The relation between dopamine-regulating genes, neurocognition, and aging

The decline in certain kinds of memory and other higher-order functions (cognitive decline) often associated with aging causes problems for individuals, their loved ones, and societies. As the population ages, the personal and financial costs of this problem are growing.

The neurotransmitter dopamine plays an important role in cognition, including working and long-term memory, possibly by regulating interactions between the striatum and prefrontal cortex. During aging, dopamine concentration, transporter availability, and receptor density decline. As these dopamine-related resources diminish, differences in genes relevant to dopamine seem to exert a growing influence on cognition. This hypothesis is supported by the finding that differences in genes relevant to dopamine, such as the receptor D₂ gene (DRD2 gene), are related to cognitive performance in older but not younger people. As yet, however, no empirical evidence links age, genetic variations in the DRD2 gene, and changes in striatal activity during tasks that require cognitive flexibility. This doctoral project therefore aims to investigate the influence of variations in the DRD2 gene on brain structure, brain function, and cognitive performance.

The project uses information from three existing sets of functional and structural magnetic resonance data. Two of these datasets come from large population-based studies, the Swedish National Study on Aging and Care (SNAC-K) and the Betula study. The third is a smaller community-based study on emotion and cognition (EMOCOG).

The research is funded by the Swedish Brain Foundation (Hjärnfonden).