Date of Award


Document Type


Degree Name

Medical Doctor (MD)



First Advisor

Dana M. Small


Accumulating studies report a negative relationship between obesity and performance on tasks of executive function, memory, and reward-based learning. More recently, an analysis of the Human Connectome Project data revealed an unexpected, but strong negative association between body mass index (BMI) and visuospatial ability assessed by the Penn Line Orientation task (PLOT). However, visual acuity was not assessed, and the PLOT was the only measure of visuospatial ability. We conducted behavioral and functional neuroimaging experiments to determine if this effect could be replicated, rule out visual acuity deficits, and evaluate specificity. The behavioral study comprised n=80 (40 HW, 40 OW/OB) healthy participants. Visual measures included visual acuity, visual contrast, PLOT, and higher-order visuospatial ability (as measured by the Motor-Free Visual Perception Test). Other variables included anthropomorphic measures, adiposity, heart rate variability, diet, fasting glucose, HbA1c, and physical activity. The second experiment consisted of a subgroup of 22 participants from the behavioral study, plus 5 additional individuals (n=27), who underwent scanning with fMRI while performing a line orientation task. Replicating the results of prior HCP analyses, individuals with overweight/obese performed significantly worse on the PLOT. No differences were observed on measures of visual acuity or other tests of visual perception. Linear regression of all assessed variables demonstrated that PLOT performance was solely attributable percent body fat percentage (R2=0.192, p


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