Premium
[P2–580]: SOCIAL ISOLATION, COGNITIVE RESERVE, AND COGNITION IN LATER LIFE
Author(s) -
Evans Isobel E.M.,
Wu YuTzu,
Brayne Carol,
Matthews Fiona,
Woods Bob,
Clare Linda
Publication year - 2017
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2017.06.1239
Subject(s) - cognitive reserve , cognition , psychology , mediation , social isolation , cognitive decline , isolation (microbiology) , effects of sleep deprivation on cognitive performance , developmental psychology , dementia , medicine , psychiatry , cognitive impairment , sociology , disease , biology , social science , pathology , microbiology and biotechnology
Background:The concept of cognitive reserve has been proposed to account for the interindividual differences in the impact that pathology or age-related cerebral changes has on cognition. More reserve has been associated with factors such as higher educational attainment and greater engagement in cognitively stimulating activities and these are often used as reserve proxies. However, the neurobiological mechanisms by which this occurs remain unclear. Hence, this study investigated the relationships between reserve proxies and working memory-related (WM) brain activity, and whether these relationships were associated with attenuation of age-related differences inWMperformance.Methods:Thirty-seven older adults underwent functional magnetic resonance imaging (fMRI) while performing a verbal n-back task with two levels of WM load (1& 2-back) and one control condition (0-back). For each individual, a composite reserve score was determined from a principal component analysis of typical reserve proxies questionnaires. Two separate whole-brain multiple regression analyses were conducted with educational attainment and the composite reserve score as covariates of interest, and functional activation as the dependent variable. The contrasts of interest were [1-back> 0-back] and [2-back > 0-back]. Finally, moderation analyses were conducted to determine if activation associated with reserve proxies moderates the effects of age onWMperformance. Results:Education was associated with less activation in the left medial superior frontal gyrus (BA8) in the 1-back condition and with more activation in the right caudate body in the 2-back condition. The composite reserve score was also associated with less activation in the left medial superior frontal gyrus in the 1-back condition. Moderation analyses revealed that the relationship between age and WM performance is moderated by activation associated with reserve proxies in both conditions. Conclusions: Task difficulty determines different effects of reserve proxies on WM-related activity: in less demanding conditions, reserve is associated with less activation, which is suggestive of neural efficiency, whereas, in more demanding conditions, it allows for larger recruitment. Our findings that neural activity associated with reserve proxies attenuates the deleterious effects of age on WM performance reinforce the idea that these functional differences have a protective effect.