Circuit Refinement in Mouse Visual Cortex During Development

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (19 download)

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Book Synopsis Circuit Refinement in Mouse Visual Cortex During Development by : Man Ho Wong

Download or read book Circuit Refinement in Mouse Visual Cortex During Development written by Man Ho Wong and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Circuit refinement is an important developmental process ensuring correct wiring of synaptic connections. During circuit refinement, favorable connections are generated or strengthened while unfavored ones are weakened or eliminated. Such rewiring of synaptic connections during development is not a random but a sophisticated process with activity or experience-dependent plasticity involved. Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-silent synapses, lacking AMPARs and therefore not transmitting at resting potential, act as the substrates for plasticity and lik...

Development of the Visual System

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Publisher : MIT Press
ISBN 13 : 9780262121545
Total Pages : 330 pages
Book Rating : 4.1/5 (215 download)

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Book Synopsis Development of the Visual System by : Retina Research Foundation (U.S.). Symposium

Download or read book Development of the Visual System written by Retina Research Foundation (U.S.). Symposium and published by MIT Press. This book was released on 1991 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Development of the Visual System presents a selection of current studies that clearly illustrate principles of visual system development. These range from retinal development in fish and frogs to the effects of abnormal visual experience on the primary visual cortex of the cat. The book is unique in addressing four specific and fundamental aspects of development: cell lineage and cell fate, specificity and targeting of axons, specification of visual cortex, and correlates of the critical period. Encompassing technical advances in cellular and molecular biology and in video imaging and microscopy, contributions in each of these areas provide new information at the cellular and molecular levels to complement the now classic descriptions of visual development previously available at the level of neural systems.ContributorsKaren L. Allendoerfer, David M. Altshuler, Antonella Antonini, Seymour Benzer, Edward M. Callaway, Constance L. Cepko, Hollis T. Cline, Max S. Cynader, N. W. Daw, Scott E. Fraser, K. Fox, Eckhard Friauf, Anirvan Ghosh, R. W. Guillery, William A. Harris, Christine E. Holt, Lawrence C. Katz, Susan McConnell, Pamela A. Raymond, Thomas A. Reh, Carla J. Shatz, Michael P. Stryker, Claudia A. 0. Stuermer, Mriganka Sur, David L. Turner, T. N. Wiesel

Biology of the NMDA Receptor

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Publisher : CRC Press
ISBN 13 : 142004415X
Total Pages : 368 pages
Book Rating : 4.4/5 (2 download)

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Book Synopsis Biology of the NMDA Receptor by : Antonius M. VanDongen

Download or read book Biology of the NMDA Receptor written by Antonius M. VanDongen and published by CRC Press. This book was released on 2008-10-29 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: The NMDA receptor plays a critical role in the development of the central nervous system and in adult neuroplasticity, learning, and memory. Therefore, it is not surprising that this receptor has been widely studied. However, despite the importance of rhythms for the sustenance of life, this aspect of NMDAR function remains poorly studied. Written

Mechanisms of Homeostatic Plasticity in the Mouse Visual Cortex

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (141 download)

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Book Synopsis Mechanisms of Homeostatic Plasticity in the Mouse Visual Cortex by : Rosanna Sammons

Download or read book Mechanisms of Homeostatic Plasticity in the Mouse Visual Cortex written by Rosanna Sammons and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: During development, newly established cortical circuits are undergoing a period of experience dependent refinement. Visual deprivation during this time leads to the induction of plasticity mechanisms, including homeostatic plasticity measures. These are a distinct set of plasticity mechanisms thought to play a role in maintaining stability within networks, and preventing large perturbations in overall activity levels. Homeostatic plasticity mechanisms can be divided into synaptic and intrinsic mechanisms. While details of individual mechanisms are reasonably well understood, details of how these different mechanisms are linked to one another are much less clear. In this thesis, I investigate the relationship between structural and functional forms of synaptic and intrinsic plasticity in layer 2/3 neurons in the monocular visual cortex, before and after induction of plasticity via monocular enucleation. I find that while axon initial segment (AIS) plasticity takes place following deprivation, in both pyramidal neurons, and a subset of inhibitory neurons, it does not correlate with functional measures of excitability. However, in control conditions, I do find a relationship between the synaptic inputs of a neuron, and its intrinsic excitability. Following deprivation, this relationship is altered. Specifically, I find that the activity status of the neuron affects the level of intrinsic excitability, and to some extent, the synaptic input to the cell. Putatively inactive neurons show increased excitability, and trend towards stronger synaptic input in comparison to their active counterparts. These differences between active and inactive cells may reflect the engagement of homeostatic mechanisms in inactive cells, in order to restore their activity levels.

From Neurons to Neighborhoods

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Publisher : National Academies Press
ISBN 13 : 0309069882
Total Pages : 610 pages
Book Rating : 4.3/5 (9 download)

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Book Synopsis From Neurons to Neighborhoods by : National Research Council

Download or read book From Neurons to Neighborhoods written by National Research Council and published by National Academies Press. This book was released on 2000-11-13 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: How we raise young children is one of today's most highly personalized and sharply politicized issues, in part because each of us can claim some level of "expertise." The debate has intensified as discoveries about our development-in the womb and in the first months and years-have reached the popular media. How can we use our burgeoning knowledge to assure the well-being of all young children, for their own sake as well as for the sake of our nation? Drawing from new findings, this book presents important conclusions about nature-versus-nurture, the impact of being born into a working family, the effect of politics on programs for children, the costs and benefits of intervention, and other issues. The committee issues a series of challenges to decision makers regarding the quality of child care, issues of racial and ethnic diversity, the integration of children's cognitive and emotional development, and more. Authoritative yet accessible, From Neurons to Neighborhoods presents the evidence about "brain wiring" and how kids learn to speak, think, and regulate their behavior. It examines the effect of the climate-family, child care, community-within which the child grows.

Developmental Refinement of Primary Visual Cortex Subcortical Efferents

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ISBN 13 : 9781339259222
Total Pages : pages
Book Rating : 4.2/5 (592 download)

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Book Synopsis Developmental Refinement of Primary Visual Cortex Subcortical Efferents by : Julie Dzung Luu

Download or read book Developmental Refinement of Primary Visual Cortex Subcortical Efferents written by Julie Dzung Luu and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding of how neural circuits process information from the environment, produce a percept of the external stimuli, and then evoke a behavioral response has been an ultimate goal in neuroscience. To achieve this long-standing goal, we must first understand how neural circuits are established. The functionality of a mature sensory system is highly dependent on the proper formation of precise neuronal connections that convey information about environmental stimuli to specific regions of the central nervous system. The formation of neural circuitry in the developing animal occurs in a series of regulated steps. Developing neuronal precursors first undergo a series of progressive events such as cell division, cell differentiation, cell migration, neuronal extension via elongation of their axon branches, axon guidance, and establishment of synapses. During these progressive events, neurons extend an exuberant number of axons and form an excess of broad connections. The developing nervous system will subsequently undergo a series of regressive events such as cell death, synapse elimination, and pruning of axons. These regressive events refine the immature broadly patterned neural connectivity into a mature precise neural network. Perturbations of axon pruning may result in abnormal neuronal connections, which in turn can lead to deleterious behavioral effects associated with several neuropsychological disorders. The focus of my dissertation research is on the study of regulatory mechanisms underlying axon pruning during the formation of neural circuitry in the mammalian central nervous system, specifically layer 5 pyramidal corticopontine and corticospinal neurons in the visual cortex (V1). I extensively investigate the development of V1 layer 5 pyramidal neurons because both small-scale pruning of visual corticopontine terminal zone (TZ) axons and large-scale stereotyped axon pruning of visual corticospinal tract (CST) axons occur within the same cells. Surprisingly, the precise timing of development and refinement of corticopontine and corticospinal projections of V1 layer 5 pyramidal neurons are not characterized, the mechanisms for small-scale pruning of visual corticopontine TZ axons are completely unknown, and the mechanisms for large-scale stereotyped pruning of visual CST axons are incompletely determined. For my dissertation research, I investigate the development and refinement of corticopontine and corticospinal projections from V1 layer 5 pyramidal neurons. Specifically in Chapter 2, I investigate whether both small-scale pruning of visual corticopontine TZ and large-scale pruning of visual CST axons are regulated by the same set of molecular and neural activity mechanisms or differentially regulated. I will show that both small- and large-scale stereotyped pruning of V1 efferent axons are simultaneously and coordinately regulated by the same set of mechanisms: 1) Semaphorin-3F (Sema3F) signaling through Neuropilin-2 (NPN2), Plexin-A3 (PLA3), and Plexin-A4 (PLA4) co-receptors, and 2) spontaneous retinal waves, not extrinsic visually-evoked activity. By using mouse genetics and comparative approaches, I will also present several lines of evidence to demonstrate that it is the initiation of Stage 3 spontaneous retinal waves, rather than the entire duration, that is necessary for both small-scale visual corticopontine terminal axon pruning and large-scale stereotyped visual CST pruning. In Chapter 3, I investigate the development of corticospinal projections from V1 layer 5 pyramidal neurons into the spinal cord and determine whether visual CST axons descend in multiple spinal cord locations. I will demonstrate that visual CST axons initially extend into both dorsal contralateral and ventral ipsilateral spinal cord and that subsequent large-scale stereotyped pruning will eliminate visual CST axons from both spinal cord locations. I will show that subsequent large-scale stereotyped pruning of dorsal contralateral visual CST axons is regulated by both Sema3F signaling and spontaneous retinal waves interacting along the same pathway, whereas large-scale stereotyped pruning of ventral ipsilateral visual CST axons is regulated by spontaneous retinal waves but not Sema3F signaling.Thus overall, my research has elucidated molecular and neural activity mechanisms regulating axon pruning of layer 5 V1 efferent neurons to advance understanding of regulatory mechanisms underlying axon pruning during the formation of neural circuitry in the mammalian central nervous system.

Synaptic Plasticity in the Hippocampus

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Publisher : Springer Science & Business Media
ISBN 13 : 364273202X
Total Pages : 219 pages
Book Rating : 4.6/5 (427 download)

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Book Synopsis Synaptic Plasticity in the Hippocampus by : Helmut L. Haas

Download or read book Synaptic Plasticity in the Hippocampus written by Helmut L. Haas and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the second time that I have had the honor of opening an interna tional symposium dedicated to the functions of the hippocampus here in Pecs. It was a pleasure to greet the participants in the hope that their valuable contributions will make this meeting a tradition in this town. As one of the hosts of the symposium, I had the sorrowful duty to remind you of the absence of a dear colleague, Professor Graham God dard. His tragic and untimely death represents the irreparable loss of both a friend and an excellent researcher. This symposium is dedicated to his memory. If I compare the topics of the lectures of this symposium with those of the previous one, a striking difference becomes apparent. A dominating tendency of the previous symposium was to attempt to define hippocam pal function or to offer data relevant to supporting or rejecting existing theoretical positions. No such tendency is reflected in the titles of the present symposium, in which most of the contributions deal with hip pocampal phenomena at the most elementary level. Electrical, biochemi cal, biophysical, and pharmacological events at the synaptic, membrane, or intracellular level are analyzed without raising the question of what kind of integral functions these elementary phenomena are a part of.

Webvision

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (53 download)

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Book Synopsis Webvision by : Helga Kolb

Download or read book Webvision written by Helga Kolb and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Excitatory-Inhibitory Balance

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Publisher : Springer Science & Business Media
ISBN 13 : 1461500397
Total Pages : 286 pages
Book Rating : 4.4/5 (615 download)

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Book Synopsis Excitatory-Inhibitory Balance by : Takao K. Hensch

Download or read book Excitatory-Inhibitory Balance written by Takao K. Hensch and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new perspective on brain function depends upon an understanding of the interaction and integration of excitation and inhibition. A recent surge in research activity focused on inhibitory interneurons now makes a more balanced view possible. Technological advances such as improved imaging methods, visualized patch-clamp recording, multiplex single-cell PCR, and gene-targeted deletion or knock-in mice are some of the novel tools featured in this book. This book will provide an integrated view of neuron function, operating in a balanced regime of excitation and inhibition. It is a timely contribution emphasizing how this balance is established, maintained, and modified from the molecular to system levels. The broad spectrum of topics from molecular to cellular and system/computational neuroscience will appeal to a wide audience of advanced graduate students, post-docs, and faculty. Moreover, this book this book features active young researchers from around the world, who are currently educating the brain scientists of tomorrow.

Plasticity of the Developing Visual Cortex in Normal and Mutant Mice

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Publisher :
ISBN 13 :
Total Pages : 402 pages
Book Rating : 4.:/5 (66 download)

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Book Synopsis Plasticity of the Developing Visual Cortex in Normal and Mutant Mice by : Joshua A. Gordon

Download or read book Plasticity of the Developing Visual Cortex in Normal and Mutant Mice written by Joshua A. Gordon and published by . This book was released on 1995 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Neocortex

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Publisher : MIT Press
ISBN 13 : 0262043246
Total Pages : 449 pages
Book Rating : 4.2/5 (62 download)

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Book Synopsis The Neocortex by : Wolf Singer

Download or read book The Neocortex written by Wolf Singer and published by MIT Press. This book was released on 2019-10-29 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experts review the latest research on the neocortex and consider potential directions for future research. Over the past decade, technological advances have dramatically increased information on the structural and functional organization of the brain, especially the cerebral cortex. This explosion of data has radically expanded our ability to characterize neural circuits and intervene at increasingly higher resolutions, but it is unclear how this has informed our understanding of underlying mechanisms and processes. In search of a conceptual framework to guide future research, leading researchers address in this volume the evolution and ontogenetic development of cortical structures, the cortical connectome, and functional properties of neuronal circuits and populations. They explore what constitutes “uniquely human” mental capacities and whether neural solutions and computations can be shared across species or repurposed for potentially uniquely human capacities. Contributors Danielle S. Bassett, Randy M. Bruno, Elizabeth A. Buffalo, Michael E. Coulter, Hermann Cuntz, Stanislas Dehaene, James J. DiCarlo, Pascal Fries, Karl J. Friston, Asif A. Ghazanfar, Anne-Lise Giraud, Joshua I. Gold, Scott T. Grafton, Jennifer M. Groh, Elizabeth A. Grove, Saskia Haegens, Kenneth D. Harris, Kristen M. Harris, Nicholas G. Hatsopoulos, Tarik F. Haydar, Takao K. Hensch, Wieland B. Huttner, Matthias Kaschube, Gilles Laurent, David A. Leopold, Johannes Leugering, Belen Lorente-Galdos, Jason N. MacLean, David A. McCormick, Lucia Melloni, Anish Mitra, Zoltán Molnár, Sydney K. Muchnik, Pascal Nieters, Marcel Oberlaender, Bijan Pesaran, Christopher I. Petkov, Gordon Pipa, David Poeppel, Marcus E. Raichle, Pasko Rakic, John H. Reynolds, Ryan V. Raut, John L. Rubenstein, Andrew B. Schwartz, Terrence J. Sejnowski, Nenad Sestan, Debra L. Silver, Wolf Singer, Peter L. Strick, Michael P. Stryker, Mriganka Sur, Mary Elizabeth Sutherland, Maria Antonietta Tosches, William A. Tyler, Martin Vinck, Christopher A. Walsh, Perry Zurn

The Postnatal Refinement of Interareal Circuits in Ferret Visual Cortex

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Publisher :
ISBN 13 : 9781303536755
Total Pages : 458 pages
Book Rating : 4.5/5 (367 download)

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Book Synopsis The Postnatal Refinement of Interareal Circuits in Ferret Visual Cortex by : Reem Khalil

Download or read book The Postnatal Refinement of Interareal Circuits in Ferret Visual Cortex written by Reem Khalil and published by . This book was released on 2013 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Visual cortical areas are presumed to subserve different perceptual functions as a result of their rich network of interareal anatomical circuits. Interareal circuits have been shown to undergo extensive remodeling in the postnatal period. Revealing the timing of when brain circuits mature may help us assign particular neural substrates to particular visual functions. To illuminate perceptual development, we assessed the postnatal anatomical refinement of interareal feedforward and feedback projections in ferret visual cortex. We also described the developmental trajectory of zinc levels in ferret visual cortex, reflecting a subset of glutamatergic interareal feedforward and feedback processes. We find that the period of major reorganization in feedback circuits, feedforward circuits, as well as the dramatic decline in zinc levels in ferret visual cortex occurs in the month following eye opening. In chapter 1, we demonstrated that zinc histochemistry can be reliably used to distinguish visual cortical areas in juvenile visual cortex and further reveals circuit refinement. We show that the postnatal decline in levels of synaptic zinc follows a broadly similar timecourse in multiple areas of ferret visual cortex. In chapter 2, we assessed the developmental refinement of feedback projections between primary visual cortex and extrastriate areas in the juvenile ferret brain. We reveal substantial refinement in the spatial organization of feedback projections arising from multiple visual areas to primary visual cortex of the ferret during the period after eye opening. We find that while certain aspects of feedback circuitry refine with a similar timecourse in all areas, other aspects refine asynchronously. In chapter 3, we investigated the postnatal development of feedforward projections from V1 to different target areas. Before eye opening, at 4 weeks postnatal, synaptic bouton density is very high, and interbouton interval along individual axons is quite short. In all areas examined, both bouton density decreased, and interbouton interval increased substantially from 6 weeks to 8 weeks postnatal. Therefore, feedback and feedforward cortical circuits appear to share a broadly similar developmental trajectory. Our findings are consistent with the notion that visual experience is necessary and crucial in the refinement of these cortical circuits. Furthermore, our findings suggest that at least some aspects of cortical maturation occur largely synchronously in multiple visual areas.

The Auditory Cortex

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Publisher : Springer Science & Business Media
ISBN 13 : 1441900748
Total Pages : 711 pages
Book Rating : 4.4/5 (419 download)

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Book Synopsis The Auditory Cortex by : Jeffery A. Winer

Download or read book The Auditory Cortex written by Jeffery A. Winer and published by Springer Science & Business Media. This book was released on 2010-12-02 with total page 711 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been substantial progress in understanding the contributions of the auditory forebrain to hearing, sound localization, communication, emotive behavior, and cognition. The Auditory Cortex covers the latest knowledge about the auditory forebrain, including the auditory cortex as well as the medial geniculate body in the thalamus. This book will cover all important aspects of the auditory forebrain organization and function, integrating the auditory thalamus and cortex into a smooth, coherent whole. Volume One covers basic auditory neuroscience. It complements The Auditory Cortex, Volume 2: Integrative Neuroscience, which takes a more applied/clinical perspective.

Circuit Development in the Dorsal Lateral Geniculate Nucleus (dLGN) of the Mouse

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (795 download)

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Book Synopsis Circuit Development in the Dorsal Lateral Geniculate Nucleus (dLGN) of the Mouse by : Tania Seabrook

Download or read book Circuit Development in the Dorsal Lateral Geniculate Nucleus (dLGN) of the Mouse written by Tania Seabrook and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The visual system is one of the most widely used and best understood sensory systems and the dorsal lateral geniculate nucleus (dLGN) of the mouse has emerged as a model for investigating the cellular and molecular mechanisms underlying the development and activity-dependent refinement of sensory connections. Thalamic organization is highly conserved throughout species and the dLGN of the mouse possesses many features common to higher mammals, such as carnivores and primates. Two general classes of neuron are present within the dLGN, thalamocortical relay cells and interneurons, both of which receive direct retinal input. Axons of relay cells exit dLGN and convey visual information to layer IV of cortex, whereas interneurons are involved in local circuitry. In addition, dLGN receives rich nonretinal input from numerous areas of the brain. Studies thus far have focused on the retinogeniculate pathway and the development of connections between retinal ganglion cells (RGCs) and relay cells has been well characterized. However, there are still a number of unanswered questions about circuit development in dLGN. Here we examined two aspects that are not well understood, the pattern of retinal convergence onto interneurons and the structural and functional innervation of nonretinal projections. To address the first issue we conducted in vitro whole-cell recordings from acute thalamic slices of GAD67-GFP mice, a transgenic strain in which dLGN interneurons express GFP. We also did 3-D reconstructions of biocytin-labeled interneurons using multi-photon laser scanning microscopy in conjunction with anterograde labeling of retinogeniculate projections to examine the distribution of retinal contacts. To begin to examine the development of nonretinal connections in dLGN we made use of a transgenic mouse (golli-t-GFP) to visualize corticogeniculate projections, one of the largest sources of nonretinal input to dLGN. Using this mouse we studied the timing and patterning of corticogeniculate innervation in relation to the development of the retinogeniculate pathway. We also used binocular enucleation and genetic deafferentation to test whether the retina plays a role in regulating nonretinal innervation. We found that there is a coordination of retinal and nonretinal innervation in dLGN. Projections from the retina were the first to innervate and they entered dLGN at perinatal ages. They also made functional connections with both relay cells and interneurons at early postnatal ages. Interestingly, relay cells underwent a period of retinogeniculate refinement, whereas the degree of retinal convergence onto interneurons was maintained. This possibly reflects the different roles that these two cell types have in dLGN. Both structural and functional corticogeniculate innervation was delayed in comparison and occurred postnatally, however in the absence of retinal input the timing of corticogeniculate innervation was accelerated. RGCs transmit the visual information encoded in the retina to dLGN so it may be necessary for these connections to be formed before those from nonretinal projections, which serve to modulate that signal on its way to cortex. Thus precise timing of retinal and nonretinal innervation may be important for the appropriate formation of connections in the visual system and the retina seems to be playing an important role in regulating this timing.

The Mechanisms of Reliable Coding in Mouse Visual Cortex

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Publisher :
ISBN 13 :
Total Pages : 262 pages
Book Rating : 4.:/5 (974 download)

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Book Synopsis The Mechanisms of Reliable Coding in Mouse Visual Cortex by : Rajeev Vijay Rikhye

Download or read book The Mechanisms of Reliable Coding in Mouse Visual Cortex written by Rajeev Vijay Rikhye and published by . This book was released on 2016 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: As we interact with the environment, our senses are constantly bombarded with information. Neurons in the visual cortex have to transform these complex inputs into robust and parsimonious neural codes that effectively guide behavior. The ability of neurons to efficiently convey information is, however, limited by intrinsic and shared variability. Despite this limitation, neurons in primary visual cortex (V1) are able to respond with high fidelity to relevant stimuli. My thesis proposes that high fidelity encoding can be achieved by dynamically increasing trial-to-trial response reliability. In particular, in this thesis, I use the mouse primary visual cortex (V1) as a model to understand how reliable coding arises, and why it is important for visual perception. Using a combination of novel experimental and computational techniques, my thesis identifies three main factors that can modulate intrinsic variability. My first goal was to understand the extrinsic, stimulus-dependent, factors responsible for reliably coding (Chapter 3). Natural scenes contain unique statistical properties that could be leveraged by the visual cortex for efficient coding. Thus, the first aim is to elucidate how image statistics modulate reliable coding in V1. To this end, I developed a novel noise masking procedure that allowed us to specifically perturb the spectral content of natural movies without altering the edges. Using high-speed twophoton calcium imaging in mice, I discovered that movies with stronger spatial correlations are more reliably processed by V1 neurons than movies lacking these correlations. In particular, perturbing spatial correlations in the movie dynamically altered the structure of interneuronal correlations. Movies with more naturalistic correlations typically recruited large neuronal ensembles that were weakly noise correlated. Using computational modeling, I discovered that these ensembles were able reduce shared noise through divisive normalization. Together, these findings demonstrate that natural scene statistics dynamically recruit neuronal ensembles to ensure reliable coding. Microcircuits of inhibitory interneurons lie at the heart of all cortical computations. It has been proposed that these interneurons are responsible for reliable spiking by controlling the temporal window over which synaptic inputs are integrated. However, no study has yet conclusively investigated the role of different interneuron subtypes. Thus, my second goal was to establish how natural scenes are reliably encoded by dissecting the inhibitory mechanisms underlying reliable coding (Chapter 4). Specifically, I investigated the role of somatostatin-expressing dendrite targeting interneurons (SST) and parvalbumin-expressing soma targeting interneurons (PV), which are known to provide distinct forms of inhibition onto pyramidal neurons. Using a novel combination of dual-color calcium imaging and optogenetic manipulation, I have discovered that the SST->PV inhibitory circuit plays a crucial role in modulating pyramidal cell reliability. In particular, by transiently suppressing PV neurons, SST neurons are able to route inhibition rapidly from the soma to the dendrites. Strong dendritic inhibition allows noisy inputs to be filtered out by the dendrites, while weaker somatic inhibition allows these inputs to be integrated to produce reliable spikes. In agreement with these results, I found that selectively deleting MeCP2 from these interneurons resulted in unreliable visual processing and other circuit-specific deficits, which are commonly observed in Rett Syndrome (Chapter 5). These results underscore the importance of intact inhibitory microcircuits in reliable processing. Finally, my goal was to determine why reliable coding is necessary for visual processing (Chapter 6). To this end, I trained head-fixed mice to perform a natural movie discrimination task. Mice were able to learn how to discriminate between two movies after a short training period. By perturbing the amplitude spectrum of these movies, I discovered that mice used structural information in the phase spectrum to discriminate between the different movies. This suggests that mice also use similar strategies as higher mammals for scene recognition. Inspired by this result, we trained mice on a harder target categorization task, where mice had to identify the movies from an ensemble that were more similar to the target movie to gain a water reward. We developed this movie ensemble by blending together the phase spectrum of a target and non-target movie at different fractions. Optically activating SST neurons in V1 improved the ability of mice to correctly identify "target-like" movies. This increase in behavioral performance correlated well with an increase in V1 coding reliability. Thus, reliable codes are a prerequisite for accurate visual perception. Taken together, this work bridges the gap between cells, circuits and behavior, and provides mechanistic insight into how complex visual stimuli are encoded with high fidelity in the visual cortex.

Guidelines for the Care and Use of Mammals in Neuroscience and Behavioral Research

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Author :
Publisher : National Academies Press
ISBN 13 : 030916785X
Total Pages : 223 pages
Book Rating : 4.3/5 (91 download)

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Book Synopsis Guidelines for the Care and Use of Mammals in Neuroscience and Behavioral Research by : National Research Council

Download or read book Guidelines for the Care and Use of Mammals in Neuroscience and Behavioral Research written by National Research Council and published by National Academies Press. This book was released on 2003-08-22 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: Expanding on the National Research Council's Guide for the Care and Use of Laboratory Animals, this book deals specifically with mammals in neuroscience and behavioral research laboratories. It offers flexible guidelines for the care of these animals, and guidance on adapting these guidelines to various situations without hindering the research process. Guidelines for the Care and Use of Mammals in Neuroscience and Behavioral Research offers a more in-depth treatment of concerns specific to these disciplines than any previous guide on animal care and use. It treats on such important subjects as: The important role that the researcher and veterinarian play in developing animal protocols. Methods for assessing and ensuring an animal's well-being. General animal-care elements as they apply to neuroscience and behavioral research, and common animal welfare challenges this research can pose. The use of professional judgment and careful interpretation of regulations and guidelines to develop performance standards ensuring animal well-being and high-quality research. Guidelines for the Care and Use of Mammals in Neuroscience and Behavioral Research treats the development and evaluation of animal-use protocols as a decision-making process, not just a decision. To this end, it presents the most current, in-depth information about the best practices for animal care and use, as they pertain to the intricacies of neuroscience and behavioral research.

Spike-timing dependent plasticity

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Publisher : Frontiers E-books
ISBN 13 : 2889190439
Total Pages : 575 pages
Book Rating : 4.8/5 (891 download)

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Book Synopsis Spike-timing dependent plasticity by : Henry Markram

Download or read book Spike-timing dependent plasticity written by Henry Markram and published by Frontiers E-books. This book was released on with total page 575 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hebb's postulate provided a crucial framework to understand synaptic alterations underlying learning and memory. Hebb's theory proposed that neurons that fire together, also wire together, which provided the logical framework for the strengthening of synapses. Weakening of synapses was however addressed by "not being strengthened", and it was only later that the active decrease of synaptic strength was introduced through the discovery of long-term depression caused by low frequency stimulation of the presynaptic neuron. In 1994, it was found that the precise relative timing of pre and postynaptic spikes determined not only the magnitude, but also the direction of synaptic alterations when two neurons are active together. Neurons that fire together may therefore not necessarily wire together if the precise timing of the spikes involved are not tighly correlated. In the subsequent 15 years, Spike Timing Dependent Plasticity (STDP) has been found in multiple brain brain regions and in many different species. The size and shape of the time windows in which positive and negative changes can be made vary for different brain regions, but the core principle of spike timing dependent changes remain. A large number of theoretical studies have also been conducted during this period that explore the computational function of this driving principle and STDP algorithms have become the main learning algorithm when modeling neural networks. This Research Topic will bring together all the key experimental and theoretical research on STDP.