No description available.

No description available.

No description available.

No description available.

No description available.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23813号 / 医博第4859号 / 新制||医||1059(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 中本 裕士, 教授 花川 隆, 教授 大森 孝一 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Genom åren har intresset för och satsningar på underhållning i tredimensionellt format (3D) gått i vågor. Idag har de flesta biografer stöd för att visa 3D-filmer. Utöver detta intresse har det på senare år även börjat komma mer teknik för 3D i hemmet. Det har också introducerats många nya mer immersiva och intuitiva inmatnings-enheter som bidrar till under-hållning med element av virtual reality hemma. Företagen Sony, Nintendo och Microsoft har alla lanserat olika typer av avancerade tekniker för sådana inmatnings-enheter till sina spel-system. Dessa tekniker bidrar på olika sätt till mer immersiv underhållning. På de sätt som många av teknikerna används idag blir däremot interaktionen fortfarande hämmad av att dessa kräver att man står, respektive tittar, i en viss riktning.Rapporten återger en experimentell studie som tar sikte på att undersöka om det är möjligt att med kommersiellt tillgänliga medel skapa immersiv virtual reality som är portabel och buren – för underhållning i hemmet. Inledningsvis redogörs kortfattat för människans upp-fattning av djup samt hur olika 3D-displayer fungerar. Härefter kommer vi in på virtual reality och betydelsen av en hög nivå av immersion i detta sammanhang. Beträffande virtual reality kommer däremot utgångspunkten vara mer teoretisk, för att ge en bild av åt vilket håll utvecklingen går. Denna del går därmed längre än vad experimentet omfattar, eftersom denna teori inte ännu fullt ut omsatts i praktiken. Hypotesen för experimentet är att tekniken ”head tracking”, i form av en huvudburen rörelsedetektor som känner av huvudets orientering, till viss del kan vara en lösning på problemet med immersion – eftersom jag som användare då inte är hänvisad till en viss plats. Slutligen analyseras såväl teori som experiment och man kommer fram till att VRD är en möjlig lovande framtida teknik. Hypotesen bekräftas till viss del och rapporten mynnar ut i en slutreflektion där det konstateras att teknik för att skapa ökad immersion och VR hemma finns tillgänglig – även om en del ytterligare arbete för datahantering skulle krävas för att optimera denna. / Through the years, interest in and focus on entertainment in three dimensional form (3D) has gone in waves. Today, most cinemas have support for showing 3D-movies. In addition to this interest, an increasing amount of technology for 3D at home has become available in recent years. A number of different new, more immersive and intuitive input devices with elements of virtual reality for home use, have also been introduced. The companies Sony, Nintendo and Microsoft have all launched various types of such advanced input technology for their game consoles. These techniques contribute in various ways to more immersive entertain-ment. In the way many of these technical solutions are used today, they are still limited by the requirement of standing and looking in a specific direction. The report reflects an experimental study that aims to explore the feasibility of using commercially obtainable material to create immersive virtual reality for home entertainment, which is portable and wearable. Initially it explains the basics of human depth perception, and how different 3D displays work. Hereafter, we will look at virtual reality and the im-portance of a high level of immersion in this context. In regards to virtual reality however, the starting point will be of a more theoretical nature, to give an idea of in which direction the development is heading. This part thereby goes further than what the experiment covers, because of this theory not yet beeing fully applied in practice. The hypothesis for the experiment is that the technology "head tracking", in the form of a head-mounted motion-sensor that detects the orientation of the head, in part, may be a solution to the problem of immersion – as the user isn’t dependant on a specific location.Finally an analysis of both theory and experiment is made in which it is concluded that VRD might be a promissing future technology. The hypothesis is partially confirmed and the report culminates in a final reflection where it is found that technology for creating a higher level of immersion and VR at home is available – even though some additional work with data handling would be required.

<p><strong>Purpose:</strong> Microglia are the innate immune cells of the central nervous system. Activated microglia release nitric oxide, glutamate, and superoxide radicals, which are harmful to retinal ganglion cells (RGCs). They may also benefit surviving cells by removing toxic cellular debris or by secretion of neurotrophic factors. The paradoxical role of microglia remains controversial because the nature and time-course of the injury that determines whether microglia acquire a neuroprotective or pro-inflammatory phenotype is unknown. HAPI cells are an immortalized microglial cell line, whose phenotype can be manipulated <em>in vitro</em>. It is my HYPOTHESIS that pharmacological manipulation of microglia to acquire either a pro-inflammatory or pro-survival phenotype will exacerbate neuronal cell death or enhance neuronal survival after injury, respectively.</p> <p><strong>Method:</strong> Lipopolysaccharides (LPS) were used to hyper-stimulate the HAPI cells and minocycline to maintain the HAPI cells in a quiescent state. Prior to the experiments, the HAPI cells were labelled with Wheat Germ Agglutinin conjugated to Texas Red. The HAPI cells were cultured and exposed to minocycline (10 µg/mL for 1 hour) or LPS (1 µg/mL for 24 hours). Sprague-Dawley rats then recieved intraocular (30,000 cells) or tail vein (5 million cells) injections of either the minocycline treated HAPI cells or the LPS treated HAPI cells and an optic nerve crush. Retinas were examined at 4-14 days later and the number of surviving RGCs will be determined by Brn3a labelling of RGCs. BM88 antibody labelling was done to determine the severity of the injury and to determine molecular changes after neuroinflammation.</p> <p><strong>Results: </strong>Injection of untreated HAPI cells resulted in the greater loss of RGCs early after ONC when injected into the vitreous and later after ONC when injected into the tail vein. LPS activated HAPI cells injected into the vitreous resulted in greater RGC loss with and without injury. When injected into the tail vein with ONC there was no loss of RGCs 4 days after ONC but later there was greater loss of RGCs. Minocycline treated HAPI cells injected into the vitreous resulted in greater RGC survival than when untreated HAPI cells were injected. However, when injected into the tail vein with ONC there was greater loss of RGCs. There was also BM88 down regulation after injury and this was more pronounced after HAPI cell injection.</p> <p><strong>Conclusion:</strong> Neuroprotection or cytotoxicity of microglia depends on the type of activation, time course of the injury, and if the microglia act on the axon or cell body of the retinal ganglion cell.</p> / Doctor of Philosophy (PhD)

No description available.

Axons of retinal ganglion cells (RGCs) send visual information to a number of retinorecipient regions in the brain. In rodents, visual thalamus receives dense innervations from RGC axons and is important for both image-forming and nonimage-forming visual functions. Retinal inputs invade visual thalamus during embryonic development, before the arrival of non-retinal inputs (such as local interneurons and axonal inputs from other brain regions). In this dissertation, I explore how early innervation of RGC axons affects circuitry in visual thalamus and the role of visual experience, neural activity, and molecular cues in the development. While the development of astrocytes in cortex has been well-described, they have been largely overlooked in visual thalamus. Using immunohistochemical, functional, and ultrastructural analysis, I show that astrocytes in visual thalamus reach adult-like morphological properties and functionality at retinogeniculate synapses early in development, by eye-opening and before visual experience. These studies reveal that while experience-dependent visual activity from RGC axons is critical for many aspects of visual thalamus development, astrocytic maturation occurs independent of that information about our visual environment. As with astrocytes, little progress has been made in understanding the development of interneurons in the visual thalamus. Here, I show that retinal inputs interact with thalamic astrocytes to influence the recruitment of GABAergic interneurons into visual thalamus. I found that this interaction between RGC axons and astrocytes is not dependent on neural activity of RGCs. Using transcriptomic analysis, in situ hybridization, and reporter lines, I observed thalamus-projecting RGCs express SHH and astrocytes in visual thalamus express SHH signaling molecules. My results reveal that SHH signaling between RGC axons and astrocytes is critical for astrocytic fibroblast growth factor 15 (FGF15) expression in developing visual thalamus. Ultimately, FGF15 serves as a potent motogen that is essential for thalamic interneuron migration. These data identify a novel morphogen-dependent and activity-independent mechanism that mediates crosstalk between RGCs and astrocytes to facilitate the recruitment of interneurons into the developing visual thalamus. / Doctor of Philosophy / The most dominant sense in human is the sight, which we need to interact with our environment efficiently. The retina takes up the information about our visual world and sends it to the brain, which ultimately puts everything together, for us to see properly. The visual information from the retina goes to the brain via nerves (which are essentially cables/wires of brain cells). These nerves from the retina go to many places in the brain, including a region called visual thalamus, which is the focus of my PhD work. For the past five years, I have been trying to understanding if nerves from the retina play a role in the brain formation during early development. To study this, I have used mice as a model system, as their brain regions that process visual information have very similar structural architecture to those in humans. My research shows that retinal nerves are indeed important for the development of visual thalamus. Here, I show that information from the eye is critical for migration (a process during development where brain cells move from their place of origin to their final location) of cells in visual thalamus. Discoveries made in this dissertation are important because they highlight how different cells in the central nervous system communicate with each other at the level of molecules and how these interactions are important for building circuits that are important for vision.