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Zaforas M, Miguel-Quesada C, Fernández-López E, Alonso-Calviño E, Barranco-Maresca V, Misol-Ortiz A, Aguilar J, Rosa JM. Protocol for stimulating specific rodent limb receptive fields while recording in vivo somatosensory-evoked activity. STAR Protoc 2024; 5:102972. [PMID: 38502685 PMCID: PMC10960094 DOI: 10.1016/j.xpro.2024.102972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/06/2024] [Accepted: 03/05/2024] [Indexed: 03/21/2024] Open
Abstract
Studies on sensory information processing typically focus on whisker-related tactile information, overlooking the question of how sensory inputs from other body areas are processed at cortical levels. Here, we present a protocol for stimulating specific rodent limb receptive fields while recording in vivo somatosensory-evoked activity. We describe steps for localizing cortical-hindlimb coordinates using acute peripheral stimulation, electrode placement, and the application of electrical stimulation. This protocol overcomes the challenge of inducing a reproducible and consistent stimulation of specific limbs. For complete details on the use and execution of this protocol, please refer to Miguel-Quesada et al.1.
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Affiliation(s)
- Marta Zaforas
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos. SESCAM, 45071 Toledo, Spain; Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain.
| | - Claudia Miguel-Quesada
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos. SESCAM, 45071 Toledo, Spain; Neuronal Circuits and Behaviour Group, Hospital Nacional de Parapléjicos, 45071 Toledo, Spain
| | - Elena Fernández-López
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos. SESCAM, 45071 Toledo, Spain; Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain
| | - Elena Alonso-Calviño
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos. SESCAM, 45071 Toledo, Spain; Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain
| | - Verónica Barranco-Maresca
- Neuronal Circuits and Behaviour Group, Hospital Nacional de Parapléjicos, 45071 Toledo, Spain; Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain
| | - Andrea Misol-Ortiz
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos. SESCAM, 45071 Toledo, Spain; Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain
| | - Juan Aguilar
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos. SESCAM, 45071 Toledo, Spain; Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain
| | - Juliana M Rosa
- Neuronal Circuits and Behaviour Group, Hospital Nacional de Parapléjicos, 45071 Toledo, Spain; Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain.
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2
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Miguel-Quesada C, Zaforas M, Herrera-Pérez S, Lines J, Fernández-López E, Alonso-Calviño E, Ardaya M, Soria FN, Araque A, Aguilar J, Rosa JM. Astrocytes adjust the dynamic range of cortical network activity to control modality-specific sensory information processing. Cell Rep 2023; 42:112950. [PMID: 37543946 DOI: 10.1016/j.celrep.2023.112950] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 03/21/2023] [Accepted: 07/23/2023] [Indexed: 08/08/2023] Open
Abstract
Cortical neuron-astrocyte communication in response to peripheral sensory stimulation occurs in a topographic-, frequency-, and intensity-dependent manner. However, the contribution of this functional interaction to the processing of sensory inputs and consequent behavior remains unclear. We investigate the role of astrocytes in sensory information processing at circuit and behavioral levels by monitoring and manipulating astrocytic activity in vivo. We show that astrocytes control the dynamic range of the cortical network activity, optimizing its responsiveness to incoming sensory inputs. The astrocytic modulation of sensory processing contributes to setting the detection threshold for tactile and thermal behavior responses. The mechanism of such astrocytic control is mediated through modulation of inhibitory transmission to adjust the gain and sensitivity of responding networks. These results uncover a role for astrocytes in maintaining the cortical network activity in an optimal range to control behavior associated with specific sensory modalities.
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Affiliation(s)
- Claudia Miguel-Quesada
- Neuronal Circuits and Behaviour Group, Hospital Nacional de Parapléjicos, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain; Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain
| | - Marta Zaforas
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain
| | - Salvador Herrera-Pérez
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain
| | - Justin Lines
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Elena Fernández-López
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain
| | - Elena Alonso-Calviño
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain
| | - Maria Ardaya
- Donostia International Physics Center (DIPC), 20018 San Sebastian, Spain; Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain
| | - Federico N Soria
- Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain; Ikerbasque, Basque Foundation for Science, 48009 Bilbao, Spain; Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Juan Aguilar
- Experimental Neurophysiology Group, Hospital Nacional de Parapléjicos, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain.
| | - Juliana M Rosa
- Neuronal Circuits and Behaviour Group, Hospital Nacional de Parapléjicos, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), 45071 Toledo, Spain.
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3
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Wang X, Roberts PA, Yoshimatsu T, Lagnado L, Baden T. Amacrine cells differentially balance zebrafish color circuits in the central and peripheral retina. Cell Rep 2023; 42:112055. [PMID: 36757846 DOI: 10.1016/j.celrep.2023.112055] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 11/01/2022] [Accepted: 01/18/2023] [Indexed: 02/10/2023] Open
Abstract
The vertebrate inner retina is driven by photoreceptors whose outputs are already pre-processed; in zebrafish, outer retinal circuits split "color" from "grayscale" information across four cone-photoreceptor types. It remains unclear how the inner retina processes incoming spectral information while also combining cone signals to shape grayscale functions. We address this question by imaging the light-driven responses of amacrine cells (ACs) and bipolar cells (BCs) in larval zebrafish in the presence and pharmacological absence of inner retinal inhibition. We find that ACs enhance opponency in some bipolar cells while at the same time suppressing pre-existing opponency in others, so that, depending on the retinal region, the net change in the number of color-opponent units is essentially zero. To achieve this "dynamic balance," ACs counteract intrinsic color opponency of BCs via the On channel. Consistent with these observations, Off-stratifying ACs are exclusively achromatic, while all color-opponent ACs stratify in the On sublamina.
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Affiliation(s)
- Xinwei Wang
- School of Life Sciences, University of Sussex, Biology Road, Brighton BN1 9QG, UK.
| | - Paul A Roberts
- School of Life Sciences, University of Sussex, Biology Road, Brighton BN1 9QG, UK
| | - Takeshi Yoshimatsu
- School of Life Sciences, University of Sussex, Biology Road, Brighton BN1 9QG, UK
| | - Leon Lagnado
- School of Life Sciences, University of Sussex, Biology Road, Brighton BN1 9QG, UK.
| | - Tom Baden
- School of Life Sciences, University of Sussex, Biology Road, Brighton BN1 9QG, UK; Institute of Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076 Tübingen, Germany.
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4
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Biasetti L, Rey S, Fowler M, Ratnayaka A, Fennell K, Smith C, Marshall K, Hall C, Vargas-Caballero M, Serpell L, Staras K. Elevated amyloid beta disrupts the nanoscale organization and function of synaptic vesicle pools in hippocampal neurons. Cereb Cortex 2023; 33:1263-1276. [PMID: 35368053 PMCID: PMC9930632 DOI: 10.1093/cercor/bhac134] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 02/02/2022] [Accepted: 03/07/2022] [Indexed: 11/14/2022] Open
Abstract
Alzheimer's disease is linked to increased levels of amyloid beta (Aβ) in the brain, but the mechanisms underlying neuronal dysfunction and neurodegeneration remain enigmatic. Here, we investigate whether organizational characteristics of functional presynaptic vesicle pools, key determinants of information transmission in the central nervous system, are targets for elevated Aβ. Using an optical readout method in cultured hippocampal neurons, we show that acute Aβ42 treatment significantly enlarges the fraction of functional vesicles at individual terminals. We observe the same effect in a chronically elevated Aβ transgenic model (APPSw,Ind) using an ultrastructure-function approach that provides detailed information on nanoscale vesicle pool positioning. Strikingly, elevated Aβ is correlated with excessive accumulation of recycled vesicles near putative endocytic sites, which is consistent with deficits in vesicle retrieval pathways. Using the glutamate reporter, iGluSnFR, we show that there are parallel functional consequences, where ongoing information signaling capacity is constrained. Treatment with levetiracetam, an antiepileptic that dampens synaptic hyperactivity, partially rescues these transmission defects. Our findings implicate organizational and dynamic features of functional vesicle pools as targets in Aβ-driven synaptic impairment, suggesting that interventions to relieve the overloading of vesicle retrieval pathways might have promising therapeutic value.
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Affiliation(s)
- Luca Biasetti
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Stephanie Rey
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
- National Physical Laboratory, Middlesex, TW11 0LW, United Kingdom
| | - Milena Fowler
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Arjuna Ratnayaka
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
- Faculty of Medicine, University of Southampton, SO17 1BJ, United Kingdom
| | - Kate Fennell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Catherine Smith
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Karen Marshall
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Catherine Hall
- Sussex Neuroscience, School of Psychology, University of Sussex, Brighton, BN1 9QH, United Kingdom
| | - Mariana Vargas-Caballero
- School of Biological Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ, United Kingdom
| | - Louise Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Kevin Staras
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
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5
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Knighten JM, Aziz T, Pleshinger DJ, Annamdevula N, Rich TC, Taylor MS, Andrews JF, Macarilla CT, Francis CM. Algorithm for biological second messenger analysis with dynamic regions of interest. PLoS One 2023; 18:e0284394. [PMID: 37167308 PMCID: PMC10174521 DOI: 10.1371/journal.pone.0284394] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 03/29/2023] [Indexed: 05/13/2023] Open
Abstract
Physiological function is regulated through cellular communication that is facilitated by multiple signaling molecules such as second messengers. Analysis of signal dynamics obtained from cell and tissue imaging is difficult because of intricate spatially and temporally distinct signals. Signal analysis tools based on static region of interest analysis may under- or overestimate signals in relation to region of interest size and location. Therefore, we developed an algorithm for biological signal detection and analysis based on dynamic regions of interest, where time-dependent polygonal regions of interest are automatically assigned to the changing perimeter of detected and segmented signals. This approach allows signal profiles to be rigorously and precisely tracked over time, eliminating the signal distortion observed with static methods. Integration of our approach with state-of-the-art image processing and particle tracking pipelines enabled the isolation of dynamic cellular signaling events and characterization of biological signaling patterns with distinct combinations of parameters including amplitude, duration, and spatial spread. Our algorithm was validated using synthetically generated datasets and compared with other available methods. Application of the algorithm to volumetric time-lapse hyperspectral images of cyclic adenosine monophosphate measurements in rat microvascular endothelial cells revealed distinct signal heterogeneity with respect to cell depth, confirming the utility of our approach for analysis of 5-dimensional data. In human tibial arteries, our approach allowed the identification of distinct calcium signal patterns associated with atherosclerosis. Our algorithm for automated detection and analysis of second messenger signals enables the decoding of signaling patterns in diverse tissues and identification of pathologic cellular responses.
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Affiliation(s)
- Jennifer M Knighten
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
| | - Takreem Aziz
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
| | - Donald J Pleshinger
- Department of Pharmacology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
| | - Naga Annamdevula
- Department of Pharmacology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
| | - Thomas C Rich
- Department of Pharmacology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
| | - Mark S Taylor
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
| | - Joel F Andrews
- Bioimaging Core Facility, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
| | - Christian T Macarilla
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
| | - C Michael Francis
- Department of Physiology and Cell Biology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
- Center for Lung Biology, University of South Alabama College of Medicine, Mobile, Alabama, United States of America
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6
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Patton AP, Smyllie NJ, Chesham JE, Hastings MH. Astrocytes Sustain Circadian Oscillation and Bidirectionally Determine Circadian Period, But Do Not Regulate Circadian Phase in the Suprachiasmatic Nucleus. J Neurosci 2022; 42:5522-5537. [PMID: 35610047 PMCID: PMC9295834 DOI: 10.1523/jneurosci.2337-21.2022] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 03/20/2022] [Accepted: 05/03/2022] [Indexed: 11/21/2022] Open
Abstract
The suprachiasmatic nucleus (SCN) is the master circadian clock of mammals, generating and transmitting an internal representation of environmental time that is produced by the cell-autonomous transcriptional/post-translational feedback loops (TTFLs) of the 10,000 neurons and 3500 glial cells. Recently, we showed that TTFL function in SCN astrocytes alone is sufficient to drive circadian timekeeping and behavior, raising questions about the respective contributions of astrocytes and neurons within the SCN circuit. We compared their relative roles in circadian timekeeping in mouse SCN explants, of either sex. Treatment with the glial-specific toxin fluorocitrate revealed a requirement for metabolically competent astrocytes for circuit-level timekeeping. Recombinase-mediated genetically complemented Cryptochrome (Cry) proteins in Cry1-deficient and/or Cry2-deficient SCNs were used to compare the influence of the TTFLs of neurons or astrocytes in the initiation of de novo oscillation or in pacemaking. While neurons and astrocytes both initiated de novo oscillation and lengthened the period equally, their kinetics were different, with astrocytes taking twice as long. Furthermore, astrocytes could shorten the period, but not as potently as neurons. Chemogenetic manipulation of Gi- and Gq-coupled signaling pathways in neurons acutely advanced or delayed the ensemble phase, respectively. In contrast, comparable manipulations in astrocytes were without effect. Thus, astrocytes can initiate SCN rhythms and bidirectionally control the SCN period, albeit with lower potency than neurons. Nevertheless, their activation does not influence the SCN phase. The emergent SCN properties of high-amplitude oscillation, initiation of rhythmicity, pacemaking, and phase are differentially regulated: astrocytes and neurons sustain the ongoing oscillation, but its phase is determined by neurons.SIGNIFICANCE STATEMENT The hypothalamic suprachiasmatic nucleus (SCN) encodes and disseminates time-of-day information to allow mammals to adapt their physiology to daily environmental cycles. Recent investigations have revealed a role for astrocytes, in addition to neurons, in the regulation of this rhythm. Using pharmacology, genetic complementation, and chemogenetics, we compared the abilities of neurons and astrocytes in determining the emergent SCN properties of high-amplitude oscillation, initiation of rhythmicity, pacemaking, and determination of phase. These findings parameterize the circadian properties of the astrocyte population in the SCN and reveal the types of circadian information that astrocytes and neurons can contribute within their heterogeneous cellular network.
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Affiliation(s)
- Andrew P Patton
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Nicola J Smyllie
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Johanna E Chesham
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
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7
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Blume T, Deussing M, Biechele G, Peters F, Zott B, Schmidt C, Franzmeier N, Wind K, Eckenweber F, Sacher C, Shi Y, Ochs K, Kleinberger G, Xiang X, Focke C, Lindner S, Gildehaus FJ, Beyer L, von Ungern-Sternberg B, Bartenstein P, Baumann K, Adelsberger H, Rominger A, Cumming P, Willem M, Dorostkar MM, Herms J, Brendel M. Chronic PPARγ Stimulation Shifts Amyloidosis to Higher Fibrillarity but Improves Cognition. Front Aging Neurosci 2022; 14:854031. [PMID: 35431893 PMCID: PMC9007038 DOI: 10.3389/fnagi.2022.854031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/25/2022] [Indexed: 11/30/2022] Open
Abstract
We undertook longitudinal β-amyloid positron emission tomography (Aβ-PET) imaging as a translational tool for monitoring of chronic treatment with the peroxisome proliferator-activated receptor gamma (PPARγ) agonist pioglitazone in Aβ model mice. We thus tested the hypothesis this treatment would rescue from increases of the Aβ-PET signal while promoting spatial learning and preservation of synaptic density. Here, we investigated longitudinally for 5 months PS2APP mice (N = 23; baseline age: 8 months) and AppNL–G–F mice (N = 37; baseline age: 5 months) using Aβ-PET. Groups of mice were treated with pioglitazone or vehicle during the follow-up interval. We tested spatial memory performance and confirmed terminal PET findings by immunohistochemical and biochemistry analyses. Surprisingly, Aβ-PET and immunohistochemistry revealed a shift toward higher fibrillary composition of Aβ-plaques during upon chronic pioglitazone treatment. Nonetheless, synaptic density and spatial learning were improved in transgenic mice with pioglitazone treatment, in association with the increased plaque fibrillarity. These translational data suggest that a shift toward higher plaque fibrillarity protects cognitive function and brain integrity. Increases in the Aβ-PET signal upon immunomodulatory treatments targeting Aβ aggregation can thus be protective.
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Affiliation(s)
- Tanja Blume
- DZNE – German Center for Neurodegenerative Diseases, Munich, Germany
| | - Maximilian Deussing
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Gloria Biechele
- Department of Radiology, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Finn Peters
- DZNE – German Center for Neurodegenerative Diseases, Munich, Germany
| | - Benedikt Zott
- Institute of Neuroscience, Technical University of Munich, Munich, Germany
- Department of Diagnostic and Interventional Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Claudio Schmidt
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Nicolai Franzmeier
- Institute for Stroke and Dementia Research, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Karin Wind
- DZNE – German Center for Neurodegenerative Diseases, Munich, Germany
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Florian Eckenweber
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Christian Sacher
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Yuan Shi
- DZNE – German Center for Neurodegenerative Diseases, Munich, Germany
| | - Katharina Ochs
- DZNE – German Center for Neurodegenerative Diseases, Munich, Germany
| | - Gernot Kleinberger
- Metabolic Biochemistry, Faculty of Medicine, Biomedical Center (BMC), Ludwig Maximilian University of Munich, Munich, Germany
- ISAR Bioscience GmbH, Planegg, Germany
| | - Xianyuan Xiang
- Metabolic Biochemistry, Faculty of Medicine, Biomedical Center (BMC), Ludwig Maximilian University of Munich, Munich, Germany
| | - Carola Focke
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Simon Lindner
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Franz-Josef Gildehaus
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Leonie Beyer
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Barbara von Ungern-Sternberg
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Karlheinz Baumann
- Roche Pharma Research and Early Development, Neuroscience Discovery, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Helmuth Adelsberger
- Department of Radiology, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
| | - Axel Rominger
- SyNergy, Ludwig Maximilian University of Munich, Munich, Germany
- Department of Nuclear Medicine, Inselspital Bern, Bern, Switzerland
| | - Paul Cumming
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
- School of Psychology and Counselling, Queensland University of Technology, Brisbane, QLD, Australia
| | - Michael Willem
- Metabolic Biochemistry, Faculty of Medicine, Biomedical Center (BMC), Ludwig Maximilian University of Munich, Munich, Germany
| | - Mario M. Dorostkar
- DZNE – German Center for Neurodegenerative Diseases, Munich, Germany
- Center for Neuropathology and Prion Research, Ludwig Maximilian University of Munich, Munich, Germany
| | - Jochen Herms
- DZNE – German Center for Neurodegenerative Diseases, Munich, Germany
- SyNergy, Ludwig Maximilian University of Munich, Munich, Germany
- Center for Neuropathology and Prion Research, Ludwig Maximilian University of Munich, Munich, Germany
| | - Matthias Brendel
- DZNE – German Center for Neurodegenerative Diseases, Munich, Germany
- Department of Nuclear Medicine, University Hospital of Munich, Ludwig Maximilian University of Munich, Munich, Germany
- SyNergy, Ludwig Maximilian University of Munich, Munich, Germany
- *Correspondence: Matthias Brendel,
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8
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Opposite forms of adaptation in mouse visual cortex are controlled by distinct inhibitory microcircuits. Nat Commun 2022; 13:1031. [PMID: 35210417 PMCID: PMC8873261 DOI: 10.1038/s41467-022-28635-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 01/28/2022] [Indexed: 01/29/2023] Open
Abstract
Sensory processing in the cortex adapts to the history of stimulation but the mechanisms are not understood. Imaging the primary visual cortex of mice we find here that an increase in stimulus contrast is not followed by a simple decrease in gain of pyramidal cells; as many cells increase gain to improve detection of a subsequent decrease in contrast. Depressing and sensitizing forms of adaptation also occur in different types of interneurons (PV, SST and VIP) and the net effect within individual pyramidal cells reflects the balance of PV inputs, driving depression, and a subset of SST interneurons driving sensitization. Changes in internal state associated with locomotion increase gain across the population of pyramidal cells while maintaining the balance between these opposite forms of plasticity, consistent with activation of both VIP->SST and SST->PV disinhibitory pathways. These results reveal how different inhibitory microcircuits adjust the gain of pyramidal cells signalling changes in stimulus strength. The authors describe the role of inhibitory microcircuits in the visual cortex of mice in adaptation to contrast. They show how external stimuli and internal state interact to adjust processing in the visual cortex.
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9
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Lin HH, Kuang MC, Hossain I, Xuan Y, Beebe L, Shepherd AK, Rolandi M, Wang JW. A nutrient-specific gut hormone arbitrates between courtship and feeding. Nature 2022; 602:632-638. [PMID: 35140404 PMCID: PMC9271372 DOI: 10.1038/s41586-022-04408-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 12/22/2021] [Indexed: 11/08/2022]
Abstract
Animals must set behavioural priority in a context-dependent manner and switch from one behaviour to another at the appropriate moment1-3. Here we probe the molecular and neuronal mechanisms that orchestrate the transition from feeding to courtship in Drosophila melanogaster. We find that feeding is prioritized over courtship in starved males, and the consumption of protein-rich food rapidly reverses this order within a few minutes. At the molecular level, a gut-derived, nutrient-specific neuropeptide hormone-Diuretic hormone 31 (Dh31)-propels a switch from feeding to courtship. We further address the underlying kinetics with calcium imaging experiments. Amino acids from food acutely activate Dh31+ enteroendocrine cells in the gut, increasing Dh31 levels in the circulation. In addition, three-photon functional imaging of intact flies shows that optogenetic stimulation of Dh31+ enteroendocrine cells rapidly excites a subset of brain neurons that express Dh31 receptor (Dh31R). Gut-derived Dh31 excites the brain neurons through the circulatory system within a few minutes, in line with the speed of the feeding-courtship behavioural switch. At the circuit level, there are two distinct populations of Dh31R+ neurons in the brain, with one population inhibiting feeding through allatostatin-C and the other promoting courtship through corazonin. Together, our findings illustrate a mechanism by which the consumption of protein-rich food triggers the release of a gut hormone, which in turn prioritizes courtship over feeding through two parallel pathways.
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Affiliation(s)
- Hui-Hao Lin
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Meihua Christina Kuang
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Imran Hossain
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
- Department of Electrical and Computer Engineering, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Yinan Xuan
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Laura Beebe
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Andrew K Shepherd
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Marco Rolandi
- Department of Electrical and Computer Engineering, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Jing W Wang
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA.
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10
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Tworig JM, Coate C, Feller MB. Excitatory neurotransmission activates compartmentalized calcium transients in Müller glia without affecting lateral process motility. eLife 2021; 10:73202. [PMID: 34913435 PMCID: PMC8806189 DOI: 10.7554/elife.73202] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022] Open
Abstract
Neural activity has been implicated in the motility and outgrowth of glial cell processes throughout the central nervous system. Here, we explore this phenomenon in Müller glia, which are specialized radial astroglia that are the predominant glial type of the vertebrate retina. Müller glia extend fine filopodia-like processes into retinal synaptic layers, in similar fashion to brain astrocytes and radial glia that exhibit perisynaptic processes. Using two-photon volumetric imaging, we found that during the second postnatal week, Müller glial processes were highly dynamic, with rapid extensions and retractions that were mediated by cytoskeletal rearrangements. During this same stage of development, retinal waves led to increases in cytosolic calcium within Müller glial lateral processes and stalks. These regions comprised distinct calcium compartments, distinguished by variable participation in waves, timing, and sensitivity to an M1 muscarinic acetylcholine receptor antagonist. However, we found that motility of lateral processes was unaffected by the presence of pharmacological agents that enhanced or blocked wave-associated calcium transients. Finally, we found that mice lacking normal cholinergic waves in the first postnatal week also exhibited normal Müller glial process morphology. Hence, outgrowth of Müller glial lateral processes into synaptic layers is determined by factors that are independent of neuronal activity. When it comes to studying the nervous system, neurons often steal the limelight; yet, they can only work properly thanks to an ensemble cast of cell types whose roles are only just emerging. For example, ‘glial cells’ – their name derives from the Greek word for glue – were once thought to play only a passive, supporting function in nervous tissues. Now, growing evidence shows that they are, in fact, integrated into neural circuits: their activity is influenced by neurons, and, in turn, they help neurons to function properly. The role of glial cells is becoming clear in the retina, the thin, light-sensitive layer that lines the back of the eye and relays visual information to the brain. There, beautifully intricate Müller glial cells display fine protrusions (or ‘processes') that intermingle with synapses, the busy space between neurons where chemical messengers are exchanged. These messengers can act on Müller cells, triggering cascades of molecular events that may influence the structure and function of glia. This is of particular interest during development: as Müller cells mature, they are exposed to chemicals released by more fully formed retinal neurons. Tworig et al. explored how neuronal messengers can influence the way Müller cells grow their processes. To do so, they tracked mouse retinal glial cells ‘live’ during development, showing that they were growing fine, highly dynamic processes in a region rich in synapses just as neurons and glia increased their communication. However, using drugs to disrupt this messaging for a short period did not seem to impact how the processes grew. Extending the blockade over a longer timeframe also did not change the way Müller cells developed, with the cells still acquiring their characteristic elaborate process networks. Taken together, these results suggest that the structural maturation of Müller glial cells is not impacted by neuronal signaling, giving a more refined understanding of how glia form in the retina and potentially in the brain.
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Affiliation(s)
- Joshua M Tworig
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Chandler Coate
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Marla B Feller
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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11
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P2X4 Receptors Mediate Ca 2+ Release from Lysosomes in Response to Stimulation of P2X7 and H 1 Histamine Receptors. Int J Mol Sci 2021; 22:ijms221910492. [PMID: 34638832 PMCID: PMC8508626 DOI: 10.3390/ijms221910492] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/17/2021] [Accepted: 09/22/2021] [Indexed: 01/01/2023] Open
Abstract
The P2X4 purinergic receptor is targeted to endolysosomes, where it mediates an inward current dependent on luminal ATP and pH. Activation of P2X4 receptors was previously shown to trigger lysosome fusion, but the regulation of P2X4 receptors and their role in lysosomal Ca2+ signaling are poorly understood. We show that lysosomal P2X4 receptors are activated downstream of plasma membrane P2X7 and H1 histamine receptor stimulation. When P2X4 receptors are expressed, the increase in near-lysosome cytosolic [Ca2+] is exaggerated, as detected with a low-affinity targeted Ca2+ sensor. P2X4-dependent changes in lysosome properties were triggered downstream of P2X7 receptor activation, including an enlargement of lysosomes indicative of homotypic fusion and a redistribution of lysosomes towards the periphery of the cell. Lysosomal P2X4 receptors, therefore, have a role in regulating lysosomal Ca2+ release and the regulation of lysosomal membrane trafficking.
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12
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OIsen T, Capurro A, Švent M, Pilati N, Large C, Hartell N, Hamann M. Sparsely Distributed, Pre-synaptic Kv3 K + Channels Control Spontaneous Firing and Cross-Unit Synchrony via the Regulation of Synaptic Noise in an Auditory Brainstem Circuit. Front Cell Neurosci 2021; 15:721371. [PMID: 34539351 PMCID: PMC8446535 DOI: 10.3389/fncel.2021.721371] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 08/02/2021] [Indexed: 11/13/2022] Open
Abstract
Spontaneous subthreshold activity in the central nervous system is fundamental to information processing and transmission, as it amplifies and optimizes sub-threshold signals, thereby improving action potential initiation and maintaining reliable firing. This form of spontaneous activity, which is frequently considered noise, is particularly important at auditory synapses where acoustic information is encoded by rapid and temporally precise firing rates. In contrast, when present in excess, this form of noise becomes detrimental to acoustic information as it contributes to the generation and maintenance of auditory disorders such as tinnitus. The most prominent contribution to subthreshold noise is spontaneous synaptic transmission (synaptic noise). Although numerous studies have examined the role of synaptic noise on single cell excitability, little is known about its pre-synaptic modulation owing in part to the difficulties of combining noise modulation with monitoring synaptic release. Here we study synaptic noise in the auditory brainstem dorsal cochlear nucleus (DCN) of mice and show that pharmacological potentiation of Kv3 K+ currents reduces the level of synaptic bombardment onto DCN principal fusiform cells. Using a transgenic mouse line (SyG37) expressing SyGCaMP2-mCherry, a calcium sensor that targets pre-synaptic terminals, we show that positive Kv3 K+ current modulation decreases calcium influx in a fifth of pre-synaptic boutons. Furthermore, while maintaining rapid and precise spike timing, positive Kv3 K+ current modulation increases the synchronization of local circuit neurons by reducing spontaneous activity. In conclusion, our study identifies a unique pre-synaptic mechanism which reduces synaptic noise at auditory synapses and contributes to the coherent activation of neurons in a local auditory brainstem circuit. This form of modulation highlights a new therapeutic target, namely the pre-synaptic bouton, for ameliorating the effects of hearing disorders which are dependent on aberrant spontaneous activity within the central auditory system.
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Affiliation(s)
- Timothy OIsen
- Department of Neuroscience, Psychology and Behaviour, College of Life Sciences, University of Leicester, Leicester, United Kingdom.,Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Alberto Capurro
- Department of Neuroscience, Psychology and Behaviour, College of Life Sciences, University of Leicester, Leicester, United Kingdom.,Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Maša Švent
- Department of Neuroscience, Psychology and Behaviour, College of Life Sciences, University of Leicester, Leicester, United Kingdom
| | | | - Charles Large
- Autifony Therapeutics Limited, Stevenage Bioscience Catalyst, Stevenage, United Kingdom
| | - Nick Hartell
- Department of Neuroscience, Psychology and Behaviour, College of Life Sciences, University of Leicester, Leicester, United Kingdom
| | - Martine Hamann
- Department of Neuroscience, Psychology and Behaviour, College of Life Sciences, University of Leicester, Leicester, United Kingdom.,Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
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13
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Komulainen E, Badman J, Rey S, Rulten S, Ju L, Fennell K, Kalasova I, Ilievova K, McKinnon PJ, Hanzlikova H, Staras K, Caldecott KW. Parp1 hyperactivity couples DNA breaks to aberrant neuronal calcium signalling and lethal seizures. EMBO Rep 2021; 22:e51851. [PMID: 33932076 PMCID: PMC8097344 DOI: 10.15252/embr.202051851] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 12/21/2022] Open
Abstract
Defects in DNA single-strand break repair (SSBR) are linked with neurological dysfunction but the underlying mechanisms remain poorly understood. Here, we show that hyperactivity of the DNA strand break sensor protein Parp1 in mice in which the central SSBR protein Xrcc1 is conditionally deleted (Xrcc1Nes-Cre ) results in lethal seizures and shortened lifespan. Using electrophysiological recording and synaptic imaging approaches, we demonstrate that aberrant Parp1 activation triggers seizure-like activity in Xrcc1-defective hippocampus ex vivo and deregulated presynaptic calcium signalling in isolated hippocampal neurons in vitro. Moreover, we show that these defects are prevented by Parp1 inhibition or deletion and, in the case of Parp1 deletion, that the lifespan of Xrcc1Nes-Cre mice is greatly extended. This is the first demonstration that lethal seizures can be triggered by aberrant Parp1 activity at unrepaired SSBs, highlighting PARP inhibition as a possible therapeutic approach in hereditary neurological disease.
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Affiliation(s)
- Emilia Komulainen
- Genome Damage and Stability CentreSchool of Life SciencesUniversity of SussexBrightonUK
| | - Jack Badman
- Genome Damage and Stability CentreSchool of Life SciencesUniversity of SussexBrightonUK
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
| | - Stephanie Rey
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
| | - Stuart Rulten
- Genome Damage and Stability CentreSchool of Life SciencesUniversity of SussexBrightonUK
| | - Limei Ju
- Genome Damage and Stability CentreSchool of Life SciencesUniversity of SussexBrightonUK
| | - Kate Fennell
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
| | - Ilona Kalasova
- Department of Genome DynamicsInstitute of Molecular Genetics of the Czech Academy of SciencesPragueCzech Republic
| | - Kristyna Ilievova
- Department of Genome DynamicsInstitute of Molecular Genetics of the Czech Academy of SciencesPragueCzech Republic
| | - Peter J McKinnon
- Department of GeneticsSt Jude Children’s Research HospitalMemphisTNUSA
| | - Hana Hanzlikova
- Genome Damage and Stability CentreSchool of Life SciencesUniversity of SussexBrightonUK
- Department of Genome DynamicsInstitute of Molecular Genetics of the Czech Academy of SciencesPragueCzech Republic
| | - Kevin Staras
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
| | - Keith W Caldecott
- Genome Damage and Stability CentreSchool of Life SciencesUniversity of SussexBrightonUK
- Department of Genome DynamicsInstitute of Molecular Genetics of the Czech Academy of SciencesPragueCzech Republic
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14
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Szatko KP, Korympidou MM, Ran Y, Berens P, Dalkara D, Schubert T, Euler T, Franke K. Neural circuits in the mouse retina support color vision in the upper visual field. Nat Commun 2020; 11:3481. [PMID: 32661226 PMCID: PMC7359335 DOI: 10.1038/s41467-020-17113-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 04/21/2020] [Indexed: 02/06/2023] Open
Abstract
Color vision is essential for an animal’s survival. It starts in the retina, where signals from different photoreceptor types are locally compared by neural circuits. Mice, like most mammals, are dichromatic with two cone types. They can discriminate colors only in their upper visual field. In the corresponding ventral retina, however, most cones display the same spectral preference, thereby presumably impairing spectral comparisons. In this study, we systematically investigated the retinal circuits underlying mouse color vision by recording light responses from cones, bipolar and ganglion cells. Surprisingly, most color-opponent cells are located in the ventral retina, with rod photoreceptors likely being involved. Here, the complexity of chromatic processing increases from cones towards the retinal output, where non-linear center-surround interactions create specific color-opponent output channels to the brain. This suggests that neural circuits in the mouse retina are tuned to extract color from the upper visual field, aiding robust detection of predators and ensuring the animal’s survival. Mice are able to discriminate colors, at least in the upper visual field. Here, the authors provide a comprehensive characterization of retinal circuits underlying this behavior.
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Affiliation(s)
- Klaudia P Szatko
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Graduate Training Center of Neuroscience, International Max Planck Research School, University of Tübingen, Tübingen, Germany
| | - Maria M Korympidou
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Graduate Training Center of Neuroscience, International Max Planck Research School, University of Tübingen, Tübingen, Germany.,Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Yanli Ran
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Philipp Berens
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Bioinformatics and Medical Informatics, University of Tübingen, Tübingen, Germany
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Timm Schubert
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Katrin Franke
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany. .,Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany. .,Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.
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15
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Ryan TM, Hinojosa AJ, Vroman R, Papasavvas C, Lagnado L. Correction of z-motion artefacts to allow population imaging of synaptic activity in behaving mice. J Physiol 2020; 598:1809-1827. [PMID: 32020615 PMCID: PMC7318612 DOI: 10.1113/jp278957] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/24/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Motion artefacts associated with motor behaviour are an inevitable problem of multiphoton imaging in awake behaving animals, particularly when imaging synapses. Correction of axial motion artefacts usually requires volumetric imaging resulting in slower rates of acquisition. We describe a method to correct z-motion artefacts that is easy to implement and allows population imaging of synaptic activity while scanning a single plane in a standard multiphoton microscope. The method uses a reference volume acquired in two colour channels - an activity reporter and an anatomical marker of blood vessels. The procedure estimates the z-displacement in every frame and applies an intensity correction in which the z intensity profile for each synapse is modelled as a Moffat function. We demonstrate that the method allows synaptic calcium signals to be collected from populations of synaptic boutons in mouse primary visual cortex during locomotion. ABSTRACT Functional imaging of head-fixed, behaving mice using two-photon imaging of fluorescent activity reporters has become a powerful tool for studying the function of the brain. Motion artefacts are an inevitable problem during such experiments and are routinely corrected for in x and y dimensions. However, axial (z) shifts of several microns can also occur, leading to intensity fluctuations in structures such as synapses that are small compared to the axial point-spread function of the microscope. Here we present a simple strategy to correct z-motion artefacts arising over the course of a time-series experiment in a single optical plane. Displacement in z was calculated using dye-filled blood vessels as an anatomical marker, providing high contrast images and accuracy to within ∼0.1 µm. The axial profiles of ROIs corresponding to synapses were described using a Moffat function and this 'ROI-spread function' used to correct activity traces on an ROI-by-ROI basis. We demonstrate the accuracy and utility of the procedures in simulation experiments using fluorescent beads and then apply them to correcting measurements of synaptic activity in populations of vasoactive-intestinal peptide (VIP) interneurons expressing the synaptic reporter SyGCaMP6f. Correction of z-motion artefacts had a substantial impact on the apparent correlation between synaptic activity and running speed, demonstrating the importance of correcting these when performing imaging experiments in awake mice.
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Affiliation(s)
- Thomas Michael Ryan
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonBN1 9QGUK
| | | | - Rozan Vroman
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonBN1 9QGUK
| | | | - Leon Lagnado
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonBN1 9QGUK
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16
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Ran Y, Huang Z, Baden T, Schubert T, Baayen H, Berens P, Franke K, Euler T. Type-specific dendritic integration in mouse retinal ganglion cells. Nat Commun 2020; 11:2101. [PMID: 32355170 PMCID: PMC7193577 DOI: 10.1038/s41467-020-15867-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 03/30/2020] [Indexed: 11/17/2022] Open
Abstract
Neural computation relies on the integration of synaptic inputs across a neuron’s dendritic arbour. However, it is far from understood how different cell types tune this process to establish cell-type specific computations. Here, using two-photon imaging of dendritic Ca2+ signals, electrical recordings of somatic voltage and biophysical modelling, we demonstrate that four morphologically distinct types of mouse retinal ganglion cells with overlapping excitatory synaptic input (transient Off alpha, transient Off mini, sustained Off, and F-mini Off) exhibit type-specific dendritic integration profiles: in contrast to the other types, dendrites of transient Off alpha cells were spatially independent, with little receptive field overlap. The temporal correlation of dendritic signals varied also extensively, with the highest and lowest correlation in transient Off mini and transient Off alpha cells, respectively. We show that differences between cell types can likely be explained by differences in backpropagation efficiency, arising from the specific combinations of dendritic morphology and ion channel densities. Neurons compute by integrating synaptic inputs across their dendritic arbor. Here, the authors show that distinct cell-types of mouse retinal ganglion cells that receive similar excitatory inputs have different biophysical mechanisms of input integration to generate their unique response tuning.
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Affiliation(s)
- Yanli Ran
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Ziwei Huang
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Tom Baden
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, UK
| | - Timm Schubert
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Harald Baayen
- Department of Linguistics, University of Tübingen, Tübingen, Germany
| | - Philipp Berens
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute of Bioinformatics and Medical Informatics, University of Tübingen, Tübingen, Germany
| | - Katrin Franke
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany. .,Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany. .,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.
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17
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Yang N, Smyllie NJ, Morris H, Gonçalves CF, Dudek M, Pathiranage DRJ, Chesham JE, Adamson A, Spiller DG, Zindy E, Bagnall J, Humphreys N, Hoyland J, Loudon ASI, Hastings MH, Meng QJ. Quantitative live imaging of Venus::BMAL1 in a mouse model reveals complex dynamics of the master circadian clock regulator. PLoS Genet 2020; 16:e1008729. [PMID: 32352975 PMCID: PMC7217492 DOI: 10.1371/journal.pgen.1008729] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 05/12/2020] [Accepted: 03/20/2020] [Indexed: 12/11/2022] Open
Abstract
Evolutionarily conserved circadian clocks generate 24-hour rhythms in physiology and behaviour that adapt organisms to their daily and seasonal environments. In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus is the principal co-ordinator of the cell-autonomous clocks distributed across all major tissues. The importance of robust daily rhythms is highlighted by experimental and epidemiological associations between circadian disruption and human diseases. BMAL1 (a bHLH-PAS domain-containing transcription factor) is the master positive regulator within the transcriptional-translational feedback loops (TTFLs) that cell-autonomously define circadian time. It drives transcription of the negative regulators Period and Cryptochrome alongside numerous clock output genes, and thereby powers circadian time-keeping. Because deletion of Bmal1 alone is sufficient to eliminate circadian rhythms in cells and the whole animal it has been widely used as a model for molecular disruption of circadian rhythms, revealing essential, tissue-specific roles of BMAL1 in, for example, the brain, liver and the musculoskeletal system. Moreover, BMAL1 has clock-independent functions that influence ageing and protein translation. Despite the essential role of BMAL1 in circadian time-keeping, direct measures of its intra-cellular behaviour are still lacking. To fill this knowledge-gap, we used CRISPR Cas9 to generate a mouse expressing a knock-in fluorescent fusion of endogenous BMAL1 protein (Venus::BMAL1) for quantitative live imaging in physiological settings. The Bmal1Venus mouse model enabled us to visualise and quantify the daily behaviour of this core clock factor in central (SCN) and peripheral clocks, with single-cell resolution that revealed its circadian expression, anti-phasic to negative regulators, nuclear-cytoplasmic mobility and molecular abundance.
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Affiliation(s)
- Nan Yang
- Wellcome Centre for Cell Matrix Research, University of Manchester, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Nicola J. Smyllie
- Division of Neurobiology, Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Honor Morris
- Wellcome Centre for Cell Matrix Research, University of Manchester, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Cátia F. Gonçalves
- Wellcome Centre for Cell Matrix Research, University of Manchester, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Michal Dudek
- Wellcome Centre for Cell Matrix Research, University of Manchester, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Dharshika R. J. Pathiranage
- Wellcome Centre for Cell Matrix Research, University of Manchester, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Johanna E. Chesham
- Division of Neurobiology, Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Antony Adamson
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - David G. Spiller
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Egor Zindy
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - James Bagnall
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Neil Humphreys
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Judith Hoyland
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- NIHR Manchester Musculoskeletal Biomedical Research Centre, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Andrew S. I. Loudon
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Michael H. Hastings
- Division of Neurobiology, Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Qing-Jun Meng
- Wellcome Centre for Cell Matrix Research, University of Manchester, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
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18
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Zhao Z, Klindt DA, Maia Chagas A, Szatko KP, Rogerson L, Protti DA, Behrens C, Dalkara D, Schubert T, Bethge M, Franke K, Berens P, Ecker AS, Euler T. The temporal structure of the inner retina at a single glance. Sci Rep 2020; 10:4399. [PMID: 32157103 PMCID: PMC7064538 DOI: 10.1038/s41598-020-60214-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 02/09/2020] [Indexed: 12/12/2022] Open
Abstract
The retina decomposes visual stimuli into parallel channels that encode different features of the visual environment. Central to this computation is the synaptic processing in a dense layer of neuropil, the so-called inner plexiform layer (IPL). Here, different types of bipolar cells stratifying at distinct depths relay the excitatory feedforward drive from photoreceptors to amacrine and ganglion cells. Current experimental techniques for studying processing in the IPL do not allow imaging the entire IPL simultaneously in the intact tissue. Here, we extend a two-photon microscope with an electrically tunable lens allowing us to obtain optical vertical slices of the IPL, which provide a complete picture of the response diversity of bipolar cells at a "single glance". The nature of these axial recordings additionally allowed us to isolate and investigate batch effects, i.e. inter-experimental variations resulting in systematic differences in response speed. As a proof of principle, we developed a simple model that disentangles biological from experimental causes of variability and allowed us to recover the characteristic gradient of response speeds across the IPL with higher precision than before. Our new framework will make it possible to study the computations performed in the central synaptic layer of the retina more efficiently.
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Affiliation(s)
- Zhijian Zhao
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
| | - David A Klindt
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany
- Institute for Theoretical Physics, University of Tübingen, Tübingen, Germany
| | - André Maia Chagas
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany
| | - Klaudia P Szatko
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany
| | - Luke Rogerson
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany
| | - Dario A Protti
- Department of Physiology and Bosch Institute, The University of Sydney, Sydney, Australia
| | - Christian Behrens
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Timm Schubert
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
| | - Matthias Bethge
- Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany
- Institute for Theoretical Physics, University of Tübingen, Tübingen, Germany
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
| | - Katrin Franke
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany
| | - Philipp Berens
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany
- Institute of Bioinformatics and Medical Informatics, University of Tübingen, Tübingen, Germany
| | - Alexander S Ecker
- Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany
- Institute for Theoretical Physics, University of Tübingen, Tübingen, Germany
- Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
- Department of Computer Science, University of Göttingen, Göttingen, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
- Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.
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19
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Abstract
The zebrafish (Danio rerio) has emerged as a widely used model system during the last four decades. The fact that the zebrafish larva is transparent enables sophisticated in vivo imaging, including calcium imaging of intracellular transients in many different tissues. While being a vertebrate, the reduced complexity of its nervous system and small size make it possible to follow large-scale activity in the whole brain. Its genome is sequenced and many genetic and molecular tools have been developed that simplify the study of gene function in health and disease. Since the mid 90's, the development and neuronal function of the embryonic, larval, and later, adult zebrafish have been studied using calcium imaging methods. This updated chapter is reviewing the advances in methods and research findings of zebrafish calcium imaging during the last decade. The choice of calcium indicator depends on the desired number of cells to study and cell accessibility. Synthetic calcium indicators, conjugated to dextrans and acetoxymethyl (AM) esters, are still used to label specific neuronal cell types in the hindbrain and the olfactory system. However, genetically encoded calcium indicators, such as aequorin and the GCaMP family of indicators, expressed in various tissues by the use of cell-specific promoters, are now the choice for most applications, including brain-wide imaging. Calcium imaging in the zebrafish has contributed greatly to our understanding of basic biological principles during development and adulthood, and the function of disease-related genes in a vertebrate system.
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20
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Pichler P, Lagnado L. Motor Behavior Selectively Inhibits Hair Cells Activated by Forward Motion in the Lateral Line of Zebrafish. Curr Biol 2019; 30:150-157.e3. [PMID: 31866371 PMCID: PMC6947483 DOI: 10.1016/j.cub.2019.11.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/31/2019] [Accepted: 11/05/2019] [Indexed: 12/29/2022]
Abstract
How do sensory systems disambiguate events in the external world from signals generated by the animal's own motor actions? One strategy is to use an "efference copy" of the motor command to inhibit the sensory input caused by active behavior [1]. But does inhibition of self-generated inputs also block transmission of external stimuli? We investigated this question in the lateral line, a sensory system that allows fish and amphibians to detect water currents and that contributes to behaviors such as rheotaxis [2] and predator avoidance [3, 4]. This mechanical sense begins in hair cells grouped into neuromasts dotted along the animal's body [5]. Each neuromast contains two populations of hair cells, activated by deflection in either the anterior or posterior direction [6], as well as efferent fibers that are active during motor behavior to suppress afferents projecting to the brain [7-12]. To test how far the efference copy signal modulates responses to external stimuli, we imaged neural and synaptic activity in larval zebrafish during fictive swimming. We find that efferents transmit a precise copy of the motor signal and a single spike in the motor nerve can be associated with ∼50% inhibition of glutamate release. The efference copy signal acted with high selectivity on hair cells polarized to be activated by posterior deflections, as would occur during forward motion. During swimming, therefore, "push-pull" encoding of stimulus direction by afferents of opposite polarity is disrupted while still allowing a subset of hair cells to detect stimuli originating in the external world.
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Affiliation(s)
- Paul Pichler
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK
| | - Leon Lagnado
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK.
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21
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Rogerson LE, Zhao Z, Franke K, Euler T, Berens P. Bayesian hypothesis testing and experimental design for two-photon imaging data. PLoS Comput Biol 2019; 15:e1007205. [PMID: 31374071 PMCID: PMC6693774 DOI: 10.1371/journal.pcbi.1007205] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 08/14/2019] [Accepted: 06/20/2019] [Indexed: 12/24/2022] Open
Abstract
Variability, stochastic or otherwise, is a central feature of neural activity. Yet the means by which estimates of variation and uncertainty are derived from noisy observations of neural activity is often heuristic, with more weight given to numerical convenience than statistical rigour. For two-photon imaging data, composed of fundamentally probabilistic streams of photon detections, the problem is particularly acute. Here, we present a statistical pipeline for the inference and analysis of neural activity using Gaussian Process regression, applied to two-photon recordings of light-driven activity in ex vivo mouse retina. We demonstrate the flexibility and extensibility of these models, considering cases with non-stationary statistics, driven by complex parametric stimuli, in signal discrimination, hierarchical clustering and other inference tasks. Sparse approximation methods allow these models to be fitted rapidly, permitting them to actively guide the design of light stimulation in the midst of ongoing two-photon experiments.
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Affiliation(s)
- Luke E. Rogerson
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany
- Graduate Training Center for Neuroscience, University of Tübingen, Tübingen, Germany
| | - Zhijian Zhao
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Katrin Franke
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany
| | - Philipp Berens
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany
- Institute for Bioinformatics and Medical Informatics, University of Tübingen, Tübingen, Germany
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22
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Sacher C, Blume T, Beyer L, Peters F, Eckenweber F, Sgobio C, Deussing M, Albert NL, Unterrainer M, Lindner S, Gildehaus FJ, von Ungern-Sternberg B, Brzak I, Neumann U, Saito T, Saido TC, Bartenstein P, Rominger A, Herms J, Brendel M. Longitudinal PET Monitoring of Amyloidosis and Microglial Activation in a Second-Generation Amyloid-β Mouse Model. J Nucl Med 2019; 60:1787-1793. [PMID: 31302633 DOI: 10.2967/jnumed.119.227322] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/15/2019] [Indexed: 11/16/2022] Open
Abstract
Nonphysiologic overexpression of amyloid-β (Aβ) precursor protein in common transgenic Aβ mouse models of Alzheimer disease likely hampers their translational potential. The novel App NL-G-F mouse incorporates a mutated knock-in, potentially presenting an improved model of Alzheimer disease for Aβ-targeting treatment trials. We aimed to establish serial small-animal PET of amyloidosis and neuroinflammation in App NL-G-F mice as a tool for therapy monitoring. Methods: App NL-G-F mice (20 homozygous and 21 heterogeneous) and 12 age-matched wild-type mice were investigated longitudinally from 2.5 to 10 mo of age with 18F-florbetaben Aβ PET and 18F-GE-180 18-kDa translocator protein (TSPO) PET. Voxelwise analysis of SUV ratio images was performed using statistical parametric mapping. All mice underwent a Morris water maze test of spatial learning after their final scan. Quantification of fibrillar Aβ and activated microglia by immunohistochemistry and biochemistry served for validation of the PET results. Results: The periaqueductal gray emerged as a suitable pseudo reference tissue for both tracers. Homozygous App NL-G-F mice had a rising SUV ratio in cortex and hippocampus for Aβ (+9.1%, +3.8%) and TSPO (+19.8%, +14.2%) PET from 2.5 to 10 mo of age (all P < 0.05), whereas heterozygous App NL-G-F mice did not show significant changes with age. Significant voxelwise clusters of Aβ deposition and microglial activation in homozygous mice appeared at 5 mo of age. Immunohistochemical and biochemical findings correlated strongly with the PET data. Water maze escape latency was significantly elevated in homozygous App NL-G-F mice compared with wild-type at 10 mo of age and was associated with high TSPO binding. Conclusion: Longitudinal PET in App NL-G-F knock-in mice enables monitoring of amyloidogenesis and neuroinflammation in homozygous mice but is insensitive to minor changes in heterozygous animals. The combination of PET with behavioral tasks in App NL-G-F treatment trials is poised to provide important insights in preclinical drug development.
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Affiliation(s)
- Christian Sacher
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany
| | - Tanja Blume
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany.,DZNE-German Center for Neurodegenerative Diseases, Munich, Germany
| | - Leonie Beyer
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany
| | - Finn Peters
- DZNE-German Center for Neurodegenerative Diseases, Munich, Germany
| | - Florian Eckenweber
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany
| | - Carmelo Sgobio
- DZNE-German Center for Neurodegenerative Diseases, Munich, Germany
| | - Maximilian Deussing
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany
| | - Nathalie L Albert
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany
| | - Marcus Unterrainer
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany
| | - Simon Lindner
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany
| | - Franz-Josef Gildehaus
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany
| | | | - Irena Brzak
- Neuroscience, Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
| | - Ulf Neumann
- Neuroscience, Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Saitama, Japan
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Saitama, Japan
| | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany
| | - Axel Rominger
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Department of Nuclear Medicine, Inselspital, University Hospital Bern, Bern, Switzerland; and
| | - Jochen Herms
- DZNE-German Center for Neurodegenerative Diseases, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Center of Neuropathology and Prion Research, University of Munich, Munich, Germany
| | - Matthias Brendel
- Department of Nuclear Medicine, University Hospital of Munich, LMU Munich, Munich Germany .,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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23
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Rampérez A, Bartolomé-Martín D, García-Pascual A, Sánchez-Prieto J, Torres M. Photoconversion of FM1-43 Reveals Differences in Synaptic Vesicle Recycling and Sensitivity to Pharmacological Disruption of Actin Dynamics in Individual Synapses. ACS Chem Neurosci 2019; 10:2045-2059. [PMID: 30763065 DOI: 10.1021/acschemneuro.8b00712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The cycling of synaptic vesicles ensures that neurons can communicate adequately through their synapses on repeated occasions when activity is sustained, and several steps in this cycle are modulated by actin. The effects of pharmacological stabilization of actin with jasplakinolide or its depolymerization with latrunculin A was assessed on the synaptic vesicle cycle at individual boutons of cerebellar granule cells, using FM1-43 imaging to track vesicle recycling and its photoconversion to specifically label recycled organelles. Remarkable differences in the recycling capacity of individual boutons are evident, and their dependence on the actin cytoskeleton for recycling is clear. Disrupting actin dynamics causes a loss of functional boutons, and while this indicates that exo/endocytotic cycling in boutons is fully dependent on such events, this dependence is only partial in other boutons. Indeed, exocytosis and vesicle trafficking are impaired significantly by stabilizing or depolymerizing actin, whereas repositioning recycled vesicles at the active zone seems to be dependent on actin polymerization alone. These findings support the hypothesis that different steps of synaptic vesicle cycling depend on actin dynamics and that such dependence varies among individual boutons.
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Affiliation(s)
- Alberto Rampérez
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid 28040, Spain
| | - David Bartolomé-Martín
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid 28040, Spain
| | - Angeles García-Pascual
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid 28040, Spain
| | - Jose Sánchez-Prieto
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid 28040, Spain
| | - Magdalena Torres
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid 28040, Spain
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24
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Román Rosón M, Bauer Y, Kotkat AH, Berens P, Euler T, Busse L. Mouse dLGN Receives Functional Input from a Diverse Population of Retinal Ganglion Cells with Limited Convergence. Neuron 2019; 102:462-476.e8. [PMID: 30799020 DOI: 10.1016/j.neuron.2019.01.040] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 11/08/2018] [Accepted: 01/17/2019] [Indexed: 10/27/2022]
Abstract
Mouse vision is based on the parallel output of more than 30 functional types of retinal ganglion cells (RGCs). Little is known about how representations of visual information change between retina and dorsolateral geniculate nucleus (dLGN) of the thalamus, the main relay between retina and cortex. Here, we functionally characterized responses of retrogradely labeled dLGN-projecting RGCs and dLGN neurons to the same set of visual stimuli. We found that many of the previously identified functional RGC types innervate dLGN, which maintained a high degree of functional diversity. Using a linear model to assess functional connectivity between RGC types and dLGN neurons, we found that responses of dLGN neurons could be predicted as linear combination of inputs from on average five RGC types, but only two of those had the strongest functional impact. Thus, mouse dLGN receives functional input from a diverse population of RGC types with limited convergence.
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Affiliation(s)
- Miroslav Román Rosón
- Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Institute for Ophthalmic Research, University Hospital Tübingen, 72076 Tübingen, Germany; Division of Neurobiology, Department Biology II, LMU Munich, 82151 Munich, Germany; Graduate School of Neural & Behavioural Sciences, International Max Planck Research School, University of Tübingen, 72074 Tübingen, Germany
| | - Yannik Bauer
- Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Division of Neurobiology, Department Biology II, LMU Munich, 82151 Munich, Germany; Graduate School of Systemic Neuroscience (GSN), LMU Munich, 82151 Munich, Germany
| | - Ann H Kotkat
- Division of Neurobiology, Department Biology II, LMU Munich, 82151 Munich, Germany; ENB Elite Master of Science Program in Neuroengineering, Technical University of Munich, 80333 Munich, Germany
| | - Philipp Berens
- Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Institute for Ophthalmic Research, University Hospital Tübingen, 72076 Tübingen, Germany; Bernstein Centre for Computational Neuroscience, 72076 Tübingen, Germany.
| | - Thomas Euler
- Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Institute for Ophthalmic Research, University Hospital Tübingen, 72076 Tübingen, Germany; Bernstein Centre for Computational Neuroscience, 72076 Tübingen, Germany.
| | - Laura Busse
- Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Division of Neurobiology, Department Biology II, LMU Munich, 82151 Munich, Germany; Bernstein Centre for Computational Neuroscience, 72076 Tübingen, Germany; Bernstein Centre for Computational Neuroscience, 82151 Munich, Germany.
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25
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Vasoactive intestinal peptide controls the suprachiasmatic circadian clock network via ERK1/2 and DUSP4 signalling. Nat Commun 2019; 10:542. [PMID: 30710088 PMCID: PMC6358603 DOI: 10.1038/s41467-019-08427-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 12/21/2018] [Indexed: 01/02/2023] Open
Abstract
The suprachiasmatic nucleus (SCN) co-ordinates circadian behaviour and physiology in mammals. Its cell-autonomous circadian oscillations pivot around a well characterised transcriptional/translational feedback loop (TTFL), whilst the SCN circuit as a whole is synchronised to solar time by its retinorecipient cells that express and release vasoactive intestinal peptide (VIP). The cell-autonomous and circuit-level mechanisms whereby VIP synchronises the SCN are poorly understood. We show that SCN slices in organotypic culture demonstrate rapid and sustained circuit-level circadian responses to VIP that are mediated at a cell-autonomous level. This is accompanied by changes across a broad transcriptional network and by significant VIP-directed plasticity in the internal phasing of the cell-autonomous TTFL. Signalling via ERK1/2 and tuning by its negative regulator DUSP4 are critical elements of the VIP-directed circadian re-programming. In summary, we provide detailed mechanistic insight into VIP signal transduction in the SCN at the level of genes, cells and neural circuit. The suprachiasmatic nucleus (SCN) synchronises daily rhythms of behaviour and physiology to the light-dark cycle. Vasoactive intestinal peptide (VIP) is important for mediating SCN entrainment; however, the underlying mechanisms are incompletely understood. Here, the authors show that the effects of VIP on the SCN are mediated by ERK1/2 and DUSP4.
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26
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Veruki ML, Zhou Y, Castilho Á, Morgans CW, Hartveit E. Extrasynaptic NMDA Receptors on Rod Pathway Amacrine Cells: Molecular Composition, Activation, and Signaling. J Neurosci 2019; 39:627-650. [PMID: 30459218 PMCID: PMC6343648 DOI: 10.1523/jneurosci.2267-18.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/29/2018] [Accepted: 11/14/2018] [Indexed: 12/15/2022] Open
Abstract
In the rod pathway of the mammalian retina, axon terminals of glutamatergic rod bipolar cells are presynaptic to AII and A17 amacrine cells in the inner plexiform layer. Recent evidence suggests that both amacrines express NMDA receptors, raising questions concerning molecular composition, localization, activation, and function of these receptors. Using dual patch-clamp recording from synaptically connected rod bipolar and AII or A17 amacrine cells in retinal slices from female rats, we found no evidence that NMDA receptors contribute to postsynaptic currents evoked in either amacrine. Instead, NMDA receptors on both amacrine cells were activated by ambient glutamate, and blocking glutamate uptake increased their level of activation. NMDA receptor activation also increased the frequency of GABAergic postsynaptic currents in rod bipolar cells, suggesting that NMDA receptors can drive release of GABA from A17 amacrines. A striking dichotomy was revealed by pharmacological and immunolabeling experiments, which found GluN2B-containing NMDA receptors on AII amacrines and GluN2A-containing NMDA receptors on A17 amacrines. Immunolabeling also revealed a clustered organization of NMDA receptors on both amacrines and a close spatial association between GluN2B subunits and connexin 36 on AII amacrines, suggesting that NMDA receptor modulation of gap junction coupling between these cells involves the GluN2B subunit. Using multiphoton Ca2+ imaging, we verified that activation of NMDA receptors evoked an increase of intracellular Ca2+ in dendrites of both amacrines. Our results suggest that AII and A17 amacrines express clustered, extrasynaptic NMDA receptors, with different and complementary subunits that are likely to contribute differentially to signal processing and plasticity.SIGNIFICANCE STATEMENT Glutamate is the most important excitatory neurotransmitter in the CNS, but not all glutamate receptors transmit fast excitatory signals at synapses. NMDA-type glutamate receptors act as voltage- and ligand-gated ion channels, with functional properties determined by their specific subunit composition. These receptors can be found at both synaptic and extrasynaptic sites on neurons, but the role of extrasynaptic NMDA receptors is unclear. Here, we demonstrate that retinal AII and A17 amacrine cells, postsynaptic partners at rod bipolar dyad synapses, express extrasynaptic (but not synaptic) NMDA receptors, with different and complementary GluN2 subunits. The localization of GluN2A-containing receptors to A17s and GluN2B-containing receptors to AIIs suggests a mechanism for differential modulation of excitability and signaling in this retinal microcircuit.
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Affiliation(s)
- Margaret L Veruki
- University of Bergen, Department of Biomedicine, N-5009 Bergen, Norway, and
| | - Yifan Zhou
- University of Bergen, Department of Biomedicine, N-5009 Bergen, Norway, and
| | - Áurea Castilho
- University of Bergen, Department of Biomedicine, N-5009 Bergen, Norway, and
| | - Catherine W Morgans
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon 97239
| | - Espen Hartveit
- University of Bergen, Department of Biomedicine, N-5009 Bergen, Norway, and
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27
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The Transfer Characteristics of Hair Cells Encoding Mechanical Stimuli in the Lateral Line of Zebrafish. J Neurosci 2018; 39:112-124. [PMID: 30413644 PMCID: PMC6325263 DOI: 10.1523/jneurosci.1472-18.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 10/09/2018] [Accepted: 10/12/2018] [Indexed: 12/01/2022] Open
Abstract
Hair cells transmit mechanical information by converting deflection of the hair bundle into synaptic release of glutamate. We have investigated this process in the lateral line of larval zebrafish (male and female) to understand how stimuli are encoded within a neuromast. Using multiphoton microscopy in vivo, we imaged synaptic release of glutamate using the reporter iGluSnFR as well as deflections of the cupula. We found that the neuromast is composed of a functionally diverse population of hair cells. Half the hair cells signaled cupula motion in both directions from rest, either by increasing glutamate release in response to a deflection in the positive direction or by reducing release in the negative direction. The relationship between cupula deflection and glutamate release demonstrated maximum sensitivity at displacements of just ∼40 nm in the positive direction. The remaining hair cells only signaled motion in one direction and were less sensitive, extending the operating range of the neuromast beyond 1 μm. Adaptation of the synaptic output was also heterogeneous, with some hair cells generating sustained glutamate release in response to a steady deflection of the cupula and others generating transient outputs. Finally, a distinct signal encoded a return of the cupula to rest: a large and transient burst of glutamate release from hair cells unresponsive to the initial stimulus. A population of hair cells with these different sensitivities, operating ranges, and adaptive properties will allow the neuromast to encode weak stimuli while maintaining the dynamic range to signal the amplitude and duration of stronger deflections. SIGNIFICANCE STATEMENT Hair cells transmit information about mechanical stimuli by converting very small deflections of their hair bundle into changes in the release of the neurotransmitter glutamate. We have measured this input/output relation in the live fish using a fluorescent protein and find that different hair cells vary in their mechanical sensitivity and the time course of their response. These variations will allow the fish to sense the timing and duration of both very weak stimuli (∼40 nm deflections) and strong stimuli (∼1 μm), underlying the ability of the fish to avoid predators and maintain its body position in flowing water.
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28
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Focke C, Blume T, Zott B, Shi Y, Deussing M, Peters F, Schmidt C, Kleinberger G, Lindner S, Gildehaus FJ, Beyer L, von Ungern-Sternberg B, Bartenstein P, Ozmen L, Baumann K, Dorostkar MM, Haass C, Adelsberger H, Herms J, Rominger A, Brendel M. Early and Longitudinal Microglial Activation but Not Amyloid Accumulation Predicts Cognitive Outcome in PS2APP Mice. J Nucl Med 2018; 60:548-554. [DOI: 10.2967/jnumed.118.217703] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 09/10/2018] [Indexed: 02/06/2023] Open
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29
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Al-Osta I, Mucha M, Pereda D, Piqué-Gili M, Okorocha AE, Thomas R, Hartell NA. Imaging Calcium in Hippocampal Presynaptic Terminals With a Ratiometric Calcium Sensor in a Novel Transgenic Mouse. Front Cell Neurosci 2018; 12:209. [PMID: 30072872 PMCID: PMC6060260 DOI: 10.3389/fncel.2018.00209] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Accepted: 06/26/2018] [Indexed: 11/13/2022] Open
Abstract
Genetically encoded calcium indicators (GECIs) have gained widespread use for measurement of neuronal activity but their low expression levels in transgenic mice tend to limit sensitivity. We have developed a transgenic mouse line (SyG37) that expresses a ratiometric calcium sensor, SyGCaMP2-mCherry, that is expressed throughout the brain but targeted to presynaptic terminals. Within the CA1 and CA3 regions of hippocampus of male and female mice, SyGaMP2 fluorescence responds linearly up to 10 electrical stimuli at frequencies up to 100 Hz and it can detect responses to a single stimulus. Responses in single boutons can be measured using multiphoton microscopy. The ensemble amplitude of SyGCaMP2 responses is a function of the number of stimuli applied and the number of contributing boutons. The peak responses and initial rates of calcium influx in single boutons in CA1 and CA3 were similar but the rate of calcium clearance from CA3 boutons after stimulation was significantly faster. In CA1, DNQX reduced SyGCaMP2 responses to Schaffer collateral stimulation to 86% of baseline indicating that 14% of the total response originated from presynaptic terminals of neurones synaptically driven via AMPA receptors. Theta burst stimulation induced long-term potentiation (LTP) of both SyGCaMP2 and fEPSP responses in both young and 18-month-old mice. The proportion of postsynaptically connected terminals increased significantly to 76% of the total after LTP induction. The SyG37 mouse allows stable optical detection of synaptic activation and connectivity at the single bouton level and can be used to characterize the contributions of presynaptic calcium to synaptic transmission and plasticity.
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Affiliation(s)
- Ibrahim Al-Osta
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Mariusz Mucha
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Daniel Pereda
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Marta Piqué-Gili
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Albert E Okorocha
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Roisin Thomas
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Nicholas A Hartell
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
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Zebrafish Differentially Process Color across Visual Space to Match Natural Scenes. Curr Biol 2018; 28:2018-2032.e5. [DOI: 10.1016/j.cub.2018.04.075] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/18/2018] [Accepted: 04/24/2018] [Indexed: 01/09/2023]
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Imaging Neuronal Activity in the Optic Tectum of Late Stage Larval Zebrafish. J Dev Biol 2018; 6:jdb6010006. [PMID: 29615555 PMCID: PMC5875565 DOI: 10.3390/jdb6010006] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/01/2018] [Accepted: 03/06/2018] [Indexed: 12/03/2022] Open
Abstract
The zebrafish is an established model to study the development and function of visual neuronal circuits in vivo, largely due to their optical accessibility at embryonic and larval stages. In the past decade multiple experimental paradigms have been developed to study visually-driven behaviours, particularly those regulated by the optic tectum, the main visual centre in lower vertebrates. With few exceptions these techniques are limited to young larvae (7–9 days post-fertilisation, dpf). However, many forms of visually-driven behaviour, such as shoaling, emerge at later developmental stages. Consequently, there is a need for an experimental paradigm to image the visual system in zebrafish larvae beyond 9 dpf. Here, we show that using NBT:GCaMP3 line allows for imaging neuronal activity in the optic tectum in late stage larvae until at least 21 dpf. Utilising this line, we have characterised the receptive field properties of tectal neurons of the 2–3 weeks old fish in the cell bodies and the neuropil. The NBT:GCaMP3 line provides a complementary approach and additional opportunities to study neuronal activity in late stage zebrafish larvae.
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Hoshi H, Sato F. The morphological characterization of orientation-biased displaced large-field ganglion cells in the central part of goldfish retina. J Comp Neurol 2018; 526:243-261. [PMID: 28921532 DOI: 10.1002/cne.24331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/01/2017] [Accepted: 09/04/2017] [Indexed: 11/10/2022]
Abstract
The vertebrate retina has about 30 subtypes of ganglion cells. Each ganglion cell receives synaptic inputs from specific types of bipolar and amacrine cells ramifying at the same depth of the inner plexiform layer (IPL), each of which is thought to process a specific aspect of visual information. Here, we identified one type of displaced ganglion cell in the goldfish retina which had a large and elongated dendritic field. As a population, all of these ganglion cells were oriented in the horizontal axis and perpendicular to the dorsal-ventral axis of the goldfish eye in the central part of retina. This ganglion cell has previously been classified as Type 1.2. However, the circuit elements which synapse with this ganglion cell are not yet characterized. We found that this displaced ganglion cell was directly tracer-coupled only with homologous ganglion cells at sites containing Cx35/36 puncta. We further illustrated that the processes of dopaminergic neurons often terminated next to intersections between processes of ganglion cells, close to where dopamine D1 receptors were localized. Finally, we showed that Mb1 ON bipolar cells had ribbon synapses in the axonal processes passing through the IPL and made ectopic synapses with this displaced ganglion cell that stratified into stratum 1 of the IPL. These results suggest that the displaced ganglion cell may synapse with both Mb1 cells using ectopic ribbon synapses and OFF cone bipolar cells with regular ribbon synapses in the IPL to function in both scotopic and photopic light conditions.
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Affiliation(s)
- Hideo Hoshi
- Department of Anatomy, School of Medicine, Toho University, Tokyo, Japan
| | - Fumi Sato
- Department of Anatomy, School of Medicine, Toho University, Tokyo, Japan
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Chapot CA, Behrens C, Rogerson LE, Baden T, Pop S, Berens P, Euler T, Schubert T. Local Signals in Mouse Horizontal Cell Dendrites. Curr Biol 2017; 27:3603-3615.e5. [PMID: 29174891 DOI: 10.1016/j.cub.2017.10.050] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 09/01/2017] [Accepted: 10/19/2017] [Indexed: 01/07/2023]
Abstract
The mouse retina contains a single type of horizontal cell, a GABAergic interneuron that samples from all cone photoreceptors within reach and modulates their glutamatergic output via parallel feedback mechanisms. Because horizontal cells form an electrically coupled network, they have been implicated in global signal processing, such as large-scale contrast enhancement. Recently, it has been proposed that horizontal cells can also act locally at the level of individual cone photoreceptors. To test this possibility physiologically, we used two-photon microscopy to record light stimulus-evoked Ca2+ signals in cone axon terminals and horizontal cell dendrites as well as glutamate release in the outer plexiform layer. By selectively stimulating the two mouse cone opsins with green and UV light, we assessed whether signals from individual cones remain isolated within horizontal cell dendritic tips or whether they spread across the dendritic arbor. Consistent with the mouse's opsin expression gradient, we found that the Ca2+ signals recorded from dendrites of dorsal horizontal cells were dominated by M-opsin and those of ventral horizontal cells by S-opsin activation. The signals measured in neighboring horizontal cell dendritic tips varied markedly in their chromatic preference, arguing against global processing. Rather, our experimental data and results from biophysically realistic modeling support the idea that horizontal cells can process cone input locally, extending the classical view of horizontal cell function. Pharmacologically removing horizontal cells from the circuitry reduced the sensitivity of the cone signal to low frequencies, suggesting that local horizontal cell feedback shapes the temporal properties of cone output.
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Affiliation(s)
- Camille A Chapot
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; Center for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Graduate Training Centre of Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Christian Behrens
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; Center for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Graduate Training Centre of Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Bernstein Center for Computational Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Luke E Rogerson
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; Center for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Graduate Training Centre of Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Bernstein Center for Computational Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Tom Baden
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; School of Life Sciences, University of Sussex, Brighton BN1 9RH, UK
| | - Sinziana Pop
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; Center for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Graduate Training Centre of Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Philipp Berens
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; Center for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Bernstein Center for Computational Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; Center for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Bernstein Center for Computational Neuroscience, University of Tübingen, 72076 Tübingen, Germany.
| | - Timm Schubert
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; Center for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany.
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Combined Pharmacological and Genetic Manipulations Unlock Unprecedented Temporal Elasticity and Reveal Phase-Specific Modulation of the Molecular Circadian Clock of the Mouse Suprachiasmatic Nucleus. J Neurosci 2017; 36:9326-41. [PMID: 27605609 DOI: 10.1523/jneurosci.0958-16.2016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 07/15/2016] [Indexed: 01/10/2023] Open
Abstract
UNLABELLED The suprachiasmatic nucleus (SCN) is the master circadian oscillator encoding time-of-day information. SCN timekeeping is sustained by a cell-autonomous transcriptional-translational feedback loop, whereby expression of the Period and Cryptochrome genes is negatively regulated by their protein products. This loop in turn drives circadian oscillations in gene expression that direct SCN electrical activity and thence behavior. The robustness of SCN timekeeping is further enhanced by interneuronal, circuit-level coupling. The aim of this study was to combine pharmacological and genetic manipulations to push the SCN clockwork toward its limits and, by doing so, probe cell-autonomous and emergent, circuit-level properties. Circadian oscillation of mouse SCN organotypic slice cultures was monitored as PER2::LUC bioluminescence. SCN of three genetic backgrounds-wild-type, short-period CK1ε(Tau/Tau) mutant, and long-period Fbxl3(Afh/Afh) mutant-all responded reversibly to pharmacological manipulation with period-altering compounds: picrotoxin, PF-670462 (4-[1-Cyclohexyl-4-(4-fluorophenyl)-1H-imidazol-5-yl]-2-pyrimidinamine dihydrochloride), and KNK437 (N-Formyl-3,4-methylenedioxy-benzylidine-gamma-butyrolactam). This revealed a remarkably wide operating range of sustained periods extending across 25 h, from ≤17 h to >42 h. Moreover, this range was maintained at network and single-cell levels. Development of a new technique for formal analysis of circadian waveform, first derivative analysis (FDA), revealed internal phase patterning to the circadian oscillation at these extreme periods and differential phase sensitivity of the SCN to genetic and pharmacological manipulations. For example, FDA of the CK1ε(Tau/Tau) mutant SCN treated with the CK1ε-specific inhibitor PF-4800567 (3-[(3-Chlorophenoxy)methyl]-1-(tetrahydro-2H-pyran-4-yl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine hydrochloride) revealed that period acceleration in the mutant is due to inappropriately phased activity of the CK1ε isoform. In conclusion, extreme period manipulation reveals unprecedented elasticity and temporal structure of the SCN circadian oscillation. SIGNIFICANCE STATEMENT The master circadian clock of the suprachiasmatic nucleus (SCN) encodes time-of-day information that allows mammals to predict and thereby adapt to daily environmental cycles. Using combined genetic and pharmacological interventions, we assessed the temporal elasticity of the SCN network. Despite having evolved to generate a 24 h circadian period, we show that the molecular clock is surprisingly elastic, able to reversibly sustain coherent periods between ≤17 and >42 h at the levels of individual cells and the overall circuit. Using quantitative techniques to analyze these extreme periodicities, we reveal that the oscillator progresses as a sequence of distinct stages. These findings reveal new properties of how the SCN functions as a network and should inform biological and mathematical analyses of circadian timekeeping.
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Rampérez A, Sánchez-Prieto J, Torres M. Brefeldin A sensitive mechanisms contribute to endocytotic membrane retrieval and vesicle recycling in cerebellar granule cells. J Neurochem 2017; 141:662-675. [PMID: 28295320 DOI: 10.1111/jnc.14017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 02/22/2017] [Accepted: 03/01/2017] [Indexed: 11/26/2022]
Abstract
The recycling of synaptic vesicle (SV) proteins and transmitter release occur at multiple sites along the axon. These processes are sensitive to inhibition of the small GTP binding protein ARF1, which regulates the adaptor protein 1 and 3 complex (AP-1/AP-3). As the axon matures, SV recycling becomes restricted to the presynaptic bouton, and its machinery undergoes a complex process of maturation. We used the styryl dye FM1-43 to highlight differences in the efficiency of membrane recycling at different sites in cerebellar granule cells cultured for 7 days in vitro. We used Brefeldin A (BFA) to inhibit AP-1/AP-3-mediated recycling and to test the contribution of this pathway to the heterogeneity of the responses when these cells are strongly stimulated. Combining imaging techniques and ultrastructural analyses, we found a significant decrease in the density of functional boutons and an increase in the presence of endosome-like structures within the boutons of cells incubated with BFA prior to FM1-43 loading. Such effects were not observed when BFA was added 5 min after the end of the loading step, when endocytosis was almost fully completed. In this situation, vesicles were found closer to the active zone (AZ) in boutons exposed to BFA. Together, these data suggest that the AP-1/AP-3 pathway contributes to SV recycling, affecting different steps in all boutons but not equally, and thus being partly responsible for the heterogeneity of the different recycling efficiencies. Cover Image for this issue: doi. 10.1111/jnc.13801.
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Affiliation(s)
- Alberto Rampérez
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - José Sánchez-Prieto
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Magdalena Torres
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
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36
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Brancaccio M, Patton AP, Chesham JE, Maywood ES, Hastings MH. Astrocytes Control Circadian Timekeeping in the Suprachiasmatic Nucleus via Glutamatergic Signaling. Neuron 2017; 93:1420-1435.e5. [PMID: 28285822 PMCID: PMC5376383 DOI: 10.1016/j.neuron.2017.02.030] [Citation(s) in RCA: 296] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/25/2017] [Accepted: 02/16/2017] [Indexed: 12/02/2022]
Abstract
The suprachiasmatic nucleus (SCN) of the hypothalamus orchestrates daily rhythms of physiology and behavior in mammals. Its circadian (∼24 hr) oscillations of gene expression and electrical activity are generated intrinsically and can persist indefinitely in temporal isolation. This robust and resilient timekeeping is generally regarded as a product of the intrinsic connectivity of its neurons. Here we show that neurons constitute only one “half” of the SCN clock, the one metabolically active during circadian daytime. In contrast, SCN astrocytes are active during circadian nighttime, when they suppress the activity of SCN neurons by regulating extracellular glutamate levels. This glutamatergic gliotransmission is sensed by neurons of the dorsal SCN via specific pre-synaptic NMDA receptor assemblies containing NR2C subunits. Remarkably, somatic genetic re-programming of intracellular clocks in SCN astrocytes was capable of remodeling circadian behavioral rhythms in adult mice. Thus, SCN circuit-level timekeeping arises from interdependent and mutually supportive astrocytic-neuronal signaling. SCN neurons are active during circadian day, but SCN astrocytes are active at night Astrocytes direct circadian cycles of extracellular glutamate to inhibit SCN neurons Astrocyte-derived inhibition is mediated by NMDAR2C complexes on dorsal SCN neurons Genetic re-programming of the clock in SCN astrocytes reshapes circadian behavior
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Affiliation(s)
- Marco Brancaccio
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
| | - Andrew P Patton
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Johanna E Chesham
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Elizabeth S Maywood
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Michael H Hastings
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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37
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Franke K, Berens P, Schubert T, Bethge M, Euler T, Baden T. Inhibition decorrelates visual feature representations in the inner retina. Nature 2017; 542:439-444. [PMID: 28178238 PMCID: PMC5325673 DOI: 10.1038/nature21394] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 01/18/2017] [Indexed: 01/25/2023]
Abstract
The retina extracts visual features for transmission to the brain. Different types of bipolar cell split the photoreceptor input into parallel channels and provide the excitatory drive for downstream visual circuits. Anatomically and genetically, mouse bipolar cell types have been described at great detail, but a similarly deep understanding of their functional diversity is lacking. By imaging light-driven glutamate release from more than 13,000 bipolar cell axon terminals in the intact retina, we here show that bipolar cell functional diversity is generated by the interplay of dendritic excitatory inputs and axonal inhibitory inputs. The resultant centre and surround components of bipolar cell receptive fields interact to decorrelate bipolar cell output in the spatial and temporal domain. Our findings highlight the importance of inhibitory circuits in generating functionally diverse excitatory pathways and suggest that decorrelation of parallel visual pathways begins already at the second synapse of the mouse visual system.
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Affiliation(s)
- Katrin Franke
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Graduate School of Neural &Behavioural Sciences, International Max Planck Research School, University of Tübingen, Tübingen, Germany
| | - Philipp Berens
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Timm Schubert
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Matthias Bethge
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Theoretical Physics, University of Tübingen, Tübingen, Germany.,Max Planck Institute of Biological Cybernetics, Tübingen, Germany
| | - Thomas Euler
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Tom Baden
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,School of Life Sciences, University of Sussex, Brighton, UK
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38
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Rosa JM, Ruehle S, Ding H, Lagnado L. Crossover Inhibition Generates Sustained Visual Responses in the Inner Retina. Neuron 2016; 90:308-19. [PMID: 27068790 PMCID: PMC4848346 DOI: 10.1016/j.neuron.2016.03.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 01/21/2016] [Accepted: 03/02/2016] [Indexed: 12/23/2022]
Abstract
In daylight, the input to the retinal circuit is provided primarily by cone photoreceptors acting as band-pass filters, but the retinal output also contains neuronal populations transmitting sustained signals. Using in vivo imaging of genetically encoded calcium reporters, we investigated the circuits that generate these sustained channels within the inner retina of zebrafish. In OFF bipolar cells, sustained transmission was found to depend on crossover inhibition from the ON pathway through GABAergic amacrine cells. In ON bipolar cells, the amplitude of low-frequency signals was regulated by glycinergic amacrine cells, while GABAergic inhibition regulated the gain of band-pass signals. We also provide the first functional description of a subset of sustained ON bipolar cells in which synaptic activity was suppressed by fluctuations at frequencies above ∼0.2 Hz. These results map out the basic circuitry by which the inner retina generates sustained visual signals and describes a new function of crossover inhibition.
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Affiliation(s)
- Juliana M Rosa
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Sabine Ruehle
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Huayu Ding
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Leon Lagnado
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK; School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK.
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39
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Rosa JM, Bos R, Sack GS, Fortuny C, Agarwal A, Bergles DE, Flannery JG, Feller MB. Neuron-glia signaling in developing retina mediated by neurotransmitter spillover. eLife 2015; 4. [PMID: 26274565 PMCID: PMC4566075 DOI: 10.7554/elife.09590] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 08/13/2015] [Indexed: 12/21/2022] Open
Abstract
Neuron-glia interactions play a critical role in the maturation of neural circuits; however, little is known about the pathways that mediate their communication in the developing CNS. We investigated neuron-glia signaling in the developing retina, where we demonstrate that retinal waves reliably induce calcium transients in Müller glial cells (MCs). During cholinergic waves, MC calcium transients were blocked by muscarinic acetylcholine receptor antagonists, whereas during glutamatergic waves, MC calcium transients were inhibited by ionotropic glutamate receptor antagonists, indicating that the responsiveness of MCs changes to match the neurotransmitter used to support retinal waves. Using an optical glutamate sensor we show that the decline in MC calcium transients is caused by a reduction in the amount of glutamate reaching MCs. Together, these studies indicate that neurons and MCs exhibit correlated activity during a critical period of retinal maturation that is enabled by neurotransmitter spillover from retinal synapses.
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Affiliation(s)
- Juliana M Rosa
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Rémi Bos
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Georgeann S Sack
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Cécile Fortuny
- Vision Science Graduate Program, University of California, Berkeley, Berkeley, United States
| | - Amit Agarwal
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, United States
| | - Dwight E Bergles
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, United States
| | - John G Flannery
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Marla B Feller
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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40
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Jang MJ, Nam Y. NeuroCa: integrated framework for systematic analysis of spatiotemporal neuronal activity patterns from large-scale optical recording data. NEUROPHOTONICS 2015; 2:035003. [PMID: 26229973 PMCID: PMC4516777 DOI: 10.1117/1.nph.2.3.035003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/23/2015] [Indexed: 05/22/2023]
Abstract
Optical recording facilitates monitoring the activity of a large neural network at the cellular scale, but the analysis and interpretation of the collected data remain challenging. Here, we present a MATLAB-based toolbox, named NeuroCa, for the automated processing and quantitative analysis of large-scale calcium imaging data. Our tool includes several computational algorithms to extract the calcium spike trains of individual neurons from the calcium imaging data in an automatic fashion. Two algorithms were developed to decompose the imaging data into the activity of individual cells and subsequently detect calcium spikes from each neuronal signal. Applying our method to dense networks in dissociated cultures, we were able to obtain the calcium spike trains of [Formula: see text] neurons in a few minutes. Further analyses using these data permitted the quantification of neuronal responses to chemical stimuli as well as functional mapping of spatiotemporal patterns in neuronal firing within the spontaneous, synchronous activity of a large network. These results demonstrate that our method not only automates time-consuming, labor-intensive tasks in the analysis of neural data obtained using optical recording techniques but also provides a systematic way to visualize and quantify the collective dynamics of a network in terms of its cellular elements.
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Affiliation(s)
- Min Jee Jang
- Korea Advanced Institute of Science and Technology
(KAIST), Department of Bio and Brain Engineering, 291 Daehak-ro,
Yuseong-gu, Daejeon 305-701, Republic of Korea
| | - Yoonkey Nam
- Korea Advanced Institute of Science and Technology
(KAIST), Department of Bio and Brain Engineering, 291 Daehak-ro,
Yuseong-gu, Daejeon 305-701, Republic of Korea
- Address all correspondence to: Yoonkey Nam, E-mail:
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41
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Pelassa I, Zhao C, Pasche M, Odermatt B, Lagnado L. Synaptic vesicles are "primed" for fast clathrin-mediated endocytosis at the ribbon synapse. Front Mol Neurosci 2014; 7:91. [PMID: 25520613 PMCID: PMC4248811 DOI: 10.3389/fnmol.2014.00091] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 11/03/2014] [Indexed: 11/13/2022] Open
Abstract
Retrieval of synaptic vesicles can occur 1-10 s after fusion, but the role of clathrin during this process has been unclear because the classical mode of clathrin-mediated endocytosis (CME) is an order of magnitude slower, as during retrieval of surface receptors. Classical CME is thought to be rate-limited by the recruitment of clathrin, which raises the question: how is clathrin recruited during synaptic vesicle recycling? To investigate this question we applied total internal reflection fluorescence microscopy (TIRFM) to the synaptic terminal of retinal bipolar cells expressing fluorescent constructs of clathrin light-chain A. Upon calcium influx we observed a fast accumulation of clathrin within 100 ms at the periphery of the active zone. The subsequent loss of clathrin from these regions reflected endocytosis because the application of a potent clathrin inhibitor Pitstop2 dramatically slowed down this phase by ~3 fold. These results indicate that clathrin-dependent retrieval of synaptic vesicles is unusually fast, most probably because of a "priming" step involving a state of association of clathrin with the docked vesicle and with the endosomes and cisternae surrounding the ribbons. Fluorescence correlation spectroscopy (FCS) and fluorescence recovery after photobleaching (FRAP) showed that the majority of clathrin is moving with the same kinetics as synaptic vesicle proteins. Together, these results indicate that the fast endocytic mechanism operating to retrieve synaptic vesicles differs substantially from the classical mode of CME operating via formation of a coated pit.
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Affiliation(s)
| | | | | | | | - Leon Lagnado
- Medical Research Council Laboratory of Molecular Biology, Neurobiology DivisionCambridge, UK
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42
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A synaptic mechanism for temporal filtering of visual signals. PLoS Biol 2014; 12:e1001972. [PMID: 25333637 PMCID: PMC4205119 DOI: 10.1371/journal.pbio.1001972] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 09/10/2014] [Indexed: 12/22/2022] Open
Abstract
The visual system transmits information about fast and slow changes in light intensity through separate neural pathways. We used in vivo imaging to investigate how bipolar cells transmit these signals to the inner retina. We found that the volume of the synaptic terminal is an intrinsic property that contributes to different temporal filters. Individual cells transmit through multiple terminals varying in size, but smaller terminals generate faster and larger calcium transients to trigger vesicle release with higher initial gain, followed by more profound adaptation. Smaller terminals transmitted higher stimulus frequencies more effectively. Modeling global calcium dynamics triggering vesicle release indicated that variations in the volume of presynaptic compartments contribute directly to all these differences in response dynamics. These results indicate how one neuron can transmit different temporal components in the visual signal through synaptic terminals of varying geometries with different adaptational properties.
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43
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Dorostkar MM, Burgold S, Filser S, Barghorn S, Schmidt B, Anumala UR, Hillen H, Klein C, Herms J. Immunotherapy alleviates amyloid-associated synaptic pathology in an Alzheimer's disease mouse model. ACTA ACUST UNITED AC 2014; 137:3319-26. [PMID: 25281869 PMCID: PMC4240293 DOI: 10.1093/brain/awu280] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Accumulation of amyloid-beta leads to loss of functional synapses in Alzheimer’s disease. Dorostkar et al. report that immunotherapy against oligomeric amyloid-beta in the Tg2576 mouse model attenuates synapse loss near plaques, and abolishes it elsewhere. Sequestering oligomeric amyloid-beta may counteract synaptic pathology, even while fibrillar amyloid load remains unchanged. Cognitive decline in Alzheimer’s disease is attributed to loss of functional synapses, most likely caused by synaptotoxic, oligomeric forms of amyloid-β. Many treatment options aim at reducing amyloid-β levels in the brain, either by decreasing its production or by increasing its clearance. We quantified the effects of immunotherapy directed against oligomeric amyloid-β in Tg2576 mice, a mouse model of familial Alzheimer’s disease. Treatment of 12-month-old mice with oligomer-specific (A-887755) or conformation-unspecific (6G1) antibodies for 8 weeks did not affect fibrillar plaque density or growth. We also quantified densities of DLG4 (previously known as PSD95) expressing post-synapses and synapsin expressing presynapses immunohistochemically. We found that both pre- and post-synapses were strongly reduced in the vicinity of plaques, whereas distant from plaques, in the cortex and hippocampal CA1 field, only post-synapses were reduced. Immunotherapy alleviated this synapse loss. Synapse loss was completely abolished distant from plaques, whereas it was only attenuated in the vicinity of plaques. These results suggest that fibrillar plaques may act as reservoirs for synaptotoxic, oligomeric amyloid-β and that sequestering oligomers suffices to counteract synaptic pathology. Therefore, cognitive function may be improved by immunotherapy even when the load of fibrillar amyloid remains unchanged.
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Affiliation(s)
- Mario M Dorostkar
- 1 Centre for Neuropathology and Prion Research, Ludwig Maximilian University, Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Steffen Burgold
- 1 Centre for Neuropathology and Prion Research, Ludwig Maximilian University, Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Severin Filser
- 2 Department of Translational Brain Research, German Centre for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Stefan Barghorn
- 3 AbbVie Deutschland GmbH and Co. KG, Neuroscience Discovery Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Boris Schmidt
- 4 Clemens Schoepf-Institute for Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Petersenstrasse 22, 64287 Darmstadt, Germany
| | - Upendra Rao Anumala
- 4 Clemens Schoepf-Institute for Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Petersenstrasse 22, 64287 Darmstadt, Germany
| | - Heinz Hillen
- 3 AbbVie Deutschland GmbH and Co. KG, Neuroscience Discovery Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Corinna Klein
- 3 AbbVie Deutschland GmbH and Co. KG, Neuroscience Discovery Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Jochen Herms
- 1 Centre for Neuropathology and Prion Research, Ludwig Maximilian University, Feodor-Lynen-Str. 23, 81377 Munich, Germany 2 Department of Translational Brain Research, German Centre for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany 5 Munich Cluster of Systems Neurology (SyNergy), Ludwig Maximilian University, Schillerstraße 44, 80336 Munich, Germany
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Neuner J, Ovsepian SV, Dorostkar M, Filser S, Gupta A, Michalakis S, Biel M, Herms J. Pathological α-synuclein impairs adult-born granule cell development and functional integration in the olfactory bulb. Nat Commun 2014; 5:3915. [PMID: 24867427 PMCID: PMC4050256 DOI: 10.1038/ncomms4915] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 04/18/2014] [Indexed: 12/21/2022] Open
Abstract
Although the role of noxious α-synuclein (α-SYN) in the degeneration of midbrain dopaminergic
neurons and associated motor deficits of Parkinson’s disease is
recognized, its impact on non-motor brain circuits and related symptoms remains
elusive. Through combining in vivo two-photon imaging with time-coded
labelling of neurons in the olfactory bulb of A30P α-SYN transgenic mice, we show impaired growth and
branching of dendrites of adult-born granule cells (GCs), with reduced gain and
plasticity of dendritic spines. The spine impairments are especially pronounced
during the critical phase of integration of new neurons into existing circuits.
Functionally, retarded dendritic expansion translates into reduced electrical
capacitance with enhanced intrinsic excitability and responsiveness of GCs to
depolarizing inputs, while the spine loss correlates with decreased frequency of
AMPA-mediated miniature EPSCs.
Changes described here are expected to interfere with the functional integration and
survival of new GCs into bulbar networks, contributing towards olfactory deficits
and related behavioural impairments. Aggregation-prone forms of α-synuclein lead to
degeneration of midbrain dopaminergic neurons, as seen in Parkinson’s
disease, but less is known about the effects that the noxious protein has in other brain
regions. Here, the authors investigate the effect of a pathological form of
α-synuclein on the functional integration of new neurons into the olfactory
bulb of adult mice.
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Affiliation(s)
- Johanna Neuner
- Center for Neuropathology and Prion Research, Department for Translationsal Brain Research, Ludwig Maximilian University, Feodor-Lynen-Strassee 23, Munich 81377, Germany
| | - Saak V Ovsepian
- German Center for Neurodegeneratione Diseases (DZNE), Department for Translational Brain Research, Feodor-Lynen-Strasse 23, Munich 81377, Germany
| | - Mario Dorostkar
- Center for Neuropathology and Prion Research, Department for Translationsal Brain Research, Ludwig Maximilian University, Feodor-Lynen-Strassee 23, Munich 81377, Germany
| | - Severin Filser
- German Center for Neurodegeneratione Diseases (DZNE), Department for Translational Brain Research, Feodor-Lynen-Strasse 23, Munich 81377, Germany
| | - Aayush Gupta
- Center for Neuropathology and Prion Research, Department for Translationsal Brain Research, Ludwig Maximilian University, Feodor-Lynen-Strassee 23, Munich 81377, Germany
| | - Stylianos Michalakis
- Center for Integrated Protein Science Munich, (CiPSM) and Department of Pharmacy-Center for Drug Research, Ludwig Maximilian University, Butenandtstrasse 5-13, Munich 81377, Germany
| | - Martin Biel
- Center for Integrated Protein Science Munich, (CiPSM) and Department of Pharmacy-Center for Drug Research, Ludwig Maximilian University, Butenandtstrasse 5-13, Munich 81377, Germany
| | - Jochen Herms
- 1] German Center for Neurodegeneratione Diseases (DZNE), Department for Translational Brain Research, Feodor-Lynen-Strasse 23, Munich 81377, Germany [2] Munich Cluster of Systems Neurology (SyNergy), Ludwig Maximilian University, Feodor-Lynen-Strasse 23, Munich 81377, Germany
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Automatic segmentation of odor maps in the mouse olfactory bulb using regularized non-negative matrix factorization. Neuroimage 2014; 98:279-88. [PMID: 24769181 DOI: 10.1016/j.neuroimage.2014.04.041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 02/27/2014] [Accepted: 04/12/2014] [Indexed: 11/20/2022] Open
Abstract
Segmentation of functional parts in image series of functional activity is a common problem in neuroscience. Here we apply regularized non-negative matrix factorization (rNMF) to extract glomeruli in intrinsic optical signal (IOS) images of the olfactory bulb. Regularization allows us to incorporate prior knowledge about the spatio-temporal characteristics of glomerular signals. We demonstrate how to identify suitable regularization parameters on a surrogate dataset. With appropriate regularization segmentation by rNMF is more resilient to noise and requires fewer observations than conventional spatial independent component analysis (sICA). We validate our approach in experimental data using anatomical outlines of glomeruli obtained by 2-photon imaging of resting synapto-pHluorin fluorescence. Taken together, we show that rNMF provides a straightforward method for problem tailored source separation that enables reliable automatic segmentation of functional neural images, with particular benefit in situations with low signal-to-noise ratio as in IOS imaging.
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Baden T, Schubert T, Chang L, Wei T, Zaichuk M, Wissinger B, Euler T. A Tale of Two Retinal Domains: Near-Optimal Sampling of Achromatic Contrasts in Natural Scenes through Asymmetric Photoreceptor Distribution. Neuron 2013; 80:1206-17. [DOI: 10.1016/j.neuron.2013.09.030] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2013] [Indexed: 01/10/2023]
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Esposti F, Johnston J, Rosa JM, Leung KM, Lagnado L. Olfactory stimulation selectively modulates the OFF pathway in the retina of zebrafish. Neuron 2013; 79:97-110. [PMID: 23849198 PMCID: PMC3710973 DOI: 10.1016/j.neuron.2013.05.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2013] [Indexed: 01/11/2023]
Abstract
Cross-modal regulation of visual performance by olfactory stimuli begins in the retina, where dopaminergic interneurons receive projections from the olfactory bulb. However, we do not understand how olfactory stimuli alter the processing of visual signals within the retina. We investigated this question by in vivo imaging activity in transgenic zebrafish expressing SyGCaMP2 in bipolar cell terminals and GCaMP3.5 in ganglion cells. The food-related amino acid methionine reduced the gain and increased sensitivity of responses to luminance and contrast transmitted through OFF bipolar cells but not ON. The effects of olfactory stimulus were blocked by inhibiting dopamine uptake and release. Activation of dopamine receptors increased the gain of synaptic transmission in vivo and potentiated synaptic calcium currents in isolated bipolar cells. These results indicate that olfactory stimuli alter the sensitivity of the retina through the dopaminergic regulation of presynaptic calcium channels that control the gain of synaptic transmission through OFF bipolar cells. Olfactory stimuli regulate transmission of signals through retinal bipolar cells Modulation of synaptic gain and sensitivity occur in OFF bipolar cells but not ON An inhibitor of dopamine uptake blocks odor-induced changes in synaptic gain Dopamine potentiates presynaptic calcium channels in isolated bipolar cells
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Affiliation(s)
- Federico Esposti
- Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, UK
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Lueke K, Kaiser T, Svetlitchny A, Welzel O, Wenzel EM, Tyagarajan S, Kornhuber J, Groemer TW. Basic presynaptic functions in hippocampal neurons are not affected by acute or chronic lithium treatment. J Neural Transm (Vienna) 2013; 121:211-9. [DOI: 10.1007/s00702-013-1087-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 08/27/2013] [Indexed: 01/27/2023]
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Nikolaev A, Leung KM, Odermatt B, Lagnado L. Synaptic mechanisms of adaptation and sensitization in the retina. Nat Neurosci 2013; 16:934-41. [PMID: 23685718 PMCID: PMC3924174 DOI: 10.1038/nn.3408] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/24/2013] [Indexed: 12/30/2022]
Abstract
Sensory systems continually adjust the way stimuli are processed. What are the circuit mechanisms underlying this plasticity? We investigated how synapses in the retina of zebrafish adjust to changes in the temporal contrast of a visual stimulus by imaging activity in vivo. Following an increase in contrast, bipolar cell synapses with strong initial responses depressed, whereas synapses with weak initial responses facilitated. Depression and facilitation predominated in different strata of the inner retina, where bipolar cell output was anticorrelated with the activity of amacrine cell synapses providing inhibitory feedback. Pharmacological block of GABAergic feedback converted facilitating bipolar cell synapses into depressing ones. These results indicate that depression intrinsic to bipolar cell synapses causes adaptation of the ganglion cell response to contrast, whereas depression in amacrine cell synapses causes sensitization. Distinct microcircuits segregating to different layers of the retina can cause simultaneous increases or decreases in the gain of neural responses.
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Affiliation(s)
- Anton Nikolaev
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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50
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Renninger SL, Orger MB. Two-photon imaging of neural population activity in zebrafish. Methods 2013; 62:255-67. [PMID: 23727462 DOI: 10.1016/j.ymeth.2013.05.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 05/21/2013] [Accepted: 05/22/2013] [Indexed: 02/08/2023] Open
Abstract
Rapidly developing imaging technologies including two-photon microscopy and genetically encoded calcium indicators have opened up new possibilities for recording neural population activity in awake, behaving animals. In the small, transparent zebrafish, it is even becoming possible to image the entire brain of a behaving animal with single-cell resolution, creating brain-wide functional maps. In this chapter, we comprehensively review past functional imaging studies in zebrafish, and the insights that they provide into the functional organization of neural circuits. We further offer a basic primer on state-of-the-art methods for in vivo calcium imaging in the zebrafish, including building a low-cost two-photon microscope and highlight possible challenges and technical considerations.
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Affiliation(s)
- Sabine L Renninger
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Avenida Brasília, Doca de Pedrouços, Lisbon, Portugal
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