lab, EPFL, 1015 Lausanne, Switzerland
| | - Martin Telefont
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | | | - Thomas Tränkler
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Werner Van Geit
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Jafet Villafranca Díaz
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Richard Walker
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Yun Wang
- Key Laboratory of Visual Science and National Ministry of Health, School of Optometry and Opthalmology, Wenzhou Medical College, Wenzhou 325003, China; Caritas St. Elizabeth's Medical Center, Genesys Research Institute, Tufts University, Boston, MA 02111, USA
| | - Stefano M Zaninetta
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain; Instituto Cajal (CSIC) and CIBERNED, 28002 Madrid, Spain
| | - Sean L Hill
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Idan Segev
- Department of Neurobiology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Felix Schürmann
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
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142
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Abstract
Synaptic neurotransmission is modified at cortical connections throughout life. Varying the amplitude of the postsynaptic response is one mechanism that generates flexible signaling in neural circuits. The timing of the synaptic response may also play a role. Here, we investigated whether weakening and loss of an entire connection between excitatory cortical neurons was foreshadowed in the timing of the postsynaptic response. We made electrophysiological recordings in rat primary somatosensory cortex that was undergoing experience-dependent loss of complete local excitatory connections. The synaptic latency of pyramid-pyramid connections, which typically comprise multiple synapses, was longer and more variable. Connection strength and latency were not correlated. Instead, prolonged latency was more closely related to progression of connection loss. The action potential waveform and axonal conduction velocity were unaffected, suggesting that the altered timing of neurotransmission was attributable to a synaptic mechanism. Modeling studies indicated that increasing the latency and jitter at a subset of synapses reduced the number of action potentials fired by a postsynaptic neuron. We propose that prolonged synaptic latency and diminished temporal precision of neurotransmission are hallmarks of impending loss of a cortical connection.
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143
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DeFelipe J. The anatomical problem posed by brain complexity and size: a potential solution. Front Neuroanat 2015; 9:104. [PMID: 26347617 PMCID: PMC4542575 DOI: 10.3389/fnana.2015.00104] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 07/21/2015] [Indexed: 01/08/2023] Open
Abstract
Over the years the field of neuroanatomy has evolved considerably but unraveling the extraordinary structural and functional complexity of the brain seems to be an unattainable goal, partly due to the fact that it is only possible to obtain an imprecise connection matrix of the brain. The reasons why reaching such a goal appears almost impossible to date is discussed here, together with suggestions of how we could overcome this anatomical problem by establishing new methodologies to study the brain and by promoting interdisciplinary collaboration. Generating a realistic computational model seems to be the solution rather than attempting to fully reconstruct the whole brain or a particular brain region.
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Affiliation(s)
- Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales (Centro de Tecnología Biomédica: UPM), Instituto Cajal (CSIC) and CIBERNED Madrid, Spain
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144
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Turkheimer FE, Leech R, Expert P, Lord LD, Vernon AC. The brain's code and its canonical computational motifs. From sensory cortex to the default mode network: A multi-scale model of brain function in health and disease. Neurosci Biobehav Rev 2015; 55:211-22. [PMID: 25956253 DOI: 10.1016/j.neubiorev.2015.04.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 04/01/2015] [Accepted: 04/25/2015] [Indexed: 12/21/2022]
Affiliation(s)
| | - Robert Leech
- Division of Brain Sciences, Imperial College London, London, UK
| | - Paul Expert
- Institute of Psychiatry, King's College London, London, UK
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145
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Malkin S, Kim K, Tikhonov D, Magazanik L, Zaitsev A. Statistical models suggest presence of two distinct subpopulations of miniature EPSCs in fast-spiking interneurons of rat prefrontal cortex. Neuroscience 2015; 301:508-19. [DOI: 10.1016/j.neuroscience.2015.06.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 06/18/2015] [Accepted: 06/18/2015] [Indexed: 01/30/2023]
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146
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Mengod G, Palacios JM, Cortés R. Cartography of 5-HT1A and 5-HT2A Receptor Subtypes in Prefrontal Cortex and Its Projections. ACS Chem Neurosci 2015; 6:1089-98. [PMID: 25739427 DOI: 10.1021/acschemneuro.5b00023] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Since the development of chemical neuroanatomical tools in the 1960s, a tremendous wealth of information has been generated on the anatomical components of the serotonergic system, at the microscopic level in the brain including the prefrontal cortex (PFC). The PFC receives a widespread distribution of serotonin (5-hydroxytryptamine, 5-HT) terminals from the median and dorsal raphe nuclei. 5-HT receptors were first visualized using radioligand autoradiography in the late 1980s and early 1990s and showed, in contrast to 5-HT innervation, a differential distribution of binding sites associated with different 5-HT receptor subtypes. Due to the cloning of the different 5-HT receptor subtype genes in the late 1980s and early 1990s, it was possible, using in situ hybridization histochemistry, to localize cells expressing mRNA for these receptors. Double in situ hybridization histochemistry and immunohistochemistry allowed for the chemical characterization of the phenotype of cells expressing 5-HT receptors. Tract tracing technology allowed a detailed cartography of the neuronal connections of PFC and other brain areas. Based on these data, maps have been constructed that reflect our current understanding of the different circuits where 5-HT receptors can modulate the electrophysiological, pharmacological, and behavioral functions of the PFC. We will review current knowledge regarding the cellular localization of 5-HT1A and 5-HT2A receptors in mammalian PFC and their possible functions in the neuronal circuits of the PFC. We will discuss data generated in our laboratory as well as in others, focusing on localization in the pyramidal and GABAergic neuronal cell populations in different mammalian species using molecular neuroanatomy and on the connections with other brain regions.
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Affiliation(s)
- Guadalupe Mengod
- Department
of
Neurochemistry and Neuropharmacology, IIBB-CSIC, IDIBAPS, CIBERNED, Barcelona 08036, Spain
| | | | - Roser Cortés
- Department
of
Neurochemistry and Neuropharmacology, IIBB-CSIC, IDIBAPS, CIBERNED, Barcelona 08036, Spain
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147
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Fields RD, Woo DH, Basser PJ. Glial Regulation of the Neuronal Connectome through Local and Long-Distant Communication. Neuron 2015; 86:374-86. [PMID: 25905811 DOI: 10.1016/j.neuron.2015.01.014] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
If "the connectome" represents a complete map of anatomical and functional connectivity in the brain, it should also include glia. Glia define and regulate both the brain's anatomical and functional connectivity over a broad range of length scales, spanning the whole brain to subcellular domains of synaptic interactions. This Perspective article examines glial interactions with the neuronal connectome (including long-range networks, local circuits, and individual synaptic connections) and highlights opportunities for future research. Our understanding of the structure and function of the neuronal connectome would be incomplete without an understanding of how all types of glia contribute to neuronal connectivity and function, from single synapses to circuits.
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Affiliation(s)
- R Douglas Fields
- Nervous System Development and Plasticity Section, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA.
| | - Dong Ho Woo
- Nervous System Development and Plasticity Section, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Peter J Basser
- Section on Tissue Biophysics and Biomimetics, Program on Pediatric Imaging and Tissue Sciences, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA
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148
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Ramaswamy S, Markram H. Anatomy and physiology of the thick-tufted layer 5 pyramidal neuron. Front Cell Neurosci 2015; 9:233. [PMID: 26167146 PMCID: PMC4481152 DOI: 10.3389/fncel.2015.00233] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 06/08/2015] [Indexed: 11/13/2022] Open
Abstract
The thick-tufted layer 5 (TTL5) pyramidal neuron is one of the most extensively studied neuron types in the mammalian neocortex and has become a benchmark for understanding information processing in excitatory neurons. By virtue of having the widest local axonal and dendritic arborization, the TTL5 neuron encompasses various local neocortical neurons and thereby defines the dimensions of neocortical microcircuitry. The TTL5 neuron integrates input across all neocortical layers and is the principal output pathway funneling information flow to subcortical structures. Several studies over the past decades have investigated the anatomy, physiology, synaptology, and pathophysiology of the TTL5 neuron. This review summarizes key discoveries and identifies potential avenues of research to facilitate an integrated and unifying understanding on the role of a central neuron in the neocortex.
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Affiliation(s)
- Srikanth Ramaswamy
- Blue Brain Project, Ecole Polytechnique Fédérale de Lausanne, Campus Biotech Geneva, Switzerland
| | - Henry Markram
- Blue Brain Project, Ecole Polytechnique Fédérale de Lausanne, Campus Biotech Geneva, Switzerland
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149
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O'Connor WT, O'Shea SD. Clozapine and GABA transmission in schizophrenia disease models. Pharmacol Ther 2015; 150:47-80. [DOI: 10.1016/j.pharmthera.2015.01.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 01/06/2015] [Indexed: 11/30/2022]
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150
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Large-scale spatiotemporal spike patterning consistent with wave propagation in motor cortex. Nat Commun 2015; 6:7169. [PMID: 25994554 PMCID: PMC4443713 DOI: 10.1038/ncomms8169] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 04/14/2015] [Indexed: 11/18/2022] Open
Abstract
Aggregate signals in cortex are known to be spatiotemporally organized as propagating waves across the cortical surface, but it remains unclear whether the same is true for spiking activity in individual neurons. Furthermore, the functional interactions between cortical neurons are well documented but their spatial arrangement on the cortical surface has been largely ignored. Here we use a functional network analysis to demonstrate that a subset of motor cortical neurons in non-human primates spatially coordinate their spiking activity in a manner that closely matches wave propagation measured in the beta oscillatory band of the local field potential. We also demonstrate that sequential spiking of pairs of neuron contains task-relevant information that peaks when the neurons are spatially oriented along the wave axis. We hypothesize that the spatial anisotropy of spike patterning may reflect the underlying organization of motor cortex and may be a general property shared by other cortical areas. Aggregate signals in cortex are spatiotemporally organized as propagating waves across the cortical surface. Here the authors demonstrate that neurons in primary motor cortex of monkeys spatially coordinate their spiking activity in a manner that closely matches wave propagation.
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