Working memory load-dependent brain response predicts behavioral training gains in older adults.
In the domain of working memory (WM), a sigmoid-shaped relationship between WM load and brain activation patterns has been demonstrated in younger adults. It has been suggested that age-related alterations of this pattern are associated with changes in neural efficiency and capacity. At the same time, WM training studies have shown that some older adults are able to increase their WM performance through training. In this study, functional magnetic resonance imaging during an n-back WM task at different WM load levels was applied to compare blood oxygen level-dependent (BOLD) responses between younger and older participants and to predict gains in WM performance after a subsequent 12-session WM training procedure in older adults. We show that increased neural efficiency and capacity, as reflected by more "youth-like" brain response patterns in regions of interest of the frontoparietal WM network, were associated with better behavioral training outcome beyond the effects of age, sex, education, gray matter volume, and baseline WM performance. Furthermore, at low difficulty levels, decreases in BOLD response were found after WM training. Results indicate that both neural efficiency (i.e., decreased activation at comparable performance levels) and capacity (i.e., increasing activation with increasing WM load) of a WM-related network predict plasticity of the WM system, whereas WM training may specifically increase neural efficiency in older adults.
Department of Psychology, Humboldt-Universität zu Berlin, D-12489 Berlin, Germany, Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité-Universitätsmedizin Berlin, D-10117 Berlin, Germany, Social and Preventive Medicine, University of Potsdam, D-14469 Potsdam, Germany, and Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, D-10117 Berlin, Germany.
Stephan
S
Heinzel
Robert C
RC
Lorenz
Wolf-Rüdiger
WR
Brockhaus
Torsten
T
Wüstenberg
Norbert
N
Kathmann
Andreas
A
Heinz
Michael A
MA
Rapp
D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D055815:Young Adult
aging; fMRI; neuroimaging; plasticity; training; working memory