Figure 2.

Pathmodel of multimodal imaging measurements. Mediation analysis (n = 29) revealed that the influence of dopamine synthesis capacity on BOLD parameter estimates (c path, solid arrow) was mediated by glutamate concentration within the striatum. When excluding mediator influence, the dopamine‐BOLD relationship did not remain significant (c′ path, dashed line). Furthermore, mediator glutamate concentration was positively associated with dopamine synthesis capacity (a path) and BOLD parameter estimates (b path). MRS = Magnetic resonance spectroscopy; PET = Positron emission tomography; BOLD = Blood oxygen level dependent; fMRI = functional magnetic resonance imaging. [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]