Cognitive Aging, Executive Function, and Fractional Anisotropy: A Diffusion Tensor MR Imaging Study
S.M. Grievea,
L.M. Williamsb,c,
R.H. Pauld,
C.R. Clarke and
E. Gordona
a The Brain Resource International Database, The Brain Resource Company, Ultimo, Australia
b The Brain Dynamics Centre, Westmead Hospital, Westmead, Australia
c School of Psychological Medicine, University of Sydney, Sydney, Australia
d Department of Psychiatry, Centers for Behavioral and Preventive Medicine, Brown Medical School, Providence, RI
e Cognitive Neuroscience Laboratory and School of Psychology, Flinders University, Adelaide, Australia
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Fig 1. Scatterplots displaying the relationship between FA and age (A). FA decreases linearly with age (ß = 0.010/year; 95% CI, 0.007–0.013 year; r2 = 0.371; P < .001).
B, FA and time to completion for the executive maze test. Higher FA is associated with faster completion of the maze, a relationship described by a linear trend (ß = –24 seconds per 0.01 FA unit; 95% CI, 16–33 seconds per 0.01 FA; r2 = 0.274; P < .001).
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Fig 2. A, A series of axial images at 10-mm intervals showing T-scores (in color) superimposed over a representative high-resolution anatomic magnetization-prepared rapid acquisition of gradient echo (MPRAGE) image in standardized MNI space. Bilateral cluster of voxels are present in the frontal and parietal lobes (sections +28 to +48 mm); in addition, significant voxels connect these regions to the anterior thalamus (sections –2 to +28 mm).
B, A series of coronal sections at 10-mm intervals showing the connection between the frontal and parietal significant voxels with the anterior thalamus (section –6 mm). Bilateral clusters of voxels represent brain regions where a significant negative association between FA and age exists. These clusters indicate regions in which FA loss is greatest in advancing age.
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Fig 3. A, A series of axial images at 10-mm intervals showing T-scores (in color) superimposed over a representative high-resolution anatomic MPRAGE image in standardized MNI space. Bilateral cluster of voxels are present in the frontal and parietal lobes (sections +28 to +48 mm), in addition significant voxels connect these regions to the anterior thalamus (sections –2 to +28 mm).
B, A series of coronal sections at 10-mm intervals showing the connection between the frontal and parietal significant voxels with the anterior thalamus (section –6 mm). Color voxels represent regions of association between voxel FA and overall time score in an executive function task is significant.
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Fig 4. A maximum intensity projection image displaying the age-related FA changes superimposed over the significant regions of FA associated with altered performance in executive function task. The volume of the age-FA cluster was 29.4 mL versus 49.5 mL in the executive function-FA association cluster.
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