Browsing by Subject "vision"
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Item CEHD Aspirations & Expectations(University of Minnesota: College of Education and Human Development, 2006-10-24) Bailey, DarlyneThe new College of Education and Human Development is a world leader in discovering, creating, sharing, and applying principles and practices of multiculturalism and multidisciplinary scholarship to advance teaching and learning and to enhance the psychological, physical, and social development of children, youth, and adults across the lifespan in families, organizations, and communities.Item Delineating the Neural Correlates of Visual Awareness through the Integration of Multimodal Neuroimaging and Noninvasive Electrical Neuromodulation(2016-12) Roy, AbhrajeetIn recent years, there has been a push to develop a fundamental theory of consciousness in the neuroscience community. However, to date, the physical mechanisms underlying conscious awareness remain unclear. The major aim of this dissertation was to delineate neural correlates of consciousness through the integration of multimodal functional neuroimaging and noninvasive electrical neuromodulation. To this extent, we utilized simultaneous EEG-fMRI imaging to investigate both the electrophysiological and hemodynamic correlates of visual awareness during binocular rivalry. Binocular rivalry is a classic visual phenomenon in which one’s perception spontaneously fluctuates between two different images that are presented simultaneously to the viewer, one to each eye. These random alternations in visual awareness occur despite the static dichoptic input, making binocular rivalry a promising framework for the study of brain networks involved in consciousness. In addition, we evaluated the feasibility of using transcranial direct/alternating current stimulation to modulate behavioral and electrophysiological correlates of rivalry and visual perception in general. Our findings point to the existence of multiple neural networks operating independently during rivalry for its resolution. Differential patterns of activation in fronto-parietal networks and across the default mode network were associated with both subjective changes in visual awareness and maintaining perceptual stability during rivalry. Collectively, our findings suggest that suppression of eye-specific neural activity during rivalry is mainly due to bottom-up processing in early visual cortex, while fronto-parietal activity appears more generalized and predominantly related to attentional processes and conscious awareness of changes in sensory information.Item The Impact of the Minnesota Principals' Academy on High School Principal Decision-Making(2018-08) Knuth, JoannAbstract High school principals make numerous decisions daily. Decision-‐making is a complicated process requiring multiple pieces of data, synthesizing them, looking at the big picture, setting targets, and strategically thinking through actions, looking at risks, assumptions, and belief systems. If a wrong decision, even a seemingly minor one, is made, it can haunt the principal’s leadership for a long time. This research investigated the impact of the Minnesota Principals’ Academy (MPA), an 18-‐month long executive professional development program for practicing principals on their perceptions and skills with regard to decision-‐making. Fourteen of seventeen eligible principals who had completed the MPA agreed to be interviewed, representing a cross-‐section of high schools from urban, suburban, and greater Minnesota schools, with student populations from under 600 to over 2,200. Using a structured interview protocol, with probes to expand responses and report experiences, principals’ responses were coded and analyzed, looking for both common and unique themes. Findings revealed that the more experienced the principal, the greater the pattern of consulting with others before making difficult decisions. Another concept that emerged from the data was the key role of vision to principals’ leadership. Having a vision appeared to shape and influence all aspects of principals’ decision-‐making and leadership. A striking aspect of the data was the commonality of principals’ vision across all participants and their commitment to the commonality of that vision. Every principal interviewed noted that participating in the MPA deepened their belief in the importance of vision to their leadership and making sound decisions for their schools and students.Item The Role Of D-Serine In Normal Retinal Function And Implications For Psychiatry(2019-08) Torres Jimenez, NathaliaThere is a lack of objective measurements for assessing the progression of mental disorders such as schizophrenia. Biomarkers for schizophrenia would be an invaluable asset to identify at-risk individuals objectively, which should consequently improve the person’s prognosis and treatment. One such candidate for becoming a biomarker for schizophrenia is the flash-electroretinogram (fERG), an ophthalmological tool that assesses retinal integrity. Prior research had conflicting results, with some studies showing that people with schizophrenia have a reduced response from photoreceptors and bipolar cells. However, it has been unclear why abnormalities would occur that early in the retinal pathway when mouse studies that investigated monoamine deprivation, such as dopamine, did not reflect those deficits. An alternative reason for an altered fERG is that it may reflect reduced N-methyl-d-aspartate receptor (NMDAR) function, which has been postulated to explain some of the pathology exhibited in people with schizophrenia. However, no retinal field potentials in the outer retina had been attributed to NMDAR function. One way to induce hypofunction of the NMDAR is by reducing the availability of its co-agonist, either glycine or D-serine, since the NMDAR needs both glutamate and a co-agonist for activation. I examined how D-serine deprivation and its excess affects the outer retinal field potentials, and whether it has implications for psychiatry. We report the first fERG study in a genetic mouse model of schizophrenia characterized by NMDAR hypofunction from genetic silencing of serine racemase expression (SR-/-), an enzyme that converts L-serine to D-serine. We analyzed fERG components under mesopic-adapted conditions that reflect outer retinal function, the a-wave and the b-wave, to determine the resemblance to the human fERG from people with schizophrenia. In all the analyses, I included sex as a factor, due to thevii sex differences underlying the disease. We tested pharmacologically-induced hyperfunction of the NMDAR in WT mice by introducing D-serine. Lastly, we analyzed human fERG and pattern-electroretinogram (PERG) studies to assess outer and inner retinal function. I report that hypo- or hyper-function of the NMDAR, through changes in available D-serine, profoundly affects the temporal scale of photoreceptor and bipolar cell signaling, as well as the amplitude of bipolar cell currents. This work mirrors the deficits observed in people with schizophrenia. Including sex as a factor in analyses showed that D-serine affects male mice more profoundly regardless of genotype, suggesting that NMDAR and D-serine are involved in the retinal field potentials of the outer retina and are dependent on the animal’s sex. These studies also suggest that either there is a functional NMDAR component to the outer retinal field potentials or that D-serine has another role in the retina aside from being an endogenous co-agonist for the NMDAR. This implicates the involvement of gonadal hormones and D-serine in retinal functional integrity. Our human analyses reflect deficits in the retinal ganglion cell layer, and a trending reduction of the signal corresponding to bipolar cells. Furthermore, the human data analyses also showed an interaction between sex, with deficits affecting males with schizophrenia more profoundly. This work elevates the potential of the fERG to differentiate between healthy controls and subjects with schizophrenia, and to detect sex differences known to be present in schizophreniaItem Strategic Positioning Framing Concepts(University of Minnesota, 2004-10-11) University of Minnesota: Office of the President