Fiber bundle length and cognition: a length-based tractography MRI study.
Executive function (EF) and cognitive processing speed (CPS) are two cognitive performance domains that decline with advanced age. Reduced EF and CPS are known to correlate with age-related frontal-lobe volume loss. However, it remains unclear whether white matter microstructure in these regions is associated with age-related decline in EF and/or CPS. We utilized quantitative tractography metrics derived from diffusion-tensor MRI to investigate the relationship between the mean fiber bundle lengths (FBLs) projecting to different lobes, and EF/CPS performance in 73 healthy aging adults. We measured aspects of EF and CPS with the Trail Making Test (TMT), Color-Word Interference Test, Letter-Number Sequencing (L-N Seq), and Symbol Coding. Results revealed that parietal and occipital FBLs explained a significant portion of variance in EF. Frontal, temporal, and occipital FBLs explained a significant portion of variance in CPS. Shorter occipital FBLs were associated with poorer performance on the EF tests TMT-B and CWIT 3. Shorter frontal, parietal, and occipital FBLs were associated with poorer performance on L-N Seq and Symbol Coding. Shorter frontal and temporal FBLs were associated with lower performance on CPS tests TMT-A and CWIT 1. Shorter FBLs were also associated with increased age. Results suggest an age-related FBL shortening in specific brain regions related to poorer EF and CPS performance among older adults. Overall, results support both the frontal aging hypothesis and processing speed theory, suggesting that each mechanism is contributing to age-related cognitive decline.
Department of Psychology, University of Missouri - Saint Louis, 1 University Boulevard, Stadler Hall 442C, Saint Louis, MO, 63121, 314 - 805 - 3684, USA. ambn98@mail.umsl.edu.
Ashley M
AM
Behrman-Lay
Department of Psychology, University of Missouri - Saint Louis, 1 University Boulevard, Stadler Hall 442C, Saint Louis, MO, 63121, 314 - 805 - 3684, USA.
Christina
C
Usher
Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway, St. Louis, MO, 63110, USA.
Thomas E
TE
Conturo
Department of Psychiatry & Human Behavior, Alpert Medical School, Brown University, Box G-A, Providence, RI, 02912, USA.
Stephen
S
Correia
Computer Science Department, Brown University, Box 1910, Providence, RI, 02912, USA.
David H
DH
Laidlaw
Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN, 37232, USA.
Elizabeth M
EM
Lane
Department of Psychology, University of Missouri - Saint Louis, 1 University Boulevard, Stadler Hall 442C, Saint Louis, MO, 63121, 314 - 805 - 3684, USA.
Jacob
J
Bolzenius
Department of Psychology, University of Missouri - Saint Louis, 1 University Boulevard, Stadler Hall 442C, Saint Louis, MO, 63121, 314 - 805 - 3684, USA.
Jodi M
JM
Heaps
Department of Psychology, University of Missouri - Saint Louis, 1 University Boulevard, Stadler Hall 442C, Saint Louis, MO, 63121, 314 - 805 - 3684, USA.
Lauren E
LE
Salminen
Department of Psychology, University of Missouri - Saint Louis, 1 University Boulevard, Stadler Hall 442C, Saint Louis, MO, 63121, 314 - 805 - 3684, USA.
Laurie M
LM
Baker
Computer Science Department, Brown University, Box 1910, Providence, RI, 02912, USA.
Ryan
R
Cabeen
Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway, St. Louis, MO, 63110, USA.
Erbil
E
Akbudak
Department of Biostatistics and Center for Statistical Sciences, Brown University, Box G-S121-7, 121 S, Main Street, Providence, RI, 02912, USA.
Xi
X
Luo
Center for Computation and Visualization, Brown University, Box 1824, Providence, RI, 02912, USA.
Peisi
P
Yan
Department of Psychology, University of Missouri - Saint Louis, 1 University Boulevard, Stadler Hall 442C, Saint Louis, MO, 63121, 314 - 805 - 3684, USA.
Robert H
RH
Paul
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology* / Q000523:psychology*; D001921:Brain / Q000473:pathology*; D003071:Cognition; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D056324:Diffusion Tensor Imaging / Q000379:methods; D056344:Executive Function; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology; D009483:Neuropsychological Tests
Aging; Cognitive processing speed; DTI; Executive function; Fiber bundle lengths; White matter