White matter correlates of temporal discounting in older adults

Abstract

Temporal discounting, the tendency to select a smaller reward offered sooner over a larger reward offered at a later time, has been associated with a number of real-world decision-making outcomes important for health and wellbeing. Neurobiological mechanisms supporting temporal discounting have been explored among younger participants, and these have considered white matter integrity. However, the white matter correlates of temporal discounting in older adults are unclear. We hypothesized that greater temporal discounting would be associated with poorer white matter integrity measures, more specifically lower fractional anisotropy and higher trace, in older adults. Participants were 302 older persons without dementia (mean age = 81.38, mean years of education = 15.75, 75.5% female, mean MMSE = 28.29) from the Rush Memory and Aging Project, a community-based longitudinal study of aging. Temporal discounting was assessed using standard elicitation questions. White matter integrity was assessed with diffusion tensor imaging (DTI). Regression models were adjusted for the effects of age, sex, education, and white matter lesions. Secondary models further adjusted for global cognition. Results revealed significant associations between temporal discounting and white matter integrity measures (FA and trace) in bilateral frontal, frontostriatal, and temporal-parietal lobe white matter tracts, and results remained significant after further accounting for global cognition. These results suggest that temporal discounting is inversely associated with white matter integrity in old age and that this association is independent of global cognition.

Regionconnect: Rapidly extracting standardized brain connectivity information in voxel-wise neuroimaging studies

“…Regionconnect and other resources developed in this work have already been applied successfully in healthy young adults as well as other populations. Regionconnect was recently used in voxel-wise investigations involving diffusion tensor imaging data on older adults ( Han et al, 2016 ; 2018 ; Lamar et al, 2019 ), and also in a study of aging with ex-vivo MRI but no diffusion data ( Gaiteri et al, 2019 ). The online interactive version of regionconnect that allows the user to easily select and update a white matter region of interest has been used in education for exploring healthy adult brain connectivity.…”

Investigating associations of delay discounting with brain structure, working memory, and episodic memory

“…2015 ). The largest study in the field thus far ( Han et al. 2018 ) found a negative association between temporal discounting and white matter integrity in bilateral frontal, fronto-striatal, and temporoparietal tracts in older persons.…”

Neural markers of procrastination in white matter microstructures and networks

“…First, the denoizing for the residual information of diffusion was done. Then, instead of the default FMRIB58 template, the IIT Human Brain Atlas (IIT‐HBA, v.4.1, http://www.iit.edu/%7Emri) template was used for the nonlinear registration and thinning of the native FA/MD/LDH map to facilitate the construction of the mean skeleton (Han et al., 2018; Varentsova et al., 2014). Furthermore, individual FA/MD/LDH maps were projected onto the mean skeleton and estimated the maximum local FA/MD/LDH points.…”