Agnieszka Zofia Burzynska1, Claudia Preuschhof1, Lars Bckman1,2, Lars Nyberg3, Shu-Chen Li1, Ulman Lindenberger1, Hauke Reiner Heekeren1,4
1Max Planck Institute for Human Development, Berlin, Germany; 2Aging Research Center, Karolinska Institute, Stockholm, Sweden; 3Department of Radiation Sciences and Integrative Medical Biology , Ume, Sweden; 4Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
Using tract-based-spatial-statistics we obtained the center-of-tract radial and axial diffusivity from 80 younger and 63 older adults. We found that the correlation of radial with axial diffusivity was higher in older than in younger adults for all investigated regions. This observation was independent of the direction of mean age differences in both DTI measures and thus may reflect a general age-related microstructural alteration common to most white matter regions, such as an increase in the extracellular space. The white matter diffusivity properties in late adulthood may result from tract-specific combination of fiber geometry and age-related alterations.