student research day - Case Western Reserve University School of ...

Min Deng
Neural Substrates of Age-related Decline in Executive Functions: In vivo measures of gray-matter
abnormalities from magnetic resonance imaging.
M. Deng, A. Bakkour, BC Dickerson
Martinos Imaging Center
MGH, HMS
Background: Executive functions are of fundamental importance for independent function in daily life, and are
impaired in Alzheimer’s disease, ADHD, schizophrenia and aging. Yet there is a major gap in our knowledge of the
anatomical substrates associated with executive function loss.
The purpose of this study was to identify regions of cortical thinning associated with decreased performance on
executive function in healthy older adults using MRI. We hypothesized that the trigger for EF decline would cause
gray matter changes in neuro-anatomical regions associated with executive functioning in the elderly and these
anatomical changes might be the basis for the associated clinical deterioration.
Methods: Thirty-six subjects ≥ 65 years old and free of diseases that could cause cognitive deficits were scanned
with a high-resolution Seimens Avanto 1.5T MRI scanner, followed immediately by a cognitive evaluation. A priori
cortical regions associated with executive function were established using primary and tertiary literature search.
Cortical thickness measurements were calculated using FreeSurfer based on established methods. Thickness
measurements in a priori regions were correlated with performance on two executive function tests - Trails-making
test and Verbal Fluency test. Correlations were tested for statistical significance using Pearson Correlation.
Results: Cortical thinning regions associated with decreased performance on Trails-making test were found in right
dorsolateral prefrontal cortex, right posterior cingulate, left supramarginal, and left rostral anterior cingulate
regions (P ≤ 0.05). Decreased performance in Verbal Fluency test correlated with thinning of right supramarginal,
right parietal, and left medial orbital frontal regions (P ≤ 0.05).
Conclusion: Decreased performance on the Trails-making and Verbal Fluency test is correlated with thinning of
specific cortical regions in frontal, parietal, and cingulate regions. These findings suggest a gray-matter neuro-
anatomical basis for loss of executive function.
Supported by MSTAR fellowship (M.D.) and NIH Grant K23-AG22509
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