Semaya, Emily2021-04-122021-04-122021-01https://hdl.handle.net/11299/219290University of Minnesota M.S. thesis.January 2021. Major: Neuroscience. Advisor: Cheryl Olman. 1 computer file (PDF); iv, 29 pages.The phenomenon of visual surround suppression demonstrates the importance of context to the comprehension of visual stimuli. This effect can be used in contrast discrimination tasks to study gain control in the visual system. We developed a four-alternative forced-choice contrast discrimination task using naturalistic texture stimuli to determine the influence of realistic, complex visual stimuli on contrast discrimination in visually normal participants. Texture type and Orientation of the center and surround stimuli were found to have significant main effects on response. Textures surrounding a target with parallel orientation tended to result in more surround suppression than those with orthogonal orientation, although these trends were not significant. These results contribute to our understanding of the differences in responses between simple, artificial stimuli and naturalistic stimuli, and inform the development of future studies to clarify these findings.enThesis or Dissertation