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Alterations in brain white matter contributing to age-related slowing of task switching performance: The role of radial diffusivity and magnetization transfer ratio
Serbruyns, Leen Leunissen, Inge van Ruitenbeek, Peter Pauwels, Lisa Caeyenberghs, Karen Solesio-Jofre, Elena Geurts, Monique Cuypers, Koen Meesen, Raf L. Sunaert, Stefan
Serbruyns, Leen
Leunissen, Inge
van Ruitenbeek, Peter
Pauwels, Lisa
Caeyenberghs, Karen
Solesio-Jofre, Elena
Geurts, Monique
Cuypers, Koen
Meesen, Raf L.
Sunaert, Stefan
Abstract
Successfully switching between tasks is critical in many daily activities. Age-related slowing of this switching behavior has been documented extensively, but the underlying neural mechanisms remain unclear. Here, we investigated the contribution of brain white matter changes associated with myelin alterations to age-related slowing of switching performance. Diffusion tensor imaging derived radial diffusivity ( RD ) and magnetization transfer imaging derived magnetization transfer ratio ( MTR ) were selected as myelin sensitive measures. These metrics were studied in relation to mixing cost ( i.e., the increase in reaction time during task blocks that require task switching ) on a local-global switching task in young ( n = 24 ) and older ( n = 22 ) adults. Results showed that higher age was associated with widespread increases in RD and decreases in MTR, indicative of white matter deterioration, possibly due to demyelination. Older adults also showed a higher mixing cost, implying slowing of switching performance. Finally, mediation analyses demonstrated that decreases in MTR of the bilateral superior corona radiata contributed to the observed slowing of switching performance with increasing age. These findings provide evidence for a role of cortico-subcortical white matter changes in task switching performance deterioration with healthy aging.
Keywords
aging, mixing cost, switch cost, diffusion tensor imaging, magnetization transfer imaging, mediation
Date
2016
Type
Journal article
Journal
Human Brain Mapping
Book
Volume
37
Issue
11
Page Range
4084-4098
Article Number
ACU Department
Relation URI
Source URL
Event URL
Open Access Status
License
File Access
Controlled