Perceptual Organization in Parkinson’s Disease: A Behavioral Investigation of Basal Ganglia Dysfunction
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.