Perceptual Organization in Parkinson’s Disease: A Behavioral Investigation of Basal Ganglia Dysfunction
Abstract
The basal ganglia provide a major neural system through which the cortex affects behavior. Most notable among these effects are those related to the voluntary control of movement as seen in neurodegenerative disorders like Parkinson’s disease (PD). Well known tests of visual perception in PD “explicitly” measure object recognition (a high-level visual process) but “implicitly” rely on intact mid-level visual processes like grouping and figure-ground segmentation to structure the image. Hence, exploring the importance of the basal ganglia in perceptual organization (PO) abilities by examining the specific impairments incurred with the damage of such a vital structure is imperative. Therefore, this study attempted to investigate PD performance in tasks in computerized classic gestalt perception experiments with the aim of identifying any mid-level visuo-perceptual deficits. Differences were observed in the grouping by proximity dot counting task but not in other tasks that involved figure-ground segregation, part detection in embedded contexts or shape discrimination.
General Audience Abstract
Damage to the basal ganglia, a group of structures in the subcortical part of the brain (below the cerebral cortex), has long been associated primarily with Parkinson’s Disease (PD), a neurological disorder that manifests with symptoms like muscle rigidity and tremors. While several key visual and perceptual problems have also been connected to this area, very few studies have tried to describe the mechanisms by which PD functionally alters their ability to perceive the visual world. Hence, this study attempted to investigate PD performance in computerized classic perception experiments with the aim of exploring mechanisms that organize incoming visual information to structure the image called perceptual organization (PO). Differences were observed in tasks that tested their ability to group “dots” when they are varied by proximity to each other but not in other tasks that involved their ability to segregate figures from the ground, detect parts of shapes in embedded contexts or discriminate between shapes.
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