Abstract
Episodic memory performance declines with increasing age, and older adults typically show reduced activation of inferior temporo-parietal cortices in functional magnetic resonance imaging (fMRI) studies of episodic memory formation. Given the age-related cortical volume loss, it is conceivable that age-related reduction of memory-related fMRI activity may be partially attributable to reduced grey matter volume (GMV). We performed a voxel-wise multimodal neuroimaging analysis of fMRI correlates of successful memory encoding, using regional GMV as covariate. In a large cohort of healthy adults (106 young, 111 older), older adults showed reduced GMV across the entire neocortex and reduced encoding-related activation of inferior temporal and parieto-occipital cortices compared to young adults. Importantly, these reduced fMRI activations during successful encoding in older adults could in part be attributed to lower regional GMV. Our results highlight the importance of controlling for structural MRI differences in fMRI studies in older adults but also demonstrate that age-related differences in memory-related fMRI activity cannot be attributed to structural variability alone.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Disclosure statement/conflicts of interest: The authors have nothing to disclose.
Data availability: The data and analysis scripts/toolboxes used here are available online and linked in the Methods section. Group-level results data are available via OSF.
Minor additions to results and discussion
2 Effects of GMV on SME per age group are not reported here due to space limitations, but thresholded contrast images can be found in our OSF repository.
