Excessive brain iron negatively affects working memory and related processes but the impact of cortical iron on task-relevant, cortical brain networks is unknown. We hypothesized that high cortical iron concentration may disrupt functional circuitry within cortical networks supporting working memory performance. Fifty-five healthy older adults completed an N-Back working memory paradigm while functional magnetic resonance imaging (fMRI) was performed. Participants also underwent quantitative susceptibility mapping (QSM) imaging for assessment of non-heme brain iron concentration. Additionally, pseudo continuous arterial spin labeling scans were obtained to control for potential contributions of cerebral blood volume and structural brain images were used to control for contributions of brain volume. Task performance was positively correlated with strength of task-based functional connectivity (tFC) between brain regions of the frontoparietal working memory network. However, higher cortical iron concentration was associated with lower tFC within this frontoparietal network and with poorer working memory performance after controlling for both cerebral blood flow and brain volume. Our results suggest that high cortical iron concentration disrupts communication within frontoparietal networks supporting working memory and is associated with reduced working memory performance in older adults.

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Published in NeuroImage, v. 223, 117309.

© 2020 The Authors

This is an open access article under the CC BY-NC-ND license. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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This work was supported by the National Institutes of Health (grant numbers NIA R01AG055449 , NIA P30 AG028383 and NIGMS S10 OD023573).

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Supplementary material associated with this article can be found, in the online version, at https://doi.org/10.1016/j.neuroimage.2020.117309. It is also available for download as the additional file at the end of this record.

1-s2.0-S1053811920307953-mmc1.docx (356 kB)
Supplementary material