Dopaminergic neuromodulation of episodic memory in old age
- Goran Papenberg
- 26 April 2017
- Faculty of Social and Behavioural Sciences
2333 AK Leiden
The role of dopamine in modulating episodic memory performance
The dopamine system is fundamental for a variety of cognitive processes. In my talk, I focus on dopamine’s role in modulating episodic memory performance. First, I present data from candidate gene studies showing that dopamine-relevant genes affect episodic memory stronger in older than younger adults. Disproportionate age-related impairments are typically observed for older individuals carrying disadvantageous alleles of different candidate genes. Interestingly, findings show that dopamine receptor efficacy may be particularly relevant for associative memory, which declines more with aging than item memory. Second, I present data from a large-scale positron emission tomography (PET) study (n=181; aged 64-68 years) assessing dopamine D2 receptor availability in the human brain using the 11C-raclopride radioligand. Binding potential is the typical outcome measure of PET assessments, and a product of receptor density and ligand affinity for the receptor. I describe the ”landscape” of D2 receptor availability in the human brain with respect to local receptor availability and interregional associations according to anatomical and functional dopamine pathways. Moreover, correlations between regional D2 receptor availability and cognition will be presented. The strongest associations are seen for episodic memory, and these vary as a function of genetic predisposition in ligand affinity (C957T polymorphism of the dopamine D2 receptor gene). Associations between binding potential and cognition were mainly observed in individuals with genetic predispositions for low-to-average affinity. This finding will be discussed in terms of high ligand affinity being a possible indicator of poor dopamine system integrity.