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Full-Text Articles in Ophthalmology

Retinal Ganglion Cells Underlying Visual Perception And Predation In Mice, Keith Patrick Johnson May 2021

Retinal Ganglion Cells Underlying Visual Perception And Predation In Mice, Keith Patrick Johnson

Arts & Sciences Electronic Theses and Dissertations

The spike trains of retinal ganglion cells (RGCs) are the sole source of visual information to the brain. In mice, more than 40 RGC types send signals to more than 50 brain areas. RGCs that perform nonlinear operations to extract specific visual features (e.g., the motion of an object against a background) are called feature detectors. Those that linearly integrate local changes in light inten-sity are known as pixel encoders. Most mouse RGC types are feature detectors. In the first part of my dissertation, I discovered a pixel encoder RGC type in mice, the PixON-RGC. I revealed how the unique …


Understanding The Molecular Pathogenesis Of Retinal Neurodegeneration, Jonathan B. Lin May 2020

Understanding The Molecular Pathogenesis Of Retinal Neurodegeneration, Jonathan B. Lin

Arts & Sciences Electronic Theses and Dissertations

Retinal degenerative diseases are a major cause of morbidity in modern society because visual impairment significantly decreases the quality of life of patients. A significant challenge in treating retinal degenerative diseases is their genetic and phenotypic heterogeneity. Furthermore, limitations in our understanding of disease pathophysiology have led to reliance on therapies that often treat disease endpoints rather than addressing disease etiology and/or pathophysiology. The long-term goal of my thesis research was to provide molecular and cellular insights into the pathophysiology underlying diverse retinal degenerative diseases, which may lead to much-needed, novel therapeutic approaches. During the first part of my thesis …


Electrophysiology Of The Inner Retina In Health And Disease: Eaat5 In The Rod Bipolar Cell And Oscillatory Potentials In Diabetes, Gregory William Bligard May 2020

Electrophysiology Of The Inner Retina In Health And Disease: Eaat5 In The Rod Bipolar Cell And Oscillatory Potentials In Diabetes, Gregory William Bligard

Arts & Sciences Electronic Theses and Dissertations

The inner retina is a highly tractable location for the study of neural networks in the central nervous system and improving our understanding of the inner retina is important for the treatment of a number of ophthalmic diseases. This dissertation aims to improve understanding of the inner retina in two parts: first, a basic neuroscientific project concerning normal neuronal processing in the inner retina at a cellular level, and second, a translational ophthalmologic project regarding the development in the inner retina of a common disease. In mammals, modulation of the amplitude of dim visual signals primarily occurs at axon terminals …


Basic Vision Research With Clinical Applications And Science Education Assessments, Andrew Wilson Jun 2017

Basic Vision Research With Clinical Applications And Science Education Assessments, Andrew Wilson

Electronic Theses and Dissertations

Visual Acuity (VA) examinations are one of the most commonly conducted medical assessment throughout the world. Recent advances in computer technology allows for new forms of visual assessment to be conducted. In Part I of this thesis I demonstrate the capability of an automated computer program named VISION to assess human visual acuities. Different color combinations of an object against a background emitted from a computer screen are used to examine a variety of human color vision acuities. Results indicated a large difference in acuity scores between human subjects tested with these different color combinations. A single human subject exhibits …


GabaB Receptor Attenuation Of GabaA Currents In Neurons Of The Mammalian Central Nervous System, Wen Shen, Changlong Nan, Peter T. Nelson, Harris Ripps, Malcolm M. Slaughter Mar 2017

GabaB Receptor Attenuation Of GabaA Currents In Neurons Of The Mammalian Central Nervous System, Wen Shen, Changlong Nan, Peter T. Nelson, Harris Ripps, Malcolm M. Slaughter

Pathology and Laboratory Medicine Faculty Publications

Ionotropic receptors are tightly regulated by second messenger systems and are often present along with their metabotropic counterparts on a neuron's plasma membrane. This leads to the hypothesis that the two receptor subtypes can interact, and indeed this has been observed in excitatory glutamate and inhibitory GABA receptors. In both systems the metabotropic pathway augments the ionotropic receptor response. However, we have found that the metabotropic GABAB receptor can suppress the ionotropic GABAA receptor current, in both the in vitro mouse retina and in human amygdala membrane fractions. Expression of amygdala membrane microdomains in Xenopus oocytes by microtransplantation …


Boundary Contour Based Surface Representation., Yong Su Dec 2014

Boundary Contour Based Surface Representation., Yong Su

Electronic Theses and Dissertations

We receive most information about our surrounding space and objects through the eyes. To reconstruct the 3D space and objects in the visual system from the 2D retinal images, surface representation must be a critical intermediate stage in the visual processing stream. It is hypothesized in the dissertation that the visual system represents textured surface by a border-to-interior strategy: boundary contours would be encoded first and then border-ownership assignments would be resolved. This process would solve the related problems such as figure-ground segregation, surface depth relationship, occlusion, transparency, etc. As a result, the boundary contours of the surfaces would be …


Transcranial Magnetic Stimulation Of The Prefrontal Cortex Delays Contralateral Endogenous Saccades, Tony Ro, Avishai Henik, Liana Machado, Robert D. Rafal Jul 1997

Transcranial Magnetic Stimulation Of The Prefrontal Cortex Delays Contralateral Endogenous Saccades, Tony Ro, Avishai Henik, Liana Machado, Robert D. Rafal

Publications and Research

The contributions of the superior prefrontal cortex (SPFC) and the superior parietal lobule (SPL) in generating voluntary endogenous and reflexive visually guided saccades were investigated using transcranial magnetic stimulation (TMS). Subjects made choice saccades to the left or right visual field in response to a central arrowhead (endogenous go signal) or a peripheral asterisk (exogenous go signal) that were presented along with a single TMS pulse at varying temporal intervals. TMS over the SPFC increased latencies for saccades made in response to an endogenous go signal toward the contralateral hemifield. No effects were observed when the go signal was exogenous …