In this paper, we aim to investigate the relevance of different neurotransmitter systems in Alzheimer’s disease by relating interindividual differences in regional brain volumes of projection areas with high versus low neurotransmitter dependencies—as evident in receptor densities—to disease biomarkers (CSF p-tau and Aß) as well as cognitive performance in a cross-sectional sample of three participant groups: (i) healthy controls (HCs), (ii) SCD and (iii) MCI/mild Alzheimer’s disease dementia patients (AD). This evidence concerns the gene MAPT and dementia.