Role of dopamine and gray matter density in aging effects and individual differences of functional connectomes

• Published in: Brain Structure and Function Vol. 226; no. 3; pp. 743 - 758
• Main Authors: Garzón, Benjamín, Lövdén, Martin, de Boer, Lieke, Axelsson, Jan, Riklund, Katrine, Bäckman, Lars, Nyberg, Lars, Guitart-Masip, Marc
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2021; Springer Nature B.V
• Subjects: Age; Age differences; Aging; Biomedical and Life Sciences; Biomedicine; Brain mapping; Cell Biology; Dopamine; Dopamine D1 receptors; fMRI; Functional connectome; Functional magnetic resonance imaging; Neural networks; Neurology; Neurosciences; Neurovetenskaper; Original; Original Article; PET; Psychology; Psykologi; Substantia grisea; Aging; fMRI; Dopamine; Functional connectome; PET
• ISSN: 1863-2653; 1863-2661; 1863-2661; 0340-2061
• DOI: 10.1007/s00429-020-02205-4

With increasing age, functional connectomes become dissimilar across normal individuals, reflecting heterogenous aging effects on functional connectivity (FC). We investigated the distribution of these effects across the connectome and their relationship with age-related differences in dopamine (DA) D1 receptor availability and gray matter density (GMD). With this aim, we determined aging effects on mean and interindividual variance of FC using fMRI in 30 younger and 30 older healthy subjects and mapped the contribution of each connection to the patterns of age-related similarity loss. Aging effects on mean FC accounted mainly for the dissimilarity between connectomes of younger and older adults, and were related, across brain regions, to aging effects on DA D1 receptor availability. Aging effects on the variance of FC indicated a global increase in variance with advancing age, explained connectome dissimilarity among older subjects and were related to aging effects on variance of GMD. The relationship between aging and the similarity of connectomes can thus be partly explained by age differences in DA modulation and gray matter structure.