Oh-Sang Kwon

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A transfer of training design was used to examine the role of the Index of Difficulty (ID) on transfer of learning in a sequential Fitts's law task. Specifically, the role of the ratio between the accuracy and size of movement (ID) in transfer was examined. Transfer of skilled movement is better when both the size and accuracy of movement are changed by the(More)
Strategies of saccadic planning must take into account both the required level of accuracy of the saccades, and the time and resources needed to plan and execute the movements. To determine relationships between accuracy and time, we studied sequences of saccades made to scan a set of stationary targets located at the corners of an imaginary square. Target(More)
Visual input is remarkably diverse. Certain sensory inputs are more probable than others, mirroring statistical regularities of the visual environment. The visual system exploits many of these regularities, resulting, on average, in better inferences about visual stimuli. However, by incorporating prior knowledge into perceptual decisions, visual processing(More)
Despite growing evidence for perceptual interactions between motion and position, no unifying framework exists to account for these two key features of our visual experience. We show that percepts of both object position and motion derive from a common object-tracking system--a system that optimally integrates sensory signals with a realistic model of(More)
Because of uncertainty and noise, the brain should use accurate internal models of the statistics of objects in scenes to interpret sensory signals. Moreover, the brain should adapt its internal models to the statistics within local stimulus contexts. Consider the problem of hitting a baseball. The impoverished nature of the visual information available(More)
Stereopsis is the rich impression of three-dimensionality, based on binocular disparity-the differences between the two retinal images of the same world. However, a substantial proportion of the population is stereo-deficient, and relies mostly on monocular cues to judge the relative depth or distance of objects in the environment. Here we trained adults(More)
White matter hyperintensity (WMH) is commonly detected in patients with Alzheimer's disease (AD), but its role in cortical impairment is unclear. This study investigated the effects of WMH on gray matter (GM) volume in patients with AD. We consecutively enrolled 84 patients with AD and 35 normal controls, who underwent brain MRI and were then classified(More)
We investigated the availability of motor unit number estimation (MUNE) as a quantitative method to assess the severity and clinical progression of amyotrophic lateral sclerosis (ALS). The 143 ALS patients were evaluated by statistical MUNE and the revised amyotrophic lateral sclerosis functional rating scale (ALSFRS-R). By using mean values of MUNE(More)
We report a case of 54-yr-old woman who presented with 4-extremities weakness and sensory changes, followed by cervical spinal cord lesion in magnetic resonance imaging. Based on the suspicion of spinal tumor, spinal cord biopsy was performed, and the histology revealed multinucleated giant cells, lymphocytes and aggregated histiocytes within granulomatous(More)