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Friedrichsen K, Hsiang JC, Lin CI, McCoy L, Valkova K, Kerschensteiner D, Morgan JL. Subcellular pathways through VGluT3-expressing mouse amacrine cells provide locally tuned object-motion-selective signals in the retina. Nat Commun 2024; 15:2965. [PMID: 38580652 PMCID: PMC10997783 DOI: 10.1038/s41467-024-46996-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 03/15/2024] [Indexed: 04/07/2024] Open
Abstract
VGluT3-expressing mouse retinal amacrine cells (VG3s) respond to small-object motion and connect to multiple types of bipolar cells (inputs) and retinal ganglion cells (RGCs, outputs). Because these input and output connections are intermixed on the same dendrites, making sense of VG3 circuitry requires comparing the distribution of synapses across their arbors to the subcellular flow of signals. Here, we combine subcellular calcium imaging and electron microscopic connectomic reconstruction to analyze how VG3s integrate and transmit visual information. VG3s receive inputs from all nearby bipolar cell types but exhibit a strong preference for the fast type 3a bipolar cells. By comparing input distributions to VG3 dendrite responses, we show that VG3 dendrites have a short functional length constant that likely depends on inhibitory shunting. This model predicts that RGCs that extend dendrites into the middle layers of the inner plexiform encounter VG3 dendrites whose responses vary according to the local bipolar cell response type.
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Affiliation(s)
- Karl Friedrichsen
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, USA
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
- Graduate Program in Neuroscience, Washington University in St. Louis, St. Louis, USA
| | - Jen-Chun Hsiang
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, USA
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
- Graduate Program in Neuroscience, Washington University in St. Louis, St. Louis, USA
| | - Chin-I Lin
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, USA
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
- Graduate Program in Neuroscience, Washington University in St. Louis, St. Louis, USA
| | - Liam McCoy
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, USA
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Katia Valkova
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, USA
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Daniel Kerschensteiner
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, USA.
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, USA.
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA.
| | - Josh L Morgan
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, USA.
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO, USA.
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA.
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2
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Luu P, Fraser SE, Schneider F. More than double the fun with two-photon excitation microscopy. Commun Biol 2024; 7:364. [PMID: 38531976 DOI: 10.1038/s42003-024-06057-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 03/15/2024] [Indexed: 03/28/2024] Open
Abstract
For generations researchers have been observing the dynamic processes of life through the lens of a microscope. This has offered tremendous insights into biological phenomena that span multiple orders of time- and length-scales ranging from the pure magic of molecular reorganization at the membrane of immune cells, to cell migration and differentiation during development or wound healing. Standard fluorescence microscopy techniques offer glimpses at such processes in vitro, however, when applied in intact systems, they are challenged by reduced signal strengths and signal-to-noise ratios that result from deeper imaging. As a remedy, two-photon excitation (TPE) microscopy takes a special place, because it allows us to investigate processes in vivo, in their natural environment, even in a living animal. Here, we review the fundamental principles underlying TPE aimed at basic and advanced microscopy users interested in adopting TPE for intravital imaging. We focus on applications in neurobiology, present current trends towards faster, wider and deeper imaging, discuss the combination with photon counting technologies for metabolic imaging and spectroscopy, as well as highlight outstanding issues and drawbacks in development and application of these methodologies.
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Affiliation(s)
- Peter Luu
- Translational Imaging Center, Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Biological Sciences, Division of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Scott E Fraser
- Translational Imaging Center, Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Biological Sciences, Division of Molecular and Computational Biology, University of Southern California, Los Angeles, CA, 90089, USA
- Alfred Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Falk Schneider
- Translational Imaging Center, Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA, 90089, USA.
- Dana and David Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA, 90089, USA.
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3
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Berry MH, Leffler J, Allen CN, Sivyer B. Functional subtypes of rodent melanopsin ganglion cells switch roles between night and day illumination. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.26.554902. [PMID: 38168436 PMCID: PMC10760181 DOI: 10.1101/2023.08.26.554902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs), contain the photopigment melanopsin, and influence both image and non-image forming behaviors. Despite being categorized into multiple types (M1-M6), physiological variability within these types suggests our current understanding of ipRGCs is incomplete. We used multi-electrode array (MEA) recordings and unbiased cluster analysis under synaptic blockade to identify 8 functional clusters of ipRGCs, each with distinct photosensitivity and response timing. We used Cre mice to drive the expression of channelrhodopsin in SON-ipRGCs, enabling the localization of distinct ipRGCs in the dorsal retina. Additionally, we conducted a retrospective unbiased cluster analysis of ipRGC photoresponses to light stimuli across scotopic, mesopic, and photopic intensities, aimed at activating both rod and cone inputs to ipRGCs. Our results revealed shared and distinct synaptic inputs to the identified functional clusters, demonstrating that ipRGCs encode visual information with high fidelity at low light intensities, but poorly at photopic light intensities, when melanopsin activation is highest. Collectively, our findings support a framework with at least 8 functional subtypes of ipRGCs, each encoding luminance with distinct spike outputs, highlighting the inherent functional diversity and complexity of ipRGCs and suggesting a reevaluation of their contributions to retinal function and visual perception under varying light conditions.
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Affiliation(s)
- Michael H. Berry
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239
- Medical Scientist Training program, Oregon Health & Science University, Portland, OR, 97239
| | - Joseph Leffler
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239
| | - Charles N. Allen
- Oregon Institute of Occupational Health Sciences, Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, 97239
| | - Benjamin Sivyer
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239
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4
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Zhang X, Lee H, Zhang Y, Walmsley TS, Li D, Levine E, Xu YQ. Probing Light-Stimulated Activities in the Retina via Transparent Graphene Electrodes. ACS APPLIED BIO MATERIALS 2022; 5:305-312. [PMID: 35034456 PMCID: PMC10505038 DOI: 10.1021/acsabm.1c01091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Graphene has triggered tremendous research due to its superior properties. In particular, the intrinsic high light transmission illustrates the unique advantage in neural biosensing. Here, we combine perforated flexible graphene electrodes with microfluidic platforms to explore real-time extracellular electrical activities of retinal ganglion cells (RGCs). Under light stimulation, the transparent graphene electrodes have demonstrated the capability of recording the electrical activities of stimulated RGCs in direct contact. Different types of RGCs have shown three distinct light induced patterns, ON, OFF, and ON-OFF, which are primarily operated by cone photoreceptors. Moreover, the observed spiking waveforms can be divided into two groups: the biphasic waveform usually occurs at contacts with soma, while the triphasic waveform is likely related to the axon. Under high K+ stimulation, the graphene electrodes exhibit higher electrical sensitivity than gold counterparts with an average 2.5-fold enhancement in spiking amplitude. Furthermore, a strong response has been observed with the firing rate first increasing and then ceasing, which could be due to the potassium-induced neural depolarization. These results show that graphene electrodes can be a promising candidate in the electrophysiology studies of retina and offer a route to engineering future two-dimensional materials-based biosensors.
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Affiliation(s)
- Xiaosi Zhang
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Hannah Lee
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37235, USA
| | - Yuchen Zhang
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Thayer S. Walmsley
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA
| | - Deyu Li
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Edward Levine
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37235, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Ya-Qiong Xu
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN 37235, USA
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA
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5
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Huang C, Zeldenrust F, Celikel T. Cortical Representation of Touch in Silico. Neuroinformatics 2022; 20:1013-1039. [PMID: 35486347 PMCID: PMC9588483 DOI: 10.1007/s12021-022-09576-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2022] [Indexed: 12/31/2022]
Abstract
With its six layers and ~ 12,000 neurons, a cortical column is a complex network whose function is plausibly greater than the sum of its constituents'. Functional characterization of its network components will require going beyond the brute-force modulation of the neural activity of a small group of neurons. Here we introduce an open-source, biologically inspired, computationally efficient network model of the somatosensory cortex's granular and supragranular layers after reconstructing the barrel cortex in soma resolution. Comparisons of the network activity to empirical observations showed that the in silico network replicates the known properties of touch representations and whisker deprivation-induced changes in synaptic strength induced in vivo. Simulations show that the history of the membrane potential acts as a spatial filter that determines the presynaptic population of neurons contributing to a post-synaptic action potential; this spatial filtering might be critical for synaptic integration of top-down and bottom-up information.
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Affiliation(s)
- Chao Huang
- grid.9647.c0000 0004 7669 9786Department of Biology, University of Leipzig, Leipzig, Germany
| | - Fleur Zeldenrust
- grid.5590.90000000122931605Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Tansu Celikel
- grid.5590.90000000122931605Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, the Netherlands ,grid.213917.f0000 0001 2097 4943School of Psychology, Georgia Institute of Technology, Atlanta, GA USA
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6
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Fang Y, Prominski A, Rotenberg MY, Meng L, Acarón Ledesma H, Lv Y, Yue J, Schaumann E, Jeong J, Yamamoto N, Jiang Y, Elbaz B, Wei W, Tian B. Micelle-enabled self-assembly of porous and monolithic carbon membranes for bioelectronic interfaces. NATURE NANOTECHNOLOGY 2021; 16:206-213. [PMID: 33288948 PMCID: PMC8801202 DOI: 10.1038/s41565-020-00805-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 10/26/2020] [Indexed: 05/08/2023]
Abstract
Real-world bioelectronics applications, including drug delivery systems, biosensing and electrical modulation of tissues and organs, largely require biointerfaces at the macroscopic level. However, traditional macroscale bioelectronic electrodes usually exhibit invasive or power-inefficient architectures, inability to form uniform and subcellular interfaces, or faradaic reactions at electrode surfaces. Here, we develop a micelle-enabled self-assembly approach for a binder-free and carbon-based monolithic device, aimed at large-scale bioelectronic interfaces. The device incorporates a multi-scale porous material architecture, an interdigitated microelectrode layout and a supercapacitor-like performance. In cell training processes, we use the device to modulate the contraction rate of primary cardiomyocytes at the subcellular level to target frequency in vitro. We also achieve capacitive control of the electrophysiology in isolated hearts, retinal tissues and sciatic nerves, as well as bioelectronic cardiac sensing. Our results support the exploration of device platforms already used in energy research to identify new opportunities in bioelectronics.
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Affiliation(s)
- Yin Fang
- Department of Chemistry, University of Chicago, Chicago, IL, USA.
| | - Aleksander Prominski
- Department of Chemistry, University of Chicago, Chicago, IL, USA
- The James Franck Institute, University of Chicago, Chicago, IL, USA
| | | | - Lingyuan Meng
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, USA
| | - Héctor Acarón Ledesma
- The Graduate Program in Biophysical Sciences, University of Chicago, Chicago, IL, USA
| | - Yingying Lv
- The James Franck Institute, University of Chicago, Chicago, IL, USA
| | - Jiping Yue
- Department of Chemistry, University of Chicago, Chicago, IL, USA
| | - Erik Schaumann
- Department of Chemistry, University of Chicago, Chicago, IL, USA
- The James Franck Institute, University of Chicago, Chicago, IL, USA
| | - Junyoung Jeong
- Department of Computer Science, University of Chicago, Chicago, IL, USA
| | - Naomi Yamamoto
- Department of Chemistry, University of Chicago, Chicago, IL, USA
| | - Yuanwen Jiang
- Department of Chemistry, University of Chicago, Chicago, IL, USA
- The James Franck Institute, University of Chicago, Chicago, IL, USA
| | - Benayahu Elbaz
- The Division of Multiple Sclerosis and Neuroimmunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Wei Wei
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
| | - Bozhi Tian
- Department of Chemistry, University of Chicago, Chicago, IL, USA.
- The James Franck Institute, University of Chicago, Chicago, IL, USA.
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA.
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7
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Schuetzenberger A, Borst A. Seeing Natural Images through the Eye of a Fly with Remote Focusing Two-Photon Microscopy. iScience 2020; 23:101170. [PMID: 32502966 PMCID: PMC7270611 DOI: 10.1016/j.isci.2020.101170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/02/2020] [Accepted: 05/12/2020] [Indexed: 11/30/2022] Open
Abstract
Visual systems of many animals, including the fruit fly Drosophila, represent the surrounding space as 2D maps, formed by populations of neurons. Advanced genetic tools make the fly visual system especially well accessible. However, in typical in vivo preparations for two-photon calcium imaging, relatively few neurons can be recorded at the same time. Here, we present an extension to a conventional two-photon microscope, based on remote focusing, which enables real-time rotation of the imaging plane, and thus flexible alignment to cellular structures, without resolution or speed trade-off. We simultaneously record from over 100 neighboring cells spanning the 2D retinotopic map. We characterize its representation of moving natural images, which we find is comparable to noise predictions. Our method increases throughput 10-fold and allows us to visualize a significant fraction of the fly's visual field. Furthermore, our system can be applied in general for a more flexible investigation of neural circuits.
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Affiliation(s)
- Anna Schuetzenberger
- Department Circuits - Computation - Models, Max-Planck-Institute of Neurobiology, 82152 Planegg, Germany; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität, 82152 Planegg, Germany.
| | - Alexander Borst
- Department Circuits - Computation - Models, Max-Planck-Institute of Neurobiology, 82152 Planegg, Germany; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität, 82152 Planegg, Germany.
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8
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Jayant K, Wenzel M, Bando Y, Hamm JP, Mandriota N, Rabinowitz JH, Plante IJL, Owen JS, Sahin O, Shepard KL, Yuste R. Flexible Nanopipettes for Minimally Invasive Intracellular Electrophysiology In Vivo. Cell Rep 2019; 26:266-278.e5. [PMID: 30605681 PMCID: PMC7263204 DOI: 10.1016/j.celrep.2018.12.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 10/23/2018] [Accepted: 12/04/2018] [Indexed: 12/01/2022] Open
Abstract
Intracellular recordings in vivo remains the best technique to link single-neuron electrical properties to network function. Yet existing methods are limited in accuracy, throughput, and duration, primarily via washout, membrane damage, and movement-induced failure. Here, we introduce flexible quartz nanopipettes (inner diameters of 10-25 nm and spring constant of ∼0.08 N/m) as nanoscale analogs of traditional glass microelectrodes. Nanopipettes enable stable intracellular recordings (seal resistances of 500 to ∼800 MΩ, 5 to ∼10 cells/nanopipette, and duration of ∼1 hr) in anaesthetized and awake head-restrained mice, exhibit minimal diffusional flux, and facilitate precise recording and stimulation. When combined with quantum-dot labels and microprisms, nanopipettes enable two-photon targeted electrophysiology from both somata and dendrites, and even paired recordings from neighboring neurons, while permitting simultaneous population imaging across cortical layers. We demonstrate the versatility of this method by recording from parvalbumin-positive (Pv) interneurons while imaging seizure propagation, and we find that Pv depolarization block coincides with epileptic spread. Flexible nanopipettes present a simple method to procure stable intracellular recordings in vivo.
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Affiliation(s)
- Krishna Jayant
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA; Department of Biological Sciences, Columbia University, New York, NY 10027, USA; NeuroTechnology Center, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA.
| | - Michael Wenzel
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; NeuroTechnology Center, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Yuki Bando
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; NeuroTechnology Center, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Jordan P Hamm
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; NeuroTechnology Center, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Nicola Mandriota
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Jake H Rabinowitz
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
| | - Ilan Jen-La Plante
- Department of Chemistry, Columbia University, New York, NY 10027, USA; NeuroTechnology Center, Columbia University, New York, NY 10027, USA
| | - Jonathan S Owen
- Department of Chemistry, Columbia University, New York, NY 10027, USA; NeuroTechnology Center, Columbia University, New York, NY 10027, USA
| | - Ozgur Sahin
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; Department of Physics, Columbia University, New York, NY 10027, USA; NeuroTechnology Center, Columbia University, New York, NY 10027, USA
| | - Kenneth L Shepard
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA; Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA; NeuroTechnology Center, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Rafael Yuste
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA; NeuroTechnology Center, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
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9
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Localizing Proton-Mediated Inhibitory Feedback at the Retinal Horizontal Cell-Cone Synapse with Genetically-Encoded pH Probes. J Neurosci 2018; 39:651-662. [PMID: 30504272 DOI: 10.1523/jneurosci.1541-18.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 11/12/2018] [Accepted: 11/17/2018] [Indexed: 11/21/2022] Open
Abstract
Lateral inhibition in the vertebrate retina depends on a negative feedback synapse between horizontal cells (HCs) and rod and cone photoreceptors. A change in pH is thought to be the signal for negative feedback, but its spatial profile in the synaptic cleft is unknown. Here we use three different membrane proteins, each fused to the same genetically-encoded pH-sensitive Green Fluorescent Protein (GFP) (pHluorin), to probe synaptic pH in retina from transgenic zebrafish (Danio rerio) of either sex. We used the cone transducin promoter to express SynaptopHluorin (pHluorin on vesicle-associated membrane protein (VAMP2)) or CalipHluorin (pHluorin on an L-type Ca2+ channel) and the HC-specific connexin-55.5 promoter to express AMPApHluorin (pHluorin on an AMPA receptor). Stimulus light led to increased fluorescence of all three probes, consistent with alkalinization of the synaptic cleft. The receptive field size, sensitivity to surround illumination, and response to activation of an alien receptor expressed exclusively in HCs, are consistent with lateral inhibition as the trigger for alkalinization. However, SynaptopHluorin and AMPApHluorin, which are displaced farther from cone synaptic ribbons than CalipHluorin, reported a smaller pH change. Hence, unlike feedforward glutamatergic transmission, which spills over to allow cross talk between terminals in the cone network, the pH change underlying HC feedback is compartmentalized to individual synaptic invaginations within a cone terminal, consistent with private line communication.SIGNIFICANCE STATEMENT Lateral inhibition (LI) is a fundamental feature of information processing in sensory systems, enhancing contrast sensitivity and enabling edge discrimination. Horizontal cells (HCs) are the first cellular substrate of LI in the vertebrate retina, but the synaptic mechanisms underlying LI are not completely understood, despite decades of study. This paper makes a significant contribution to our understanding of LI, by showing that each HC-cone synapse is a "private-line" that operates independently from other HC-cone connections. Using transgenic zebrafish expressing pHluorin, a pH-sensitive GFP variant spliced onto three different protein platforms expressed either in cones or HCs we show that the feedback pH signal is constrained to individual cone terminals, and more stringently, to individual synaptic contact sites within each terminal.
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10
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Morrie RD, Feller MB. A Dense Starburst Plexus Is Critical for Generating Direction Selectivity. Curr Biol 2018; 28:1204-1212.e5. [PMID: 29606419 PMCID: PMC5916530 DOI: 10.1016/j.cub.2018.03.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 02/27/2018] [Accepted: 03/01/2018] [Indexed: 01/02/2023]
Abstract
Starburst amacrine cell (SAC) morphology is considered central to retinal direction selectivity. In Sema6A-/- mice, SAC dendritic arbors are smaller and no longer radially symmetric, leading to a reduction in SAC dendritic plexus density. Sema6A-/- mice also have a dramatic reduction in the directional tuning of retinal direction-selective ganglion cells (DSGCs). Here we show that the loss of DSGC tuning in Sema6A-/- mice is due to reduced null direction inhibition, even though strong asymmetric SAC-DSGC connectivity and SAC dendritic direction selectivity are maintained. Hence, the reduced coverage factor of SAC dendrites leads specifically to a loss of null direction inhibition. Moreover, SAC dendrites are no longer strictly tuned to centrifugal motion, indicating that SAC morphology is critical in coordinating synaptic connectivity and dendritic integration to generate direction selectivity.
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Affiliation(s)
- Ryan D Morrie
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Marla B Feller
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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11
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Abstract
Abstract
How direction of image motion is detected as early as at the level of the vertebrate eye has been intensively studied in retina research. Although the first direction-selective (DS) retinal ganglion cells were already described in the 1960s and have since then been in the focus of many studies, scientists are still puzzled by the intricacy of the neuronal circuits and computational mechanisms underlying retinal direction selectivity. The fact that the retina can be easily isolated and studied in a Petri dish-by presenting light stimuli while recording from the various cell types in the retinal circuits-in combination with the extensive anatomical, molecular and physiological knowledge about this part of the brain presents a unique opportunity for studying this intriguing visual circuit in detail. This article provides a brief overview of the history of research on retinal direction selectivity, but then focuses on the past decade and the progress achieved, in particular driven by methodological advances in optical recording techniques, molecular genetics approaches and large-scale ultrastructural reconstructions. As it turns out, retinal direction selectivity is a complex, multi-tiered computation, involving dendrite-intrinsic mechanisms as well as several types of network interactions on the basis of highly selective, likely genetically predetermined synaptic connectivity. Moreover, DS ganglion cell types appear to be more diverse than previously thought, differing not only in their preferred direction and response polarity, but also in physiology, DS mechanism, dendritic morphology and, importantly, the target area of their projections in the brain.
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12
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Zhang Y, Dodson KH, Fischer R, Wang R, Li D, Sappington RM, Xu YQ. Probing electrical signals in the retina via graphene-integrated microfluidic platforms. NANOSCALE 2016; 8:19043-19049. [PMID: 27812594 PMCID: PMC5115917 DOI: 10.1039/c6nr07290a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Graphene has attracted extensive attention in biological and biomedical fields due to its unique physical properties and excellent biocompatibility. We combine graphene field-effect transistors and scanning photocurrent microscopy with microfluidic platforms to investigate electrical signals in mouse retina. Remarkable photocurrent signals were detected from the graphene underneath the optic nerve head (ONH) of the retina, where the electrical activity from this region can modulate the carrier concentration of the graphene and induce local potential gradients. These built-in electrical potential gradients can efficiently separate photo-excited electron-hole pairs, leading to strong photocurrent responses in the graphene underneath the ONH. We also show that no significant photocurrent signal was observed in the graphene underneath either dehydrated or fixed retinal tissues, verifying that the photocurrent responses generated in the graphene underneath the ONH were indeed induced by the electrical activity in living retina. This method not only provides a way to investigate electrical processes in living retinal tissues, but also offers opportunities to study many other cellular systems involving cell-cell interactions through electrical signaling.
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Affiliation(s)
- Yuchen Zhang
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, USA
| | - Kirsten H. Dodson
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Rachel Fischer
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Pharmacology, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Rui Wang
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA
| | - Deyu Li
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Rebecca M. Sappington
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Pharmacology, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Ya-Qiong Xu
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, USA
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA
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Cameron M, Kékesi O, Morley JW, Tapson J, Breen PP, van Schaik A, Buskila Y. Calcium Imaging of AM Dyes Following Prolonged Incubation in Acute Neuronal Tissue. PLoS One 2016; 11:e0155468. [PMID: 27183102 PMCID: PMC4868260 DOI: 10.1371/journal.pone.0155468] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 04/30/2016] [Indexed: 12/12/2022] Open
Abstract
Calcium-imaging is a sensitive method for monitoring calcium dynamics during neuronal activity. As intracellular calcium concentration is correlated to physiological and pathophysiological activity of neurons, calcium imaging with fluorescent indicators is one of the most commonly used techniques in neuroscience today. Current methodologies for loading calcium dyes into the tissue require prolonged incubation time (45-150 min), in addition to dissection and recovery time after the slicing procedure. This prolonged incubation curtails experimental time, as tissue is typically maintained for 6-8 hours after slicing. Using a recently introduced recovery chamber that extends the viability of acute brain slices to more than 24 hours, we tested the effectiveness of calcium AM staining following long incubation periods post cell loading and its impact on the functional properties of calcium signals in acute brain slices and wholemount retinae. We show that calcium dyes remain within cells and are fully functional >24 hours after loading. Moreover, the calcium dynamics recorded >24 hrs were similar to the calcium signals recorded in fresh tissue that was incubated for <4 hrs. These results indicate that long exposure of calcium AM dyes to the intracellular cytoplasm did not alter the intracellular calcium concentration, the functional range of the dye or viability of the neurons. This data extends our previous work showing that a custom recovery chamber can extend the viability of neuronal tissue, and reliable data for both electrophysiology and imaging can be obtained >24hrs after dissection. These methods will not only extend experimental time for those using acute neuronal tissue, but also may reduce the number of animals required to complete experimental goals.
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Affiliation(s)
- Morven Cameron
- Biomedical Engineering and Neuroscience group, The MARCS Institute, Western Sydney University, Penrith, NSW, Australia
| | - Orsolya Kékesi
- School of Medicine, Western Sydney University, Penrith, NSW, Australia
- Biomedical Engineering and Neuroscience group, The MARCS Institute, Western Sydney University, Penrith, NSW, Australia
| | - John W. Morley
- School of Medicine, Western Sydney University, Penrith, NSW, Australia
- Biomedical Engineering and Neuroscience group, The MARCS Institute, Western Sydney University, Penrith, NSW, Australia
| | - Jonathan Tapson
- School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Paul P. Breen
- School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - André van Schaik
- School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Yossi Buskila
- School of Medicine, Western Sydney University, Penrith, NSW, Australia
- Biomedical Engineering and Neuroscience group, The MARCS Institute, Western Sydney University, Penrith, NSW, Australia
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Bar-Noam AS, Farah N, Shoham S. Correction-free remotely scanned two-photon in vivo mouse retinal imaging. LIGHT, SCIENCE & APPLICATIONS 2016; 5:e16007. [PMID: 30167112 PMCID: PMC6059848 DOI: 10.1038/lsa.2016.7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 08/14/2015] [Accepted: 08/17/2015] [Indexed: 05/16/2023]
Abstract
Non-invasive fluorescence retinal imaging in small animals is an important requirement for an array of translational vision applications. The in vivo two-photon imaging of the mouse retina may enable the long-term investigation of the structure and function of healthy and diseased retinal tissue. However, to date, this has only been possible using relatively complex adaptive-optics systems. Here, the optical modeling of the murine eye and of the imaging system is used to achieve correction-free two-photon microscopy through the pupil of a mouse eye to yield high-quality, optically sectioned fundus images. By remotely scanning the focus using an electronically tunable lens, high-resolution three-dimensional fluorescein angiograms and cellular-scale images are acquired, thus introducing a correction-free baseline performance level for two-photon in vivo retinal imaging. Moreover, the system enables functional calcium imaging of repeated retinal responses to light stimulation using the genetically encoded indicator, GCaMP6s. These results and the simplicity of the new add-on optics are an important step toward several structural, functional, and multimodal imaging applications that will benefit from the tight optical sectioning and the use of near-infrared light.
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Affiliation(s)
- Adi Schejter Bar-Noam
- />Faculty of Biomedical Engineering, Technion – Israel Institute of Technology, Kiryat HaTechnion, Haifa 32000, Israel
| | - Nairouz Farah
- />Faculty of Biomedical Engineering, Technion – Israel Institute of Technology, Kiryat HaTechnion, Haifa 32000, Israel
| | - Shy Shoham
- />Faculty of Biomedical Engineering, Technion – Israel Institute of Technology, Kiryat HaTechnion, Haifa 32000, Israel
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15
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Newkirk GS, Hoon M, Wong RO, Detwiler PB. Response Properties of a Newly Identified Tristratified Narrow Field Amacrine Cell in the Mouse Retina. PLoS One 2015; 10:e0137702. [PMID: 26352594 PMCID: PMC4564219 DOI: 10.1371/journal.pone.0137702] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 08/19/2015] [Indexed: 11/27/2022] Open
Abstract
Amacrine cells were targeted for whole cell recording using two-photon fluorescence microscopy in a transgenic mouse line in which the promoter for dopamine receptor 2 drove expression of green fluorescent protein in a narrow field tristratified amacrine cell (TNAC) that had not been studied previously. Light evoked a multiphasic response that was the sum of hyperpolarizing and depolarization synaptic inputs consistent with distinct dendritic ramifications in the off and on sublamina of the inner plexiform layer. The amplitude and waveform of the response, which consisted of an initial brief hyperpolarization at light onset followed by recovery to a plateau potential close to dark resting potential and a hyperpolarizing response at the light offset varied little over an intensity range from 0.4 to ~10^6 Rh*/rod/s. This suggests that the cell functions as a differentiator that generates an output signal (a transient reduction in inhibitory input to downstream retina neurons) that is proportional to the derivative of light input independent of its intensity. The underlying circuitry appears to consist of rod and cone driven on and off bipolar cells that provide direct excitatory input to the cell as well as to GABAergic amacrine cells that are synaptically coupled to TNAC. Canonical reagents that blocked excitatory (glutamatergic) and inhibitory (GABA and glycine) synaptic transmission had effects on responses to scotopic stimuli consistent with the rod driven component of the proposed circuit. However, responses evoked by photopic stimuli were paradoxical and could not be interpreted on the basis of conventional thinking about the neuropharmacology of synaptic interactions in the retina.
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Affiliation(s)
- G. S. Newkirk
- Department of Physiology & Biophysics and Program in Neurobiology & Behavior, University of Washington, Seattle, Washington, United States of America
- * E-mail: (GSN); (PBD)
| | - M. Hoon
- Department of Biological Structure, University of Washington, Seattle, Washington, United States of America
| | - R. O. Wong
- Department of Biological Structure, University of Washington, Seattle, Washington, United States of America
| | - P. B. Detwiler
- Department of Physiology & Biophysics and Program in Neurobiology & Behavior, University of Washington, Seattle, Washington, United States of America
- * E-mail: (GSN); (PBD)
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16
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Margolis DJ, Gartland AJ, Singer JH, Detwiler PB. Network oscillations drive correlated spiking of ON and OFF ganglion cells in the rd1 mouse model of retinal degeneration. PLoS One 2014; 9:e86253. [PMID: 24489706 PMCID: PMC3904909 DOI: 10.1371/journal.pone.0086253] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/12/2013] [Indexed: 11/19/2022] Open
Abstract
Following photoreceptor degeneration, ON and OFF retinal ganglion cells (RGCs) in the rd-1/rd-1 mouse receive rhythmic synaptic input that elicits bursts of action potentials at ∼ 10 Hz. To characterize the properties of this activity, RGCs were targeted for paired recording and morphological classification as either ON alpha, OFF alpha or non-alpha RGCs using two-photon imaging. Identified cell types exhibited rhythmic spike activity. Cross-correlation of spike trains recorded simultaneously from pairs of RGCs revealed that activity was correlated more strongly between alpha RGCs than between alpha and non-alpha cell pairs. Bursts of action potentials in alpha RGC pairs of the same type, i.e. two ON or two OFF cells, were in phase, while bursts in dissimilar alpha cell types, i.e. an ON and an OFF RGC, were 180 degrees out of phase. This result is consistent with RGC activity being driven by an input that provides correlated excitation to ON cells and inhibition to OFF cells. A2 amacrine cells were investigated as a candidate cellular mechanism and found to display 10 Hz oscillations in membrane voltage and current that persisted in the presence of antagonists of fast synaptic transmission and were eliminated by tetrodotoxin. Results support the conclusion that the rhythmic RGC activity originates in a presynaptic network of electrically coupled cells including A2s via a Na(+)-channel dependent mechanism. Network activity drives out of phase oscillations in ON and OFF cone bipolar cells, entraining similar frequency fluctuations in RGC spike activity over an area of retina that migrates with changes in the spatial locus of the cellular oscillator.
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Affiliation(s)
- David J. Margolis
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, United States of America
- * E-mail: (DJM); (PBD)
| | - Andrew J. Gartland
- Department Physiology and Biophysics and Program in Neurobiology and Behavior, University of Washington, Seattle, Washington, United States of America
| | - Joshua H. Singer
- Department of Biology, University of Maryland, College Park, Maryland, United States of America
| | - Peter B. Detwiler
- Department Physiology and Biophysics and Program in Neurobiology and Behavior, University of Washington, Seattle, Washington, United States of America
- * E-mail: (DJM); (PBD)
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17
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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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18
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Schrödel T, Prevedel R, Aumayr K, Zimmer M, Vaziri A. Brain-wide 3D imaging of neuronal activity in Caenorhabditis elegans with sculpted light. Nat Methods 2013; 10:1013-20. [PMID: 24013820 DOI: 10.1038/nmeth.2637] [Citation(s) in RCA: 190] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/07/2013] [Indexed: 12/18/2022]
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Liu K, Wang Y, Yin Z, Weng C. Light-evoked currents in retinal ganglion cells from dystrophic RCS rats. Ophthalmic Res 2013; 50:141-50. [PMID: 23948861 DOI: 10.1159/000351639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 03/24/2013] [Indexed: 11/19/2022]
Abstract
PURPOSE To study the electrophysiological properties of the light-evoked currents in ganglion cells in situations of retinal degeneration. METHODS We investigated light-evoked currents in ganglion cells by performing whole-cell patch-clamp recordings from ganglion cells using a retina-stretched preparation from Royal College of Surgeons (RCS) rats, a model of retinal degeneration and congenic controls at different ages. Pharmacological inhibitors of the AMPA receptor (NBQX), GABA receptor (BMI), and sodium channels (TTX) were used to identify the components of the light-evoked currents in ON, OFF and ON-OFF retinal ganglion cells. RESULTS We found that the light-evoked currents in ganglion cells from control rats were inhibited by NBQX, BMI and TTX, suggesting that AMPA receptors, GABA receptors and sodium channels contribute to these currents in ganglion cells. However, only AMPA receptor-mediated currents were recorded in RCS rats. Light-evoked inward currents were absent in the majority of ganglion cells from RCS rats, particularly at the later stages of retinal degeneration. At earlier stages of retinal degeneration, we found that both the timing and amplitude of light-evoked currents are significantly different in ganglion cells from RCS and control rats. CONCLUSIONS Our study furthers the understanding of the electrophysiological characteristics of retinal ganglion cells during retinal degeneration, and provides insight into the optimal timing for the treatment of retinal degeneration.
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Affiliation(s)
- Kang Liu
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, PR China
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20
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Masihzadeh O, Ammar DA, Kahook MY, Lei TC. Coherent anti-stokes Raman scattering (CARS) microscopy: a novel technique for imaging the retina. Invest Ophthalmol Vis Sci 2013; 54:3094-101. [PMID: 23580484 DOI: 10.1167/iovs.13-11642] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To image the cellular and noncellular structures of the retina in an intact mouse eye without the application of exogenous fluorescent labels using noninvasive, nondestructive techniques. METHODS Freshly enucleated mouse eyes were imaged using two nonlinear optical techniques: coherent anti-Stokes Raman scattering (CARS) and two-photon autofluorescence (TPAF). Cross sectional transverse sections and sequential flat (en face) sagittal sections were collected from a region of sclera approximately midway between the limbus and optic nerve. Imaging proceeded from the surface of the sclera to a depth of ∼60 μm. RESULTS The fluorescent signal from collagen fibers within the sclera was evident in the TPAF channel; the scleral collagen fibers showed no organization and appeared randomly packed. The sclera contained regions lacking TPAF and CARS fluorescence of ∼3 to 15 μm in diameter that could represent small vessels or scleral fibroblasts. Intense punctate CARS signals from the retinal pigment epithelial layer were of a size and shape of retinyl storage esters. Rod outer segments could be identified by the CARS signal from their lipid-rich plasma membranes. CONCLUSIONS CARS microscopy can be used to image the outer regions of the mammalian retina without the use of a fluorescent dye or exogenously expressed recombinant protein. With technical advancements, CARS/TPAF may represent a new avenue for noninvasively imaging the retina and might complement modalities currently used in clinical practice.
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Affiliation(s)
- Omid Masihzadeh
- Department of Ophthalmology, University of Colorado Denver, Aurora, Colorado, USA
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21
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Newkirk GS, Hoon M, Wong RO, Detwiler PB. Inhibitory inputs tune the light response properties of dopaminergic amacrine cells in mouse retina. J Neurophysiol 2013; 110:536-52. [PMID: 23636722 DOI: 10.1152/jn.00118.2013] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Dopamine (DA) is a neuromodulator that in the retina adjusts the circuitry for visual processing in dim and bright light conditions. It is synthesized and released from retinal interneurons called dopaminergic amacrine cells (DACs), whose basic physiology is not yet been fully characterized. To investigate their cellular and input properties as well as light responses, DACs were targeted for whole cell recording in isolated retina using two-photon fluorescence microscopy in a mouse line where the dopamine receptor 2 promoter drives green fluorescent protein (GFP) expression. Differences in membrane properties gave rise to cell-to-cell variation in the pattern of resting spontaneous spike activity ranging from silent to rhythmic to periodic burst discharge. All recorded DACs were light sensitive and generated responses that varied with intensity. The threshold response to light onset was a hyperpolarizing potential change initiated by rod photoreceptors that was blocked by strychnine, indicating a glycinergic amacrine input onto DACs at light onset. With increasing light intensity, the ON response acquired an excitatory component that grew to dominate the response to the strongest stimuli. Responses to bright light (photopic) stimuli also included an inhibitory OFF response mediated by GABAergic amacrine cells driven by the cone OFF pathway. DACs expressed GABA (GABA(A)α1 and GABA(A)α3) and glycine (α2) receptor clusters on soma, axon, and dendrites consistent with the light response being shaped by dual inhibitory inputs that may serve to tune spike discharge for optimal DA release.
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Affiliation(s)
- G S Newkirk
- Department of Physiology & Biophysics and Program in Neurobiology & Behavior, University of Washington, Seattle, WA, USA
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23
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Abstract
Calcium mediates various neuronal functions. The complexity of neuronal Ca²⁺ signaling is well exemplified by retinal cone photoreceptors, which, with their distinct compartmentalization, offer unique possibilities for studying the diversity of Ca²⁺ functions in a single cell. Measuring subcellular Ca²⁺ signals in cones under physiological conditions is not only fundamental for understanding cone function, it also bears important insights into pathophysiological processes governing retinal neurodegeneration. However, due to the proximity of light-sensitive outer segments to other cellular compartments, optical measurements of light-evoked Ca²⁺ responses in cones are challenging. We addressed this problem by generating a transgenic mouse (HR2.1:TN-XL) in which both short- and middle-wavelength-sensitive cones selectively express the genetically encoded ratiometric Ca²⁺ biosensor TN-XL. We show that HR2.1:TN-XL allows recording of light-evoked Ca²⁺ responses using two-photon imaging in individual cone photoreceptor terminals and to probe phototransduction and its diverse regulatory mechanisms with pharmacology at subcellular resolution. To further test this system, we asked whether the classical, nitric oxide (NO)-soluble guanylyl-cyclase (sGC)-cGMP pathway could modulate Ca²⁺ in cone terminals. Surprisingly, NO reduced Ca²⁺ resting levels in mouse cones, without evidence for direct sGC involvement. In conclusion, HR2.1:TN-XL mice offer unprecedented opportunities to elucidate light-driven Ca²⁺ dynamics and their (dys)regulation in cone photoreceptors.
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Correlated variations in the parameters that regulate dendritic calcium signaling in mouse retinal ganglion cells. J Neurosci 2012; 31:18353-63. [PMID: 22171038 DOI: 10.1523/jneurosci.4212-11.2011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The amplitude and time course of stimulus-evoked second messenger signals carried by intracellular changes in free calcium ([Ca](free)) depend on the total influx of Ca(2+), the fraction bound to endogenous buffer and the rate of extrusion. Estimates of the values of these three parameters in proximal dendrites of 15 mouse α retinal ganglion cells were made using the "added buffer" method and found to vary greatly from one experiment to the next. The variations in the measured parameters were strongly correlated across the sample of cells. This reduced the variability in the amplitude and time course of the dendritic Ca(2+) signal and suggests that the expression of Ca(2+) channels, binding proteins and extrusion mechanisms is homeostatically coordinated to maintain the amplitude and kinetics of the Ca(2+) signal within a physiologically appropriate range.
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Abstract
How does the brain compute? Answering this question necessitates neuronal connectomes, annotated graphs of all synaptic connections within defined brain areas. Further, understanding the energetics of the brain's computations requires vascular graphs. The assembly of a connectome requires sensitive hardware tools to measure neuronal and neurovascular features in all three dimensions, as well as software and machine learning for data analysis and visualization. We present the state of the art on the reconstruction of circuits and vasculature that link brain anatomy and function. Analysis at the scale of tens of nanometers yields connections between identified neurons, while analysis at the micrometer scale yields probabilistic rules of connection between neurons and exact vascular connectivity.
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Pottek M, Knop GC, Weiler R, Dedek K. Electrophysiological characterization of GFP-expressing cell populations in the intact retina. J Vis Exp 2011:3457. [PMID: 22105413 PMCID: PMC3308615 DOI: 10.3791/3457] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Studying the physiological properties and synaptic connections of specific neurons in the intact tissue is a challenge for those cells that lack conspicuous morphological features or show a low population density. This applies particularly to retinal amacrine cells, an exceptionally multiform class of interneurons that comprise roughly 30 subtypes in mammals(1). Though being a crucial part of the visual processing by shaping the retinal output(2), most of these subtypes have not been studied up to now in a functional context because encountering these cells with a recording electrode is a rare event. Recently, a multitude of transgenic mouse lines is available that express fluorescent markers like green fluorescent protein (GFP) under the control of promoters for membrane receptors or enzymes that are specific to only a subset of neurons in a given tissue(3,4). These pre-labeled cells are therefore accessible to directed microelectrode targeting under microscopic control, permitting the systematic study of their physiological properties in situ. However, excitation of fluorescent markers is accompanied by the risk of phototoxicity for the living tissue. In the retina, this approach is additionally hampered by the problem that excitation light causes appropriate stimulation of the photoreceptors, thus inflicting photopigment bleaching and transferring the retinal circuits into a light-adapted condition. These drawbacks are overcome by using infrared excitation delivered by a mode-locked laser in short pulses of the femtosecond range. Two-photon excitation provides energy sufficient for fluorophore excitation and at the same time restricts the excitation to a small tissue volume minimizing the hazards of photodamage(5). Also, it leaves the retina responsive to visual stimuli since infrared light (>850 nm) is only poorly absorbed by photopigments(6). In this article we demonstrate the use of a transgenic mouse retina to attain electrophysiological in situ recordings from GFP-expressing cells that are visually targeted by two-photon excitation. The retina is prepared and maintained in darkness and can be subjected to optical stimuli which are projected through the condenser of the microscope (Figure 1). Patch-clamp recording of light responses can be combined with dye filling to reveal the morphology and to check for gap junction-mediated dye coupling to neighboring cells, so that the target cell can by studied on different experimental levels.
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Affiliation(s)
- Mark Pottek
- Department of Neurobiology, University of Oldenburg
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27
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Borst A, Euler T. Seeing Things in Motion: Models, Circuits, and Mechanisms. Neuron 2011; 71:974-94. [PMID: 21943597 DOI: 10.1016/j.neuron.2011.08.031] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2011] [Indexed: 12/31/2022]
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Azeredo da Silveira R, Roska B. Cell types, circuits, computation. Curr Opin Neurobiol 2011; 21:664-71. [PMID: 21641794 DOI: 10.1016/j.conb.2011.05.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Revised: 05/10/2011] [Accepted: 05/10/2011] [Indexed: 12/25/2022]
Abstract
How does the connectivity of a neuronal circuit, together with the individual properties of the cell types that take part in it, result in a given computation? We examine this question in the context of retinal circuits. We suggest that the retina can be viewed as a parallel assemblage of many small computational devices, highly stereotypical and task-specific circuits afferent to a given ganglion cell type, and we discuss some rules that govern computation in these devices. Multi-device processing in retina poses conceptual problems when it is contrasted with cortical processing. We lay out open questions both on processing in retinal circuits and on implications for cortical processing of retinal inputs.
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Affiliation(s)
- Rava Azeredo da Silveira
- Department of Physics and Department of Cognitive Studies, École Normale Supérieure, Paris, France.
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29
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Wiring specificity in the direction-selectivity circuit of the retina. Nature 2011; 471:183-8. [PMID: 21390125 DOI: 10.1038/nature09818] [Citation(s) in RCA: 573] [Impact Index Per Article: 44.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 01/10/2011] [Indexed: 02/01/2023]
Abstract
The proper connectivity between neurons is essential for the implementation of the algorithms used in neural computations, such as the detection of directed motion by the retina. The analysis of neuronal connectivity is possible with electron microscopy, but technological limitations have impeded the acquisition of high-resolution data on a large enough scale. Here we show, using serial block-face electron microscopy and two-photon calcium imaging, that the dendrites of mouse starburst amacrine cells make highly specific synapses with direction-selective ganglion cells depending on the ganglion cell's preferred direction. Our findings indicate that a structural (wiring) asymmetry contributes to the computation of direction selectivity. The nature of this asymmetry supports some models of direction selectivity and rules out others. It also puts constraints on the developmental mechanisms behind the formation of synaptic connections. Our study demonstrates how otherwise intractable neurobiological questions can be addressed by combining functional imaging with the analysis of neuronal connectivity using large-scale electron microscopy.
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Briggman KL, Euler T. Bulk electroporation and population calcium imaging in the adult mammalian retina. J Neurophysiol 2011; 105:2601-9. [PMID: 21346205 DOI: 10.1152/jn.00722.2010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The optical recording of light-evoked activity in populations of neurons in the mammalian retina offers several benefits over the use of multielectrode arrays. However, population imaging has been hindered by the effective loading of synthetic fluorescent indicators, especially in the mature tissue. We have therefore developed an electroporation method to label the complete ganglion cell layer of the adult mammalian retina. We optimized the protocol such that the retina recovers from electroporation and generates responses to visual stimuli. The method can be used with a diverse set of indicators with a range of affinities and emission wavelengths. It therefore can be combined with transgenic animals expressing fluorescent markers to target specific neuronal types. Importantly, the ganglion cell layer remains accessible for subsequent intracellular recording and morphological identification.
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Affiliation(s)
- Kevin L Briggman
- Department of Biomedical Optics, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany.
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Calcium homeostasis of acutely denervated and lesioned dentate gyrus in organotypic entorhino-hippocampal co-cultures. Cell Calcium 2010; 47:242-52. [PMID: 20053446 DOI: 10.1016/j.ceca.2009.12.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 11/04/2009] [Accepted: 12/07/2009] [Indexed: 12/20/2022]
Abstract
Denervation of neurons, e.g. upon traumatic injury or neuronal degeneration, induces transneuronal degenerative events, such as spine loss, dendritic pruning, and even cell loss. We studied one possible mechanism proposed to trigger such events, i.e. excess glutamate release from severed axons conveyed transsynaptically via postsynaptic calcium influx. Using 2-photon microscopical calcium imaging in organotypic entorhino-hippocampal co-cultures, we show that acute transection of the perforant path elicits two independent effects on calcium homeostasis in the dentate gyrus: a brief, short-latency elevation of postsynaptic calcium levels in denervated granule cells, which can be blocked by preincubation with tetrodotoxin, and a long-latency astroglial calcium wave, not blocked by tetrodotoxin and propagating slowly through the hippocampus. While neuronal calcium elevations upon axonal transection placed remote from the target area were similar to those elicited by brief trains of electrical stimulation of the perforant path, large-scale calcium signals were observed upon lesions placed close to or within the dendritic field of granule cells. Concordantly, induction of c-fos in denervated neurons coincided spatially with cell populations showing prolonged calcium elevations upon concomitant dendritic damage. Since denervation of dentate granule cells by remote transection of the perforant path induces transsynaptic dendritic reorganization in the utilized organotypic cultures, a generalized breakdown of the cellular calcium homeostasis is unlikely to underlie these transneuronal changes.
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Easwaramoorthi S, Shin JY, Cho S, Kim P, Inokuma Y, Tsurumaki E, Osuka A, Kim D. Versatile Photophysical Properties ofmeso-Aryl-Substituted Subporphyrins: Dipolar and Octupolar Charge-Transfer Interactions. Chemistry 2009; 15:12005-17. [DOI: 10.1002/chem.200901671] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Crousillac S, Colonna J, McMains E, Dewey JS, Gleason E. Sphingosine-1-phosphate elicits receptor-dependent calcium signaling in retinal amacrine cells. J Neurophysiol 2009; 102:3295-309. [PMID: 19776367 DOI: 10.1152/jn.00119.2009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Evidence is emerging indicating that sphingosine-1-phosphate (S1P) participates in signaling in the retina. To determine whether S1P might be involved in signaling in the inner retina specifically, we examine the effects of this sphingolipid on cultured retinal amacrine cells. Whole cell voltage-clamp recordings reveal that S1P activates a cation current that is dependent on signaling through G(i) and phospholipase C. These observations are consistent with the involvement of members of the S1P receptor family of G-protein-coupled receptors in the production of the current. Immunocytochemistry and PCR amplification provide evidence for the expression of S1P1R and S1P3R in amacrine cells. The receptor-mediated channel activity is shown to be highly sensitive to blockade by lanthanides consistent with the behavior of transient receptor potential canonical (TRPC) channels. PCR products amplified from amacrine cells reveal that TRPCs 1 and 3-7 channel subunits have the potential to be expressed. Because TRPC channels provide a Ca(2+) entry pathway, we asked whether S1P caused cytosolic Ca(2+) elevations in amacrine cells. We show that S1P-dependent Ca(2+) elevations do occur in these cells and that they might be mediated by S1P1R and S1P3R. The Ca(2+) elevations are partially due to release from internal stores, but the largest contribution is from influx across the plasma membrane. The effect of inhibition of sphingosine kinase suggests that the production of cytosolic S1P underlies the sustained nature of the Ca(2+) elevations. Elucidation of the downstream effects of these signals will provide clues to the role of S1P in regulating inner retinal function.
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Affiliation(s)
- Scott Crousillac
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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Pfeffer M, Müller CM, Mordel J, Meissl H, Ansari N, Deller T, Korf HW, von Gall C. The mammalian molecular clockwork controls rhythmic expression of its own input pathway components. J Neurosci 2009; 29:6114-23. [PMID: 19439589 PMCID: PMC6665491 DOI: 10.1523/jneurosci.0275-09.2009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2009] [Revised: 03/10/2009] [Accepted: 04/03/2009] [Indexed: 02/04/2023] Open
Abstract
The core molecular clockwork in the suprachiasmatic nucleus (SCN) is based on autoregulatory feedback loops of transcriptional activators (CLOCK/NPAS2 and BMAL1) and inhibitors (mPER1-2 and mCRY1-2). To synchronize the phase of the molecular clockwork to the environmental day and night condition, light at dusk and dawn increases mPer expression. However, the signal transduction pathways differ remarkably between the day/night and the night/day transition. Light during early night leads to intracellular Ca(2+) release by neuronal ryanodine receptors (RyRs), resulting in phase delays. Light during late night triggers an increase in guanylyl cyclase activity, resulting in phase advances. To date, it is still unknown how the core molecular clockwork regulates the availability of the respective input pathway components. Therefore, we examined light resetting mechanisms in mice with an impaired molecular clockwork (BMAL1(-/-)) and the corresponding wild type (BMAL1(+/+)) using in situ hybridization, real-time PCR, immunohistochemistry, and a luciferase reporter system. In addition, intracellular calcium concentrations (Ca(2+)(i)) were measured in SCN slices using two-photon microscopy. In the SCN of BMAL1(-/-) mice Ryr mRNA and RyR protein levels were reduced, and light-induced mPer expression was selectively impaired during early night. Transcription assays with NIH3T3 fibroblasts showed that Ryr expression was activated by CLOCK::BMAL1 and inhibited by mCRY1. The Ca(2+)(i) response of SCN cells to the RyR agonist caffeine was reduced in BMAL1(-/-) compared with BMAL1(+/+) mice. Our findings provide the first evidence that the mammalian molecular clockwork influences Ryr expression and thus controls its own photic input pathway components.
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Affiliation(s)
| | - Christian M. Müller
- Institut für klinische Neuroanatomie, Dr. Senckenbergische Anatomie, Johann Wolfgang Goethe-Universität, 60590 Frankfurt am Main, Germany, and
| | - Jérôme Mordel
- Abteilung Neuroanatomie, Max-Planck-Institut für Hirnforschung, 60528 Frankfurt am Main, Germany
| | - Hilmar Meissl
- Abteilung Neuroanatomie, Max-Planck-Institut für Hirnforschung, 60528 Frankfurt am Main, Germany
| | - Nariman Ansari
- Emmy Noether Nachwuchsgruppe
- Institut für Anatomie II, and
| | - Thomas Deller
- Institut für klinische Neuroanatomie, Dr. Senckenbergische Anatomie, Johann Wolfgang Goethe-Universität, 60590 Frankfurt am Main, Germany, and
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35
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Li L, Tian YP, Yang JX, Sun PP, Wu JY, Zhou HP, Zhang SY, Jin BK, Xing XJ, Wang CK, Li M, Cheng GH, Tang HH, Huang WH, Tao XT, Jiang MH. Facile Synthesis and Systematic Investigations of a Series of Novel Bent-Shaped Two-Photon Absorption Chromophores Based on Pyrimidine. Chem Asian J 2009; 4:668-80. [DOI: 10.1002/asia.200800402] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mancuso JJ, Larson AM, Wensel TG, Saggau P. Multiphoton adaptation of a commercial low-cost confocal microscope for live tissue imaging. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:034048. [PMID: 19566340 PMCID: PMC3651892 DOI: 10.1117/1.3139850] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The Nikon C1 confocal laser scanning microscope is a relatively inexpensive and user-friendly instrument. We describe a straightforward method to convert the C1 for multiphoton microscopy utilizing direct coupling of a femtosecond near-infrared laser into the scan head and fiber optic transmission of emission light to the three-channel detector box. Our adapted system can be rapidly switched between confocal and multiphoton mode, requires no modification to the original system, and uses only a few custom-made parts. The entire system, including scan mirrors and detector box, remain under the control of the user-friendly Nikon EZ-C1 software without modification.
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Affiliation(s)
- James J. Mancuso
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza Houston, TX 77030
| | - Adam M. Larson
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza Houston, TX 77030
| | - Theodore G. Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza Houston, TX 77030
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza Houston, TX 77030
| | - Peter Saggau
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza Houston, TX 77030
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Behrend MR, Ahuja AK, Humayun MS, Weiland JD, Chow RH. Selective labeling of retinal ganglion cells with calcium indicators by retrograde loading in vitro. J Neurosci Methods 2009; 179:166-72. [PMID: 19428523 DOI: 10.1016/j.jneumeth.2009.01.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 01/22/2009] [Accepted: 01/22/2009] [Indexed: 11/26/2022]
Abstract
Here we present a retrograde loading technique that makes it possible for the first time to rapidly load a calcium indicator in the majority of retinal ganglion cells (RGCs) in salamander retina, and then to observe physiological activity of these dye-loaded cells. Dextran-conjugated calcium indicator, dissolved in water, was applied to the optic nerve stump. Following dye loading, the isolated retina was mounted on a microelectrode array to demonstrate that electrical activity and calcium activity were preserved, as the retina responded to electrical stimuli.
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Affiliation(s)
- Matthew R Behrend
- Dept. of Electrical Engineering, University of Southern California, Los Angeles, CA 90033, USA
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38
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Collings J, Poon SY, Le Droumaguet C, Charlot M, Katan C, Pålsson LO, Beeby A, Mosely J, Kaiser HM, Kaufmann D, Wong WY, Blanchard-Desce M, Marder T. The Synthesis and One- and Two-Photon Optical Properties of Dipolar, Quadrupolar and Octupolar Donor-Acceptor Molecules Containing Dimesitylboryl Groups. Chemistry 2009; 15:198-208. [DOI: 10.1002/chem.200801719] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Euler T, Hausselt SE, Margolis DJ, Breuninger T, Castell X, Detwiler PB, Denk W. Eyecup scope--optical recordings of light stimulus-evoked fluorescence signals in the retina. Pflugers Arch 2008; 457:1393-414. [PMID: 19023590 DOI: 10.1007/s00424-008-0603-5] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 10/09/2008] [Accepted: 10/15/2008] [Indexed: 12/22/2022]
Abstract
Dendritic signals play an essential role in processing visual information in the retina. To study them in neurites too small for electrical recording, we developed an instrument that combines a multi-photon (MP) microscope with a through-the-objective high-resolution visual stimulator. An upright microscope was designed that uses the objective lens for both MP imaging and delivery of visual stimuli to functionally intact retinal explants or eyecup preparations. The stimulator consists of a miniature liquid-crystal-on-silicon display coupled into the optical path of an infrared-excitation laser-scanning microscope. A pair of custom-made dichroic filters allows light from the excitation laser and three spectral bands ('colors') from the stimulator to reach the retina, leaving two intermediate bands for fluorescence imaging. Special optics allow displacement of the stimulator focus relative to the imaging focus. Spatially resolved changes in calcium-indicator fluorescence in response to visual stimuli were recorded in dendrites of different types of mammalian retinal neurons.
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Affiliation(s)
- Thomas Euler
- Department of Biomedical Optics, Max-Planck-Institute for Medical Research, Jahnstr. 29, 69120 Heidelberg, Germany.
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40
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Elsner AE, Muller MS. Laser applications and system considerations in ocular imaging. LASER & PHOTONICS REVIEWS 2008; 2:350-376. [PMID: 21052482 PMCID: PMC2967783 DOI: 10.1002/lpor.200810015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Accepted: 06/20/2008] [Indexed: 05/30/2023]
Abstract
We review laser applications for primarily in vivo ocular imaging techniques, describing their constraints based on biological tissue properties, safety, and the performance of the imaging system. We discuss the need for cost effective sources with practical wavelength tuning capabilities for spectral studies. Techniques to probe the pathological changes of layers beneath the highly scattering retina and diagnose the onset of various eye diseases are described. The recent development of several optical coherence tomography based systems for functional ocular imaging is reviewed, as well as linear and nonlinear ocular imaging techniques performed with ultrafast lasers, emphasizing recent source developments and methods to enhance imaging contrast.
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Affiliation(s)
- Ann E Elsner
- Indiana University School of Optometry Bloomington, IN, 47405, USA
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41
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Girardot C, Lemercier G, Mulatier JC, Andraud C, Chauvin J, Baldeck P. Novel 5-(oligofluorenyl)-1,10-phenanthroline type ligands: synthesis, linear and two-photon absorption properties. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.01.080] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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42
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Targeted patch-clamp recordings and single-cell electroporation of unlabeled neurons in vivo. Nat Methods 2007; 5:61-7. [DOI: 10.1038/nmeth1150] [Citation(s) in RCA: 277] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Accepted: 11/26/2007] [Indexed: 11/08/2022]
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43
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Denk W. Principles of multiphoton-excitation fluorescence microscopy. Cold Spring Harb Protoc 2007; 2007:pdb.top23. [PMID: 21356958 DOI: 10.1101/pdb.top23] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
INTRODUCTIONFluorescence microscopy has been gaining importance in quantitative biological research due to dramatic improvements in fluorophores, optical systems, light sources, and detectors. In particular, confocal fluorescence microscopy, usually by laser scanning, has for the first time allowed the observation of biological processes with high spatial resolution inside intact living tissue. Often called "optical sectioning," this method allows spatial reconstruction of 3D specimens without the use of a microtome. This article presents the physical mechanisms upon which the properties of multiphoton microscopy are based and discusses some practical aspects of its implementation.
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44
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Sen M, McMains E, Gleason E. Local influence of mitochondrial calcium transport in retinal amacrine cells. Vis Neurosci 2007; 24:663-78. [PMID: 17697441 DOI: 10.1017/s0952523807070551] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Accepted: 05/26/2007] [Indexed: 11/07/2022]
Abstract
Ca2+-dependent synaptic transmission from retinal amacrine cells is thought to be initiated locally at dendritic processes. Hence, understanding the spatial and temporal impact of Ca2+ transport is fundamental to understanding how amacrine cells operate. Here, we provide the first examination of the local effects of mitochondrial Ca2+ transport in neuronal processes. By combining mitochondrial localization with measurements of cytosolic Ca2+, the local impacts of mitochondrial Ca2+ transport for two types of Ca2+ signals were investigated. Disruption of mitochondrial Ca2+ uptake with carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP) produces cytosolic Ca2+ elevations. The amplitudes of these elevations decline with distance from mitochondria suggesting that they are related to mitochondrial Ca2+ transport. The time course of the FCCP-dependent Ca2+ elevations depend on the availability of ER Ca2+ and we provide evidence that Ca2+ is released primarily via nearby ryanodine receptors. These results indicate that interactions between the ER and mitochondria influence cytosolic Ca2+ in amacrine cell processes and cell bodies. We also demonstrate that the durations of glutamate-dependent Ca2+ elevations are dependent on their proximity to mitochondria in amacrine cell processes. Consistent with this observation, disruption of mitochondrial Ca2+ transport alters the duration of glutamate-dependent Ca2+ elevations near mitochondria but not at sites more than 10 microm away. These results indicate that mitochondria influence local Ca2+-dependent signaling in amacrine cell processes.
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Affiliation(s)
- Madhumita Sen
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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45
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Imanishi Y, Lodowski K, Koutalos Y. Two-photon microscopy: shedding light on the chemistry of vision. Biochemistry 2007; 46:9674-84. [PMID: 17676772 PMCID: PMC2718834 DOI: 10.1021/bi701055g] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Two-photon microscopy (TPM) has come to occupy a prominent place in modern biological research with its ability to resolve the three-dimensional distribution of molecules deep inside living tissue. TPM can employ two different types of signals, fluorescence and second harmonic generation, to image biological structures with subcellular resolution. Two-photon excited fluorescence imaging is a powerful technique with which to monitor the dynamic behavior of the chemical components of tissues, whereas second harmonic imaging provides novel ways to study their spatial organization. Using TPM, great strides have been made toward understanding the metabolism, structure, signal transduction, and signal transmission in the eye. These include the characterization of the spatial distribution, transport, and metabolism of the endogenous retinoids, molecules essential for the detection of light, as well as the elucidation of the architecture of the living cornea. In this review, we present and discuss the current applications of TPM for the chemical and structural imaging of the eye. In addition, we address what we see as the future potential of TPM for eye research. This relatively new method of microscopy has been the subject of numerous technical improvements in terms of the optics and indicators used, improvements that should lead to more detailed biochemical characterizations of the eyes of live animals and even to imaging of the human eye in vivo.
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Affiliation(s)
- Yoshikazu Imanishi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio
- To whom correspondence should be addressed:Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965. Phone: 216-368-5226. Fax: 216-368-1300. E-mail: (Y. I.); Department of Ophthalmology, Medical University of South, Carolina, Charleston, South Carolina 29425. Phone:843-792-9180. Fax: 843-792-1723. E-mail:(Y. K.)
| | - Kerrie Lodowski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Yiannis Koutalos
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South, Carolina
- To whom correspondence should be addressed:Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965. Phone: 216-368-5226. Fax: 216-368-1300. E-mail: (Y. I.); Department of Ophthalmology, Medical University of South, Carolina, Charleston, South Carolina 29425. Phone:843-792-9180. Fax: 843-792-1723. E-mail:(Y. K.)
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46
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Agulhon C, Platel JC, Kolomiets B, Forster V, Picaud S, Brocard J, Faure P, Brulet P. Bioluminescent imaging of Ca2+ activity reveals spatiotemporal dynamics in glial networks of dark-adapted mouse retina. J Physiol 2007; 583:945-58. [PMID: 17627996 PMCID: PMC2277207 DOI: 10.1113/jphysiol.2007.135715] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Glial Ca(2+) excitability plays a key role in reciprocal neuron-glia communication. In the retina, neuron-glia signalling is expected to be maximal in the dark, but the glial Ca(2+) signal characteristics under such conditions have not been evaluated. To address this question, we used bioluminescence imaging to monitor spontaneous Ca(2+) changes under dark conditions selectively in Müller cells, the principal retinal glial cells. By combining this imaging approach with network analysis, we demonstrate that activity in Müller cells is organized in networks of coactive cells, involving 2-16 cells located distantly and/or in clusters. We also report that spontaneous activity of small networks (2-6 Müller cells) repeat over time, sometimes in the same sequential order, revealing specific temporal dynamics. In addition, we show that networks of coactive glial cells are inhibited by TTX, indicating that ganglion and/or amacrine neuronal cells probably regulate Müller cell network properties. These results represent the first demonstration that spontaneous activity in adult Müller cells is patterned into correlated networks that display repeated sequences of coactivations over time. Furthermore, our bioluminescence technique provides a novel tool to study the dynamic characteristics of glial Ca(2+) events in the retina under dark conditions, which should greatly facilitate future investigations of retinal dark-adaptive processes.
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47
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Hausselt SE, Euler T, Detwiler PB, Denk W. A dendrite-autonomous mechanism for direction selectivity in retinal starburst amacrine cells. PLoS Biol 2007; 5:e185. [PMID: 17622194 PMCID: PMC1906843 DOI: 10.1371/journal.pbio.0050185] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Accepted: 05/15/2007] [Indexed: 11/18/2022] Open
Abstract
Detection of image motion direction begins in the retina, with starburst amacrine cells (SACs) playing a major role. SACs generate larger dendritic Ca(2+) signals when motion is from their somata towards their dendritic tips than for motion in the opposite direction. To study the mechanisms underlying the computation of direction selectivity (DS) in SAC dendrites, electrical responses to expanding and contracting circular wave visual stimuli were measured via somatic whole-cell recordings and quantified using Fourier analysis. Fundamental and, especially, harmonic frequency components were larger for expanding stimuli. This DS persists in the presence of GABA and glycine receptor antagonists, suggesting that inhibitory network interactions are not essential. The presence of harmonics indicates nonlinearity, which, as the relationship between harmonic amplitudes and holding potential indicates, is likely due to the activation of voltage-gated channels. [Ca(2+)] changes in SAC dendrites evoked by voltage steps and monitored by two-photon microscopy suggest that the distal dendrite is tonically depolarized relative to the soma, due in part to resting currents mediated by tonic glutamatergic synaptic input, and that high-voltage-activated Ca(2+) channels are active at rest. Supported by compartmental modeling, we conclude that dendritic DS in SACs can be computed by the dendrites themselves, relying on voltage-gated channels and a dendritic voltage gradient, which provides the spatial asymmetry necessary for direction discrimination.
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Affiliation(s)
- Susanne E Hausselt
- Department of Biomedical Optics, Max-Planck Institute for Medical Research, Heidelberg, Germany
| | - Thomas Euler
- Department of Biomedical Optics, Max-Planck Institute for Medical Research, Heidelberg, Germany
- * To whom correspondence should be addressed. E-mail:
| | - Peter B Detwiler
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington, United States of America
| | - Winfried Denk
- Department of Biomedical Optics, Max-Planck Institute for Medical Research, Heidelberg, Germany
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48
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Sheng Z, Choi SY, Dharia A, Li J, Sterling P, Kramer RH. Synaptic Ca2+ in darkness is lower in rods than cones, causing slower tonic release of vesicles. J Neurosci 2007; 27:5033-42. [PMID: 17494689 PMCID: PMC6672389 DOI: 10.1523/jneurosci.5386-06.2007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Rod and cone photoreceptors use specialized biochemistry to generate light responses that differ in their sensitivity and kinetics. However, it is unclear whether there are also synaptic differences that affect the transmission of visual information. Here, we report that in the dark, rods tonically release synaptic vesicles at a much slower rate than cones, as measured by the release of the fluorescent vesicle indicator FM1-43. To determine whether slower release results from a lower Ca2+ sensitivity or a lower dark concentration of Ca2+, we imaged fluorescent indicators of synaptic vesicle cycling and intraterminal Ca2+. We report that the Ca2+ sensitivity of release is indistinguishable in rods and cones, consistent with their possessing similar release machinery. However, the dark intraterminal Ca2+ concentration is lower in rods than in cones, as determined by two-photon Ca2+ imaging. The lower level of dark Ca2+ ensures that rods encode intensity with a slower vesicle release rate that is better matched to the lower information content of dim light.
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Affiliation(s)
- Zejuan Sheng
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, and
| | - Sue-Yeon Choi
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, and
| | - Ajay Dharia
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, and
| | - Jian Li
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Peter Sterling
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Richard H. Kramer
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, and
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49
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Margolis DJ, Detwiler PB. Different mechanisms generate maintained activity in ON and OFF retinal ganglion cells. J Neurosci 2007; 27:5994-6005. [PMID: 17537971 PMCID: PMC3136104 DOI: 10.1523/jneurosci.0130-07.2007] [Citation(s) in RCA: 161] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neuronal discharge is driven by either synaptic input or cell-autonomous intrinsic pacemaker activity. It is commonly assumed that the resting spike activity of retinal ganglion cells (RGCs), the output cells of the retina, is driven synaptically, because retinal photoreceptors and second-order cells tonically release neurotransmitter. Here we show that ON and OFF RGCs generate maintained activity through different mechanisms: ON cells depend on tonic excitatory input to drive resting activity, whereas OFF cells continue to fire in the absence of synaptic input. In addition to spontaneous activity, OFF cells exhibit other properties of pacemaker neurons, including subthreshold oscillations, burst firing, and rebound excitation. Thus, variable weighting of synaptic mechanisms and intrinsic properties underlies differences in the generation of maintained activity in these parallel retinal pathways.
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Affiliation(s)
- David J Margolis
- Program in Neurobiology and Behavior and Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195, USA.
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50
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Davenport CM, Detwiler PB, Dacey DM. Functional polarity of dendrites and axons of primate A1 amacrine cells. Vis Neurosci 2007; 24:449-57. [PMID: 17550636 PMCID: PMC3130004 DOI: 10.1017/s0952523807070010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Accepted: 12/16/2006] [Indexed: 11/06/2022]
Abstract
The A1 cell is an axon-bearing amacrine cell of the primate retina with a diffusely stratified, moderately branched dendritic tree (approximately 400 microm diameter). Axons arise from proximal dendrites forming a second concentric, larger arborization (>4 mm diameter) of thin processes with bouton-like swellings along their length. A1 cells are ON-OFF transient cells that fire a brief high frequency burst of action potentials in response to light (Stafford & Dacey, 1997). It has been hypothesized that A1 cells receive local input to their dendrites, with action potentials propagating output via the axons across the retina, serving a global inhibitory function. To explore this hypothesis we recorded intracellularly from A1 cells in an in vitro macaque monkey retina preparation. A1 cells have an antagonistic center-surround receptive field structure for the ON and OFF components of the light response. Blocking the ON pathway with L-AP4 eliminated ON center responses but not OFF center responses or ON or OFF surround responses. Blocking GABAergic inhibition with picrotoxin increased response amplitudes without affecting receptive field structure. TTX abolished action potentials, with little effect on the sub-threshold light response or basic receptive field structure. We also used multi-photon laser scanning microscopy to record light-induced calcium transients in morphologically identified dendrites and axons of A1 cells. TTX completely abolished such calcium transients in the axons but not in the dendrites. Together these results support the current model of A1 function, whereby the dendritic tree receives synaptic input that determines the center-surround receptive field; and action potentials arise in the axons, which propagate away from the dendritic field across the retina.
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Affiliation(s)
- Christopher M Davenport
- Neurobiology and Behavior Graduate Program, University of Washington, Seattle, Washington 98195, USA.
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