Synaptic Processes
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Biophysical Network Modelling of the Dlgn Circuit: Different Effects of Triadic and Axonal Inhibition on Visual Responses of Relay Cells
RESEARCH ARTICLE Biophysical Network Modelling of the dLGN Circuit: Different Effects of Triadic and Axonal Inhibition on Visual Responses of Relay Cells Thomas Heiberg1, Espen Hagen1,2, Geir Halnes1, Gaute T. Einevoll1,3* 1 Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Ås, Norway, 2 Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and a11111 JARA BRAIN Institute I, Jülich Research Centre, Jülich, Germany, 3 Department of Physics, University of Oslo, Oslo, Norway * [email protected] Abstract OPEN ACCESS Despite its prominent placement between the retina and primary visual cortex in the early Citation: Heiberg T, Hagen E, Halnes G, Einevoll GT visual pathway, the role of the dorsal lateral geniculate nucleus (dLGN) in molding and regu- (2016) Biophysical Network Modelling of the dLGN lating the visual signals entering the brain is still poorly understood. A striking feature of the Circuit: Different Effects of Triadic and Axonal Inhibition on Visual Responses of Relay Cells. PLoS dLGN circuit is that relay cells (RCs) and interneurons (INs) form so-called triadic synapses, Comput Biol 12(5): e1004929. doi:10.1371/journal. where an IN dendritic terminal can be simultaneously postsynaptic to a retinal ganglion cell pcbi.1004929 (GC) input and presynaptic to an RC dendrite, allowing for so-called triadic inhibition. Taking Editor: Arnd Roth, University College London, advantage of a recently developed biophysically detailed multicompartmental model for an UNITED KINGDOM IN, we here investigate putative effects of these different inhibitory actions of INs, i.e., triadic Received: August 29, 2015 inhibition and standard axonal inhibition, on the response properties of RCs. -
Nervous Tissue
Nervous Tissue Prof.Prof. ZhouZhou LiLi Dept.Dept. ofof HistologyHistology andand EmbryologyEmbryology Organization:Organization: neuronsneurons (nerve(nerve cells)cells) neuroglialneuroglial cellscells Function:Function: Ⅰ Neurons 1.1. structurestructure ofof neuronneuron somasoma neuriteneurite a.a. dendritedendrite b.b. axonaxon 1.11.1 somasoma (1)(1) nucleusnucleus LocatedLocated inin thethe centercenter ofof soma,soma, largelarge andand palepale--stainingstaining nucleusnucleus ProminentProminent nucleolusnucleolus (2)(2) cytoplasmcytoplasm (perikaryon)(perikaryon) a.a. NisslNissl bodybody b.b. neurofibrilneurofibril NisslNissl’’ss bodiesbodies LM:LM: basophilicbasophilic massmass oror granulesgranules Nissl’s Body (TEM) EMEM:: RERRER,, freefree RbRb FunctionFunction:: producingproducing thethe proteinprotein ofof neuronneuron structurestructure andand enzymeenzyme producingproducing thethe neurotransmitterneurotransmitter NeurofibrilNeurofibril thethe structurestructure LM:LM: EM:EM: NeurofilamentNeurofilament micmicrotubulerotubule FunctionFunction cytoskeleton,cytoskeleton, toto participateparticipate inin substancesubstance transporttransport LipofuscinLipofuscin (3)(3) CellCell membranemembrane excitableexcitable membranemembrane ,, receivingreceiving stimutation,stimutation, fromingfroming andand conductingconducting nervenerve impulesimpules neurite: 1.2 Dendrite dendritic spine spine apparatus Function: 1.3 Axon axon hillock, axon terminal, axolemma Axoplasm: microfilament, microtubules, neurofilament, mitochondria, -
Synaptic Ultrastructure of Functionally and Morphologically Characterized Neurons of the Superficial Spinal Dorsal Horn Cat
The Journal of Neuroscience, June 1989, g(8): 1848-l 883 Synaptic Ultrastructure of Functionally and Morphologically Characterized Neurons of the Superficial Spinal Dorsal Horn Cat M. Wthelyi, A. R. Light, and E. Ft. Per1 Department of Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, and Second Department of Anatomy, Semmelweis University, Budapest, Hungary Recordings of neuronal unitary discharges evoked by pri- neurons, regardless of gross configuration, were found to mary afferent input were made in the superficial part of the have vesicles in their dendrites, but 3 nocireceptiveneurons spinal cord’s dorsal horn, the marginal zone and substantia received synapses from presynaptic dendritic profiles. gelatinosa (also known as laminae I and II) , using fine mi- cropipette electrodes filled with HRP. After physiological The superficial dorsal horn, laminae I and II, of the spinal cord characterization with respect to primary afferent input, HRP (Brown and Rethelyi, 1981) receivesprimary afferent input prin- was injected intracellularly iontophoretically into the record- cipally or exclusively from fine fibers, myelinated and unmy- ed neuron. Following histochemical processing, the neurons elinated, that pass through the lateral division of the dorsal so delineated were studied at the light and electron micro- rootlets (Sindou et al., 1974; Snyder, 1977; Light and Perl, 1979a, scopic levels. No clear relationship between function and b). However, from the functional standpoint, the input to the either general cellular configuration or synaptic ultrastruc- region from the periphery is diverse (Kumazawa and Perl, 1978; ture appeared in these analyses, although the concentration Rethelyi et al., 1979; Perl, 1984). There have been numerous of dendritic distribution could be related to the nature of descriptions of the structure of neurons and terminal axon sys- primary afferent excitation. -
Absence of S100A4 in the Mouse Lens Induces an Aberrant Retina-Specific Differentiation Program and Cataract
www.nature.com/scientificreports OPEN Absence of S100A4 in the mouse lens induces an aberrant retina‑specifc diferentiation program and cataract Rupalatha Maddala1*, Junyuan Gao2, Richard T. Mathias2, Tylor R. Lewis1, Vadim Y. Arshavsky1,3, Adriana Levine4, Jonathan M. Backer4,5, Anne R. Bresnick4 & Ponugoti V. Rao1,3* S100A4, a member of the S100 family of multifunctional calcium‑binding proteins, participates in several physiological and pathological processes. In this study, we demonstrate that S100A4 expression is robustly induced in diferentiating fber cells of the ocular lens and that S100A4 (−/−) knockout mice develop late‑onset cortical cataracts. Transcriptome profling of lenses from S100A4 (−/−) mice revealed a robust increase in the expression of multiple photoreceptor‑ and Müller glia‑specifc genes, as well as the olfactory sensory neuron‑specifc gene, S100A5. This aberrant transcriptional profle is characterized by corresponding increases in the levels of proteins encoded by the aberrantly upregulated genes. Ingenuity pathway network and curated pathway analyses of diferentially expressed genes in S100A4 (−/−) lenses identifed Crx and Nrl transcription factors as the most signifcant upstream regulators, and revealed that many of the upregulated genes possess promoters containing a high‑density of CpG islands bearing trimethylation marks at histone H3K27 and/or H3K4, respectively. In support of this fnding, we further documented that S100A4 (−/−) knockout lenses have altered levels of trimethylated H3K27 and H3K4. Taken together, -
Electrical Synapses and Their Functional Interactions with Chemical Synapses
REVIEWS Electrical synapses and their functional interactions with chemical synapses Alberto E. Pereda Abstract | Brain function relies on the ability of neurons to communicate with each other. Interneuronal communication primarily takes place at synapses, where information from one neuron is rapidly conveyed to a second neuron. There are two main modalities of synaptic transmission: chemical and electrical. Far from functioning independently and serving unrelated functions, mounting evidence indicates that these two modalities of synaptic transmission closely interact, both during development and in the adult brain. Rather than conceiving synaptic transmission as either chemical or electrical, this article emphasizes the notion that synaptic transmission is both chemical and electrical, and that interactions between these two forms of interneuronal communication might be required for normal brain development and function. Communication between neurons is required for Electrical and chemical synapses are now known to brain function, and the quality of such communica- coexist in most organisms and brain structures, but details tion enables hardwired neural networks to act in a of the properties and distribution of these two modalities of dynamic fashion. Functional interactions between transmission are still emerging. Most research efforts neurons occur at anatomically identifiable cellular have focused on exploring the mechanisms of chemi- regions called synapses. Although the nature of synaptic cal transmission, and considerably less is known transmission has been an area of enormous controversy about those underlying electrical transmission. It was (BOX 1), two main modalities of synaptic transmission — thought that electrical synapses were more abundant namely, chemical and electrical — are now recognized. At in invertebrates and cold-blooded vertebrates than chemical synapses, information is transferred through in mammals. -
Spatiotemporal Adaptation in the Corticogeniculate Loop
Physik-Department Technische UniversitÄat MuncÄ hen Theoretische Physik Spatiotemporal Adaptation in the Corticogeniculate Loop Ulrich Hillenbrand VollstÄandiger Abdruck der von der FakultÄat furÄ Physik der Technischen UniversitÄat MuncÄ hen zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften genehmigten Dissertation. Vorsitzender: Univ.-Prof. Dr. M. Kleber PruferÄ der Dissertation: 1. Univ.-Prof. Dr. J. L. van Hemmen 2. Univ.-Prof. Dr. E. Sackmann Die Dissertation wurde am 29.02.2000 bei der Technischen UniversitÄat MuncÄ hen eingereicht und durch die FakultÄat furÄ Physik am 16.01.2001 angenommen. Acknowledgments It is my pleasure to thank Professor Dr. J. Leo van Hemmen for cultivating an environment at his institute for creative exploration and growth of new ideas. Open-mindedness and, at the same time, a strong sense for scien- ti¯c value are of particular importance and delicacy in a ¯eld at the interface between empirical biological diversity and mathematical rigor. Leo van Hem- men combines both in his attitude and has always promoted the according style of work. Moreover, I like to thank the individuals who populated this environment. They always were supportive in that each one of them showed sincere interest in the other's scienti¯c concerns. More subtilely, the distinguished sense of humor that we shared helped to overcome one or the other tense period. I am especially indebted to those of my colleagues who spent a signi¯cant amount of their time on maintaining our local computer network, most no- tably Armin Bartsch, Moritz Franosch, and Oliver Wenisch. Without their kind support, things would have got stuck in computer trouble more than once. -
11 Introduction to the Nervous System and Nervous Tissue
11 Introduction to the Nervous System and Nervous Tissue ou can’t turn on the television or radio, much less go online, without seeing some- 11.1 Overview of the Nervous thing to remind you of the nervous system. From advertisements for medications System 381 Yto treat depression and other psychiatric conditions to stories about celebrities and 11.2 Nervous Tissue 384 their battles with illegal drugs, information about the nervous system is everywhere in 11.3 Electrophysiology our popular culture. And there is good reason for this—the nervous system controls our of Neurons 393 perception and experience of the world. In addition, it directs voluntary movement, and 11.4 Neuronal Synapses 406 is the seat of our consciousness, personality, and learning and memory. Along with the 11.5 Neurotransmitters 413 endocrine system, the nervous system regulates many aspects of homeostasis, including 11.6 Functional Groups respiratory rate, blood pressure, body temperature, the sleep/wake cycle, and blood pH. of Neurons 417 In this chapter we introduce the multitasking nervous system and its basic functions and divisions. We then examine the structure and physiology of the main tissue of the nervous system: nervous tissue. As you read, notice that many of the same principles you discovered in the muscle tissue chapter (see Chapter 10) apply here as well. MODULE 11.1 Overview of the Nervous System Learning Outcomes 1. Describe the major functions of the nervous system. 2. Describe the structures and basic functions of each organ of the central and peripheral nervous systems. 3. Explain the major differences between the two functional divisions of the peripheral nervous system. -
Neuronal Signaling Neuroscience Fundamentals > the Nerve Cell > the Nerve Cell
Neuronal Signaling Neuroscience Fundamentals > The Nerve Cell > The Nerve Cell NEURONAL SIGNALING SUMMARY ACTION POTENTIALS See: Action Potentials Key Features • All-or-nothing events • Self-propagating • Conduction speed determined by axon diameter (thicker means faster) and amount of myelination (more myelin means faster transmission). CHEMICAL SYNAPSE Steps of Chemical Synapsis 1) The action potential travels down axon of presynaptic neuron. 2) Vesicle fuses with plasma membrane and releases neurotransmitter into the synaptic cleft. 3) Neurotransmitters bind to ligand-gated ion channels, opening them. 4) Ions entering through the open channels cause a depolarization of the membrane, opening voltage-gated ion channels. 5) Ions pass through these voltage-gated ion channels, causing further depolarization of the membrane. 6) This depolarization (action potential) travels along the membrane as more voltage-gated ion channels are opened. ELECTRICAL SYNAPSE • Cytoplasms of adjacent neurons are connected, allowing ions (and action potentials) to travel directly to the next cell. NEURONAL CODING OF STIMULUS STRENGTH Action Potential Frequency • Stimulus strength is based on frequency of action potentials. Action Potential Strength • Strong stimuli can produce another action potential during the relative refractory period. 1 / 7 ABSOLUTE REFRACTORY PERIOD No further action potentials • Voltage-gated sodium channels are open or inactivated so another stimulus, no matter its strength, CANNOT elicit another action potential. RELATIVE REFRACTORY -
Mitral Cell Spike Synchrony Modulated by Dendrodendritic Synapse Location
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by PubMed Central ORIGINAL RESEARCH ARTICLE published: 30 January 2012 COMPUTATIONAL NEUROSCIENCE doi: 10.3389/fncom.2012.00003 Mitral cell spike synchrony modulated by dendrodendritic synapse location Thomas S. McTavish 1*, Michele Migliore 2, Gordon M. Shepherd 1 and Michael L. Hines 3 1 Department of Neurobiology, School of Medicine, Yale University, New Haven, CT, USA 2 Institute of Biophysics, National Research Council, Palermo, Italy 3 Department of Computer Science, Yale University, New Haven, CT, USA Edited by: On their long lateral dendrites, mitral cells of the olfactory bulb form dendrodendritic Ken Miller, Columbia University, synapses with large populations of granule cell interneurons. The mitral-granule cell USA microcircuit operating through these reciprocal synapses has been implicated in inducing Reviewed by: synchrony between mitral cells. However, the specific mechanisms of mitral cell Brent Doiron, University of Pittsburgh, USA synchrony operating through this microcircuit are largely unknown and are complicated Carmen Canavier, LSU Health by the finding that distal inhibition on the lateral dendrites does not modulate mitral Sciences Center, USA cell spikes. In order to gain insight into how this circuit synchronizes mitral cells *Correspondence: within its spatial constraints, we built on a reduced circuit model of biophysically Thomas S. McTavish, Department of realistic multi-compartment mitral and granule cells to explore systematically the roles of Neurobiology, Yale School of Medicine, 333 Cedar Street, dendrodendritic synapse location and mitral cell separation on synchrony. The simulations New Haven, CT, 06510-3206, USA. showed that mitral cells can synchronize when separated at arbitrary distances through e-mail: [email protected] a shared set of granule cells, but synchrony is optimally attained when shared granule cells form two balanced subsets, each subset clustered near to a soma of the mitral cell pairs. -
Synapse Transmission
Synapse Transmission There are two types of synapses found in your body: electrical and chemical. Electrical synapses allow the direct passage of ions and signaling molecules from cell to cell. In contrast, chemical synapses do not pass the signal directly from the presynaptic cell to the postsynaptic cell. In a chemical synapse, an action potential in the presynaptic neuron leads to the release of a chemical messenger called aneurotransmitter. The neurotransmitter then diffuses across the synapse and binds to receptors on the postsynaptic cell. Binding of the neurotransmitter leads to the production of an electrical signal in the postsynaptic cell. Why does the body have two types of synapses? Each type of synapse has functional advantages and disadvantages. An electrical synapse passes the signal very quickly, which allows groups of cells to act in unison. A chemical synapse takes much longer to transmit the signal from one cell to the next; however, chemical synapses allow neurons to integrate information from multiple presynaptic neurons, determining whether or not the postsynaptic cell will continue to propagate the signal. Neurons respond differently based on information transmitted by multiple chemical synapses. Let’s take a closer look at the structure and function of each type of synapse. Electrical synapses transmit action potentials via the direct flow of electrical current at gap junctions. Gap junctions are formed when two adjacent cells have transmembrane pores that align. The membranes of the two cells are linked together and the aligned pores form a passage between the cells. Consequently, several types of molecules and ions are allowed to pass between the cells. -
Synaptic Transmission Dr
Synaptic Transmission Dr. Simge Aykan Department of Physiology Synaptic Transmission • Biological process by which a neuron communicates with a target cell across a synapse • Synapse is an anatomically specialized junction between two neurons, at which the electrical activity in a presynaptic neuron influences the electrical activity of a postsynaptic neuron • Synapse can be between a neuron and a • Neuron • Muscle • Gland cell Synaptic Transmission • The average neuron forms several thousand synaptic connections and receives a similar number • The Purkinje cell of the cerebellum receives up to 100,000 synaptic inputs • 1011 neurons, 1014 (100 trillion!) synapses Synaptic Transmission • Electrical synapse transmission: transfer of electrical signals through gap junctions • Chemical synaptic transmission: release of a neurotransmitter from the pre-synaptic neuron, and neurotransmitter binding to specific post-synaptic receptors Electrical Synapses • Connection through gap junctions • Narrow gap between membranes (3 nm) • Connexin connexon gap junction • Direct ion passage from one neuron to another • Big enough for many small organic molecules to pass through (1-2 nm) • Mostly between dendrites Electrical Synapses • Electrical postsynaptic potential (PSP) induced by ionic current flow (1 mV or less) Electrical Synapses • Advantages • Extremely rapid • Orchestrating the actions of large groups of neurons • Can transmit metabolic signals between cells • Less common in vertebrate nervous system • Require a large area of contact; restricting -
Kalziumdynamik in Körnerzellen Des Bulbus Olfactorius Der Maus
Aus dem Physiologischen Institut der Ludwig-Maximilians-Universität München Vorstand Prof. Dr. M.Götz Lehrstruhl für Physiologische Genomik Kalziumdynamik in Körnerzellen des Bulbus olfactorius der Maus Dissertation zum Erwerb des Doktorgrades der Humanbiologie an der Medizinischen Fakultät der Ludwig-Maximilians-Universität zu München vorgelegt von Olga Stroh-Vasenev aus Tomsk 2012 Mit Genehmigung der Medizinischen Fakultät der Universität München 1. Berichterstatter: Prof. Dr. Bernd Sutor Mitberichterstatter: Prof. Dr. Thomas Witt Priv.Doz. Dr. Eike Krause Mitbetreuung durch den promovierten Mitarbeiter: Dr. Veronica Egger Dekan: Prof. Dr. Dr.h.c. Maximilian Reiser, FACR, FRCR Tag der mündlichen Prüfung: 18.09.2012 „Wäre das menschliche Gehirn so simpel, dass wir es erfassen könnten, wären wir so simpel, dass wir es nicht könnten.“ Immanuel Kant Inhaltsverzeichnis 0 Zusammenfassung 1 0.1 Summary 1 1 Einleitung 3 1.1 Synaptische Verschaltung im Bulbus olfactorius 3 1.2 Dendritische synaptische Kalziumsignale in Körnerzellen 4 1.3 Langsamer Zeitverlauf der Körnerzell-vermittelten Inhibition 5 1.4 Synaptische Körnerzell-Aktionspotenziale 6 1.5 Rolle der TRP-Kanäle beim neuronalen Kalziumeintritt 7 1.6 Ziele der vorliegenden Arbeit 9 1.6.1 Aufklärung der molekularen Identität von ICAN (Stroh et al. 2012) 9 1.6.2 Endogene Pufferung von Körnerzell-Ca2+-Signalen (Egger und Stroh, 9 2009) 1.7 Eigener Beitrag 9 1.8 Referenzen 10 2 Ergebnisse 13 2.1 Publikation Stroh O. et al., Journal of Neuroscience 2012 13 2.2 Publikation Egger V. & Stroh O., Journal of Physiology 2009 56 3 Veröffentlichungen 93 4 Danksagung 94 0 Zusammenfassung Der häufigste neuronale Verbindungstyp im Riechkolben (Bulbus olfactorius) der Säuger ist die reziproke dendrodendritische Synapse zwischen den glutamatergen Mitralzellen (den Prin- zipalneuronen des Bulbus) und den GABAergen Körnerzellen.