1
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Moya-Díaz J, Simões P, Lagnado L. Substance P and dopamine form a "push-pull" system that diurnally regulates retinal gain. Curr Biol 2024; 34:5028-5039.e3. [PMID: 39419032 DOI: 10.1016/j.cub.2024.09.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 08/07/2024] [Accepted: 09/18/2024] [Indexed: 10/19/2024]
Abstract
The operation of the retina, like other brain circuits, is under modulatory control. One coordinator of changes in retinal function is dopamine, a neuromodulator released in a light-dependent way to adjust vision on a diurnal cycle. Here, we demonstrate that substance P is a similarly powerful retinal modulator that interacts with the dopamine system. By imaging glutamatergic synaptic transmission in larval zebrafish, we find that substance P decreases the contrast sensitivity of ON and OFF visual channels up to 8-fold, with suppression of visual signals being strongest through the "transient" pathway responding to higher frequencies. These actions are exerted in the morning, in large part by suppressing the amplification of visual signals by dopamine, but substance P is almost completely inactive in the afternoon. Modulation of retinal gain is accompanied by changes in patterns of vesicle release at the synapses of bipolar cells: increased gain shifts coding of stimulus strength from the rate of release events to their amplitude generated by a process of multivesicular release (MVR). Together, these actions of substance P reduce the flow of visual information, measured in bits, ∼3-fold. Thus, whereas dopamine "pushes" the retina to transmit information at higher rates in the afternoon, substance P acts in antiphase to suppress dopamine signaling and "pull down" information transmission in the morning.
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Affiliation(s)
- José Moya-Díaz
- Neuroscience, School of Life Sciences, University of Sussex, Sussex, Brighton BN19QG, UK
| | - Patrício Simões
- Neuroscience, School of Life Sciences, University of Sussex, Sussex, Brighton BN19QG, UK
| | - Leon Lagnado
- Neuroscience, School of Life Sciences, University of Sussex, Sussex, Brighton BN19QG, UK.
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2
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Dey H, Perez-Hurtado M, Heidelberger R. Syntaxin 3B: A SNARE Protein Required for Vision. Int J Mol Sci 2024; 25:10665. [PMID: 39408994 PMCID: PMC11476516 DOI: 10.3390/ijms251910665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2024] [Revised: 09/24/2024] [Accepted: 09/25/2024] [Indexed: 10/20/2024] Open
Abstract
Syntaxin 3 is a member of a large protein family of syntaxin proteins that mediate fusion between vesicles and their target membranes. Mutations in the ubiquitously expressed syntaxin 3A splice form give rise to a serious gastrointestinal disorder in humans called microvillus inclusion disorder, while mutations that additionally involve syntaxin 3B, a splice form that is expressed primarily in retinal photoreceptors and bipolar cells, additionally give rise to an early onset severe retinal dystrophy. In this review, we discuss recent studies elucidating the roles of syntaxin 3B and the regulation of syntaxin 3B functionality in membrane fusion and neurotransmitter release in the vertebrate retina.
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Affiliation(s)
| | | | - Ruth Heidelberger
- Department of Neurobiology and Anatomy, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX 77030, USA; (H.D.)
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3
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Doszyn O, Dulski T, Zmorzynska J. Diving into the zebrafish brain: exploring neuroscience frontiers with genetic tools, imaging techniques, and behavioral insights. Front Mol Neurosci 2024; 17:1358844. [PMID: 38533456 PMCID: PMC10963419 DOI: 10.3389/fnmol.2024.1358844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 02/27/2024] [Indexed: 03/28/2024] Open
Abstract
The zebrafish (Danio rerio) is increasingly used in neuroscience research. Zebrafish are relatively easy to maintain, and their high fecundity makes them suitable for high-throughput experiments. Their small, transparent embryos and larvae allow for easy microscopic imaging of the developing brain. Zebrafish also share a high degree of genetic similarity with humans, and are amenable to genetic manipulation techniques, such as gene knockdown, knockout, or knock-in, which allows researchers to study the role of specific genes relevant to human brain development, function, and disease. Zebrafish can also serve as a model for behavioral studies, including locomotion, learning, and social interactions. In this review, we present state-of-the-art methods to study the brain function in zebrafish, including genetic tools for labeling single neurons and neuronal circuits, live imaging of neural activity, synaptic dynamics and protein interactions in the zebrafish brain, optogenetic manipulation, and the use of virtual reality technology for behavioral testing. We highlight the potential of zebrafish for neuroscience research, especially regarding brain development, neuronal circuits, and genetic-based disorders and discuss its certain limitations as a model.
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Affiliation(s)
| | | | - J. Zmorzynska
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw (IIMCB), Warsaw, Poland
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4
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Grabner CP, Futagi D, Shi J, Bindokas V, Kitano K, Schwartz EA, DeVries SH. Mechanisms of simultaneous linear and nonlinear computations at the mammalian cone photoreceptor synapse. Nat Commun 2023; 14:3486. [PMID: 37328451 PMCID: PMC10276006 DOI: 10.1038/s41467-023-38943-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 05/22/2023] [Indexed: 06/18/2023] Open
Abstract
Neurons enhance their computational power by combining linear and nonlinear transformations in extended dendritic trees. Rich, spatially distributed processing is rarely associated with individual synapses, but the cone photoreceptor synapse may be an exception. Graded voltages temporally modulate vesicle fusion at a cone's ~20 ribbon active zones. Transmitter then flows into a common, glia-free volume where bipolar cell dendrites are organized by type in successive tiers. Using super-resolution microscopy and tracking vesicle fusion and postsynaptic responses at the quantal level in the thirteen-lined ground squirrel, Ictidomys tridecemlineatus, we show that certain bipolar cell types respond to individual fusion events in the vesicle stream while other types respond to degrees of locally coincident events, creating a gradient across tiers that are increasingly nonlinear. Nonlinearities emerge from a combination of factors specific to each bipolar cell type including diffusion distance, contact number, receptor affinity, and proximity to glutamate transporters. Complex computations related to feature detection begin within the first visual synapse.
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Affiliation(s)
- Chad P Grabner
- Institute for Auditory Neuroscience, University Medical Center Göttingen, 37075, Göttingen, Germany
- Synaptic Nanophysiology Group, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Daiki Futagi
- College of Information Science and Engineering, Ritsumeikan University, Shiga, Japan
- Center for Systems Visual Science, Organization of Science and Technology, Ritsumeikan University, Shiga, Japan
- Ritsumeikan Global Innovation Research Organisation, Ritsumeikan University, Shiga, Japan
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Jun Shi
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Vytas Bindokas
- Dept of Pharmacological and Physiological Sciences, The University of Chicago, Chicago, IL, 60637, USA
| | - Katsunori Kitano
- College of Information Science and Engineering, Ritsumeikan University, Shiga, Japan
- Center for Systems Visual Science, Organization of Science and Technology, Ritsumeikan University, Shiga, Japan
| | - Eric A Schwartz
- Dept of Pharmacological and Physiological Sciences, The University of Chicago, Chicago, IL, 60637, USA
| | - Steven H DeVries
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
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5
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Pennock RL, Coddington LT, Yan X, Overstreet-Wadiche L, Wadiche JI. Afferent convergence to a shared population of interneuron AMPA receptors. Nat Commun 2023; 14:3113. [PMID: 37253743 PMCID: PMC10229553 DOI: 10.1038/s41467-023-38854-2] [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: 12/19/2022] [Accepted: 05/12/2023] [Indexed: 06/01/2023] Open
Abstract
Precise alignment of pre- and postsynaptic elements optimizes the activation of glutamate receptors at excitatory synapses. Nonetheless, glutamate that diffuses out of the synaptic cleft can have actions at distant receptors, a mode of transmission called spillover. To uncover the extrasynaptic actions of glutamate, we localized AMPA receptors (AMPARs) mediating spillover transmission between climbing fibers and molecular layer interneurons in the cerebellar cortex. We found that climbing fiber spillover generates calcium transients mediated by Ca2+-permeable AMPARs at parallel fiber synapses. Spillover occludes parallel fiber synaptic currents, indicating that separate, independently regulated afferent pathways converge onto a common pool of AMPARs. Together these findings demonstrate a circuit motif wherein glutamate 'spill-in' from an unconnected afferent pathway co-opts synaptic receptors, allowing activation of postsynaptic AMPARs even when canonical glutamate release is suppressed.
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Affiliation(s)
- Reagan L Pennock
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Luke T Coddington
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
- Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, 20147, USA
| | - Xiaohui Yan
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | | | - Jacques I Wadiche
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
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6
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Martínez San Segundo P, Terni B, Llobet A. Multivesicular release favors short term synaptic depression in hippocampal autapses. Front Cell Neurosci 2023; 17:1057242. [PMID: 37265578 PMCID: PMC10230035 DOI: 10.3389/fncel.2023.1057242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 04/10/2023] [Indexed: 06/03/2023] Open
Abstract
Presynaptic terminals of the central nervous system can support univesicular and multivesicular synchronous release of neurotransmitters, however, the functional implications of the prevalence of one mechanism over the other are yet unresolved. Here, we took advantage of the expression of SF-iGluSnFR.S72A in the astrocytic feeder layer of autaptic hippocampal neuronal cultures to associate the liberation of glutamate to excitatory postsynaptic currents. The presence of the glutamate sensor in glial cells avoided any interference with the function of endogenous postsynaptic receptors. It was possible to optically detect changes in neurotransmitter release probability, which was heterogeneous among synaptic boutons studied. For each neuron investigated, the liberation of neurotransmitters occurred through a predominant mechanism. The prevalence of multivesicular over univesicular release increased synaptic strength and enhanced short-term synaptic depression. These results show that the preference of hippocampal boutons to synchronously release one or more vesicles determines the strength and low pass filtering properties of the synapses established.
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Affiliation(s)
- Pablo Martínez San Segundo
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Beatrice Terni
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Artur Llobet
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
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7
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Nij Bijvank J, Maillette de Buy Wenniger L, de Graaf P, Petzold A. Clinical review of retinotopy. Br J Ophthalmol 2023; 107:304-312. [PMID: 34887243 DOI: 10.1136/bjophthalmol-2021-320563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 11/14/2021] [Indexed: 11/03/2022]
Abstract
Two observations made 29 years apart are the cornerstones of this review on the contributions of Dr Gordon T. Plant to understanding pathology affecting the optic nerve. The first observation laid the anatomical basis in 1990 for the interpretation of optical coherence tomography (OCT) findings in 2009. Retinal OCT offers clinicians detailed in vivo structural imaging of individual retinal layers. This has led to novel observations which were impossible to make using ophthalmoscopy. The technique also helps to re-introduce the anatomically grounded concept of retinotopy to clinical practise. This review employs illustrations of the anatomical basis for retinotopy through detailed translational histological studies and multimodal brain-eye imaging studies. The paths of the prelaminar and postlaminar axons forming the optic nerve and their postsynaptic path from the dorsal lateral geniculate nucleus to the primary visual cortex in humans are described. With the mapped neuroanatomy in mind we use OCT-MRI pairings to discuss the patterns of neurodegeneration in eye and brain that are a consequence of the hard wired retinotopy: anterograde and retrograde axonal degeneration which can, within the visual system, propagate trans-synaptically. The technical advances of OCT and MRI for the first time enable us to trace axonal degeneration through the entire visual system at spectacular resolution. In conclusion, the neuroanatomical insights provided by the combination of OCT and MRI allows us to separate incidental findings from sinister pathology and provides new opportunities to tailor and monitor novel neuroprotective strategies.
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Affiliation(s)
- Jenny Nij Bijvank
- Departments of Ophthalmology and Neurology, Expertise Centre Neuro-ophthalmology, Amsterdam UMC Locatie VUmc, Amsterdam, The Netherlands
| | | | - Pim de Graaf
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.,Department of Neurology, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Axel Petzold
- Departments of Ophthalmology and Neurology, Expertise Centre Neuro-ophthalmology, Amsterdam UMC Locatie VUmc, Amsterdam, The Netherlands .,Moorfields Eye Hospital, City Road; The National Hospital for Neurology and Neurosurgery and the UCL Institute of Neurology, Queen Square, London, London, UK
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8
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Tian H, Wang C, Chen Y, Zheng L, Jing H, Xu L, Wang X, Liu Y, Hao J. Optically modulated ionic conductivity in a hydrogel for emulating synaptic functions. SCIENCE ADVANCES 2023; 9:eadd6950. [PMID: 36791203 PMCID: PMC9931204 DOI: 10.1126/sciadv.add6950] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 01/11/2023] [Indexed: 06/18/2023]
Abstract
Ion-conductive hydrogels, with ions as signal carriers, have become promising candidates to construct functional ionotronics for sensing, actuating, and robotics engineering. However, rational modulation of ionic migration to mimic biological information processing, including learning and memory, remains challenging to be realized in hydrogel materials. Here, we develop a hybrid hydrogel with optically modulated ionic conductivity to emulate the functions of a biological synapse. Through a responsive supramolecular approach, optical stimuli can trigger the release of mobile ions for tuning the conductivity of the hydrogel, which is analogous to the modulation of synaptic plasticity. As a proof of concept, this hydrogel can be used as an information processing unit to perceive different optical stimuli and regulate the grasping motion of a robotic hand, performing logical motion feedback with "learning-experience" function. Our ionic hydrogel provides a valuable strategy toward developing bioinspired ionotronic systems and pushes forward the functional applications of hydrogel materials.
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Affiliation(s)
- Huasheng Tian
- Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong, China
- Suzhou Research Institute, Shandong University, Suzhou, Jiangsu, China
| | - Chen Wang
- Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong, China
| | - Yuwei Chen
- Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong, China
| | - Liping Zheng
- Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong, China
| | - Houchao Jing
- Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong, China
- Suzhou Research Institute, Shandong University, Suzhou, Jiangsu, China
| | - Lin Xu
- Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong, China
- Suzhou Research Institute, Shandong University, Suzhou, Jiangsu, China
| | - Xuanqi Wang
- School of Software, Shandong University, Jinan, Shandong, China
| | - Yaqing Liu
- Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong, China
- Suzhou Research Institute, Shandong University, Suzhou, Jiangsu, China
| | - Jingcheng Hao
- Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong, China
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9
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Hao Y, Toulmé E, König B, Rosenmund C, Plested AJR. Targeted sensors for glutamatergic neurotransmission. eLife 2023; 12:e84029. [PMID: 36622100 PMCID: PMC9917459 DOI: 10.7554/elife.84029] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 01/06/2023] [Indexed: 01/10/2023] Open
Abstract
Optical report of neurotransmitter release allows visualisation of excitatory synaptic transmission. Sensitive genetically-encoded fluorescent glutamate reporters operating with a range of affinities and emission wavelengths are available. However, without targeting to synapses, the specificity of the fluorescent signal is uncertain, compared to sensors directed at vesicles or other synaptic markers. We fused the state-of-the-art reporter iGluSnFR to glutamate receptor auxiliary proteins in order to target it to postsynaptic sites. Chimeras of Stargazin and gamma-8 that we named SnFR-γ2 and SnFR-γ8, were enriched at synapses, retained function and reported spontaneous glutamate release in rat hippocampal cells, with apparently diffraction-limited spatial precision. In autaptic mouse neurons cultured on astrocytic microislands, evoked neurotransmitter release could be quantitatively detected at tens of synapses in a field of view whilst evoked currents were recorded simultaneously. These experiments revealed a specific postsynaptic deficit from Stargazin overexpression, resulting in synapses with normal neurotransmitter release but without postsynaptic responses. This defect was reverted by delaying overexpression. By working at different calcium concentrations, we determined that SnFR-γ2 is a linear reporter of the global quantal parameters and short-term synaptic plasticity, whereas iGluSnFR is not. On average, half of iGluSnFR regions of interest (ROIs) showing evoked fluorescence changes had intense rundown, whereas less than 5% of SnFR-γ2 ROIs did. We provide an open-source analysis suite for extracting quantal parameters including release probability from fluorescence time series of individual and grouped synaptic responses. Taken together, postsynaptic targeting improves several properties of iGluSnFR and further demonstrates the importance of subcellular targeting for optogenetic actuators and reporters.
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Affiliation(s)
- Yuchen Hao
- Institute of Biology, Cellular Biophysics, Humboldt-Universität zu BerlinBerlinGermany
- Leibniz-Forschungsinstitut für Molekulare PharmakologieBerlinGermany
| | - Estelle Toulmé
- Institute for Neurophysiology, Charité - Universitätsmedizin BerlinBerlinGermany
| | - Benjamin König
- Institute of Biology, Cellular Biophysics, Humboldt-Universität zu BerlinBerlinGermany
- Leibniz-Forschungsinstitut für Molekulare PharmakologieBerlinGermany
| | - Christian Rosenmund
- Institute for Neurophysiology, Charité - Universitätsmedizin BerlinBerlinGermany
- NeuroCure Cluster of ExcellenceBerlinGermany
| | - Andrew JR Plested
- Institute of Biology, Cellular Biophysics, Humboldt-Universität zu BerlinBerlinGermany
- Leibniz-Forschungsinstitut für Molekulare PharmakologieBerlinGermany
- NeuroCure Cluster of ExcellenceBerlinGermany
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10
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Johnson E, Clark M, Oncul M, Pantiru A, MacLean C, Deuchars J, Deuchars SA, Johnston J. Graded spikes differentially signal neurotransmitter input in cerebrospinal fluid contacting neurons of the mouse spinal cord. iScience 2022; 26:105914. [PMID: 36691620 PMCID: PMC9860393 DOI: 10.1016/j.isci.2022.105914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 12/06/2022] [Accepted: 12/27/2022] [Indexed: 12/31/2022] Open
Abstract
The action potential and its all-or-none nature is fundamental to neural communication. Canonically, the action potential is initiated once voltage-activated Na+ channels are activated, and their rapid kinetics of activation and inactivation give rise to the action potential's all-or-none nature. Here we demonstrate that cerebrospinal fluid contacting neurons (CSFcNs) surrounding the central canal of the mouse spinal cord employ a different strategy. Rather than using voltage-activated Na+ channels to generate binary spikes, CSFcNs use two different types of voltage-activated Ca2+ channel, enabling spikes of different amplitude. T-type Ca2+ channels generate small amplitude spikes, whereas larger amplitude spikes require high voltage-activated Cd2+-sensitive Ca2+ channels. We demonstrate that these different amplitude spikes can signal input from different transmitter systems; purinergic inputs evoke smaller T-type dependent spikes whereas cholinergic inputs evoke larger spikes that do not rely on T-type channels. Different synaptic inputs to CSFcNs can therefore be signaled by the spike amplitude.
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Affiliation(s)
- Emily Johnson
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Marilyn Clark
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Merve Oncul
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Andreea Pantiru
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Claudia MacLean
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Jim Deuchars
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Susan A. Deuchars
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Jamie Johnston
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK,Corresponding author
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11
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Dürst CD, Wiegert JS, Schulze C, Helassa N, Török K, Oertner TG. Vesicular release probability sets the strength of individual Schaffer collateral synapses. Nat Commun 2022; 13:6126. [PMID: 36253353 PMCID: PMC9576736 DOI: 10.1038/s41467-022-33565-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 09/22/2022] [Indexed: 12/24/2022] Open
Abstract
Information processing in the brain is controlled by quantal release of neurotransmitters, a tightly regulated process. From ultrastructural analysis, it is known that presynaptic boutons along single axons differ in the number of vesicles docked at the active zone. It is not clear whether the probability of these vesicles to get released (pves) is homogenous or also varies between individual boutons. Here, we optically measure evoked transmitter release at individual Schaffer collateral synapses at different calcium concentrations, using the genetically encoded glutamate sensor iGluSnFR. Fitting a binomial model to measured response amplitude distributions allowed us to extract the quantal parameters N, pves, and q. We find that Schaffer collateral boutons typically release single vesicles under low pves conditions and switch to multivesicular release in high calcium saline. The potency of individual boutons is highly correlated with their vesicular release probability while the number of releasable vesicles affects synaptic output only under high pves conditions.
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Affiliation(s)
- Céline D Dürst
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg (ZMNH), 20251, Hamburg, Germany
- Department of Basic Neurosciences, Center for Neurosciences (CMU), University of Geneva, 1211, Geneva, Switzerland
| | - J Simon Wiegert
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg (ZMNH), 20251, Hamburg, Germany
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg (ZMNH), 20251, Hamburg, Germany
| | - Christian Schulze
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg (ZMNH), 20251, Hamburg, Germany
| | - Nordine Helassa
- Cell Biology and Genetics Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London, SW17 0RE, UK
- Department of Cardiovascular and Metabolic Medicine, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - Katalin Török
- Cell Biology and Genetics Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London, SW17 0RE, UK
| | - Thomas G Oertner
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg (ZMNH), 20251, Hamburg, Germany.
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12
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Mendonça PRF, Tagliatti E, Langley H, Kotzadimitriou D, Zamora-Chimal CG, Timofeeva Y, Volynski KE. Asynchronous glutamate release is enhanced in low release efficacy synapses and dispersed across the active zone. Nat Commun 2022; 13:3497. [PMID: 35715404 PMCID: PMC9206079 DOI: 10.1038/s41467-022-31070-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 05/31/2022] [Indexed: 11/09/2022] Open
Abstract
The balance between fast synchronous and delayed asynchronous release of neurotransmitters has a major role in defining computational properties of neuronal synapses and regulation of neuronal network activity. However, how it is tuned at the single synapse level remains poorly understood. Here, using the fluorescent glutamate sensor SF-iGluSnFR, we image quantal vesicular release in tens to hundreds of individual synaptic outputs from single pyramidal cells with 4 millisecond temporal and 75 nm spatial resolution. We find that the ratio between synchronous and asynchronous synaptic vesicle exocytosis varies extensively among synapses supplied by the same axon, and that the synchronicity of release is reduced at low release probability synapses. We further demonstrate that asynchronous exocytosis sites are more widely distributed within the release area than synchronous sites. Together, our results reveal a universal relationship between the two major functional properties of synapses - the timing and the overall efficacy of neurotransmitter release.
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Affiliation(s)
- Philipe R F Mendonça
- University College London Institute of Neurology, London, UK. .,Department of Physiology and Biophysics, Federal University of Minas Gerais, Gerais, Brazil.
| | - Erica Tagliatti
- University College London Institute of Neurology, London, UK
| | - Helen Langley
- University College London Institute of Neurology, London, UK
| | | | | | - Yulia Timofeeva
- University College London Institute of Neurology, London, UK. .,Department of Computer Science, University of Warwick, Coventry, UK.
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13
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Diurnal changes in the efficiency of information transmission at a sensory synapse. Nat Commun 2022; 13:2613. [PMID: 35551183 PMCID: PMC9098879 DOI: 10.1038/s41467-022-30202-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 04/21/2022] [Indexed: 11/29/2022] Open
Abstract
Neuromodulators adapt sensory circuits to changes in the external world or the animal’s internal state and synapses are key control sites for such plasticity. Less clear is how neuromodulation alters the amount of information transmitted through the circuit. We investigated this question in the context of the diurnal regulation of visual processing in the retina of zebrafish, focusing on ribbon synapses of bipolar cells. We demonstrate that contrast-sensitivity peaks in the afternoon accompanied by a four-fold increase in the average Shannon information transmitted from an active zone. This increase reflects higher synaptic gain, lower spontaneous “noise” and reduced variability of evoked responses. Simultaneously, an increase in the probability of multivesicular events with larger information content increases the efficiency of transmission (bits per vesicle) by factors of 1.5-2.7. This study demonstrates the multiplicity of mechanisms by which a neuromodulator can adjust the synaptic transfer of sensory information. Neuromodulators can adjust how sensory signals are processed. In this study, the authors demonstrate how time of day affects the way information is transmitted in the zebrafish retina.
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14
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Liu JK, Karamanlis D, Gollisch T. Simple model for encoding natural images by retinal ganglion cells with nonlinear spatial integration. PLoS Comput Biol 2022; 18:e1009925. [PMID: 35259159 PMCID: PMC8932571 DOI: 10.1371/journal.pcbi.1009925] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 03/18/2022] [Accepted: 02/14/2022] [Indexed: 01/05/2023] Open
Abstract
A central goal in sensory neuroscience is to understand the neuronal signal processing involved in the encoding of natural stimuli. A critical step towards this goal is the development of successful computational encoding models. For ganglion cells in the vertebrate retina, the development of satisfactory models for responses to natural visual scenes is an ongoing challenge. Standard models typically apply linear integration of visual stimuli over space, yet many ganglion cells are known to show nonlinear spatial integration, in particular when stimulated with contrast-reversing gratings. We here study the influence of spatial nonlinearities in the encoding of natural images by ganglion cells, using multielectrode-array recordings from isolated salamander and mouse retinas. We assess how responses to natural images depend on first- and second-order statistics of spatial patterns inside the receptive field. This leads us to a simple extension of current standard ganglion cell models. We show that taking not only the weighted average of light intensity inside the receptive field into account but also its variance over space can partly account for nonlinear integration and substantially improve response predictions of responses to novel images. For salamander ganglion cells, we find that response predictions for cell classes with large receptive fields profit most from including spatial contrast information. Finally, we demonstrate how this model framework can be used to assess the spatial scale of nonlinear integration. Our results underscore that nonlinear spatial stimulus integration translates to stimulation with natural images. Furthermore, the introduced model framework provides a simple, yet powerful extension of standard models and may serve as a benchmark for the development of more detailed models of the nonlinear structure of receptive fields. For understanding how sensory systems operate in the natural environment, an important goal is to develop models that capture neuronal responses to natural stimuli. For retinal ganglion cells, which connect the eye to the brain, current standard models often fail to capture responses to natural visual scenes. This shortcoming is at least partly rooted in the fact that ganglion cells may combine visual signals over space in a nonlinear fashion. We here show that a simple model, which not only considers the average light intensity inside a cell’s receptive field but also the variance of light intensity over space, can partly account for these nonlinearities and thereby improve current standard models. This provides an easy-to-obtain benchmark for modeling ganglion cell responses to natural images.
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Affiliation(s)
- Jian K. Liu
- University Medical Center Göttingen, Department of Ophthalmology, Göttingen, Germany
- Bernstein Center for Computational Neuroscience Göttingen, Göttingen, Germany
- School of Computing, University of Leeds, Leeds, United Kingdom
| | - Dimokratis Karamanlis
- University Medical Center Göttingen, Department of Ophthalmology, Göttingen, Germany
- Bernstein Center for Computational Neuroscience Göttingen, Göttingen, Germany
- International Max Planck Research School for Neurosciences, Göttingen, Germany
| | - Tim Gollisch
- University Medical Center Göttingen, Department of Ophthalmology, Göttingen, Germany
- Bernstein Center for Computational Neuroscience Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
- * E-mail:
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15
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Hao Y, Plested AJ. Seeing glutamate at central synapses. J Neurosci Methods 2022; 375:109531. [DOI: 10.1016/j.jneumeth.2022.109531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 12/15/2022]
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16
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Srivastava P, de Rosenroll G, Matsumoto A, Michaels T, Turple Z, Jain V, Sethuramanujam S, Murphy-Baum BL, Yonehara K, Awatramani GB. Spatiotemporal properties of glutamate input support direction selectivity in the dendrites of retinal starburst amacrine cells. eLife 2022; 11:81533. [PMID: 36346388 PMCID: PMC9674338 DOI: 10.7554/elife.81533] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
The asymmetric summation of kinetically distinct glutamate inputs across the dendrites of retinal 'starburst' amacrine cells is one of the several mechanisms that have been proposed to underlie their direction-selective properties, but experimentally verifying input kinetics has been a challenge. Here, we used two-photon glutamate sensor (iGluSnFR) imaging to directly measure the input kinetics across individual starburst dendrites. We found that signals measured from proximal dendrites were relatively sustained compared to those measured from distal dendrites. These differences were observed across a range of stimulus sizes and appeared to be shaped mainly by excitatory rather than inhibitory network interactions. Temporal deconvolution analysis suggests that the steady-state vesicle release rate was ~3 times larger at proximal sites compared to distal sites. Using a connectomics-inspired computational model, we demonstrate that input kinetics play an important role in shaping direction selectivity at low stimulus velocities. Taken together, these results provide direct support for the 'space-time wiring' model for direction selectivity.
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Affiliation(s)
| | | | - Akihiro Matsumoto
- Danish Research Institute of Translational Neuroscience, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus UniversityAarhusDenmark
| | - Tracy Michaels
- Department of Biology, University of VictoriaVictoriaCanada
| | - Zachary Turple
- Department of Biology, University of VictoriaVictoriaCanada
| | - Varsha Jain
- Department of Biology, University of VictoriaVictoriaCanada
| | | | | | - Keisuke Yonehara
- Danish Research Institute of Translational Neuroscience, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus UniversityAarhusDenmark
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17
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Matsumoto A, Agbariah W, Nolte SS, Andrawos R, Levi H, Sabbah S, Yonehara K. Direction selectivity in retinal bipolar cell axon terminals. Neuron 2021; 109:2928-2942.e8. [PMID: 34390651 PMCID: PMC8478419 DOI: 10.1016/j.neuron.2021.07.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 06/18/2021] [Accepted: 07/09/2021] [Indexed: 12/20/2022]
Abstract
The ability to encode the direction of image motion is fundamental to our sense of vision. Direction selectivity along the four cardinal directions is thought to originate in direction-selective ganglion cells (DSGCs) because of directionally tuned GABAergic suppression by starburst cells. Here, by utilizing two-photon glutamate imaging to measure synaptic release, we reveal that direction selectivity along all four directions arises earlier than expected at bipolar cell outputs. Individual bipolar cells contained four distinct populations of axon terminal boutons with different preferred directions. We further show that this bouton-specific tuning relies on cholinergic excitation from starburst cells and GABAergic inhibition from wide-field amacrine cells. DSGCs received both tuned directionally aligned inputs and untuned inputs from among heterogeneously tuned glutamatergic bouton populations. Thus, directional tuning in the excitatory visual pathway is incrementally refined at the bipolar cell axon terminals and their recipient DSGC dendrites by two different neurotransmitters co-released from starburst cells.
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Affiliation(s)
- Akihiro Matsumoto
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Ole Worms Allé 8, 8000 Aarhus C, Denmark
| | - Weaam Agbariah
- Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Stella Solveig Nolte
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Ole Worms Allé 8, 8000 Aarhus C, Denmark
| | - Rawan Andrawos
- Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Hadara Levi
- Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Shai Sabbah
- Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel.
| | - Keisuke Yonehara
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Ole Worms Allé 8, 8000 Aarhus C, Denmark.
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18
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Van Dyck M, Mishra RK, Pestana F, Verstraelen P, Lavreysen H, Pita-Almenar JD, Kashikar ND, De Vos WH. High-throughput Analysis of Synaptic Activity in Electrically Stimulated Neuronal Cultures. Neuroinformatics 2021; 19:737-750. [PMID: 34374965 DOI: 10.1007/s12021-021-09536-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2021] [Indexed: 10/20/2022]
Abstract
Synaptic dysfunction is a hallmark of various neurodegenerative and neurodevelopmental disorders. To interrogate synapse function in a systematic manner, we have established an automated high-throughput imaging pipeline based on fluorescence microscopy acquisition and image analysis of electrically stimulated synaptic transmission in neuronal cultures. Identification and measurement of synaptic signal fluctuations is achieved by means of an image analysis algorithm based on singular value decomposition. By exploiting the synchronicity of the evoked responses, the algorithm allows disentangling distinct temporally correlated patterns of firing synapse populations or cell types that are present in the same recording. We demonstrate the performance of the analysis with a pilot compound screen and show that the multiparametric readout allows classifying treatments by their spatiotemporal fingerprint. The image analysis and visualization software has been made publicly available on Github ( https://www.github.com/S3Toolbox ). The streamlined automation of multi-well image acquisition, electrical stimulation, analysis, and meta-data warehousing facilitates large-scale synapse-oriented screens and, in doing so, it will accelerate the drug discovery process.
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Affiliation(s)
- Michiel Van Dyck
- Laboratory of Cell Biology and Histology, University of Antwerp, CDE, Antwerp, Belgium.,Janssen Research and Development, Neuroscience Therapeutic Area, Beerse, Belgium
| | - Rajiv K Mishra
- iOligos Technologies Private Limited, 1703, CB2, Supertech Capetown, Sector-74, 201301, Noida, India
| | - Francisco Pestana
- Janssen Research and Development, Neuroscience Therapeutic Area, Beerse, Belgium
| | - Peter Verstraelen
- Laboratory of Cell Biology and Histology, University of Antwerp, CDE, Antwerp, Belgium
| | - Hilde Lavreysen
- Janssen Research and Development, Neuroscience Therapeutic Area, Beerse, Belgium
| | - Juan D Pita-Almenar
- Janssen Research and Development, Neuroscience Therapeutic Area, Beerse, Belgium
| | - Nachiket D Kashikar
- Resolve BioSciences GmbH, Creative Campus Monheim Gebäude A03, Alfred-Nobel-Strasse 10, 40789, Monheim am Rhein, Germany.
| | - Winnok H De Vos
- Laboratory of Cell Biology and Histology, University of Antwerp, CDE, Antwerp, Belgium.
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19
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Pottackal J, Singer JH, Demb JB. Computational and Molecular Properties of Starburst Amacrine Cell Synapses Differ With Postsynaptic Cell Type. Front Cell Neurosci 2021; 15:660773. [PMID: 34381333 PMCID: PMC8351878 DOI: 10.3389/fncel.2021.660773] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 06/08/2021] [Indexed: 11/22/2022] Open
Abstract
A presynaptic neuron can increase its computational capacity by transmitting functionally distinct signals to each of its postsynaptic cell types. To determine whether such computational specialization occurs over fine spatial scales within a neurite arbor, we investigated computation at output synapses of the starburst amacrine cell (SAC), a critical component of the classical direction-selective (DS) circuit in the retina. The SAC is a non-spiking interneuron that co-releases GABA and acetylcholine and forms closely spaced (<5 μm) inhibitory synapses onto two postsynaptic cell types: DS ganglion cells (DSGCs) and neighboring SACs. During dynamic optogenetic stimulation of SACs in mouse retina, whole-cell recordings of inhibitory postsynaptic currents revealed that GABAergic synapses onto DSGCs exhibit stronger low-pass filtering than those onto neighboring SACs. Computational analyses suggest that this filtering difference can be explained primarily by presynaptic properties, rather than those of the postsynaptic cells per se. Consistent with functionally diverse SAC presynapses, blockade of N-type voltage-gated calcium channels abolished GABAergic currents in SACs but only moderately reduced GABAergic and cholinergic currents in DSGCs. These results jointly demonstrate how specialization of synaptic outputs could enhance parallel processing in a compact interneuron over fine spatial scales. Moreover, the distinct transmission kinetics of GABAergic SAC synapses are poised to support the functional diversity of inhibition within DS circuitry.
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Affiliation(s)
- Joseph Pottackal
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, United States.,Department of Biology, University of Maryland, College Park, College Park, MD, United States
| | - Joshua H Singer
- Department of Biology, University of Maryland, College Park, College Park, MD, United States
| | - Jonathan B Demb
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, United States.,Department of Ophthalmology and Visual Science, Yale University, New Haven, CT, United States.,Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, United States.,Department of Neuroscience, Yale University, New Haven, CT, United States
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20
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Abstract
The use of spectral information in natural light to inform behaviour is one of the oldest and most fundamental abilities of visual systems. It long-predates animals' venture onto the land, and even the appearance of image-forming eyes. Accordingly, circuits for colour vision evolved under the surface of ancient oceans for hundreds of millions of years. These aquatic beginnings fundamentally underpin, and likely constrain, the organisation of modern visual systems. In contrast to our detailed circuit level understanding from diverse terrestrial vertebrates, however, comparatively little is known about their aquatic counterparts. Here, I summarise some of what is known about neural circuits for colour vision in fish, the most species-diverse group of vertebrates. With a focus on zebrafish, I will explore how their computational strategies are linked to the statistics of natural light in the underwater world, and how their study might help us understand vision in general, including in our own eyes.
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21
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Thoreson WB. Transmission at rod and cone ribbon synapses in the retina. Pflugers Arch 2021; 473:1469-1491. [PMID: 33779813 DOI: 10.1007/s00424-021-02548-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 02/23/2021] [Accepted: 02/25/2021] [Indexed: 12/29/2022]
Abstract
Light-evoked voltage responses of rod and cone photoreceptor cells in the vertebrate retina must be converted to a train of synaptic vesicle release events for transmission to downstream neurons. This review discusses the processes, proteins, and structures that shape this critical early step in vision, focusing on studies from salamander retina with comparisons to other experimental animals. Many mechanisms are conserved across species. In cones, glutamate release is confined to ribbon release sites although rods are also capable of release at non-ribbon sites. The role of non-ribbon release in rods remains unclear. Release from synaptic ribbons in rods and cones involves at least three vesicle pools: a readily releasable pool (RRP) matching the number of membrane-associated vesicles along the ribbon base, a ribbon reserve pool matching the number of additional vesicles on the ribbon, and an enormous cytoplasmic reserve. Vesicle release increases in parallel with Ca2+ channel activity. While the opening of only a few Ca2+ channels beneath each ribbon can trigger fusion of a single vesicle, sustained release rates in darkness are governed by the rate at which the RRP can be replenished. The number of vacant release sites, their functional status, and the rate of vesicle delivery in turn govern replenishment. Along with an overview of the mechanisms of exocytosis and endocytosis, we consider specific properties of ribbon-associated proteins and pose a number of remaining questions about this first synapse in the visual system.
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Affiliation(s)
- Wallace B Thoreson
- Truhlsen Eye Institute, Departments of Ophthalmology & Visual Sciences and Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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22
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Yedutenko M, Howlett MHC, Kamermans M. High Contrast Allows the Retina to Compute More Than Just Contrast. Front Cell Neurosci 2021; 14:595193. [PMID: 33519381 PMCID: PMC7843368 DOI: 10.3389/fncel.2020.595193] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 12/22/2020] [Indexed: 11/29/2022] Open
Abstract
The goal of sensory processing is to represent the environment of an animal. All sensory systems share a similar constraint: they need to encode a wide range of stimulus magnitudes within their narrow neuronal response range. The most efficient way, exploited by even the simplest nervous systems, is to encode relative changes in stimulus magnitude rather than the absolute magnitudes. For instance, the retina encodes contrast, which are the variations of light intensity occurring in time and in space. From this perspective, it is easy to understand why the bright plumage of a moving bird gains a lot of attention, while an octopus remains motionless and mimics its surroundings for concealment. Stronger contrasts simply cause stronger visual signals. However, the gains in retinal performance associated with higher contrast are far more than what can be attributed to just a trivial linear increase in signal strength. Here we discuss how this improvement in performance is reflected throughout different parts of the neural circuitry, within its neural code and how high contrast activates many non-linear mechanisms to unlock several sophisticated retinal computations that are virtually impossible in low contrast conditions.
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Affiliation(s)
- Matthew Yedutenko
- Retinal Signal Processing Lab, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
| | - Marcus H. C. Howlett
- Retinal Signal Processing Lab, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
| | - Maarten Kamermans
- Retinal Signal Processing Lab, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
- Department of Biomedical Physics and Biomedical Optics, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
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23
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Pottackal J, Singer JH, Demb JB. Receptoral Mechanisms for Fast Cholinergic Transmission in Direction-Selective Retinal Circuitry. Front Cell Neurosci 2020; 14:604163. [PMID: 33324168 PMCID: PMC7726240 DOI: 10.3389/fncel.2020.604163] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 10/22/2020] [Indexed: 01/09/2023] Open
Abstract
Direction selectivity represents an elementary sensory computation that can be related to underlying synaptic mechanisms. In mammalian retina, direction-selective ganglion cells (DSGCs) respond strongly to visual motion in a "preferred" direction and weakly to motion in the opposite, "null" direction. The DS mechanism depends on starburst amacrine cells (SACs), which provide null direction-tuned GABAergic inhibition and untuned cholinergic excitation to DSGCs. GABAergic inhibition depends on conventional synaptic transmission, whereas cholinergic excitation apparently depends on paracrine (i.e., non-synaptic) transmission. Despite its paracrine mode of transmission, cholinergic excitation is more transient than GABAergic inhibition, yielding a temporal difference that contributes essentially to the DS computation. To isolate synaptic mechanisms that generate the distinct temporal properties of cholinergic and GABAergic transmission from SACs to DSGCs, we optogenetically stimulated SACs while recording postsynaptic currents (PSCs) from DSGCs in mouse retina. Direct recordings from channelrhodopsin-2-expressing (ChR2+) SACs during quasi-white noise (WN) (0-30 Hz) photostimulation demonstrated precise, graded optogenetic control of SAC membrane current and potential. Linear systems analysis of ChR2-evoked PSCs recorded in DSGCs revealed cholinergic transmission to be faster than GABAergic transmission. A deconvolution-based analysis showed that distinct postsynaptic receptor kinetics fully account for the temporal difference between cholinergic and GABAergic transmission. Furthermore, GABAA receptor blockade prolonged cholinergic transmission, identifying a new functional role for GABAergic inhibition of SACs. Thus, fast cholinergic transmission from SACs to DSGCs arises from at least two distinct mechanisms, yielding temporal properties consistent with conventional synapses despite its paracrine nature.
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Affiliation(s)
- Joseph Pottackal
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, United States
| | - Joshua H. Singer
- Department of Biology, University of Maryland, College Park, MD, United States
| | - Jonathan B. Demb
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, United States
- Department of Ophthalmology and Visual Science, Yale University, New Haven, CT, United States
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, United States
- Department of Neuroscience, Yale University, New Haven, CT, United States
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24
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Local Design Principles at Hippocampal Synapses Revealed by an Energy-Information Trade-Off. eNeuro 2020; 7:ENEURO.0521-19.2020. [PMID: 32847867 PMCID: PMC7540928 DOI: 10.1523/eneuro.0521-19.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 12/01/2022] Open
Abstract
Synapses across different brain regions display distinct structure-function relationships. We investigated the interplay of fundamental design constraints that shape the transmission properties of the excitatory CA3-CA1 pyramidal cell connection, a prototypic synapse for studying the mechanisms of learning in the mammalian hippocampus. This small synapse is characterized by probabilistic release of transmitter, which is markedly facilitated in response to naturally occurring trains of action potentials. Based on a physiologically motivated computational model of the rat CA3 presynaptic terminal, we show how unreliability and short-term dynamics of vesicular release work together to regulate the trade-off of information transfer versus energy use. We propose that individual CA3-CA1 synapses are designed to operate near the maximum possible capacity of information transmission in an efficient manner. Experimental measurements reveal a wide range of vesicular release probabilities at hippocampal synapses, which may be a necessary consequence of long-term plasticity and homeostatic mechanisms that manifest as presynaptic modifications of the release probability. We show that the timescales and magnitude of short-term plasticity (STP) render synaptic information transfer nearly independent of differences in release probability. Thus, individual synapses transmit optimally while maintaining a heterogeneous distribution of presynaptic strengths indicative of synaptically-encoded memory representations. Our results support the view that organizing principles that are evident on higher scales of neural organization percolate down to the design of an individual synapse.
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25
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Yoshimatsu T, Schröder C, Nevala NE, Berens P, Baden T. Fovea-like Photoreceptor Specializations Underlie Single UV Cone Driven Prey-Capture Behavior in Zebrafish. Neuron 2020; 107:320-337.e6. [PMID: 32473094 PMCID: PMC7383236 DOI: 10.1016/j.neuron.2020.04.021] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/13/2020] [Accepted: 04/21/2020] [Indexed: 01/04/2023]
Abstract
In the eye, the function of same-type photoreceptors must be regionally adjusted to process a highly asymmetrical natural visual world. Here, we show that UV cones in the larval zebrafish area temporalis are specifically tuned for UV-bright prey capture in their upper frontal visual field, which may use the signal from a single cone at a time. For this, UV-photon detection probability is regionally boosted more than 10-fold. Next, in vivo two-photon imaging, transcriptomics, and computational modeling reveal that these cones use an elevated baseline of synaptic calcium to facilitate the encoding of bright objects, which in turn results from expressional tuning of phototransduction genes. Moreover, the light-driven synaptic calcium signal is regionally slowed by interactions with horizontal cells and later accentuated at the level of glutamate release driving retinal networks. These regional differences tally with variations between peripheral and foveal cones in primates and hint at a common mechanistic origin.
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Affiliation(s)
| | - Cornelius Schröder
- Institute of Ophthalmic Research, University of Tübingen, Tübingen 72076, Germany; Center for Integrative Neuroscience, University of Tübingen, Tübingen 72076, Germany
| | - Noora E Nevala
- School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK
| | - Philipp Berens
- Institute of Ophthalmic Research, University of Tübingen, Tübingen 72076, Germany; Center for Integrative Neuroscience, University of Tübingen, Tübingen 72076, Germany; Institute for Bioinformatics and Medical Informatics, University of Tübingen, Tübingen 72076, Germany
| | - Tom Baden
- School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK; Institute of Ophthalmic Research, University of Tübingen, Tübingen 72076, Germany.
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26
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Li Z, Dong Z, Bai X, Liu M. Characterizing the orientation selectivity in V1 and V4 of macaques by quadratic phase coupling. J Neural Eng 2020; 17:036028. [PMID: 32480396 DOI: 10.1088/1741-2552/ab9843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Orientation selectivity is one of the significant characteristics of neurons in the primary visual cortex (V1). Some neurons in extrastriate visual cortical areas also exhibit certain orientation selectivity. But it is still not well understood that how the orientation selectivity generates. Most previous studies about the orientation selectivity are based on the spike firing rate. However, the spikes are prone to be biased by the detection and sorting algorithms. Then, in this paper, the local field potential (LFP) is adopted to investigate the mechanism of orientation selectivity. APPROACH We used the quadratic phase coupling (QPC), which was calculated by wavelet bicoherence, to describe the characteristics of orientation selectivity available in V1 and V4. The raw wideband neural signals were recorded by two chronically implanted multi-electrode arrays, which were placed in V1 and V4 respectively in two macaques performing a selective visual attention task. MAIN RESULTS There is a strong correlation between the total bicoherence (TotalBic), which is a quantization for the overall QPC of frequency pairs in gamma band, and the grating orientation. Furthermore, the QPC distribution at the non-preferred orientation is mainly concentrated in the low frequencies (30-40 Hz) of gamma; while the QPC distribution at the preferred orientation concentrates in both the low frequencies and high frequencies (60-80 Hz) of gamma. In addition, the TotalBic of the gamma-band LFP between V1 and V4 varies with the grating orientations, indicating that the QPC is available in the feedforward link and the gamma-band LFP in V1 modulates the QPC in V4. SIGNIFICANCE The QPC reflects the orientations of the sinusoidal grating and describes the interaction of gamma-band LFP between different brain regions. Our results suggest that the QPC is an alternative avenue to explore the mechanism for generating orientation selectivity of visual neurons effectively.
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Affiliation(s)
- Zhaohui Li
- School of Information Science and Engineering, Yanshan University, Qinhuangdao, People's Republic of China. Hebei Key Laboratory of Information Transmission and Signal Processing, Yanshan University, Qinhuangdao, People's Republic of China
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27
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Ryan TM, Hinojosa AJ, Vroman R, Papasavvas C, Lagnado L. Correction of z-motion artefacts to allow population imaging of synaptic activity in behaving mice. J Physiol 2020; 598:1809-1827. [PMID: 32020615 PMCID: PMC7318612 DOI: 10.1113/jp278957] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/24/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Motion artefacts associated with motor behaviour are an inevitable problem of multiphoton imaging in awake behaving animals, particularly when imaging synapses. Correction of axial motion artefacts usually requires volumetric imaging resulting in slower rates of acquisition. We describe a method to correct z-motion artefacts that is easy to implement and allows population imaging of synaptic activity while scanning a single plane in a standard multiphoton microscope. The method uses a reference volume acquired in two colour channels - an activity reporter and an anatomical marker of blood vessels. The procedure estimates the z-displacement in every frame and applies an intensity correction in which the z intensity profile for each synapse is modelled as a Moffat function. We demonstrate that the method allows synaptic calcium signals to be collected from populations of synaptic boutons in mouse primary visual cortex during locomotion. ABSTRACT Functional imaging of head-fixed, behaving mice using two-photon imaging of fluorescent activity reporters has become a powerful tool for studying the function of the brain. Motion artefacts are an inevitable problem during such experiments and are routinely corrected for in x and y dimensions. However, axial (z) shifts of several microns can also occur, leading to intensity fluctuations in structures such as synapses that are small compared to the axial point-spread function of the microscope. Here we present a simple strategy to correct z-motion artefacts arising over the course of a time-series experiment in a single optical plane. Displacement in z was calculated using dye-filled blood vessels as an anatomical marker, providing high contrast images and accuracy to within ∼0.1 µm. The axial profiles of ROIs corresponding to synapses were described using a Moffat function and this 'ROI-spread function' used to correct activity traces on an ROI-by-ROI basis. We demonstrate the accuracy and utility of the procedures in simulation experiments using fluorescent beads and then apply them to correcting measurements of synaptic activity in populations of vasoactive-intestinal peptide (VIP) interneurons expressing the synaptic reporter SyGCaMP6f. Correction of z-motion artefacts had a substantial impact on the apparent correlation between synaptic activity and running speed, demonstrating the importance of correcting these when performing imaging experiments in awake mice.
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Affiliation(s)
- Thomas Michael Ryan
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonBN1 9QGUK
| | | | - Rozan Vroman
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonBN1 9QGUK
| | | | - Leon Lagnado
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonBN1 9QGUK
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Dembla E, Dembla M, Maxeiner S, Schmitz F. Synaptic ribbons foster active zone stability and illumination-dependent active zone enrichment of RIM2 and Cav1.4 in photoreceptor synapses. Sci Rep 2020; 10:5957. [PMID: 32249787 PMCID: PMC7136232 DOI: 10.1038/s41598-020-62734-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 03/18/2020] [Indexed: 02/08/2023] Open
Abstract
Rod photoreceptor synapses use large, ribbon-type active zones for continuous synaptic transmission during light and dark. Since ribbons are physically connected to the active zones, we asked whether illumination-dependent changes of ribbons influence Cav1.4/RIM2 protein clusters at the active zone and whether these illumination-dependent effects at the active zone require the presence of the synaptic ribbon. We found that synaptic ribbon length and the length of presynaptic Cav1.4/RIM2 clusters are tightly correlated. Dark-adaptation did not change the number of ribbons and active zone puncta. However, mean ribbon length and length of presynaptic Cav1.4/RIM2 clusters increased significantly during dark-adaptation when tonic exocytosis is highest. In the present study, we identified by the analyses of synaptic ribbon-deficient RIBEYE knockout mice that synaptic ribbons are (1) needed to stabilize Cav1.4/RIM2 at rod photoreceptor active zones and (2) are required for the darkness-induced active zone enrichment of Cav1.4/RIM2. These data propose a role of the ribbon in active zone stabilization and suggest a homeostatic function of the ribbon in illumination-dependent active zone remodeling.
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Affiliation(s)
- Ekta Dembla
- Institute of Anatomy and Cell Biology, Department of Neuroanatomy, Saarland University, Medical School, 66421, Homburg, Germany.
| | - Mayur Dembla
- Institute of Anatomy and Cell Biology, Department of Neuroanatomy, Saarland University, Medical School, 66421, Homburg, Germany
| | - Stephan Maxeiner
- Institute of Anatomy and Cell Biology, Department of Neuroanatomy, Saarland University, Medical School, 66421, Homburg, Germany
- Institute of Anatomy and Cell Biology, Saarland University, AG Krasteva-Christ, 66421, Homburg, Germany
| | - Frank Schmitz
- Institute of Anatomy and Cell Biology, Department of Neuroanatomy, Saarland University, Medical School, 66421, Homburg, Germany.
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29
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Baden T, Euler T, Berens P. Understanding the retinal basis of vision across species. Nat Rev Neurosci 2019; 21:5-20. [PMID: 31780820 DOI: 10.1038/s41583-019-0242-1] [Citation(s) in RCA: 151] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2019] [Indexed: 12/12/2022]
Abstract
The vertebrate retina first evolved some 500 million years ago in ancestral marine chordates. Since then, the eyes of different species have been tuned to best support their unique visuoecological lifestyles. Visual specializations in eye designs, large-scale inhomogeneities across the retinal surface and local circuit motifs mean that all species' retinas are unique. Computational theories, such as the efficient coding hypothesis, have come a long way towards an explanation of the basic features of retinal organization and function; however, they cannot explain the full extent of retinal diversity within and across species. To build a truly general understanding of vertebrate vision and the retina's computational purpose, it is therefore important to more quantitatively relate different species' retinal functions to their specific natural environments and behavioural requirements. Ultimately, the goal of such efforts should be to build up to a more general theory of vision.
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Affiliation(s)
- Tom Baden
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, UK. .,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Philipp Berens
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Bioinformatics and Medical Informatics, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany
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30
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Hays CL, Grassmeyer JJ, Wen X, Janz R, Heidelberger R, Thoreson WB. Simultaneous Release of Multiple Vesicles from Rods Involves Synaptic Ribbons and Syntaxin 3B. Biophys J 2019; 118:967-979. [PMID: 31653448 DOI: 10.1016/j.bpj.2019.10.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/25/2019] [Accepted: 10/03/2019] [Indexed: 02/05/2023] Open
Abstract
First proposed as a specialized mode of release at sensory neurons possessing ribbon synapses, multivesicular release has since been described throughout the central nervous system. Many aspects of multivesicular release remain poorly understood. We explored mechanisms underlying simultaneous multivesicular release at ribbon synapses in salamander retinal rod photoreceptors. We assessed spontaneous release presynaptically by recording glutamate transporter anion currents (IA(glu)) in rods. Spontaneous IA(glu) events were correlated in amplitude and kinetics with simultaneously measured miniature excitatory postsynaptic currents in horizontal cells. Both measures indicated that a significant fraction of events is multiquantal, with an analysis of IA(glu) revealing that multivesicular release constitutes ∼30% of spontaneous release events. IA(glu) charge transfer increased linearly with event amplitude showing that larger events involve greater glutamate release. The kinetics of large and small IA(glu) events were identical as were rise times of large and small miniature excitatory postsynaptic currents, indicating that the release of multiple vesicles during large events is highly synchronized. Effects of exogenous Ca2+ buffers suggested that multiquantal, but not uniquantal, release occurs preferentially near Ca2+ channels clustered beneath synaptic ribbons. Photoinactivation of ribbons reduced the frequency of spontaneous multiquantal events without affecting uniquantal release frequency, showing that spontaneous multiquantal release requires functional ribbons. Although both occur at ribbon-style active zones, the absence of cross-depletion indicates that evoked and spontaneous multiquantal release from ribbons involve different vesicle pools. Introducing an inhibitory peptide into rods to interfere with the SNARE protein, syntaxin 3B, selectively reduced multiquantal event frequency. These results support the hypothesis that simultaneous multiquantal release from rods arises from homotypic fusion among neighboring vesicles on ribbons and involves syntaxin 3B.
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Affiliation(s)
- Cassandra L Hays
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska; Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska
| | - Justin J Grassmeyer
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska; Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska
| | - Xiangyi Wen
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska; West China Hospital, Sichuan University, Chengdu, Sichuan, P.R. China
| | - Roger Janz
- Department of Neurobiology and Anatomy, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas; The University of Texas MD Anderson Cancer Center University of Texas Health Graduate School of Biomedical Sciences, Houston, Texas
| | - Ruth Heidelberger
- Department of Neurobiology and Anatomy, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas; The University of Texas MD Anderson Cancer Center University of Texas Health Graduate School of Biomedical Sciences, Houston, Texas
| | - Wallace B Thoreson
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska; Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska.
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