1
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Shallow MC, Tian L, Lin H, Lefton KB, Chen S, Dougherty JD, Culver JP, Lambo ME, Hengen KB. At the onset of active whisking, the input layer of barrel cortex exhibits a 24 h window of increased excitability that depends on prior experience. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.04.597353. [PMID: 38895408 PMCID: PMC11185658 DOI: 10.1101/2024.06.04.597353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
The development of motor control over sensory organs is a critical milestone in sensory processing, enabling active exploration and shaping of the sensory environment. However, whether the onset of sensory organ motor control directly influences the development of corresponding sensory cortices remains unknown. Here, we exploit the late onset of whisking behavior in mice to address this question in the somatosensory system. Using ex vivo electrophysiology, we discovered a transient increase in the intrinsic excitability of excitatory neurons in layer IV of the barrel cortex, which processes whisker input, precisely coinciding with the onset of active whisking at postnatal day 14 (P14). This increase in neuronal gain was specific to layer IV, independent of changes in synaptic strength, and required prior sensory experience. Strikingly, the effect was not observed in layer II/III of the barrel cortex or in the visual cortex upon eye opening, suggesting a unique interaction between the development of active sensing and the thalamocortical input layer in the somatosensory system. Predictive modeling indicated that changes in active membrane conductances alone could reliably distinguish P14 neurons in control but not whisker-deprived hemispheres. Our findings demonstrate an experience-dependent, lamina-specific refinement of neuronal excitability tightly linked to the emergence of active whisking. This transient increase in the gain of the thalamic input layer coincides with a critical period for synaptic plasticity in downstream layers, suggesting a role in facilitating cortical maturation and sensory processing. Together, our results provide evidence for a direct interaction between the development of motor control and sensory cortex, offering new insights into the experience-dependent development and refinement of sensory systems. These findings have broad implications for understanding the interplay between motor and sensory development, and how the mechanisms of perception cooperate with behavior.
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Affiliation(s)
| | - Lucy Tian
- Department of Biology, Washington University in Saint Louis
| | - Hudson Lin
- Department of Biology, Washington University in Saint Louis
| | - Katheryn B Lefton
- Department of Biology, Washington University in Saint Louis
- Department of Neuroscience, Washington University in Saint Louis
| | - Siyu Chen
- Department of Genetics, Washington University in Saint Louis
| | | | - Joe P Culver
- Department of Radiology, Washington University in Saint Louis
| | - Mary E Lambo
- Department of Biology, Washington University in Saint Louis
| | - Keith B Hengen
- Department of Biology, Washington University in Saint Louis
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2
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Waxman EA, Dungan LV, DeFlitch LM, Merchant JP, Gagne AL, Goldberg EM, French DL. Reproducible Differentiation of Human Pluripotent Stem Cells into Two-Dimensional Cortical Neuron Cultures with Checkpoints for Success. Curr Protoc 2023; 3:e948. [PMID: 38148714 PMCID: PMC10753927 DOI: 10.1002/cpz1.948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
The patterning of excitatory cortical neurons from human pluripotent stem cells (hPSCs) is a desired technique for the study of neurodevelopmental disorders, as neurons can be created and compared from control hPSC lines, hPSC lines generated from patients, and CRISPR-modified hPSC lines. Therefore, this technique allows for the examination of disease phenotypes and assists in the development of potential new therapeutics for neurodevelopmental disorders. Many protocols, however, are optimized for use with specific hPSC lines or within a single laboratory, and they often provide insufficient guidance on how to identify positive stages in the differentiation or how to troubleshoot. Here, we present an efficient and reproducible directed differentiation protocol to generate two-dimensional cultures of hPSC-derived excitatory cortical neurons without intermediary embryoid body formation. This novel protocol is supported by our data generated with five independent hPSC lines and in two independent laboratories. Importantly, as neuronal differentiations follow a long time course to reach maturity, we provide extensive guidance regarding morphological and flow cytometry checkpoints allowing for early indications of successful differentiation. We also include extensive troubleshooting tips and support protocols to assist the operator. The goal of this protocol is to assist others in the successful differentiation of excitatory cortical neurons from hPSCs. © 2023 Wiley Periodicals LLC. Basic Protocol: Directed differentiation of hPSCs into excitatory cortical neurons Support Protocol 1: Harvesting and fixing cells for flow cytometry analyses Support Protocol 2: Performing flow cytometry analyses Support Protocol 3: Thawing NPCs from a cryopreserved stock Alternate Protocol 1: Continuing Expansion of NPCs Alternate Protocol 2: Treatment of neurons with Ara-C to ablate radial glia Support Protocol 4: Experimental methods for validation of excitatory cortical neurons.
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Affiliation(s)
- Elisa A. Waxman
- Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Center for Epilepsy and NeuroDevelopmental Disorders (ENDD), The Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Lea V. Dungan
- Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Center for Epilepsy and NeuroDevelopmental Disorders (ENDD), The Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Leah M. DeFlitch
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Julie P. Merchant
- Departments of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Alyssa L. Gagne
- Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Ethan M. Goldberg
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- The Epilepsy NeuroGenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Departments of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Deborah L. French
- Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Center for Epilepsy and NeuroDevelopmental Disorders (ENDD), The Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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3
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Murasawa H, Soumiya H, Kobayashi H, Imai J, Nagase T, Fukumitsu H. Neonatal bilateral whisker trimming in male mice age-dependently alters brain neurotransmitter levels and causes adolescent onsets of social behavior abnormalities. Biomed Res 2023; 44:147-160. [PMID: 37544736 DOI: 10.2220/biomedres.44.147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Tactile perception via whiskers is important in rodent behavior. Whisker trimming during the neonatal period affects mouse behaviors related to both whisker-based tactile cognition and social performance. However, the molecular basis of these phenomena is not completely understood. To solve this issue, we investigated developmental changes in transmitters and metabolites in various brain regions of male mice subjected to bilateral whisker trimming during the neonatal period (10 days after birth [BWT10 mice]). We discovered significantly lower levels of 3-methoxy-4-hydroxyphenyl glycol (MHPG), the major noradrenaline metabolite, in various brain regions of male BWT10 mice at both early/late adolescent stages (at P4W and P8W). However, reduced levels of dopamine (DA) and their metabolites were more significantly identified at P8W in the nuclear origins of monoamine (midbrain and medulla oblongata) and the limbic system (frontal cortex, amygdala, and hippocampus) than at P4W. Furthermore, the onset of social behavior deficits (P6W) was observed later to the impairment of whisker-based tactile cognitive behaviors (P4W). Taken together, these findings suggest that whisker-mediated tactile cognition may contribute toprogressive abnormalities in social behaviors in BWT10 mice accompanied by impaired development of dopaminergic systems.
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Affiliation(s)
- Hiroyasu Murasawa
- Laboratory of Molecular Biology, Department of Biofunctional Analysis, Gifu Pharmaceutical University
- Hashima Laboratory, Nihon Bioresearch Inc
| | - Hitomi Soumiya
- Laboratory of Molecular Biology, Department of Biofunctional Analysis, Gifu Pharmaceutical University
| | - Hiroyuki Kobayashi
- Laboratory of Molecular Biology, Department of Biofunctional Analysis, Gifu Pharmaceutical University
- Hashima Laboratory, Nihon Bioresearch Inc
| | - Jun Imai
- Hashima Laboratory, Nihon Bioresearch Inc
| | | | - Hidefumi Fukumitsu
- Laboratory of Molecular Biology, Department of Biofunctional Analysis, Gifu Pharmaceutical University
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4
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Nakazawa S, Iwasato T. Spatial organization and transitions of spontaneous neuronal activities in the developing sensory cortex. Dev Growth Differ 2021; 63:323-339. [PMID: 34166527 DOI: 10.1111/dgd.12739] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 12/30/2022]
Abstract
The sensory cortex underlies our ability to perceive and interact with the external world. Sensory perceptions are controlled by specialized neuronal circuits established through fine-tuning, which relies largely on neuronal activity during the development. Spontaneous neuronal activity is an essential driving force of neuronal circuit refinement. At early developmental stages, sensory cortices display spontaneous activities originating from the periphery and characterized by correlated firing arranged spatially according to the modality. The firing patterns are reorganized over time and become sparse, which is typical for the mature brain. This review focuses mainly on rodent sensory cortices. First, the features of the spontaneous activities during early postnatal stages are described. Then, the developmental changes in the spatial organization of the spontaneous activities and the transition mechanisms involved are discussed. The identification of the principles controlling the spatial organization of spontaneous activities in the developing sensory cortex is essential to understand the self-organization process of neuronal circuits.
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Affiliation(s)
- Shingo Nakazawa
- Laboratory of Mammalian Neural Circuits, National Institute of Genetics, Mishima, Japan.,Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
| | - Takuji Iwasato
- Laboratory of Mammalian Neural Circuits, National Institute of Genetics, Mishima, Japan.,Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), Mishima, Japan
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5
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Bragg-Gonzalo L, De León Reyes NS, Nieto M. Genetic and activity dependent-mechanisms wiring the cortex: Two sides of the same coin. Semin Cell Dev Biol 2021; 118:24-34. [PMID: 34030948 DOI: 10.1016/j.semcdb.2021.05.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/27/2021] [Accepted: 05/08/2021] [Indexed: 01/17/2023]
Abstract
The cerebral cortex is responsible for the higher-order functions of the brain such as planning, cognition, or social behaviour. It provides us with the capacity to interact with and transform our world. The substrates of cortical functions are complex neural circuits that arise during development from the dynamic remodelling and progressive specialization of immature undefined networks. Here, we review the genetic and activity-dependent mechanisms of cortical wiring focussing on the importance of their interaction. Cortical circuits emerge from an initial set of neuronal types that engage in sequential forms of embryonic and postnatal activity. Such activities further complement the cells' genetic programs, increasing neuronal diversity and modifying the electrical properties while promoting selective connectivity. After a temporal window of enhanced plasticity, the main features of mature circuits are established. Failures in these processes can lead to neurodevelopmental disorders whose treatment remains elusive. However, a deeper dissection of cortical wiring will pave the way for innovative therapies.
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Affiliation(s)
- L Bragg-Gonzalo
- Department of Cellular and Molecular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, (CNB-CSIC) Campus de Cantoblanco, Darwin 3, 28049 Madrid, Spain
| | - N S De León Reyes
- Department of Cellular and Molecular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, (CNB-CSIC) Campus de Cantoblanco, Darwin 3, 28049 Madrid, Spain; Instituto de Neurociencias de Alicante, CSIC-UMH, 03550 San Juan de Alicante, Spain
| | - M Nieto
- Department of Cellular and Molecular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, (CNB-CSIC) Campus de Cantoblanco, Darwin 3, 28049 Madrid, Spain.
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6
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Jamann N, Dannehl D, Lehmann N, Wagener R, Thielemann C, Schultz C, Staiger J, Kole MHP, Engelhardt M. Sensory input drives rapid homeostatic scaling of the axon initial segment in mouse barrel cortex. Nat Commun 2021; 12:23. [PMID: 33397944 PMCID: PMC7782484 DOI: 10.1038/s41467-020-20232-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 11/16/2020] [Indexed: 12/12/2022] Open
Abstract
The axon initial segment (AIS) is a critical microdomain for action potential initiation and implicated in the regulation of neuronal excitability during activity-dependent plasticity. While structural AIS plasticity has been suggested to fine-tune neuronal activity when network states change, whether it acts in vivo as a homeostatic regulatory mechanism in behaviorally relevant contexts remains poorly understood. Using the mouse whisker-to-barrel pathway as a model system in combination with immunofluorescence, confocal analysis and electrophysiological recordings, we observed bidirectional AIS plasticity in cortical pyramidal neurons. Furthermore, we find that structural and functional AIS remodeling occurs in distinct temporal domains: Long-term sensory deprivation elicits an AIS length increase, accompanied with an increase in neuronal excitability, while sensory enrichment results in a rapid AIS shortening, accompanied by a decrease in action potential generation. Our findings highlight a central role of the AIS in the homeostatic regulation of neuronal input-output relations.
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Affiliation(s)
- Nora Jamann
- Axonal Signaling Group, Netherlands Institute for Neurosciences (NIN), Royal Netherlands Academy for Arts and Sciences (KNAW), Amsterdam, The Netherlands
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Dominik Dannehl
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Nadja Lehmann
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Robin Wagener
- Clinic of Neurology, University Hospital Heidelberg, Heidelberg, Germany
| | - Corinna Thielemann
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Christian Schultz
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Jochen Staiger
- Institute of Neuroanatomy, University Medical Center, Georg August University of Göttingen, Göttingen, Germany
| | - Maarten H P Kole
- Axonal Signaling Group, Netherlands Institute for Neurosciences (NIN), Royal Netherlands Academy for Arts and Sciences (KNAW), Amsterdam, The Netherlands.
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
| | - Maren Engelhardt
- Institute of Neuroanatomy, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
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7
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Joy MT, Carmichael ST. Encouraging an excitable brain state: mechanisms of brain repair in stroke. Nat Rev Neurosci 2021; 22:38-53. [PMID: 33184469 PMCID: PMC10625167 DOI: 10.1038/s41583-020-00396-7] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2020] [Indexed: 02/02/2023]
Abstract
Stroke induces a plastic state in the brain. This period of enhanced plasticity leads to the sprouting of new axons, the formation of new synapses and the remapping of sensory-motor functions, and is associated with motor recovery. This is a remarkable process in the adult brain, which is normally constrained in its levels of neuronal plasticity and connectional change. Recent evidence indicates that these changes are driven by molecular systems that underlie learning and memory, such as changes in cellular excitability during memory formation. This Review examines circuit changes after stroke, the shared mechanisms between memory formation and brain repair, the changes in neuronal excitability that underlie stroke recovery, and the molecular and pharmacological interventions that follow from these findings to promote motor recovery in animal models. From these findings, a framework emerges for understanding recovery after stroke, central to which is the concept of neuronal allocation to damaged circuits. The translation of the concepts discussed here to recovery in humans is underway in clinical trials for stroke recovery drugs.
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Affiliation(s)
- Mary T Joy
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - S Thomas Carmichael
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA.
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8
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Vianna-Barbosa R, Bahia CP, Sanabio A, de Freitas GPA, Madeiro da Costa RF, Garcez PP, Miranda K, Lent R, Tovar-Moll F. Myelination of Callosal Axons Is Hampered by Early and Late Forelimb Amputation in Rats. Cereb Cortex Commun 2020; 2:tgaa090. [PMID: 34296146 PMCID: PMC8152840 DOI: 10.1093/texcom/tgaa090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 11/17/2020] [Accepted: 11/22/2020] [Indexed: 11/14/2022] Open
Abstract
Deafferentation is an important determinant of plastic changes in the CNS, which consists of a loss of inputs from the body periphery or from the CNS itself. Although cortical reorganization has been well documented, white matter plasticity was less explored. Our goal was to investigate microstructural interhemispheric connectivity changes in early and late amputated rats. For that purpose, we employed diffusion-weighted magnetic resonance imaging, as well as Western blotting, immunohistochemistry, and electron microscopy of sections of the white matter tracts to analyze the microstructural changes in the corticospinal tract and in the corpus callosum (CC) sector that contains somatosensory fibers integrating cortical areas representing the forelimbs and compare differences in rats undergoing forelimb amputation as neonates, with those amputated as adults. Results showed that early amputation induced decreased fractional anisotropy values and reduction of total myelin amount in the cerebral peduncle contralateral to the amputation. Both early and late forelimb amputations induced decreased myelination of callosal fibers. While early amputation affected myelination of thinner axons, late amputation disrupted axons of all calibers. Since the CC provides a modulation of inhibition and excitation between the hemispheres, we suggest that the demyelination observed among callosal fibers may misbalance this modulation.
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Affiliation(s)
- Rodrigo Vianna-Barbosa
- Post-Graduate Program in Morphological Sciences, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro CEP 21941-902, Brazil.,National Center of Structural Biology and Bioimaging, Federal University of Rio de Janeiro, Rio de Janeiro CEP 21941-902, Brazil
| | - Carlomagno P Bahia
- Institute of Health Sciences, Federal University of Pará, Pará CEP 66035-160, Brazil
| | - Alexandre Sanabio
- Post-Graduate Program in Morphological Sciences, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro CEP 21941-902, Brazil
| | - Gabriella P A de Freitas
- Post-Graduate Program in Morphological Sciences, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro CEP 21941-902, Brazil
| | | | - Patricia P Garcez
- Post-Graduate Program in Morphological Sciences, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro CEP 21941-902, Brazil
| | - Kildare Miranda
- National Center of Structural Biology and Bioimaging, Federal University of Rio de Janeiro, Rio de Janeiro CEP 21941-902, Brazil.,Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro CEP 21941-902, Brazil
| | - Roberto Lent
- Post-Graduate Program in Morphological Sciences, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro CEP 21941-902, Brazil.,D'Or Institute of Research and Education (IDOR), Rio de Janeiro, CEP 22281-100, Brazil
| | - Fernanda Tovar-Moll
- Post-Graduate Program in Morphological Sciences, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro CEP 21941-902, Brazil.,National Center of Structural Biology and Bioimaging, Federal University of Rio de Janeiro, Rio de Janeiro CEP 21941-902, Brazil.,D'Or Institute of Research and Education (IDOR), Rio de Janeiro, CEP 22281-100, Brazil
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9
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Oruro EM, Pardo GVE, Lucion AB, Calcagnotto ME, Idiart MAP. Maturation of pyramidal cells in anterior piriform cortex may be sufficient to explain the end of early olfactory learning in rats. ACTA ACUST UNITED AC 2019; 27:20-32. [PMID: 31843979 PMCID: PMC6919191 DOI: 10.1101/lm.050724.119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 11/12/2019] [Indexed: 01/09/2023]
Abstract
Studies have shown that neonate rodents exhibit high ability to learn a preference for novel odors associated with thermo-tactile stimuli that mimics maternal care. Artificial odors paired with vigorous strokes in rat pups younger than 10 postnatal days (P), but not older, rapidly induce an orientation-approximation behavior toward the conditioned odor in a two-choice preference test. The olfactory bulb (OB) and the anterior olfactory cortex (aPC), both modulated by norepinephrine (NE), have been identified as part of a neural circuit supporting this transitory olfactory learning. One possible explanation at the neuronal level for why the odor-stroke pairing induces consistent orientation-approximation behavior in <P10 pups, but not in >P10, is the coincident activation of prior existent neurons in the aPC mediating this behavior. Specifically, odor-stroke conditioning in <P10 pups may activate more mother/nest odor's responsive aPC neurons than in >P10 pups, promoting orientation-approximation behavior in the former but not in the latter. In order to test this hypothesis, we performed in vitro patch-clamp recordings of the aPC pyramidal neurons from rat pups from two age groups (P5–P8 and P14–P17) and built computational models for the OB-aPC neural circuit based on this physiological data. We conditioned the P5–P8 OB-aPC artificial circuit to an odor associated with NE activation (representing the process of maternal odor learning during mother–infant interactions inside the nest) and then evaluated the response of the OB-aPC circuit to the presentation of the conditioned odor. The results show that the number of responsive aPC neurons to the presentation of the conditioned odor in the P14–P17 OB-aPC circuit was lower than in the P5–P8 circuit, suggesting that at P14–P17, the reduced number of responsive neurons to the conditioned (maternal) odor might not be coincident with the responsive neurons for a second conditioned odor.
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Affiliation(s)
- Enver Miguel Oruro
- Neurocomputational and Language Processing Laboratory, Institute of Physics, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 91501-970 Brazil.,Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90035-003 Brazil.,Neuroscience Graduate Program, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90050-170 Brazil
| | - Grace V E Pardo
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90035-003 Brazil.,Department of Physiology, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90050-170 Brazil.,Centre for Interdisciplinary Science and Society Studies, Universidad de Ciencias y Humanidades, Los Olivos, Lima, 15314 Peru
| | - Aldo B Lucion
- Department of Physiology, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90050-170 Brazil
| | - Maria Elisa Calcagnotto
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90035-003 Brazil.,Neuroscience Graduate Program, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90050-170 Brazil
| | - Marco A P Idiart
- Neurocomputational and Language Processing Laboratory, Institute of Physics, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 91501-970 Brazil.,Neuroscience Graduate Program, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 90050-170 Brazil
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10
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Booker SA, Domanski APF, Dando OR, Jackson AD, Isaac JTR, Hardingham GE, Wyllie DJA, Kind PC. Altered dendritic spine function and integration in a mouse model of fragile X syndrome. Nat Commun 2019; 10:4813. [PMID: 31645626 PMCID: PMC6811549 DOI: 10.1038/s41467-019-11891-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 07/23/2019] [Indexed: 12/23/2022] Open
Abstract
Cellular and circuit hyperexcitability are core features of fragile X syndrome and related autism spectrum disorder models. However, the cellular and synaptic bases of this hyperexcitability have proved elusive. We report in a mouse model of fragile X syndrome, glutamate uncaging onto individual dendritic spines yields stronger single-spine excitation than wild-type, with more silent spines. Furthermore, fewer spines are required to trigger an action potential with near-simultaneous uncaging at multiple spines. This is, in part, from increased dendritic gain due to increased intrinsic excitability, resulting from reduced hyperpolarization-activated currents, and increased NMDA receptor signaling. Using super-resolution microscopy we detect no change in dendritic spine morphology, indicating no structure-function relationship at this age. However, ultrastructural analysis shows a 3-fold increase in multiply-innervated spines, accounting for the increased single-spine glutamate currents. Thus, loss of FMRP causes abnormal synaptogenesis, leading to large numbers of poly-synaptic spines despite normal spine morphology, thus explaining the synaptic perturbations underlying circuit hyperexcitability. Fragile X syndrome and autism spectrum disorders are associated with circuit hyperexcitability, however, its cellular and synaptic bases are not well understood. Here, the authors report abnormal synaptogenesis with an increased prevalence of polysynaptic spines with normal morphology in a mouse model of fragile X.
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Affiliation(s)
- Sam A Booker
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Centre for Brain Development and Repair, NCBS, GKVK Campus, Bangalore, 560065, India
| | - Aleksander P F Domanski
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK
| | - Owen R Dando
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Centre for Brain Development and Repair, NCBS, GKVK Campus, Bangalore, 560065, India.,UK Dementia Research Institute, University of Edinburgh, Chancellor's Buildings, Little France, Edinburgh, EH16 4SB, UK
| | - Adam D Jackson
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Centre for Brain Development and Repair, NCBS, GKVK Campus, Bangalore, 560065, India
| | - John T R Isaac
- Developmental Synaptic Plasticity Section, NINDS, NIH, Bethesda, MD, 20892, USA.,Janssen Neuroscience, J&J London Innovation Centre, One Chapel Place, London, W1G 0B, UK
| | - Giles E Hardingham
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Centre for Brain Development and Repair, NCBS, GKVK Campus, Bangalore, 560065, India.,UK Dementia Research Institute, University of Edinburgh, Chancellor's Buildings, Little France, Edinburgh, EH16 4SB, UK
| | - David J A Wyllie
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK. .,Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK. .,Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK. .,Centre for Brain Development and Repair, NCBS, GKVK Campus, Bangalore, 560065, India.
| | - Peter C Kind
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK. .,Patrick Wild Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK. .,Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK. .,Centre for Brain Development and Repair, NCBS, GKVK Campus, Bangalore, 560065, India.
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11
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Saba L, Viscomi MT, Martini A, Caioli S, Mercuri NB, Guatteo E, Zona C. Modified age-dependent expression of NaV1.6 in an ALS model correlates with motor cortex excitability alterations. Neurobiol Dis 2019; 130:104532. [PMID: 31302244 DOI: 10.1016/j.nbd.2019.104532] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 06/28/2019] [Accepted: 07/10/2019] [Indexed: 12/13/2022] Open
Abstract
Cortical hyperexcitability is an early and intrinsic feature of Amyotrophic Lateral Sclerosis (ALS), but the mechanisms underlying this critical neuronal dysfunction are poorly understood. Recently, we have demonstrated that layer V pyramidal neurons (PNs) in the primary motor cortex (M1) of one-month old (P30) G93A ALS mice display an early hyperexcitability status compared to Control mice. In order to investigate the time-dependent evolution of the cortical excitability in the G93A ALS model, here we have performed an electrophysiological and immunohistochemical study at three different mouse ages. M1 PNs from 14-days old (P14) G93A mice have shown no excitability alterations, while M1 PNs from 3-months old (P90) G93A mice have shown a hypoexcitability status, compared to Control mice. These age-dependent cortical excitability dysfunctions correlate with a similar time-dependent trend of the persistent sodium current (INaP) amplitude alterations, suggesting that INaP may play a crucial role in the G93A cortical excitability aberrations. Specifically, immunohistochemistry experiments have indicated that the expression level of the NaV1.6 channel, one of the voltage-gated Na+ channels mainly distributed within the central nervous system, varies in G93A primary motor cortex during disease progression, according to the excitability and INaP alterations, but not in other cortical areas. Microfluorometry experiments, combined with electrophysiological recordings, have verified that P30 G93A PNs hyperexcitability is associated to a greater accumulation of intracellular calcium ([Ca2+]i) compared to Control PNs, and that this difference is still present when G93A and Control PNs fire action potentials at the same frequency. These results suggest that [Ca2+]i de-regulation in G93A PNs may contribute to neuronal demise and that the NaV1.6 channels could be a potential therapeutic target to ameliorate ALS disease progression.
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Affiliation(s)
- Luana Saba
- Department of Systems Medicine, University of Rome "Tor Vergata" via Montpellier 1, Rome 00133, Italy
| | - Maria Teresa Viscomi
- Università Cattolica del Sacro Cuore, Istituto di Istologia ed Embriologia, Fondazione Policlinico Universitario A. Gemelli, Largo F. Vito 1, Rome 00168, Italy
| | - Alessandro Martini
- IRCCS Fondazione Santa Lucia, via del Fosso di Fiorano 64, Rome 00143, Italy
| | - Silvia Caioli
- IRCCS Fondazione Santa Lucia, via del Fosso di Fiorano 64, Rome 00143, Italy
| | - Nicola Biagio Mercuri
- Department of Systems Medicine, University of Rome "Tor Vergata" via Montpellier 1, Rome 00133, Italy; IRCCS Fondazione Santa Lucia, via del Fosso di Fiorano 64, Rome 00143, Italy
| | - Ezia Guatteo
- IRCCS Fondazione Santa Lucia, via del Fosso di Fiorano 64, Rome 00143, Italy; Department of Motor Science and Wellness, University of Naples 'Parthenope', Via Medina 40, Naples 80133, Italy
| | - Cristina Zona
- Department of Systems Medicine, University of Rome "Tor Vergata" via Montpellier 1, Rome 00133, Italy; IRCCS Fondazione Santa Lucia, via del Fosso di Fiorano 64, Rome 00143, Italy.
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12
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Segregated Subnetworks of Intracortical Projection Neurons in Primary Visual Cortex. Neuron 2018; 100:1313-1321.e6. [DOI: 10.1016/j.neuron.2018.10.023] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/13/2018] [Accepted: 10/11/2018] [Indexed: 11/23/2022]
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13
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Yu S, Lin Z, Xiao Z. [Changes of membrane properties and synaptic stability of rat retinal ganglion cells during postnatal development]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2018; 38:1100-1106. [PMID: 30377110 DOI: 10.12122/j.issn.1673-4254.2018.09.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate the changes in the membrane properties and synaptic stability of the rat retinal ganglion cells (RGCs) during postnatal development. METHODS Whole-cell patch-clamp technique was used to record the action potentials (AP) and miniature excitatory postsynaptic currents (mEPSC) of SD rat RGCs at postnatal days 7, 14 and 40. The active and passive membrane properties and the synaptic stability (measured by the amplitude, frequency, rise time and decay time of mEPSC) of the RGCs were analyzed using Patchmaster software. RESULTS Comparison of the RGCs in SD rats across different postnatal ages revealed significant changes in the electrophysiological characteristics of the RGCs during postnatal development. The discharge rate was significantly greater while the AP half-peak width was significantly smaller at postnatal day 15 (P15) than at P7 (P < 0.01), but were both similar between P15 and P40 (P=0.086); in terms of the passive membrane properties, the membrane time constant gradually decreased during the development. The frequency of mEPSCs increased significantly over time during postnatal development (P < 0.01), but was similar between P15 and P40 rats. CONCLUSIONS In SD rats, the membrane properties and synaptic stability of the RGCs undergo alterations following a specific pattern, which highlights a critical period where distinct changes occur in the electrophysiological characteristics of RGCs, followed by gradual stabilization over time. Such changes in the electrophysiological characteristics represent the basic characteristics of RGCs for visual signal processing, and understanding of this mechanism may provide insights into the exact role of the RGC in visual information processing.
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Affiliation(s)
- Siqi Yu
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Zhengrong Lin
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Zhongju Xiao
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
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14
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van der Bourg A, Yang JW, Reyes-Puerta V, Laurenczy B, Wieckhorst M, Stüttgen MC, Luhmann HJ, Helmchen F. Layer-Specific Refinement of Sensory Coding in Developing Mouse Barrel Cortex. Cereb Cortex 2018; 27:4835-4850. [PMID: 27620976 DOI: 10.1093/cercor/bhw280] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 08/17/2016] [Indexed: 12/20/2022] Open
Abstract
Rodent rhythmic whisking behavior matures during a critical period around 2 weeks after birth. The functional adaptations of neocortical circuitry during this developmental period remain poorly understood. Here, we characterized stimulus-evoked neuronal activity across all layers of mouse barrel cortex before, during, and after the onset of whisking behavior. Employing multi-electrode recordings and 2-photon calcium imaging in anesthetized mice, we tested responses to rostro-caudal whisker deflections, axial "tapping" stimuli, and their combination from postnatal day 10 (P10) to P28. Within this period, whisker-evoked activity of neurons displayed a general decrease in layer 2/3 (L2/3) and L4, but increased in L5 and L6. Distinct alterations in neuronal response adaptation during the 2-s period of stimulation at ~5 Hz accompanied these changes. Moreover, single-unit analysis revealed that response selectivity in favor of either lateral deflection or axial tapping emerges in deeper layers within the critical period around P14. For superficial layers we confirmed this finding using calcium imaging of L2/3 neurons, which also exhibited emergence of response selectivity as well as progressive sparsification and decorrelation of evoked responses around P14. Our results demonstrate layer-specific development of sensory responsiveness and response selectivity in mouse somatosensory cortex coinciding with the onset of exploratory behavior.
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Affiliation(s)
- Alexander van der Bourg
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, CH-8057 Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, CH-8057 Zurich, Switzerland
| | - Jenq-Wei Yang
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, D-55128 Mainz, Germany
| | - Vicente Reyes-Puerta
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, D-55128 Mainz, Germany
| | - Balazs Laurenczy
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, CH-8057 Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, CH-8057 Zurich, Switzerland
| | - Martin Wieckhorst
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, CH-8057 Zurich, Switzerland
| | - Maik C Stüttgen
- Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg University, D-55128 Mainz, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, D-55128 Mainz, Germany
| | - Fritjof Helmchen
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, CH-8057 Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, CH-8057 Zurich, Switzerland
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15
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Fernandez FR, Rahsepar B, White JA. Differences in the Electrophysiological Properties of Mouse Somatosensory Layer 2/3 Neurons In Vivo and Slice Stem from Intrinsic Sources Rather than a Network-Generated High Conductance State. eNeuro 2018; 5:ENEURO.0447-17.2018. [PMID: 29662946 PMCID: PMC5898699 DOI: 10.1523/eneuro.0447-17.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/01/2018] [Accepted: 03/20/2018] [Indexed: 01/29/2023] Open
Abstract
Synaptic activity in vivo can potentially alter the integration properties of neurons. Using recordings in awake mice, we targeted somatosensory layer 2/3 pyramidal neurons and compared neuronal properties with those from slices. Pyramidal cells in vivo had lower resistance and gain values, as well as broader spikes and increased spike frequency adaptation compared to the same cells in slices. Increasing conductance in neurons using dynamic clamp to levels observed in vivo, however, did not lessen the differences between in vivo and slice conditions. Further, local application of tetrodotoxin (TTX) in vivo blocked synaptic-mediated membrane voltage fluctuations but had little impact on pyramidal cell membrane input resistance and time constant values. Differences in electrophysiological properties of layer 2/3 neurons in mouse somatosensory cortex, therefore, stem from intrinsic sources separate from synaptic-mediated membrane voltage fluctuations.
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Affiliation(s)
- Fernando R Fernandez
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215
| | - Bahar Rahsepar
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215
| | - John A White
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215
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16
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Anastasiades PG, Marques‐Smith A, Butt SJB. Studies of cortical connectivity using optical circuit mapping methods. J Physiol 2018; 596:145-162. [PMID: 29110301 PMCID: PMC5767689 DOI: 10.1113/jp273463] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 10/11/2017] [Indexed: 11/08/2022] Open
Abstract
An important consideration when probing the function of any neuron is to uncover the source of synaptic input onto the cell, its intrinsic physiology and efferent targets. Over the years, electrophysiological approaches have generated considerable insight into these properties in a variety of cortical neuronal subtypes and circuits. However, as researchers explore neuronal function in greater detail, they are increasingly turning to optical techniques to bridge the gap between local network interactions and behaviour. The application of optical methods has increased dramatically over the past decade, spurred on by the optogenetic revolution. In this review, we provide an account of recent innovations, providing researchers with a primer detailing circuit mapping strategies in the cerebral cortex. We will focus on technical aspects of performing neurotransmitter uncaging and channelrhodopsin-assisted circuit mapping, with the aim of identifying common pitfalls that can negatively influence the collection of reliable data.
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17
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Chen AN, Meliza CD. Phasic and tonic cell types in the zebra finch auditory caudal mesopallium. J Neurophysiol 2017; 119:1127-1139. [PMID: 29212920 DOI: 10.1152/jn.00694.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The caudal mesopallium (CM) is a cortical-level area in the songbird auditory pathway where selective, invariant responses to familiar songs emerge. To characterize the cell types that perform this computation, we made whole cell recordings from brain slices in juvenile zebra finches ( Taeniopygia guttata) of both sexes. We found three groups of putatively excitatory neurons with distinct firing patterns. Tonic cells produced sustained responses to depolarizing step currents, phasic cells produced only a few spikes at the onset, and an intermediate group was also phasic but responded for up to a few hundred milliseconds. Phasic cells had smaller dendritic fields, higher resting potentials, and strong low-threshold outward rectification. Pharmacological treatment with voltage-gated potassium channel antagonists 4-aminopyridine and α-dendrotoxin converted phasic to tonic firing. When stimulated with broadband currents, phasic cells fired coherently with frequencies up to 20-30 Hz, whereas tonic neurons were more responsive to frequencies around 0-10 Hz. The distribution of peak coherence frequencies was similar to the distribution of temporal modulation rates in zebra finch song. We reproduced these observations in a single-compartment biophysical model by varying cell size and the magnitude of a slowly inactivating, low-threshold potassium current ( ILT). These data suggest that intrinsic dynamics in CM are matched to the temporal statistics of conspecific song. NEW & NOTEWORTHY In songbirds, the caudal mesopallium is a key brain area involved in recognizing the songs of other individuals. This study identifies three cell types in this area with distinct firing patterns (tonic, phasic, and intermediate) that reflect differences in cell size and a low-threshold potassium current. The phasic-firing neurons, which do not have a counterpart in mammalian auditory cortex, are better able to follow rapid modulations at the frequencies found in song.
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Affiliation(s)
- Andrew N Chen
- Neuroscience Graduate Program, University of Virginia , Charlottesville, Virginia
| | - C Daniel Meliza
- Neuroscience Graduate Program, University of Virginia , Charlottesville, Virginia.,Department of Psychology, University of Virginia , Charlottesville, Virginia
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18
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Coordinated Expression of Two Types of Low-Threshold K + Channels Establishes Unique Single Spiking of Mauthner Cells among Segmentally Homologous Neurons in the Zebrafish Hindbrain. eNeuro 2017; 4:eN-NWR-0249-17. [PMID: 29085904 PMCID: PMC5659376 DOI: 10.1523/eneuro.0249-17.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 09/28/2017] [Accepted: 09/29/2017] [Indexed: 01/15/2023] Open
Abstract
Expression of different ion channels permits homologously-generated neurons to acquire different types of excitability and thus code various kinds of input information. Mauthner (M) series neurons in the teleost hindbrain consist of M cells and their morphological homologs, which are repeated in adjacent segments and share auditory inputs. When excited, M cells generate a single spike at the onset of abrupt stimuli, while their homologs encode input intensity with firing frequency. Our previous study in zebrafish showed that immature M cells burst phasically at 2 d postfertilization (dpf) and acquire single spiking at 4 dpf by specific expression of auxiliary Kvβ2 subunits in M cells in association with common expression of Kv1.1 channels in the M series. Here, we further reveal the ionic mechanisms underlying this functional differentiation. Pharmacological blocking of Kv7/KCNQ in addition to Kv1 altered mature M cells to fire tonically, similar to the homologs. In contrast, blocking either channel alone caused M cells to burst phasically. M cells at 2 dpf fired tonically after blocking Kv7. In situ hybridization revealed specific Kv7.4/KCNQ4 expression in M cells at 2 dpf. Kv7.4 and Kv1.1 channels expressed in Xenopus oocytes exhibited low-threshold outward currents with slow and fast rise times, while coexpression of Kvβ2 accelerated and increased Kv1.1 currents, respectively. Computational models, modified from a mouse cochlear neuron model, demonstrated that Kv7.4 channels suppress repetitive firing to produce spike-frequency adaptation, while Kvβ2-associated Kv1.1 channels increase firing threshold and decrease the onset latency of spiking. Altogether, coordinated expression of these low-threshold K+ channels with Kvβ2 functionally differentiates M cells among homologous neurons.
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19
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Haridas S, Ganapathi R, Kumar M, Manda K. Whisker dependent responsiveness of C57BL/6J mice to different behavioral test paradigms. Behav Brain Res 2017; 336:51-58. [PMID: 28822693 DOI: 10.1016/j.bbr.2017.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/24/2017] [Accepted: 08/05/2017] [Indexed: 11/28/2022]
Abstract
Whisker trimming is very common in C57BL/6J mice. Dewhiskering may lead to an alteration in the thalamocortical connectivity and relevant behavioral functions. Since C57BL/6J is a commonly used strain for neurobehavioral studies, it is important to examine how whisker dependent heterogeneity affects the internal validity of behavioral phenotypes. The present study aimed to investigate the responsiveness of mice to different behavioral test paradigms in the presence or absence of whiskers. We employed two models of whisker deprivation: Acute Whisker Desensitization (AWD) and Chronic Habitual Dewhiskering (CHD). The AWD model blocks whisker sensation by lidocaine application. For CHD model, mice at the age of 12 weeks were carefully scrutinized for presence or absence of whiskers and divided into three groups, the whiskered mice, partially dewhiskered mice and completely dewhiskered mice. The whisker-dependent behavioral functions were assessed using open field test, novel object recognition test, marble burying test and forced swim test. Our results showed that habitual dewhiskering significantly altered the short-term memory and basal anxiety-like functions. Such behavioral alteration due to dewhiskering was significantly different in fully and partially dewhiskered mice, which is indicative of behavioral adaptation to the whisker desensitization. Contrary to CHD, the Acute Whisker Desensitization ameliorated behavioral compulsivity and basal anxiety. Our results suggest that vibrissal desensitization in the mice may lead to changes in their affective and cognitive state. Since, heterogeneity in whisker status may affect behavioral functions, careful inspection of the whisker status of C57BL/6J mice is recommended to increase the reproducibility and reliability of results obtained from behavioral assessments.
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Affiliation(s)
- Seenu Haridas
- NeuroBehavior Laboratory, Institute of Nuclear Medicine and Allied Sciences, Delhi, 110054, India
| | - Ramya Ganapathi
- NeuroBehavior Laboratory, Institute of Nuclear Medicine and Allied Sciences, Delhi, 110054, India
| | - Mayank Kumar
- NeuroBehavior Laboratory, Institute of Nuclear Medicine and Allied Sciences, Delhi, 110054, India
| | - Kailash Manda
- NeuroBehavior Laboratory, Institute of Nuclear Medicine and Allied Sciences, Delhi, 110054, India.
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20
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Jamann N, Jordan M, Engelhardt M. Activity-dependent axonal plasticity in sensory systems. Neuroscience 2017; 368:268-282. [PMID: 28739523 DOI: 10.1016/j.neuroscience.2017.07.035] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/23/2017] [Accepted: 07/14/2017] [Indexed: 12/21/2022]
Abstract
The rodent whisker-to-barrel cortex pathway is a classic model to study the effects of sensory experience and deprivation on neuronal circuit formation, not only during development but also in the adult. Decades of research have produced a vast body of evidence highlighting the fundamental role of neuronal activity (spontaneous and/or sensory-evoked) for circuit formation and function. In this context, it has become clear that neuronal adaptation and plasticity is not just a function of the neonatal brain, but persists into adulthood, especially after experience-driven modulation of network status. Mechanisms for structural remodeling of the somatodendritic or axonal domain include microscale alterations of neurites or synapses. At the same time, functional alterations at the nanoscale such as expression or activation changes of channels and receptors contribute to the modulation of intrinsic excitability or input-output relationships. However, it remains elusive how these forms of structural and functional plasticity come together to shape neuronal network formation and function. While specifically somatodendritic plasticity has been studied in great detail, the role of axonal plasticity, (e.g. at presynaptic boutons, branches or axonal microdomains), is rather poorly understood. Therefore, this review will only briefly highlight somatodendritic plasticity and instead focus on axonal plasticity. We discuss (i) the role of spontaneous and sensory-evoked plasticity during critical periods, (ii) the assembly of axonal presynaptic sites, (iii) axonal plasticity in the mature brain under baseline and sensory manipulation conditions, and finally (iv) plasticity of electrogenic axonal microdomains, namely the axon initial segment, during development and in the mature CNS.
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Affiliation(s)
- Nora Jamann
- Institute of Neuroanatomy, Medical Faculty Mannheim, CBTM, Heidelberg University, Germany
| | - Merryn Jordan
- Institute of Neuroanatomy, Medical Faculty Mannheim, CBTM, Heidelberg University, Germany
| | - Maren Engelhardt
- Institute of Neuroanatomy, Medical Faculty Mannheim, CBTM, Heidelberg University, Germany.
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21
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Briz CG, Navarrete M, Esteban JA, Nieto M. In Utero Electroporation Approaches to Study the Excitability of Neuronal Subpopulations and Single-cell Connectivity. J Vis Exp 2017. [PMID: 28287556 DOI: 10.3791/55139] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The nervous system is composed of an enormous range of distinct neuronal types. These neuronal subpopulations are characterized by, among other features, their distinct dendritic morphologies, their specific patterns of axonal connectivity, and their selective firing responses. The molecular and cellular mechanisms responsible for these aspects of differentiation during development are still poorly understood. Here, we describe combined protocols for labeling and characterizing the structural connectivity and excitability of cortical neurons. Modification of the in utero electroporation (IUE) protocol allows the labeling of a sparse population of neurons. This, in turn, enables the identification and tracking of the dendrites and axons of individual neurons, the precise characterization of the laminar location of axonal projections, and morphometric analysis. IUE can also be used to investigate changes in the excitability of wild-type (WT) or genetically modified neurons by combining it with whole-cell recording from acute slices of electroporated brains. These two techniques contribute to a better understanding of the coupling of structural and functional connectivity and of the molecular mechanisms controlling neuronal diversity during development. These developmental processes have important implications on axonal wiring, the functional diversity of neurons, and the biology of cognitive disorders.
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Affiliation(s)
- Carlos G Briz
- Department for Molecular and Cellular Biology, Centro Nacional de Biotecnología (CNB-CSIC)
| | - Marta Navarrete
- Molecular Neurobiology Department, Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas (CSIC-UAM)
| | - José A Esteban
- Molecular Neurobiology Department, Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas (CSIC-UAM)
| | - Marta Nieto
- Department for Molecular and Cellular Biology, Centro Nacional de Biotecnología (CNB-CSIC);
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22
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Carroll BJ, Hyson RL. A role for inhibition in deafness-induced plasticity of the avian auditory brainstem. Neuroscience 2016; 327:10-9. [PMID: 27095711 DOI: 10.1016/j.neuroscience.2016.04.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/08/2016] [Accepted: 04/09/2016] [Indexed: 01/05/2023]
Abstract
To better understand the effects of deafness on the brain, these experiments examine how disrupted balance between excitatory and inhibitory neurotransmission following the loss of excitatory input from the auditory nerve alters the central auditory system. In the avian cochlear nucleus, nucleus magnocellularis (NM), deprivation of excitatory input induced by deafness triggers neuronal death. While this neuronal death was previously accredited to the loss of excitatory drive, the present experiments examine an alternative hypothesis: that inhibitory input to NM, which may also be affected by deafness, contributes to neuronal death in NM. Using an in vitro slice preparation in which excitatory input from the auditory nerve is absent, we pharmacologically altered GABA receptor activation in NM, and assayed an early marker of neuronal health, antigenicity for the ribosomal antibody Y10B (Y10B-ir). We found that GABA decreases Y10B-ir, and that GABAA activation is necessary for the GABA-induced effect. We further found that endogenous GABAA activation similarly decreases Y10B-ir and this decrease requires extracellular Ca(2+). Our results suggest that, in the absence of excitatory input, endogenous activation of ionotropic GABAA receptors is detrimental to NM neurons.
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Affiliation(s)
- Briana J Carroll
- Department of Psychology, Florida State University, Tallahassee, FL, USA
| | - Richard L Hyson
- Department of Psychology, Florida State University, Tallahassee, FL, USA.
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23
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Soumiya H, Godai A, Araiso H, Mori S, Furukawa S, Fukumitsu H. Neonatal Whisker Trimming Impairs Fear/Anxiety-Related Emotional Systems of the Amygdala and Social Behaviors in Adult Mice. PLoS One 2016; 11:e0158583. [PMID: 27362655 PMCID: PMC4928826 DOI: 10.1371/journal.pone.0158583] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/17/2016] [Indexed: 12/30/2022] Open
Abstract
Abnormalities in tactile perception, such as sensory defensiveness, are common features in autism spectrum disorder (ASD). While not a diagnostic criterion for ASD, deficits in tactile perception contribute to the observed lack of social communication skills. However, the influence of tactile perception deficits on the development of social behaviors remains uncertain, as do the effects on neuronal circuits related to the emotional regulation of social interactions. In neonatal rodents, whiskers are the most important tactile apparatus, so bilateral whisker trimming is used as a model of early tactile deprivation. To address the influence of tactile deprivation on adult behavior, we performed bilateral whisker trimming in mice for 10 days after birth (BWT10 mice) and examined social behaviors, tactile discrimination, and c-Fos expression, a marker of neural activation, in adults after full whisker regrowth. Adult BWT10 mice exhibited significantly shorter crossable distances in the gap-crossing test than age-matched controls, indicating persistent deficits in whisker-dependent tactile perception. In contrast to controls, BWT10 mice exhibited no preference for the social compartment containing a conspecific in the three-chamber test. Furthermore, the development of amygdala circuitry was severely affected in BWT10 mice. Based on the c-Fos expression pattern, hyperactivity was found in BWT10 amygdala circuits for processing fear/anxiety-related responses to height stress but not in circuits for processing reward stimuli during whisker-dependent cued learning. These results demonstrate that neonatal whisker trimming and concomitant whisker-dependent tactile discrimination impairment severely disturbs the development of amygdala-dependent emotional regulation.
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Affiliation(s)
- Hitomi Soumiya
- Laboratory of Molecular Biology, Department of Biofunctional Analysis, Gifu Pharmaceutical University, Daigakunishi, Gifu, Japan
| | - Ayumi Godai
- Laboratory of Molecular Biology, Department of Biofunctional Analysis, Gifu Pharmaceutical University, Daigakunishi, Gifu, Japan
| | - Hiromi Araiso
- Laboratory of Molecular Biology, Department of Biofunctional Analysis, Gifu Pharmaceutical University, Daigakunishi, Gifu, Japan
| | - Shingo Mori
- Laboratory of Molecular Biology, Department of Biofunctional Analysis, Gifu Pharmaceutical University, Daigakunishi, Gifu, Japan
| | - Shoei Furukawa
- Laboratory of Molecular Biology, Department of Biofunctional Analysis, Gifu Pharmaceutical University, Daigakunishi, Gifu, Japan
| | - Hidefumi Fukumitsu
- Laboratory of Molecular Biology, Department of Biofunctional Analysis, Gifu Pharmaceutical University, Daigakunishi, Gifu, Japan
- * E-mail:
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Unbiased, High-Throughput Electron Microscopy Analysis of Experience-Dependent Synaptic Changes in the Neocortex. J Neurosci 2016; 35:16450-62. [PMID: 26674870 DOI: 10.1523/jneurosci.1573-15.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Neocortical circuits can be altered by sensory and motor experience, with experimental evidence supporting both anatomical and electrophysiological changes in synaptic properties. Previous studies have focused on changes in specific neurons or pathways-for example, the thalamocortical circuitry, layer 4-3 (L4-L3) synapses, or in the apical dendrites of L5 neurons- but a broad-scale analysis of experience-induced changes across the cortical column has been lacking. Without this comprehensive approach, a full understanding of how cortical circuits adapt during learning or altered sensory input will be impossible. Here we adapt an electron microscopy technique that selectively labels synapses, in combination with a machine-learning algorithm for semiautomated synapse detection, to perform an unbiased analysis of developmental and experience-dependent changes in synaptic properties across an entire cortical column in mice. Synapse density and length were compared across development and during whisker-evoked plasticity. Between postnatal days 14 and 18, synapse density significantly increases most in superficial layers, and synapse length increases in L3 and L5B. Removal of all but a single whisker row for 24 h led to an apparent increase in synapse density in L2 and a decrease in L6, and a significant increase in length in L3. Targeted electrophysiological analysis of changes in miniature EPSC and IPSC properties in L2 pyramidal neurons showed that mEPSC frequency nearly doubled in the whisker-spared column, a difference that was highly significant. Together, this analysis shows that data-intensive analysis of column-wide changes in synapse properties can generate specific and testable hypotheses about experience-dependent changes in cortical organization. SIGNIFICANCE STATEMENT Development and sensory experience can change synapse properties in the neocortex. Here we use a semiautomated analysis of electron microscopy images for an unbiased, column-wide analysis of synapse changes. This analysis reveals new loci for synaptic change that can be verified by targeted electrophysiological investigation. This method can be used as a platform for generating new hypotheses about synaptic changes across different brain areas and experimental conditions.
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Rodríguez-Tornos FM, Briz CG, Weiss LA, Sebastián-Serrano A, Ares S, Navarrete M, Frangeul L, Galazo M, Jabaudon D, Esteban JA, Nieto M. Cux1 Enables Interhemispheric Connections of Layer II/III Neurons by Regulating Kv1-Dependent Firing. Neuron 2016; 89:494-506. [PMID: 26804994 DOI: 10.1016/j.neuron.2015.12.020] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 04/23/2015] [Accepted: 12/01/2015] [Indexed: 01/19/2023]
Abstract
Neuronal subtype-specific transcription factors (TFs) instruct key features of neuronal function and connectivity. Activity-dependent mechanisms also contribute to wiring and circuit assembly, but whether and how they relate to TF-directed neuronal differentiation is poorly investigated. Here we demonstrate that the TF Cux1 controls the formation of the layer II/III corpus callosum (CC) projections through the developmental transcriptional regulation of Kv1 voltage-dependent potassium channels and the resulting postnatal switch to a Kv1-dependent firing mode. Loss of Cux1 function led to a decrease in the expression of Kv1 transcripts, aberrant firing responses, and selective loss of CC contralateral innervation. Firing and innervation were rescued by re-expression of Kv1 or postnatal reactivation of Cux1. Knocking down Kv1 mimicked Cux1-mediated CC axonal loss. These findings reveal that activity-dependent processes are central bona fide components of neuronal TF-differentiation programs and establish the importance of intrinsic firing modes in circuit assembly within the neocortex.
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Affiliation(s)
| | - Carlos G Briz
- Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Darwin 3, 28049 Madrid, Spain
| | - Linnea A Weiss
- Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Darwin 3, 28049 Madrid, Spain
| | - Alvaro Sebastián-Serrano
- Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Darwin 3, 28049 Madrid, Spain
| | - Saúl Ares
- Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Darwin 3, 28049 Madrid, Spain; Departamento de Matemáticas Universidad Carlos III de Madrid, Grupo Interdisciplinar de Sistemas Complejos (GISC), 28911 Leganés, Madrid, Spain
| | - Marta Navarrete
- Centro de Biología Molecular "Severo Ochoa," Consejo Superior de Investigaciones Científicas (CSIC-UAM), 28049 Madrid, Spain
| | - Laura Frangeul
- Department of Basic Neurosciences, University of Geneva, 1211 Geneva 4, Switzerland
| | - Maria Galazo
- HSCRB Harvard University, Cambridge, MA 02138, USA
| | - Denis Jabaudon
- Department of Basic Neurosciences, University of Geneva, 1211 Geneva 4, Switzerland
| | - José A Esteban
- Centro de Biología Molecular "Severo Ochoa," Consejo Superior de Investigaciones Científicas (CSIC-UAM), 28049 Madrid, Spain
| | - Marta Nieto
- Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Darwin 3, 28049 Madrid, Spain.
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Ghosh A, Purchase NC, Chen X, Yuan Q. Norepinephrine Modulates Pyramidal Cell Synaptic Properties in the Anterior Piriform Cortex of Mice: Age-Dependent Effects of β-adrenoceptors. Front Cell Neurosci 2015; 9:450. [PMID: 26635530 PMCID: PMC4652601 DOI: 10.3389/fncel.2015.00450] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/02/2015] [Indexed: 12/31/2022] Open
Abstract
Early odor preference learning in rodents occurs within a sensitive period [≤postnatal day (P)10–12], during which pups show a heightened ability to form an odor preference when a novel odor is paired with a tactile stimulation (e.g., stroking). Norepinephrine (NE) release from the locus coeruleus during stroking mediates this learning. However, in older pups, stroking loses its ability to induce learning. The cellular and circuitry mechanisms underpinning the sensitive period for odor preference learning is not well understood. We first established the sensitive period learning model in mice – odor paired with stroking induced odor preference in P8 but not P14 mice. This learning was dependent on NE-β-adrenoceptors as it was prevented by propranolol injection prior to training. We then tested whether there are developmental changes in pyramidal cell excitability and NE responsiveness in the anterior piriform cortex (aPC) in mouse pups. Although significant differences of pyramidal cell intrinsic properties were found in two age groups (P8–11 and P14+), NE at two concentrations (0.1 and 10 μM) did not alter intrinsic properties in either group. In contrast, in P8–11 pups, NE at 0.1 μM presynaptically decreased miniature IPSC and increased miniature EPSC frequencies. These effects were reversed with a higher dose of NE (10 μM), suggesting involvement of different adrenoceptor subtypes. In P14+ pups, NE at higher doses (1 and 10 μM) acted both pre- and postsynaptically to promote inhibition. These results suggest that enhanced synaptic excitation and reduced inhibition by NE in the aPC network may underlie the sensitive period.
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Affiliation(s)
- Abhinaba Ghosh
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's NL, Canada
| | - Nicole C Purchase
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's NL, Canada
| | - Xihua Chen
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's NL, Canada
| | - Qi Yuan
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's NL, Canada
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Damborsky JC, Slaton GS, Winzer-Serhan UH. Expression of Npas4 mRNA in Telencephalic Areas of Adult and Postnatal Mouse Brain. Front Neuroanat 2015; 9:145. [PMID: 26633966 PMCID: PMC4649027 DOI: 10.3389/fnana.2015.00145] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 10/30/2015] [Indexed: 12/29/2022] Open
Abstract
The transcription factor neuronal PAS domain-containing protein 4 (Npas4) is an inducible immediate early gene which regulates the formation of inhibitory synapses, and could have a significant regulatory role during cortical circuit formation. However, little is known about basal Npas4 mRNA expression during postnatal development. Here, postnatal and adult mouse brain sections were processed for isotopic in situ hybridization using an Npas4 specific cRNA antisense probe. In adults, Npas4 mRNA was found in the telencephalon with very restricted or no expression in diencephalon or mesencephalon. In most telencephalic areas, including the anterior olfactory nucleus (AON), piriform cortex, neocortex, hippocampus, dorsal caudate putamen (CPu), septum and basolateral amygdala nucleus (BLA), basal Npas4 expression was detected in scattered cells which exhibited strong hybridization signal. In embryonic and neonatal brain sections, Npas4 mRNA expression signals were very low. Starting at postnatal day 5 (P5), transcripts for Npas4 were detected in the AON, CPu and piriform cortex. At P8, additional Npas4 hybridization was found in CA1 and CA3 pyramidal layer, and in primary motor cortex. By P13, robust mRNA expression was located in layers IV and VI of all sensory cortices, frontal cortex and cingulate cortex. After onset of expression, postnatal spatial mRNA distribution was similar to that in adults, with the exception of the CPu, where Npas4 transcripts became gradually restricted to the most dorsal part. In conclusion, the spatial distribution of Npas4 mRNA is mostly restricted to telencephalic areas, and the temporal expression increases with developmental age during postnatal development, which seem to correlate with the onset of activity-driven excitatory transmission.
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Affiliation(s)
- Joanne C Damborsky
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University System Health Science Center Bryan, TX, USA
| | - G Simona Slaton
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University System Health Science Center Bryan, TX, USA
| | - Ursula H Winzer-Serhan
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University System Health Science Center Bryan, TX, USA
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Ehrlich DE, Josselyn SA. Plasticity-related genes in brain development and amygdala-dependent learning. GENES BRAIN AND BEHAVIOR 2015; 15:125-43. [PMID: 26419764 DOI: 10.1111/gbb.12255] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/12/2015] [Accepted: 09/14/2015] [Indexed: 12/31/2022]
Abstract
Learning about motivationally important stimuli involves plasticity in the amygdala, a temporal lobe structure. Amygdala-dependent learning involves a growing number of plasticity-related signaling pathways also implicated in brain development, suggesting that learning-related signaling in juveniles may simultaneously influence development. Here, we review the pleiotropic functions in nervous system development and amygdala-dependent learning of a signaling pathway that includes brain-derived neurotrophic factor (BDNF), extracellular signaling-related kinases (ERKs) and cyclic AMP-response element binding protein (CREB). Using these canonical, plasticity-related genes as an example, we discuss the intersection of learning-related and developmental plasticity in the immature amygdala, when aversive and appetitive learning may influence the developmental trajectory of amygdala function. We propose that learning-dependent activation of BDNF, ERK and CREB signaling in the immature amygdala exaggerates and accelerates neural development, promoting amygdala excitability and environmental sensitivity later in life.
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Affiliation(s)
- D E Ehrlich
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Langone Medical Center, New York, NY, USA.,Department of Otolaryngology, NYU Langone School of Medicine, New York, NY, USA
| | - S A Josselyn
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, ON, Canada.,Department of Psychology, University of Toronto, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
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29
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Reinhard SM, Razak K, Ethell IM. A delicate balance: role of MMP-9 in brain development and pathophysiology of neurodevelopmental disorders. Front Cell Neurosci 2015; 9:280. [PMID: 26283917 PMCID: PMC4518323 DOI: 10.3389/fncel.2015.00280] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 07/09/2015] [Indexed: 12/27/2022] Open
Abstract
The extracellular matrix (ECM) is a critical regulator of neural network development and plasticity. As neuronal circuits develop, the ECM stabilizes synaptic contacts, while its cleavage has both permissive and active roles in the regulation of plasticity. Matrix metalloproteinase 9 (MMP-9) is a member of a large family of zinc-dependent endopeptidases that can cleave ECM and several cell surface receptors allowing for synaptic and circuit level reorganization. It is becoming increasingly clear that the regulated activity of MMP-9 is critical for central nervous system (CNS) development. In particular, MMP-9 has a role in the development of sensory circuits during early postnatal periods, called ‘critical periods.’ MMP-9 can regulate sensory-mediated, local circuit reorganization through its ability to control synaptogenesis, axonal pathfinding and myelination. Although activity-dependent activation of MMP-9 at specific synapses plays an important role in multiple plasticity mechanisms throughout the CNS, misregulated activation of the enzyme is implicated in a number of neurodegenerative disorders, including traumatic brain injury, multiple sclerosis, and Alzheimer’s disease. Growing evidence also suggests a role for MMP-9 in the pathophysiology of neurodevelopmental disorders including Fragile X Syndrome. This review outlines the various actions of MMP-9 during postnatal brain development, critical for future studies exploring novel therapeutic strategies for neurodevelopmental disorders.
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Affiliation(s)
- Sarah M Reinhard
- Psychology Department, University of California, Riverside Riverside, CA, USA
| | - Khaleel Razak
- Psychology Department, University of California, Riverside Riverside, CA, USA
| | - Iryna M Ethell
- Biomedical Sciences Division, School of Medicine, University of California, Riverside Riverside, CA, USA
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30
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Meredith R. Sensitive and critical periods during neurotypical and aberrant neurodevelopment: A framework for neurodevelopmental disorders. Neurosci Biobehav Rev 2015; 50:180-8. [DOI: 10.1016/j.neubiorev.2014.12.001] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 10/21/2014] [Accepted: 12/01/2014] [Indexed: 01/16/2023]
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Mowery TM, Kotak VC, Sanes DH. Transient Hearing Loss Within a Critical Period Causes Persistent Changes to Cellular Properties in Adult Auditory Cortex. Cereb Cortex 2014; 25:2083-94. [PMID: 24554724 DOI: 10.1093/cercor/bhu013] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sensory deprivation can induce profound changes to central processing during developmental critical periods (CPs), and the recovery of normal function is maximal if the sensory input is restored during these epochs. Therefore, we asked whether mild and transient hearing loss (HL) during discrete CPs could induce changes to cortical cellular physiology. Electrical and inhibitory synaptic properties were obtained from auditory cortex pyramidal neurons using whole-cell recordings after bilateral earplug insertion or following earplug removal. Varying the age of HL onset revealed brief CPs of vulnerability for membrane and firing properties, as well as, inhibitory synaptic currents. These CPs closed 1 week after ear canal opening on postnatal day (P) 18. To examine whether the cellular properties could recover from HL, earplugs were removed prior to (P17) or after (P23), the closure of these CPs. The earlier age of hearing restoration led to greater recovery of cellular function, but firing rate remained disrupted. When earplugs were removed after the closure of these CPs, several changes persisted into adulthood. Therefore, long-lasting cellular deficits that emerge from transient deprivation during a CP may contribute to delayed acquisition of auditory skills in children who experience temporary HL.
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Affiliation(s)
| | | | - Dan H Sanes
- Center for Neural Science Department of Biology, New York University, New York, NY 10003, USA
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Abstract
How homeostatic processes contribute to map plasticity and stability in sensory cortex is not well-understood. Classically, sensory deprivation first drives rapid Hebbian weakening of spiking responses to deprived inputs, which is followed days later by a slow homeostatic increase in spiking responses mediated by excitatory synaptic scaling. Recently, more rapid homeostasis by inhibitory circuit plasticity has been discovered in visual cortex, but whether this process occurs in other brain areas is not known. We tested for rapid homeostasis in layer 2/3 (L2/3) of rodent somatosensory cortex, where D-row whisker deprivation drives Hebbian weakening of whisker-evoked spiking responses after an unexplained initial delay, but no homeostasis of deprived whisker responses is known. We hypothesized that the delay reflects rapid homeostasis through disinhibition, which masks the onset of Hebbian weakening of L2/3 excitatory input. We found that deprivation (3 d) transiently increased whisker-evoked spiking responses in L2/3 single units before classical Hebbian weakening (≥5 d), whereas whisker-evoked synaptic input was reduced during both periods. This finding suggests a transient homeostatic increase in L2/3 excitability. In whole-cell recordings from L2/3 neurons in vivo, brief deprivation decreased whisker-evoked inhibition more than excitation and increased the excitation-inhibition ratio. In contrast, synaptic scaling and increased intrinsic excitability were absent. Thus, disinhibition is a rapid homeostatic plasticity mechanism in rodent somatosensory cortex that transiently maintains whisker-evoked spiking in L2/3, despite the onset of Hebbian weakening of excitatory input.
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Chen CC, Bajnath A, Brumberg JC. The impact of development and sensory deprivation on dendritic protrusions in the mouse barrel cortex. ACTA ACUST UNITED AC 2014; 25:1638-53. [PMID: 24408954 DOI: 10.1093/cercor/bht415] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Dendritic protrusions (spines and filopodia) are structural indicators of synapses that have been linked to neuronal learning and memory through their morphological alterations induced by development and experienced-dependent activities. Although previous studies have demonstrated that depriving sensory experience leads to structural changes in neocortical organization, the more subtle effects on dendritic protrusions remain unclear, mostly due to focus on only one specific cell type and/or age of manipulation. Here, we show that sensory deprivation induced by whisker trimming influences the dendritic protrusions of basilar dendrites located in thalamocortical recipient lamina (IV and VI) of the mouse barrel cortex in a layer-specific manner. Following 1 month of whisker trimming after birth, the density of dendritic protrusions increased in layer IV, but decreased in layer VI. Whisker regrowth for 1 month returned protrusion densities to comparable level of age-matched controls in layer VI, but not in layer IV. In adults, chronic sensory deprivation led to an increase in protrusion densities in layer IV, but not in layer VI. In addition, chronic pharmacological blockade of N-methyl-d-aspartate receptors (NMDARs) increased protrusion density in both layers IV and VI, which returned to the control level after 1 month of drug withdrawal. Our data reveal that different cortical layers respond to chronic sensory deprivation in different ways, with more pronounced effects during developmental critical periods than adulthood. We also show that chronically blocking NMDARs activity during developmental critical period also influences the protrusion density and morphology in the cerebral cortex.
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Affiliation(s)
| | - Adesh Bajnath
- Neuroscience Program, The Graduate Center, CUNY, New York, NY 10016, USA
| | - Joshua C Brumberg
- Neuropsychology Subprogram Neuroscience Program, The Graduate Center, CUNY, New York, NY 10016, USA Department of Psychology, Queens College, CUNY, Flushing, NY 11367, USA
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Abstract
The development process of myelination varies between region and species. Fully myelinated fibers are required if mammalian neural circuits are to function normally. Histology samples at staggered time points throughout the study were examined at days 4, 5, 7, 8, 10, 14, 17, 24, 37, and 44. We suggest that the development of myelin in the juvenile rodent brain can be conveniently separated into 3 phases. Evaluation of myelin basic protein-stained sections of the areas of brain that contain the elements of the developing limbic system over the sensitive period from postnatal day (PND) 14 to 34 may provide an insight into possible toxicity that may lead to cognition and learning issues in adults. We will hope to develop this notion further in the future. The precise chronology of the development of the blood-brain barrier in rats has yet to be established; thus, there is potential for significant exposure of the juvenile brain to chemicals that do not cross the blood-brain barrier in the adult. Thus, it is suggested that evaluation of myelin development should probably be extended to all new chemical entities intended for pediatric use, and not just those that are intended for central nervous system use.
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Affiliation(s)
- Noel Downes
- Sequani Limited, Ledbury, Herefordshire, United Kingdom
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35
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Khazipov R, Minlebaev M, Valeeva G. Early gamma oscillations. Neuroscience 2013; 250:240-52. [PMID: 23872391 DOI: 10.1016/j.neuroscience.2013.07.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/27/2013] [Accepted: 07/09/2013] [Indexed: 10/26/2022]
Abstract
Gamma oscillations have long been considered to emerge late in development. However, recent studies have revealed that gamma oscillations are transiently expressed in the rat barrel cortex during the first postnatal week, a "critical" period of sensory-dependent barrel map formation. The mechanisms underlying the generation and physiological roles of early gamma oscillations (EGOs) in the development of thalamocortical circuits will be discussed in this review. In contrast to adult gamma oscillations, synchronized through gamma-rhythmic perisomatic inhibition, EGOs are primarily driven through feedforward gamma-rhythmic excitatory input from the thalamus. The recruitment of cortical interneurons to EGOs and the emergence of feedforward inhibition are observed by the end of the first postnatal week. EGOs facilitate the precise synchronization of topographically aligned thalamic and cortical neurons. The multiple replay of sensory input during EGOs supports long-term potentiation at thalamocortical synapses. We suggest that this early form of gamma oscillations, which is mechanistically different from adult gamma oscillations, guides barrel map formation during the critical developmental period.
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Affiliation(s)
- R Khazipov
- INMED - INSERM U901, University Aix-Marseille II, Marseille, France; Laboratory of Neurobiology, Kazan Federal University, Kazan, Russia.
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Chubykin AA, Roach EB, Bear MF, Shuler MGH. A cholinergic mechanism for reward timing within primary visual cortex. Neuron 2013; 77:723-35. [PMID: 23439124 DOI: 10.1016/j.neuron.2012.12.039] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2012] [Indexed: 11/30/2022]
Abstract
Neurons in rodent primary visual cortex (V1) relate operantly conditioned stimulus-reward intervals with modulated patterns of spiking output, but little is known about the locus or mechanism of this plasticity. Here we show that cholinergic basal forebrain projections to V1 are necessary for the neural acquisition, but not the expression, of reward timing in the visual cortex of awake, behaving animals. We then mimic reward timing in vitro by pairing white matter stimulation with muscarinic receptor activation at a fixed interval and show that this protocol results in the prolongation of electrically evoked spike train durations out to the conditioned interval. Together, these data suggest that V1 possesses the circuitry and plasticity to support reward time prediction learning and the cholinergic system serves as an important reinforcement signal which, in vivo, conveys to the cortex the outcome of behavior.
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Affiliation(s)
- Alexander A Chubykin
- Howard Hughes Medical Institute, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Feldmeyer D, Brecht M, Helmchen F, Petersen CC, Poulet JF, Staiger JF, Luhmann HJ, Schwarz C. Barrel cortex function. Prog Neurobiol 2013. [DOI: 10.1016/j.pneurobio.2012.11.002] [Citation(s) in RCA: 257] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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A role for silent synapses in the development of the pathway from layer 2/3 to 5 pyramidal cells in the neocortex. J Neurosci 2012; 32:13085-99. [PMID: 22993426 DOI: 10.1523/jneurosci.1262-12.2012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The integration of neurons within the developing cerebral cortex is a prolonged process dependent on a combination of molecular and physiological cues. To examine the latter we used laser scanning photostimulation (LSPS) of caged glutamate in conjunction with whole-cell patch-clamp electrophysiology to probe the integration of pyramidal cells in the sensorimotor regions of the mouse neocortex. In the days immediately after postnatal day 5 (P5) the origin of the LSPS-evoked AMPA receptor (AMPAR)-mediated synaptic inputs were diffuse and poorly defined with considerable variability between cells. Over the subsequent week this coalesced and shifted, primarily influenced by an increased contribution from layers 2/3 cells, which became a prominent motif of the afferent input onto layer 5 pyramidal cells regardless of cortical region. To further investigate this particular emergent translaminar connection, we alternated our mapping protocol between two holding potentials (-70 and +40 mV) allowing us to detect exclusively NMDA receptor (NMDAR)-mediated inputs. This revealed distal MK-801-sensitive synaptic inputs that predict the formation of the mature, canonical layer 2/3 to 5 pathway. However, these were a transient feature and had been almost entirely converted to AMPAR synapses at a later age (P16). To examine the role of activity in the recruitment of early NMDAR synapses, we evoked brief periods (20 min) of rhythmic bursting. Short intense periods of activity could cause a prolonged augmentation of the total input onto pyramidal cells up until P12; a time point when the canonical circuit has been instated and synaptic integration shifts to a more consolidatory phase.
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Bidirectional plasticity of intrinsic excitability controls sensory inputs efficiency in layer 5 barrel cortex neurons in vivo. J Neurosci 2012; 32:11377-89. [PMID: 22895720 DOI: 10.1523/jneurosci.0415-12.2012] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Responsiveness of cortical neurons to sensory inputs can be altered by experience and learning. While synaptic plasticity is generally proposed as the underlying cellular mechanism, possible contributions of activity-dependent changes in intrinsic excitability remain poorly investigated. Here, we show that periods of rhythmic firing in rat barrel cortex layer 5 pyramidal neurons can trigger a long-lasting increase or decrease in their membrane excitability in vivo. Potentiation of cortical excitability consisted of an increased firing in response to intracellular stimulation and a reduction in threshold current for spike initiation. Conversely, depression of cortical excitability was evidenced by an augmented firing threshold leading to a reduced current-evoked spiking. The direction of plasticity depended on the baseline level of spontaneous firing rate and cell excitability. We also found that changes in intrinsic excitability were accompanied by corresponding modifications in the effectiveness of sensory inputs. Potentiation and depression of cortical neuron excitability resulted, respectively, in an increased or decreased firing probability on whisker-evoked synaptic responses, without modifications in the synaptic strength itself. These data suggest that bidirectional intrinsic plasticity could play an important role in experience-dependent refinement of sensory cortical networks.
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40
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Abstract
In primary sensory neocortical areas of mammals, the distribution of sensory receptors is mapped with topographic precision and amplification in proportion to the peripheral receptor density. The visual, somatosensory and auditory cortical maps are established during a critical period in development. Throughout this window in time, the developing cortical maps are vulnerable to deleterious effects of sense organ damage or sensory deprivation. The rodent barrel cortex offers an invaluable model system with which to investigate the mechanisms underlying the formation of topographic maps and their plasticity during development. Five rows of mystacial vibrissa (whisker) follicles on the snout and an array of sinus hairs are represented by layer IV neural modules ('barrels') and thalamocortical axon terminals in the primary somatosensory cortex. Perinatal damage to the whiskers or the sensory nerve innervating them irreversibly alters the structural organization of the barrels. Earlier studies emphasized the role of the sensory periphery in dictating whisker-specific brain maps and patterns. Recent advances in molecular genetics and analyses of genetically altered mice allow new insights into neural pattern formation in the neocortex and the mechanisms underlying critical period plasticity. Here, we review the development and patterning of the barrel cortex and the critical period plasticity.
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Affiliation(s)
- Reha S Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201-1075, USA.
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Benedetti BL, Takashima Y, Wen JA, Urban-Ciecko J, Barth AL. Differential wiring of layer 2/3 neurons drives sparse and reliable firing during neocortical development. ACTA ACUST UNITED AC 2012; 23:2690-9. [PMID: 22918982 DOI: 10.1093/cercor/bhs257] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Sensory information is transmitted with high fidelity across multiple synapses until it reaches the neocortex. There, individual neurons exhibit enormous variability in responses. The source of this diversity in output has been debated. Using transgenic mice expressing the green fluorescent protein coupled to the activity-dependent gene c-fos, we identified neurons with a history of elevated activity in vivo. Focusing on layer 4 to layer 2/3 connections, a site of strong excitatory drive at an initial stage of cortical processing, we find that fluorescently tagged neurons receive significantly greater excitatory and reduced inhibitory input compared with neighboring, unlabeled cells. Differential wiring of layer 2/3 neurons arises early in development and requires sensory input to be established. Stronger connection strength is not associated with evidence for recent synaptic plasticity, suggesting that these more active ensembles may not be generated over short time scales. Paired recordings show fosGFP+ neurons spike at lower stimulus thresholds than neighboring, fosGFP- neurons. These data indicate that differences in circuit construction can underlie response heterogeneity amongst neocortical neurons.
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Affiliation(s)
- Brett L Benedetti
- Department of Biological Sciences and Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA, USA
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Kinnischtzke AK, Sewall AM, Berkepile JM, Fanselow EE. Postnatal maturation of somatostatin-expressing inhibitory cells in the somatosensory cortex of GIN mice. Front Neural Circuits 2012; 6:33. [PMID: 22666189 PMCID: PMC3364579 DOI: 10.3389/fncir.2012.00033] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 05/14/2012] [Indexed: 11/29/2022] Open
Abstract
Postnatal inhibitory neuron development affects mammalian brain function, and failure of this maturation process may underlie pathological conditions such as epilepsy, schizophrenia, and depression. Furthermore, understanding how physiological properties of inhibitory neurons change throughout development is critical to understanding the role(s) these cells play in cortical processing. One subset of inhibitory neurons that may be affected during postnatal development is somatostatin-expressing (SOM) cells. A subset of these cells is labeled with green-fluorescent protein (GFP) in a line of mice known as the GFP-positive inhibitory neurons (GIN) line. Here, we studied how intrinsic electrophysiological properties of these cells changed in the somatosensory cortex of GIN mice between postnatal ages P11 and P32+. GIN cells were targeted for whole-cell current-clamp recordings and ranges of positive and negative current steps were presented to each cell. The results showed that as the neocortical circuitry matured during this critical time period multiple intrinsic and firing properties of GIN inhibitory neurons, as well as those of excitatory (regular-spiking [RS]) cells, were altered. Furthermore, these changes were such that the output of GIN cells, but not RS cells, increased over this developmental period. We quantified changes in excitability by examining the input–output relationship of both GIN and RS cells. We found that the firing frequency of GIN cells increased with age, while the rheobase current remained constant across development. This created a multiplicative increase in the input–output relationship of the GIN cells, leading to increases in gain with age. The input–output relationship of the RS cells, on the other hand, showed primarily a subtractive shift with age, but no substantial change in gain. These results suggest that as the neocortex matures, inhibition coming from GIN cells may become more influential in the circuit and play a greater role in the modulation of neocortical activity.
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Affiliation(s)
- Amanda K Kinnischtzke
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh PA, USA
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43
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Zaitsev AV, Povysheva NV, Gonzalez-Burgos G, Lewis DA. Electrophysiological classes of layer 2/3 pyramidal cells in monkey prefrontal cortex. J Neurophysiol 2012; 108:595-609. [PMID: 22496534 DOI: 10.1152/jn.00859.2011] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The activity of supragranular pyramidal neurons in the dorsolateral prefrontal cortex (DLPFC) neurons is hypothesized to be a key contributor to the cellular basis of working memory in primates. Therefore, the intrinsic membrane properties, a crucial determinant of a neuron's functional properties, are important for the role of DLPFC pyramidal neurons in working memory. The present study aimed to investigate the biophysical properties of pyramidal cells in layer 2/3 of monkey DLPFC to create an unbiased electrophysiological classification of these cells. Whole cell voltage recordings in the slice preparation were performed in 77 pyramidal cells, and 24 electrophysiological measures of their passive and active intrinsic membrane properties were analyzed. Based on the results of cluster analysis of 16 independent electrophysiological variables, 4 distinct electrophysiological classes of monkey pyramidal cells were determined. Two classes contain regular-spiking neurons with low and high excitability and constitute 52% of the pyramidal cells sampled. These subclasses of regular-spiking neurons mostly differ in their input resistance, minimum current that evoked firing, and current-to-frequency transduction properties. A third class of pyramidal cells includes low-threshold spiking cells (17%), which fire a burst of three-five spikes followed by regular firing at all suprathreshold current intensities. The last class consists of cells with an intermediate firing pattern (31%). These cells have two modes of firing response, regular spiking and bursting discharge, depending on the strength of stimulation and resting membrane potential. Our results show that diversity in the functional properties of DLPFC pyramidal cells may contribute to heterogeneous modes of information processing during working memory and other cognitive operations that engage the activity of cortical circuits in the superficial layers of the DLPFC.
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Affiliation(s)
- A V Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint-Petersburg, Russia.
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44
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Seelke AMH, Dooley JC, Krubitzer LA. The emergence of somatotopic maps of the body in S1 in rats: the correspondence between functional and anatomical organization. PLoS One 2012; 7:e32322. [PMID: 22393398 PMCID: PMC3290658 DOI: 10.1371/journal.pone.0032322] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 01/25/2012] [Indexed: 11/29/2022] Open
Abstract
Most of what we know about cortical map development and plasticity comes from studies in mice and rats, and for the somatosensory cortex, almost exclusively from the whisker-dominated posteromedial barrel fields. Whiskers are the main effector organs of mice and rats, and their representation in cortex and subcortical pathways is a highly derived feature of murine rodents. This specialized anatomical organization may therefore not be representative of somatosensory cortex in general, especially for species that utilize other body parts as their main effector organs, like the hands of primates. For these reasons, we examined the emergence of whole body maps in developing rats using electrophysiological recording techniques. In P5, P10, P15, P20 and adult rats, multiple recordings were made in the medial portion of S1 in each animal. Subsequently, these functional maps were related to anatomical parcellations of S1 based on a variety of histological stains. We found that at early postnatal ages (P5) medial S1 was composed almost exclusively of the representation of the vibrissae. At P10, other body part representations including the hindlimb and forelimb were present, although these were not topographically organized. By P15, a clear topographic organization began to emerge coincident with a reduction in receptive field size. By P20, body maps were adult-like. This study is the first to describe how topography of the body develops in S1 in any mammal. It indicates that anatomical parcellations and functional maps are initially incongruent but become tightly coupled by P15. Finally, because anatomical and functional specificity of developing barrel cortex appears much earlier in postnatal life than the rest of the body, the entire primary somatosensory cortex should be considered when studying general topographic map formation in development.
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Affiliation(s)
- Adele M. H. Seelke
- Center for Neuroscience, University of California Davis, Davis, California, United States of America
| | - James C. Dooley
- Center for Neuroscience, University of California Davis, Davis, California, United States of America
| | - Leah A. Krubitzer
- Center for Neuroscience, University of California Davis, Davis, California, United States of America
- Department of Psychology, University of California Davis, Davis, California, United States of America
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45
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Cruz-Martín A, Crespo M, Portera-Cailliau C. Glutamate induces the elongation of early dendritic protrusions via mGluRs in wild type mice, but not in fragile X mice. PLoS One 2012; 7:e32446. [PMID: 22384253 PMCID: PMC3288094 DOI: 10.1371/journal.pone.0032446] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 01/26/2012] [Indexed: 12/11/2022] Open
Abstract
Fragile X syndrome (FXS), the most common inherited from of autism and mental impairment, is caused by transcriptional silencing of the Fmr1 gene, resulting in the loss of the RNA-binding protein FMRP. Dendritic spines of cortical pyramidal neurons in affected individuals are abnormally immature and in Fmr1 knockout (KO) mice they are also abnormally unstable. This could result in defects in synaptogenesis, because spine dynamics are critical for synapse formation. We have previously shown that the earliest dendritic protrusions, which are highly dynamic and might serve an exploratory role to reach out for axons, elongate in response to glutamate. Here, we tested the hypothesis that this process is mediated by metabotropic glutamate receptors (mGluRs) and that it is defective in Fmr1 KO mice. Using time-lapse imaging with two-photon microscopy in acute brain slices from early postnatal mice, we find that early dendritic protrusions in layer 2/3 neurons become longer in response to application of glutamate or DHPG, a Group 1 mGluR agonist. Blockade of mGluR5 signaling, which reverses some adult phenotypes of KO mice, prevented the glutamate-mediated elongation of early protrusions. In contrast, dendritic protrusions from KO mice failed to respond to glutamate. Thus, absence of FMRP may impair the ability of cortical pyramidal neurons to respond to glutamate released from nearby pre-synaptic terminals, which may be a critical step to initiate synaptogenesis and stabilize spines.
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Affiliation(s)
- Alberto Cruz-Martín
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California Los Angeles, Los Angeles, California, United States of America
| | - Michelle Crespo
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California Los Angeles, Los Angeles, California, United States of America
| | - Carlos Portera-Cailliau
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Cheetham CEJ, Fox K. The role of sensory experience in presynaptic development is cortical area specific. J Physiol 2011; 589:5691-9. [PMID: 21946850 PMCID: PMC3249043 DOI: 10.1113/jphysiol.2011.218347] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 09/26/2011] [Indexed: 11/08/2022] Open
Abstract
The postsynaptic response to a stimulus is dependent on the history of previous activity at that synapse. This short-term plasticity (STP) is a key determinant of neural network function. During postnatal development, many excitatory intracortical synapses switch from strong depression during early postnatal life, to weaker depression and in some cases facilitation in adulthood. However, it is not known whether this developmental switch is an innate feature of synaptic maturation, or whether it requires activity. We investigated this question in the barrel and visual cortex, two widely studied models of experience-dependent plasticity. We have previously defined the time course over which presynaptic development occurs in these two cortical areas, enabling us to make the first direct comparison of the role of sensory experience during synaptic development. We found that maturation of STP in visual cortex was unaffected by dark rearing from before eye opening. In marked contrast, total whisker deprivation completely blocked the developmental decrease in presynaptic release probability (Pr), and the concomitant increase in paired pulse ratio (PPR), which occur in barrel cortex during the third and fourth postnatal weeks. However, the developmental increase in the steady state response to a train of stimuli was unaffected by whisker deprivation. This supports a mechanistic link between Pr and the PPR, but dissociates Pr from the steady state amplitude during repetitive stimulation. Our findings indicate that sensory experience plays a greater role in presynaptic development at L4 to L2/3 excitatory synapses in the barrel cortex than in the visual cortex.
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Affiliation(s)
- Claire E J Cheetham
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
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47
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Liao CC, Lee LJ. Neonatal fluoxetine exposure affects the action potential properties and dendritic development in cortical subplate neurons of rats. Toxicol Lett 2011; 207:314-21. [PMID: 21986067 DOI: 10.1016/j.toxlet.2011.09.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 09/26/2011] [Accepted: 09/26/2011] [Indexed: 01/26/2023]
Abstract
Selective serotonin reuptake inhibitor (SSRI)-type antidepressants might be given to depressive pregnant women and the developing fetuses are thus exposed to these drugs. Since serotonin plays important roles in the maturation of the nervous system, early SSRI exposure might influence the fetal brain development. To test this hypothesis, we treated the neonatal rat pups with fluoxetine (Flx) from the day of birth to postnatal day (P) 4, comparable to the third trimester of human gestation, and observed the physiological and morphological features of subplate neurons (SPns), a group of cells important for early cortical development and vulnerable to neonatal neural insults. Using whole-cell patch-clamp recording technique, we examined the passive membrane properties and characteristics of action potential (AP). In SPns of Flx-treated rats, the rheobase for generating an AP was increased and the width of APs was reduced, especially in the falling phase. In the morphological aspect, the dendritic remodeling of SPns including dendritic branching, elongation and pruning were affected by early Flx treatment. Together, our results demonstrate that the teratogenic effect of early SSRI exposure on the structure and function of developing SPns and these changes may lead to undesired brain activity and distorted behaviors later in life.
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Affiliation(s)
- Chun-Chieh Liao
- Graduate Institute of Anatomy and Cell Biology, National Taiwan University, Taipei, Taiwan
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48
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Input-specific critical periods for experience-dependent plasticity in layer 2/3 pyramidal neurons. J Neurosci 2011; 31:4456-65. [PMID: 21430146 DOI: 10.1523/jneurosci.6042-10.2011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Critical periods for experience-dependent plasticity have been well characterized within sensory cortex, in which the ability of altered sensory input to drive firing rate changes has been demonstrated across brain areas. Here we show that rapid experience-dependent changes in the strength of excitatory synapses within mouse primary somatosensory cortex exhibit a critical period that is input specific and mechanistically distinct in layer 2/3 pyramidal neurons. Removal of all but a single whisker [single whisker experience (SWE)] can trigger the strengthening of individual glutamatergic synaptic contacts onto layer 2/3 neurons only during a short window during the second and third postnatal week. At both layer 4 and putative 2/3 inputs, SWE-triggered plasticity has a discrete onset, before which it cannot be induced. SWE synaptic strengthening is concluded at both inputs after the beginning of the third postnatal week, indicating that both types of inputs display a critical period for experience-dependent plasticity. Importantly, the timing of this critical period is both delayed and prolonged for layer 2/3-2/3 versus layer 4-2/3 excitatory synapses. Furthermore, plasticity at layer 2/3 inputs does not invoke the trafficking of calcium-permeable, GluR2-lacking AMPA receptors, whereas it sometimes does at layer 4 inputs. The dissociation of critical period timing and plasticity mechanisms at layer 4 and layer 2/3 synapses, despite the close apposition of these inputs along the dendrite, suggests remarkable specificity for the developmental regulation of plasticity in vivo.
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49
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Guan D, Horton LR, Armstrong WE, Foehring RC. Postnatal development of A-type and Kv1- and Kv2-mediated potassium channel currents in neocortical pyramidal neurons. J Neurophysiol 2011; 105:2976-88. [PMID: 21451062 DOI: 10.1152/jn.00758.2010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Potassium channels regulate numerous aspects of neuronal excitability, and several voltage-gated K(+) channel subunits have been identified in pyramidal neurons of rat neocortex. Previous studies have either considered the development of outward current as a whole or divided currents into transient, A-type and persistent, delayed rectifier components but did not differentiate between current components defined by α-subunit type. To facilitate comparisons of studies reporting K(+) currents from animals of different ages and to understand the functional roles of specific current components, we characterized the postnatal development of identified Kv channel-mediated currents in pyramidal neurons from layers II/III from rat somatosensory cortex. Both the persistent/slowly inactivating and transient components of the total K(+) current increased in density with postnatal age. We used specific pharmacological agents to test the relative contributions of putative Kv1- and Kv2-mediated currents (100 nM α-dendrotoxin and 600 nM stromatoxin, respectively). A combination of voltage protocol, pharmacology, and curve fitting was used to isolate the rapidly inactivating A-type current. We found that the density of all identified current components increased with postnatal age, approaching a plateau at 3-5 wk. We found no significant changes in the relative proportions or kinetics of any component between postnatal weeks 1 and 5, except that the activation time constant for A-type current was longer at 1 wk. The putative Kv2-mediated component was the largest at all ages. Immunocytochemistry indicated that protein expression for Kv4.2, Kv4.3, Kv1.4, and Kv2.1 increased between 1 wk and 4-5 wk of age.
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Affiliation(s)
- Dongxu Guan
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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50
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Zhang Z, Jiao YY, Sun QQ. Developmental maturation of excitation and inhibition balance in principal neurons across four layers of somatosensory cortex. Neuroscience 2010; 174:10-25. [PMID: 21115101 DOI: 10.1016/j.neuroscience.2010.11.045] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 10/27/2010] [Accepted: 11/21/2010] [Indexed: 11/29/2022]
Abstract
In adult cortices, the ratio of excitatory and inhibitory conductances (E/I ratio) is presumably balanced across a wide range of stimulus conditions. However, it is unknown how the E/I ratio is postnatally regulated, when the strength of synapses are rapidly changing. Yet, understanding of such a process is critically important, because there are numerous neuropsychological disorders, such as autism, epilepsy and schizophrenia, associated with disturbed E/I balances. Here we directly measured the E/I ratio underlying locally induced synaptic conductances in principal neurons from postnatal day 8 (P8) through 60. We found that (1) within each developmental period, the E/I ratio across four major cortical layers was maintained at a similar value under wide range of stimulation intensities; and (2) there was a rapid developmental decrease in the E/I ratio, which occurred within a sensitive period between P8 to P18 with exception of layer II/III. By comparing the excitatory and inhibitory conductances, as well as key synaptic protein expressions, we found a net increase in the number and strength of inhibitory, but not excitatory synapses, is responsible for the developmental decrease in the E/I ratio in the barrel cortex. The inhibitory markers were intrinsically co-regulated, gave rise to a sharp increase in the inhibitory conductance from P8 to P18. These results suggest that the tightly regulated E/I ratios in adults cortex is a result of drastic changes in relative weight of inhibitory but not excitatory synapses during critical period, and the local inhibitory structural changes are the underpinning of altered E/I ratio across postnatal development.
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Affiliation(s)
- Z Zhang
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
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