Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 33 for “"layer 4"”.
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Strength and dendritic organization of thalamocortical synapses onto excitatory layer 4 neurons
… activity, even though cortical synapses onto layer 4 (L4) neurons outnumber thalamic synapses ten to one. Previous in vitro studies have suggested that enhanced efficacy of thalamocortical (TC) relative to corticocortical (CC) synapses explains the effectiveness of the thalamus. We …
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Neocortical Layer 4 to Layer 2/3 Sensory Information Processing Investigated with Digital-Light-Projection Neuronal Photostimulation
… cortex of mice. The neocortex is organized into layers, with neuronal networks and circuits formed by layer-specific connections. While the anatomical organization of these circuits has been well characterized, the information processing and coding performed by these ensembles is poorly …
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Analyzing Ultrastructural characteristics of Post-synaptic targets of pre-identified Presynaptic Boutons in layer 3 and layer 4 of the Ferret Primary Visual cortex
… characterized pre-synaptic elements in layers 3 and 4 of the primary visual cortex (PVC). We are aiming to quantify a range of values for synaptic element morphologies as well as to correlate pre- and post-synaptic elements to find a set of rules that is prevalent in the visual cortex …
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The mouse visually evoked potential : neural correlates and functional applications
… typically focus on changes occurring in the layer 4 VEP after a variable period of visual deprivation. Layer 4 of mouse V1 receives heavy direct input from the lateral geniculate nucleus. This initial input is followed by strict hierarchical connectivity from cortical layer 4 to superficial …
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Ultrastructural correlates of axons and synapses belonging to different circuits in ferret primary visual cortex
… was to determine differences in distinctive layers of mammalian primary visual cortex through analysis of their ultrastructural characteristics. Characterizing brain circuitry using 3-dimensional reconstruction of electron microscopy images, and subsequent ultrastructural analysis of axonal …
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Effects of Whisker-Trimming on GABAA Receptors in S1 Cortex
… somatosensory cortex. Those studies focused on layer 4, a recipient of direct thalamocortical sensory input. However, supragranular layers 2/3 have been recently identified as a major locus of functional plasticity in sensory deprivation and long-term potentiation. To examine whether GABAA …
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Requirement for AMPA receptor endocytosis and long-term depression in ocular dominance plasticity
… or experience-dependent response potentiation in layer 4 of visual cortex. Additionally, we find that OD plasticity in layer 2/3 can occur in the absence of plasticity in layer 4, demonstrating the independence of OD plasticity across laminae. These data suggest that AMPAR internalization is …
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Cholinergic Control of Cortical Circuit Activity
… by acting in the superficial cortical layers, while muscarinic receptors mediated prolonged suppression in layer 4. In agreement, we found nicotinic-mediated excitation of inhibitory neurons in the supragranular layers, and muscarinic-mediated hyperpolarization of excitatory cells in …
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Calcium dynamics in dendrites and spines of spiny neurons in the somatosensory ‘barrel’ cortex of the rat
… in dendrites and spines of spiny neurons of layer 4 of the somatosensory cortex in acute thalamocortical brain slices of young (P13-P15) rats. Back-propagating action potentials (bAPs) resulted in a transient rise in Ca2+ in all dendrites and spines tested, representing a global intracellular …
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Understanding experience-dependent plasticity of cellular and network activity in the mouse primary visual cortex
… of N-methyl-D-aspartate (NMDA) receptors in layer 4 excitatory principal neurons in V1. Another simple but powerful phenomenon of an adult form of visual cortical plasticity is stimulus-selective response potentiation (SRP). SRP is induced simply through experience to the same gratings visual …
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Improving Cloud Middlebox Infrastructure for Online Services
… three fundamental problems: (1) The server-based layer-4 middleboxes are costly and inflate round-trip-time as much as 2x by processing the packets in software. (2) The middlebox instances cause traffic detouring en route from sources to destinations, which inflates network bandwidth usage by as …
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Critical requirements for NMDA receptors in experience-dependent plasticity in the visual cortex
… plasticity. First, I determined a layer-specific requirement for NMDA receptors in stimulus-specific response potentiation (SRP), which is a model for the plastic changes that may underlie perceptual learning. SRP acquisition requires NMDA receptors in the cortex, and it can be …
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Role of mGluR5 and FMRP in mouse primary somatosensory cortex
… as early as P4 in S1 prior to segregation of layer 4 cells into barrels suggesting a tropic role for glutamate in barrel formation. The expression of mGluR5 is postsynaptic during barrel formation and does not regulate tangential or radial cortical development. Its effects on barrel …
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Development and plasticity of the functional laminar mesoscale organization of the primary auditory cortex
… of auditory neurons within thalamorecipient layer 4 and supragranular layers 2/3 change over development – from before ear opening, through the critical period for auditory spectral tuning, and on to mature adult circuitry. Furthermore, this dissertation explores how brief visual deprivation …
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The role of cortical layer six in the perception and laminar representation of sensory change
… expected and actual sensory input, and the layered architecture of neocortex is presumably central to this computation. In this thesis, I examine the role of laminar differences, and specifically the role of layer 6 (L6) in the encoding and perception of stimuli that deviate from previous …
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Visual cortical plasticity : the role of parvalbumin expressing inhibitory neurons and abnormalities in models of neurodevelopmental disorders
… depression (LTD) and deprived-eye depression in layer 4 of V1 require metabotropic glutamate receptor 5 (mGluR5) signaling during postnatal development. Additionally, schizophrenia-associated protein neurogranin overexpression in V1 disrupts juvenile ocular dominance plasticity. Finally, we …
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Passive experience-dependent plasticity in mouse primary visual cortex
… local field potential (LFP) recordings in layer 4 (L4) of V1 allow for the tracking of visually evoked potentials (VEPs) in response to phase-reversing sinusoidal grating stimuli. As a given visual stimulus becomes familiar to the mouse, the VEP magnitude increases. This increase in VEP …
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Postnatal development of the somatosensory cortex in a rat model of Fragile X Syndrome
… Using whole-cell patch clamp recordings from layer 4 of S1, I found that Fmr1-/y stellate cells (SCs) are hyperexcitable during early development, in agreement with previous research. Thanks to the high temporal resolution of these recordings, I have identified multiple phases of development …
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Assessing the fate of PAHs in the Boston Inner Harbor using semipermeable membrane devices (SPMDs)
… a concentration ten times greater in the upper layer (4 m from the surface) than the lower layer (8 m from the surface). The concentrations increased with distance from the mouth of the Inner Harbor. The ratios of methyphenanthrene's-to-phenanthrene and pyrene-to-fluoranthene were calculated as …
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