1
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Schneider-Mizell CM, Bodor AL, Collman F, Brittain D, Bleckert A, Dorkenwald S, Turner NL, Macrina T, Lee K, Lu R, Wu J, Zhuang J, Nandi A, Hu B, Buchanan J, Takeno MM, Torres R, Mahalingam G, Bumbarger DJ, Li Y, Chartrand T, Kemnitz N, Silversmith WM, Ih D, Zung J, Zlateski A, Tartavull I, Popovych S, Wong W, Castro M, Jordan CS, Froudarakis E, Becker L, Suckow S, Reimer J, Tolias AS, Anastassiou CA, Seung HS, Reid RC, da Costa NM. Structure and function of axo-axonic inhibition. eLife 2021; 10:e73783. [PMID: 34851292 PMCID: PMC8758143 DOI: 10.7554/elife.73783] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
Inhibitory neurons in mammalian cortex exhibit diverse physiological, morphological, molecular, and connectivity signatures. While considerable work has measured the average connectivity of several interneuron classes, there remains a fundamental lack of understanding of the connectivity distribution of distinct inhibitory cell types with synaptic resolution, how it relates to properties of target cells, and how it affects function. Here, we used large-scale electron microscopy and functional imaging to address these questions for chandelier cells in layer 2/3 of the mouse visual cortex. With dense reconstructions from electron microscopy, we mapped the complete chandelier input onto 153 pyramidal neurons. We found that synapse number is highly variable across the population and is correlated with several structural features of the target neuron. This variability in the number of axo-axonic ChC synapses is higher than the variability seen in perisomatic inhibition. Biophysical simulations show that the observed pattern of axo-axonic inhibition is particularly effective in controlling excitatory output when excitation and inhibition are co-active. Finally, we measured chandelier cell activity in awake animals using a cell-type-specific calcium imaging approach and saw highly correlated activity across chandelier cells. In the same experiments, in vivo chandelier population activity correlated with pupil dilation, a proxy for arousal. Together, these results suggest that chandelier cells provide a circuit-wide signal whose strength is adjusted relative to the properties of target neurons.
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Affiliation(s)
| | - Agnes L Bodor
- Allen Institute for Brain SciencesSeattleUnited States
| | | | | | - Adam Bleckert
- Allen Institute for Brain SciencesSeattleUnited States
| | - Sven Dorkenwald
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Computer Science Department, Princeton UniversityPrincetonUnited States
| | - Nicholas L Turner
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Computer Science Department, Princeton UniversityPrincetonUnited States
| | - Thomas Macrina
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Computer Science Department, Princeton UniversityPrincetonUnited States
| | - Kisuk Lee
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Brain & Cognitive Sciences Department, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Ran Lu
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Jingpeng Wu
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Jun Zhuang
- Allen Institute for Brain SciencesSeattleUnited States
| | - Anirban Nandi
- Allen Institute for Brain SciencesSeattleUnited States
| | - Brian Hu
- Allen Institute for Brain SciencesSeattleUnited States
| | | | - Marc M Takeno
- Allen Institute for Brain SciencesSeattleUnited States
| | - Russel Torres
- Allen Institute for Brain SciencesSeattleUnited States
| | | | | | - Yang Li
- Allen Institute for Brain SciencesSeattleUnited States
| | | | - Nico Kemnitz
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | | | - Dodam Ih
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Jonathan Zung
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Aleksandar Zlateski
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Ignacio Tartavull
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Sergiy Popovych
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Computer Science Department, Princeton UniversityPrincetonUnited States
| | - William Wong
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Manuel Castro
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Chris S Jordan
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Emmanouil Froudarakis
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Center for Neuroscience and Artificial Intelligence, Baylor College of MedicineHoustonUnited States
| | - Lynne Becker
- Allen Institute for Brain SciencesSeattleUnited States
| | - Shelby Suckow
- Allen Institute for Brain SciencesSeattleUnited States
| | - Jacob Reimer
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Center for Neuroscience and Artificial Intelligence, Baylor College of MedicineHoustonUnited States
| | - Andreas S Tolias
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Center for Neuroscience and Artificial Intelligence, Baylor College of MedicineHoustonUnited States
- Department of Electrical and Computer Engineering, Rice UniversityHoustonUnited States
| | - Costas A Anastassiou
- Allen Institute for Brain SciencesSeattleUnited States
- Department of Neurology, University of British ColumbiaVancouverCanada
| | - H Sebastian Seung
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Computer Science Department, Princeton UniversityPrincetonUnited States
| | - R Clay Reid
- Allen Institute for Brain SciencesSeattleUnited States
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2
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Oblak AL, Lin PB, Kotredes KP, Pandey RS, Garceau D, Williams HM, Uyar A, O'Rourke R, O'Rourke S, Ingraham C, Bednarczyk D, Belanger M, Cope ZA, Little GJ, Williams SPG, Ash C, Bleckert A, Ragan T, Logsdon BA, Mangravite LM, Sukoff Rizzo SJ, Territo PR, Carter GW, Howell GR, Sasner M, Lamb BT. Comprehensive Evaluation of the 5XFAD Mouse Model for Preclinical Testing Applications: A MODEL-AD Study. Front Aging Neurosci 2021; 13:713726. [PMID: 34366832 DOI: 10.3389/fnagi.2021.71372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 06/23/2021] [Indexed: 05/23/2023] Open
Abstract
The ability to investigate therapeutic interventions in animal models of neurodegenerative diseases depends on extensive characterization of the model(s) being used. There are numerous models that have been generated to study Alzheimer's disease (AD) and the underlying pathogenesis of the disease. While transgenic models have been instrumental in understanding AD mechanisms and risk factors, they are limited in the degree of characteristics displayed in comparison with AD in humans, and the full spectrum of AD effects has yet to be recapitulated in a single mouse model. The Model Organism Development and Evaluation for Late-Onset Alzheimer's Disease (MODEL-AD) consortium was assembled by the National Institute on Aging (NIA) to develop more robust animal models of AD with increased relevance to human disease, standardize the characterization of AD mouse models, improve preclinical testing in animals, and establish clinically relevant AD biomarkers, among other aims toward enhancing the translational value of AD models in clinical drug design and treatment development. Here we have conducted a detailed characterization of the 5XFAD mouse, including transcriptomics, electroencephalogram, in vivo imaging, biochemical characterization, and behavioral assessments. The data from this study is publicly available through the AD Knowledge Portal.
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Affiliation(s)
- Adrian L Oblak
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, United States
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Peter B Lin
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | | | - Ravi S Pandey
- The Jackson Laboratory, Bar Harbor, ME, United States
| | - Dylan Garceau
- The Jackson Laboratory, Bar Harbor, ME, United States
| | | | - Asli Uyar
- The Jackson Laboratory, Bar Harbor, ME, United States
| | - Rita O'Rourke
- The Jackson Laboratory, Bar Harbor, ME, United States
| | | | - Cynthia Ingraham
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | | | - Melisa Belanger
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Zackary A Cope
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Gabriela J Little
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | | | - Carl Ash
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Adam Bleckert
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, United States
| | - Tim Ragan
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, United States
| | | | | | | | - Paul R Territo
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States
| | | | | | | | - Bruce T Lamb
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
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3
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Oblak AL, Lin PB, Kotredes KP, Pandey RS, Garceau D, Williams HM, Uyar A, O'Rourke R, O'Rourke S, Ingraham C, Bednarczyk D, Belanger M, Cope ZA, Little GJ, Williams SPG, Ash C, Bleckert A, Ragan T, Logsdon BA, Mangravite LM, Sukoff Rizzo SJ, Territo PR, Carter GW, Howell GR, Sasner M, Lamb BT. Comprehensive Evaluation of the 5XFAD Mouse Model for Preclinical Testing Applications: A MODEL-AD Study. Front Aging Neurosci 2021; 13:713726. [PMID: 34366832 PMCID: PMC8346252 DOI: 10.3389/fnagi.2021.713726] [Citation(s) in RCA: 106] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 06/23/2021] [Indexed: 12/14/2022] Open
Abstract
The ability to investigate therapeutic interventions in animal models of neurodegenerative diseases depends on extensive characterization of the model(s) being used. There are numerous models that have been generated to study Alzheimer's disease (AD) and the underlying pathogenesis of the disease. While transgenic models have been instrumental in understanding AD mechanisms and risk factors, they are limited in the degree of characteristics displayed in comparison with AD in humans, and the full spectrum of AD effects has yet to be recapitulated in a single mouse model. The Model Organism Development and Evaluation for Late-Onset Alzheimer's Disease (MODEL-AD) consortium was assembled by the National Institute on Aging (NIA) to develop more robust animal models of AD with increased relevance to human disease, standardize the characterization of AD mouse models, improve preclinical testing in animals, and establish clinically relevant AD biomarkers, among other aims toward enhancing the translational value of AD models in clinical drug design and treatment development. Here we have conducted a detailed characterization of the 5XFAD mouse, including transcriptomics, electroencephalogram, in vivo imaging, biochemical characterization, and behavioral assessments. The data from this study is publicly available through the AD Knowledge Portal.
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Affiliation(s)
- Adrian L Oblak
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, United States.,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Peter B Lin
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | | | - Ravi S Pandey
- The Jackson Laboratory, Bar Harbor, ME, United States
| | - Dylan Garceau
- The Jackson Laboratory, Bar Harbor, ME, United States
| | | | - Asli Uyar
- The Jackson Laboratory, Bar Harbor, ME, United States
| | - Rita O'Rourke
- The Jackson Laboratory, Bar Harbor, ME, United States
| | | | - Cynthia Ingraham
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | | | - Melisa Belanger
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Zackary A Cope
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Gabriela J Little
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | | | - Carl Ash
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Adam Bleckert
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, United States
| | - Tim Ragan
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, United States
| | | | | | | | - Paul R Territo
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States.,Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States
| | | | | | | | - Bruce T Lamb
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States.,Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, United States
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4
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Sawant A, Ebbinghaus BN, Bleckert A, Gamlin C, Yu WQ, Berson D, Rudolph U, Sinha R, Hoon M. Organization and emergence of a mixed GABA-glycine retinal circuit that provides inhibition to mouse ON-sustained alpha retinal ganglion cells. Cell Rep 2021; 34:108858. [PMID: 33730586 PMCID: PMC8030271 DOI: 10.1016/j.celrep.2021.108858] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 12/07/2020] [Accepted: 02/19/2021] [Indexed: 12/04/2022] Open
Abstract
In the retina, amacrine interneurons inhibit retinal ganglion cell (RGC) dendrites to shape retinal output. Amacrine cells typically use either GABA or glycine to exert synaptic inhibition. Here, we combined transgenic tools with immunohistochemistry, electrophysiology, and 3D electron microscopy to determine the composition and organization of inhibitory synapses across the dendritic arbor of a well-characterized RGC type in the mouse retina: the ON-sustained alpha RGC. We find mixed GABA-glycine receptor synapses across this RGC type, unveiling the existence of "mixed" inhibitory synapses in the retinal circuit. Presynaptic amacrine boutons with dual release sites are apposed to ON-sustained alpha RGC postsynapses. We further reveal the sequence of postsynaptic assembly for these mixed synapses: GABA receptors precede glycine receptors, and a lack of early GABA receptor expression impedes the recruitment of glycine receptors. Together our findings uncover the organization and developmental profile of an additional motif of inhibition in the mammalian retina.
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Affiliation(s)
- Abhilash Sawant
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA; Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA
| | - Briana N Ebbinghaus
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - Adam Bleckert
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Clare Gamlin
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Wan-Qing Yu
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - David Berson
- Department of Neuroscience, Brown University, Providence, RI, USA
| | - Uwe Rudolph
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Raunak Sinha
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA; Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - Mrinalini Hoon
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA; Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA.
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5
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Yin W, Brittain D, Borseth J, Scott ME, Williams D, Perkins J, Own CS, Murfitt M, Torres RM, Kapner D, Mahalingam G, Bleckert A, Castelli D, Reid D, Lee WCA, Graham BJ, Takeno M, Bumbarger DJ, Farrell C, Reid RC, da Costa NM. A petascale automated imaging pipeline for mapping neuronal circuits with high-throughput transmission electron microscopy. Nat Commun 2020; 11:4949. [PMID: 33009388 PMCID: PMC7532165 DOI: 10.1038/s41467-020-18659-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 08/28/2020] [Indexed: 11/18/2022] Open
Abstract
Electron microscopy (EM) is widely used for studying cellular structure and network connectivity in the brain. We have built a parallel imaging pipeline using transmission electron microscopes that scales this technology, implements 24/7 continuous autonomous imaging, and enables the acquisition of petascale datasets. The suitability of this architecture for large-scale imaging was demonstrated by acquiring a volume of more than 1 mm3 of mouse neocortex, spanning four different visual areas at synaptic resolution, in less than 6 months. Over 26,500 ultrathin tissue sections from the same block were imaged, yielding a dataset of more than 2 petabytes. The combined burst acquisition rate of the pipeline is 3 Gpixel per sec and the net rate is 600 Mpixel per sec with six microscopes running in parallel. This work demonstrates the feasibility of acquiring EM datasets at the scale of cortical microcircuits in multiple brain regions and species.
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6
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Vlasits AL, Morrie RD, Tran-Van-Minh A, Bleckert A, Gainer CF, DiGregorio DA, Feller MB. A Role for Synaptic Input Distribution in a Dendritic Computation of Motion Direction in the Retina. Neuron 2016; 89:1317-1330. [PMID: 26985724 DOI: 10.1016/j.neuron.2016.02.020] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Revised: 12/22/2015] [Accepted: 02/10/2016] [Indexed: 12/21/2022]
Abstract
The starburst amacrine cell in the mouse retina presents an opportunity to examine the precise role of sensory input location on neuronal computations. Using visual receptive field mapping, glutamate uncaging, two-photon Ca(2+) imaging, and genetic labeling of putative synapses, we identify a unique arrangement of excitatory inputs and neurotransmitter release sites on starburst amacrine cell dendrites: the excitatory input distribution is skewed away from the release sites. By comparing computational simulations with Ca(2+) transients recorded near release sites, we show that this anatomical arrangement of inputs and outputs supports a dendritic mechanism for computing motion direction. Direction-selective Ca(2+) transients persist in the presence of a GABA-A receptor antagonist, though the directional tuning is reduced. These results indicate a synergistic interaction between dendritic and circuit mechanisms for generating direction selectivity in the starburst amacrine cell.
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Affiliation(s)
- Anna L Vlasits
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Ryan D Morrie
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Alexandra Tran-Van-Minh
- Unit of Dynamic Neuronal Imaging, Institut Pasteur, 75724 Paris Cedex 15, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3571, 75724 Paris Cedex 15, France
| | - Adam Bleckert
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Christian F Gainer
- Department of Optometry, University of California, Berkeley, Berkeley, CA 94704, USA
| | - David A DiGregorio
- Unit of Dynamic Neuronal Imaging, Institut Pasteur, 75724 Paris Cedex 15, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3571, 75724 Paris Cedex 15, France.
| | - Marla B Feller
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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7
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Sexton TJ, Bleckert A, Turner MH, Van Gelder RN. Type I intrinsically photosensitive retinal ganglion cells of early post-natal development correspond to the M4 subtype. Neural Dev 2015; 10:17. [PMID: 26091805 PMCID: PMC4480886 DOI: 10.1186/s13064-015-0042-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 06/03/2015] [Indexed: 12/16/2022] Open
Abstract
Background Intrinsically photosensitive retinal ganglion cells (ipRGCs) mediate circadian light entrainment and the pupillary light response in adult mice. In early development these cells mediate different processes, including negative phototaxis and the timing of retinal vascular development. To determine if ipRGC physiologic properties also change with development, we measured ipRGC cell density and light responses in wild-type mouse retinas at post-natal days 8, 15 and 30. Results Melanopsin-positive cell density decreases by 17 % between post-natal days 8 and 15 and by 25 % between days 8 and 30. This decrease is due specifically to a decrease in cells co-labeled with a SMI-32, a marker for alpha-on ganglion cells (corresponding to adult morphologic type M4 ipRGCs). On multi-electrode array recordings, post-natal day 8 (P8) ipRGC light responses show more robust firing, reduced adaptation and more rapid recovery from short and extended light pulses than do the light responses of P15 and P30 ipRGCs. Three ipRGC subtypes – Types I-III – have been defined in early development based on sensitivity and latency on multielectrode array recordings. We find that Type I cells largely account for the unique physiologic properties of P8 ipRGCs. Type I cells have previously been shown to have relatively short latencies and high sensitivity. We now show that Type I cells show have rapid and robust recovery from long and short bright light exposures compared with Type II and III cells, suggesting differential light adaptation mechanisms between cell types. By P15, Type I ipRGCs are no longer detectable. Loose patch recordings of P8 M4 ipRGCs demonstrate Type I physiology. Conclusions Type I ipRGCs are found only in early development. In addition to their previously described high sensitivity and rapid kinetics, these cells are uniquely resistant to adaptation and recover quickly and fully to short and prolonged light exposure. Type I ipRGCs correspond to the SMI-32 positive, M4 subtype and largely lose melanopsin expression in development. These cells constitute a unique morphologic and physiologic class of ipRGCs functioning early in postnatal development. Electronic supplementary material The online version of this article (doi:10.1186/s13064-015-0042-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Timothy J Sexton
- Department of Ophthalmology, University of Washington, 325 9th Avenue, Seattle, WA, 98104, USA. .,Program in Neurobiology and Behavior, University of Washington, Health Sciences Center, Seattle, WA, 98195, USA.
| | - Adam Bleckert
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA. .,Program in Neurobiology and Behavior, University of Washington, Health Sciences Center, Seattle, WA, 98195, USA.
| | - Maxwell H Turner
- Department of Physiology & Biophysics, University of Washington, 1705 NE Pacific St., Seattle, WA, 98195, USA. .,Program in Neurobiology and Behavior, University of Washington, Health Sciences Center, Seattle, WA, 98195, USA.
| | - Russell N Van Gelder
- Department of Ophthalmology, University of Washington, 325 9th Avenue, Seattle, WA, 98104, USA. .,Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA. .,Department of Pathology, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA. .,Program in Neurobiology and Behavior, University of Washington, Health Sciences Center, Seattle, WA, 98195, USA.
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8
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Bleckert A, Schwartz GW, Turner MH, Rieke F, Wong ROL. Visual space is represented by nonmatching topographies of distinct mouse retinal ganglion cell types. Curr Biol 2014; 24:310-5. [PMID: 24440397 DOI: 10.1016/j.cub.2013.12.020] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 12/10/2013] [Accepted: 12/10/2013] [Indexed: 10/25/2022]
Abstract
The distributions of neurons in sensory circuits display ordered spatial patterns arranged to enhance or encode specific regions or features of the external environment. Indeed, visual space is not sampled uniformly across the vertebrate retina. Retinal ganglion cell (RGC) density increases and dendritic arbor size decreases toward retinal locations with higher sampling frequency, such as the fovea in primates and area centralis in carnivores [1]. In these locations, higher acuity at the level of individual cells is obtained because the receptive field center of a RGC corresponds approximately to the spatial extent of its dendritic arbor [2, 3]. For most species, structurally and functionally distinct RGC types appear to have similar topographies, collectively scaling their cell densities and arbor sizes toward the same retinal location [4]. Thus, visual space is represented across the retina in parallel by multiple distinct circuits [5]. In contrast, we find a population of mouse RGCs, known as alpha or alpha-like [6], that displays a nasal-to-temporal gradient in cell density, size, and receptive fields, which facilitates enhanced visual sampling in frontal visual fields. The distribution of alpha-like RGCs contrasts with other known mouse RGC types and suggests that, unlike most mammals, RGC topographies in mice are arranged to sample space differentially.
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Affiliation(s)
- Adam Bleckert
- Graduate Program in Neurobiology and Behavior, University of Washington, Seattle, WA 98195, USA; Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Gregory W Schwartz
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Maxwell H Turner
- Graduate Program in Neurobiology and Behavior, University of Washington, Seattle, WA 98195, USA; Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Fred Rieke
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, Seattle, WA 98195, USA
| | - Rachel O L Wong
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA.
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9
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Bleckert A, Parker ED, Kang Y, Pancaroglu R, Soto F, Lewis R, Craig AM, Wong ROL. Spatial relationships between GABAergic and glutamatergic synapses on the dendrites of distinct types of mouse retinal ganglion cells across development. PLoS One 2013; 8:e69612. [PMID: 23922756 PMCID: PMC3724919 DOI: 10.1371/journal.pone.0069612] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 06/11/2013] [Indexed: 12/02/2022] Open
Abstract
Neuronal output requires a concerted balance between excitatory and inhibitory (I/E) input. Like other circuits, inhibitory synaptogenesis in the retina precedes excitatory synaptogenesis. How then do neurons attain their mature balance of I/E ratios despite temporal offset in synaptogenesis? To directly compare the development of glutamatergic and GABAergic synapses onto the same cell, we biolistically transfected retinal ganglion cells (RGCs) with PSD95CFP, a marker of glutamatergic postsynaptic sites, in transgenic Thy1YFPγ2 mice in which GABAA receptors are fluorescently tagged. We mapped YFPγ2 and PSD95CFP puncta distributions on three RGC types at postnatal day P12, shortly before eye opening, and at P21 when robust light responses in RGCs are present. The mature IGABA/E ratios varied among ON-Sustained (S) A-type, OFF-S A-type, and bistratified direction selective (DS) RGCs. These ratios were attained at different rates, before eye-opening for ON-S and OFF-S A-type, and after eye-opening for DS RGCs. At both ages examined, the IGABA/E ratio was uniform across the arbors of the three RGC types. Furthermore, measurements of the distances between neighboring PSD95CFP and YFPγ2 puncta on RGC dendrites indicate that their local relationship is established early in development, and cannot be predicted by random organization. These close spatial associations between glutamatergic and GABAergic postsynaptic sites appear to represent local synaptic arrangements revealed by correlative light and EM reconstructions of a single RGC's dendrites. Thus, although RGC types have different IGABA/E ratios and establish these ratios at separate rates, the local relationship between excitatory and inhibitory inputs appear similarly constrained across the RGC types studied.
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Affiliation(s)
- Adam Bleckert
- Graduate Program in Neurobiology and Behavior, University of Washington, Seattle, Washington, United States of America
- Department of Biological Structure, University of Washington, Seattle, Washington, United States of America
| | - Edward D. Parker
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States of America
| | - YunHee Kang
- Psychiatry, Brain Research Center, Vancouver, British Columbia, Canada
| | - Raika Pancaroglu
- Psychiatry, Brain Research Center, Vancouver, British Columbia, Canada
| | - Florentina Soto
- Department of Biological Structure, University of Washington, Seattle, Washington, United States of America
| | - Renate Lewis
- Transgenic Vector Core, Washington University, St. Louis, Missouri, United States of America
| | - Ann Marie Craig
- Psychiatry, Brain Research Center, Vancouver, British Columbia, Canada
| | - Rachel O. L. Wong
- Department of Biological Structure, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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10
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Abstract
We investigated actin's function in vesicle recycling and exocytosis at lamprey synapses and show that FM1-43 puncta and phalloidin-labeled filamentous actin (F-actin) structures are colocalized, yet recycling vesicles are not contained within F-actin clusters. Additionally, phalloidin also labels a plasma membrane-associated cortical actin. Injection of fluorescent G-actin revealed activity-independent dynamic actin incorporation into presynaptic synaptic vesicle clusters but not into cortical actin. Latrunculin-A, which sequesters G-actin, dispersed vesicle-associated actin structures and prevented subsequent labeled G-actin and phalloidin accumulation at presynaptic puncta, yet cortical phalloidin labeling persisted. Dispersal of presynaptic F-actin structures by latrunculin-A did not disrupt vesicle clustering or recycling or alter the amplitude or kinetics of excitatory postsynaptic currents (EPSCs). However, it slightly enhanced release during repetitive stimulation. While dispersal of presynaptic actin puncta with latrunculin-A failed to disperse synaptic vesicles or inhibit synaptic transmission, presynaptic phalloidin injection blocked exocytosis and reduced endocytosis measured by action potential-evoked FM1-43 staining. Furthermore, phalloidin stabilization of only cortical actin following pretreatment with latrunculin-A was sufficient to inhibit synaptic transmission. Conversely, treatment of axons with jasplakinolide, which induces F-actin accumulation but disrupts F-actin structures in vivo, resulted in increased synaptic transmission accompanied by a loss of phalloidin labeling of cortical actin but no loss of actin labeling within vesicle clusters. Marked synaptic deficits seen with phalloidin stabilization of cortical F-actin, in contrast to the minimal effects of disruption of a synaptic vesicle-associated F-actin, led us to conclude that two structurally and functionally distinct pools of actin exist at presynaptic sites.
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Affiliation(s)
- Adam Bleckert
- Dept. of Biological Sciences, Univ. of Illinois at Chicago, Chicago, IL 60607, USA
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11
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Nowack A, Malarkey EB, Yao J, Bleckert A, Hill J, Bajjalieh SM. Levetiracetam reverses synaptic deficits produced by overexpression of SV2A. PLoS One 2011; 6:e29560. [PMID: 22220214 PMCID: PMC3248421 DOI: 10.1371/journal.pone.0029560] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 11/30/2011] [Indexed: 11/18/2022] Open
Abstract
Levetiracetam is an FDA-approved drug used to treat epilepsy and other disorders of the nervous system. Although it is known that levetiracetam binds the synaptic vesicle protein SV2A, how drug binding affects synaptic functioning remains unknown. Here we report that levetiracetam reverses the effects of excess SV2A in autaptic hippocampal neurons. Expression of an SV2A-EGFP fusion protein produced a ∼1.5-fold increase in synaptic levels of SV2, and resulted in reduced synaptic release probability. The overexpression phenotype parallels that seen in neurons from SV2 knockout mice, which experience severe seizures. Overexpression of SV2A also increased synaptic levels of the calcium-sensor protein synaptotagmin, an SV2-binding protein whose stability and trafficking are regulated by SV2. Treatment with levetiracetam rescued normal neurotransmission and restored normal levels of SV2 and synaptotagmin at the synapse. These results indicate that changes in SV2 expression in either direction impact neurotransmission, and suggest that levetiracetam may modulate SV2 protein interactions.
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Affiliation(s)
- Amy Nowack
- Department of Pharmacology, University of Washington, Seattle, Washington, United States of America
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12
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Soto F, Bleckert A, Lewis R, Kang Y, Kerschensteiner D, Craig AM, Wong ROL. Coordinated increase in inhibitory and excitatory synapses onto retinal ganglion cells during development. Neural Dev 2011; 6:31. [PMID: 21864334 PMCID: PMC3179698 DOI: 10.1186/1749-8104-6-31] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 08/24/2011] [Indexed: 01/29/2023] Open
Abstract
Background Neuronal output is shaped by a balance of excitation and inhibition. How this balance is attained in the central nervous system during development is not well understood, and is complicated by the fact that, in vivo, GABAergic and glycinergic synaptogenesis precedes that of glutamatergic synapses. Here, we determined the distributions of inhibitory postsynaptic sites on the dendritic arbors of individual neurons, and compared their developmental patterns with that of excitatory postsynaptic sites. We focused on retinal ganglion cells (RGCs), the output neurons of the retina, which receive excitatory input from bipolar cells and inhibitory input from amacrine cells. To visualize and map inhibitory postsynaptic sites, we generated transgenic mice in which RGCs express fluorescently tagged Neuroligin 2 (YFP-NL2) under the control of the Thy1 promoter. By labeling RGC dendrites biolistically in YFP-NL2-expressing retinas, we were able to map the spatial distribution and thus densities of inhibitory postsynaptic sites on the dendritic arbors of individual large-field RGCs across ages. Results We demonstrate that YFP-NL2 is present at inhibitory synapses in the inner plexiform layer by its co-localization with gephyrin, the γ2 subunit of the GABAA receptor and glycine receptors. YFP-NL2 puncta were apposed to the vesicular inhibitory transmitter transporter VGAT but not to CtBP2, a marker of presynaptic ribbons found at bipolar cell terminals. Similar patterns of co-localization with synaptic markers were observed for endogenous NL2. We also verified that expression of YFP-NL2 in the transgenic line did not significantly alter spontaneous inhibitory synaptic transmission onto RGCs. Using these mice, we found that, on average, the density of inhibitory synapses on individual arbors increased gradually until eye opening (postnatal day 15). A small centro-peripheral gradient in density found in mature arbors was apparent at the earliest age we examined (postnatal day 8). Unexpectedly, the adult ratio of inhibitory/excitatory postsynaptic sites was rapidly attained, shortly after glutamatergic synaptogenesis commenced (postnatal day 7). Conclusion Our observations suggest that bipolar and amacrine cell synaptogenesis onto RGCs appear coordinated to rapidly attain a balanced ratio of excitatory and inhibitory synapse densities prior to the onset of visual experience.
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Affiliation(s)
- Florentina Soto
- Department of Biological Structure, University of Washington, 1950 Pacific Ave, Seattle, WA 98195, USA
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13
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Bleckert A, Wong ROL. Identifying roles for neurotransmission in circuit assembly: insights gained from multiple model systems and experimental approaches. Bioessays 2011; 33:61-72. [PMID: 21110347 DOI: 10.1002/bies.201000095] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the adult nervous system, chemical neurotransmission between neurons is essential for information processing. However, neurotransmission is also important for patterning circuits during development, but its precise roles have yet to be identified, and some remain highly debated. Here, we highlight viewpoints that have come to be widely accepted or still challenged. We discuss how distinct techniques and model systems employed to probe the developmental role of neurotransmission may reconcile disparate ideas. We underscore how the effects of perturbing neurotransmission during development vary with model systems, the stage of development when transmission is altered, the nature of the perturbation, and how connectivity is assessed. Based on findings in circuits with connectivity arranged in layers, we raise the possibility that there exist constraints in neuronal network design that limit the role of neurotransmission. We propose that activity-dependent mechanisms are effective in refining connectivity patterns only when inputs from different cells are close enough, spatially, to influence each other's outcome.
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Affiliation(s)
- Adam Bleckert
- Department of Biological Structure, University of Washington, Seattle, WA, USA
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