Abstract
Age-related differences in white matter (WM) integrity are substantial, but it is unknown whether between-subject variability in WM integrity influences the capacity for cognitive improvement. We investigated the effects of memory training related to active and passive control conditions in older adults and tested whether WM integrity at baseline was predictive of training benefits. We hypothesized that (1) memory improvement would be restricted to the training group, (2) widespread areas would show greater mean diffusivity (MD) and lower fractional anisotropy in older adults relative to young adults, and (3) within these areas, variability in WM microstructure in the older group would be predictive of training gains. The results showed that only the group receiving training improved their memory. Significant age differences in MD and fractional anisotropy were found in widespread areas. Within these areas, voxelwise analyses showed a negative relationship between MD and memory improvement in 3 clusters, indicating that WM integrity could serve as a marker for the ability to adapt in response to cognitive challenges in aging.
Highlights
Brain functions can be modified in response to changing environments and demands throughout the life span (Bavelier et al, 2012; Dahlin et al, 2008; Lovden et al, 2010)
To test whether the relationship between white matter (WM) integrity and memory improvement was specific to training-related gains, we investigated the relationship between WM integrity at baseline and improvement on the Digit Span Backwards test, a test where the participants were asked to render a sequence of numbers backwards
This study aimed to investigate the effects of a memorytraining intervention in older adults relative to active and passive control groups, and to test whether individual differences in WM integrity could serve as a predictor for cognitive gains
Summary
Brain functions can be modified in response to changing environments and demands throughout the life span (Bavelier et al, 2012; Dahlin et al, 2008; Lovden et al, 2010). A number of studies indicate that age-related variance in cognitive functioning is related to individual variability in the WM microstructure (Madden et al, 2012). The predominant findings from diffusion tensor imaging studies are increased mean diffusivity (MD) and decreased fractional anisotropy (FA) with aging, albeit accompanied by substantial individual variability (Bennett and Madden, 2014; Salami et al, 2012; Sexton et al, 2014; Westlye et al, 2010). MD represents the mean molecular motion independent of tissue directionality and is suggested to relate to cellular properties such as size and integrity (Basser, 1995; Pierpaoli et al, 1996). WM integrity can be further characterized by axial diffusivity (AD) and radial diffusivity (RD), which represent the rate of diffusion along the primary and secondary axes of the diffusion ellipsoid, respectively (Bennett and Madden, 2014)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
