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C-19 An fMRI Study of Age-Associated Changes in Basic Visual Discrimination


 
 
 The study was conducted to determine age-associated changes in functional brain response, measured with fMRI, during visual discrimination with regard to three elementary components of visual perception: shape, location, and velocity. A secondary aim was to validate the method used to isolate the hypothesized brain regions associated with these perceptual functions.
 
 
 
 Items from the Visual Assessment Battery (VAB), a simultaneous match-to-sample task, assessed visual discrimination in 40 healthy adults during fMRI. Participants were aged 51-91 and recruited from a larger community sample for a study on normal aging. The tasks were designed to isolate neural recruitment during discrimination of either location, shape, or velocity by using tasks that were identical aside from the perceptual skill required to complete them.
 
 
 
 The Location task uniquely activated the dorsal visual processing stream, the Shape task the ventral stream, and the Velocity task V5/MT. Greater age was associated with greater neural recruitment, particularly in frontal areas (uncorrected voxel-level p < .001, family-wise error cluster-level p□.05).
 
 
 
 Results validated the specialization of brain regions for spatial, perceptual, and movement discriminations and the use of the VAB to assess functioning localized to these regions. Anterior neural recruitment during visual discrimination increases with age.
