Dorsolateral Prefrontal Functional Connectivity Predicts Working Memory Training Gains

Sofia Faraza; Julia Waldenmaier; Martin Dyrba; Dominik Wolf; Florian U Fischer; Kristel Knaepen; Bianca Kollmann; Oliver Tüscher; Harald Binder; Andreas Mierau; David Riedel; Andreas Fellgiebel; Stefan Teipel

doi:10.3389/fnagi.2021.592261

Dorsolateral Prefrontal Functional Connectivity Predicts Working Memory Training Gains

Front Aging Neurosci. 2021 Mar 1:13:592261. doi: 10.3389/fnagi.2021.592261. eCollection 2021.

Authors

Sofia Faraza¹, Julia Waldenmaier¹, Martin Dyrba², Dominik Wolf^{3

4}, Florian U Fischer^{3

4}, Kristel Knaepen⁵, Bianca Kollmann^{3

6}, Oliver Tüscher^{3

6}, Harald Binder⁷, Andreas Mierau^{5

8}, David Riedel⁵, Andreas Fellgiebel^{3

4}, Stefan Teipel^{1

2}

Affiliations

¹ Department of Psychosomatic Medicine and Psychotherapy, Rostock University Medical Center, Rostock, Germany.
² German Center for Neurodegenerative Diseases (DZNE), Rostock, Germany.
³ Department of Psychiatry and Psychotherapy, University Medical Center Mainz, Mainz, Germany.
⁴ Center for Mental Health in Old Age, Mainz, Germany.
⁵ Institute of Movement and Neurosciences, German Sport University Cologne, Cologne, Germany.
⁶ Leibnitz Institute for Resilience Research (LIR), Mainz, Germany.
⁷ Institute of Medical Biometry and Statistics (IMBI), Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany.
⁸ Department of Exercise and Sport Science, LUNEX International University of Health, Exercise and Sports, Differdange, Luxembourg.

Abstract

Background: Normal aging is associated with working memory decline. A decrease in working memory performance is associated with age-related changes in functional activation patterns in the dorsolateral prefrontal cortex (DLPFC). Cognitive training can improve cognitive performance in healthy older adults. We implemented a cognitive training study to assess determinants of generalization of training gains to untrained tasks, a key indicator for the effectiveness of cognitive training. We aimed to investigate the association of resting-state functional connectivity (FC) of DLPFC with working memory performance improvement and cognitive gains after the training. Method: A sample of 60 healthy older adults (mean age: 68 years) underwent a 4-week neuropsychological training, entailing a working memory task. Baseline resting-state functional MRI (rs-fMRI) images were acquired in order to investigate the FC of DLPFC. To evaluate training effects, participants underwent a neuropsychological assessment before and after the training. A second follow-up assessment was applied 12 weeks after the training. We used cognitive scores of digit span backward and visual block span backward tasks representing working memory function. The training group was divided into subjects who had and who did not have training gains, which was defined as a higher improvement in working memory tasks than the control group (N = 19). Results: A high FC of DLPFC of the right hemisphere was significantly associated with training gains and performance improvement in the visuospatial task. The maintenance of cognitive gains was restricted to the time period directly after the training. The training group showed performance improvement in the digit span backward task. Conclusion: Functional activation patterns of the DLPFC were associated with the degree of working memory training gains and visuospatial performance improvement. Although improvement through cognitive training and acquisition of training gains are possible in aging, they remain limited.

Keywords: cognitive training; dorsolateral prefrontal cortex; functional connectivity; healthy older adults; working memory gains.