Diffusion Imaging Analysis of the Functional Heterogeneity in the Dopaminergic System: Correlates with Prospective Memory

Dopamine neurons are essential for several aspects of cognition. Several decades of Parkinson’s Disease (PD) research have revealed that the deterioration of these neurons is associated with a wide range of cognitive deficits such as attention, motor coordination, and memory. The diversity of these deficits is a demonstration of the structural and functional heterogeneity within the dopaminergic system; projections from the substantia nigra and the ventral tegmental area to striatum have targets in the frontal and medial temporal cortices. It is known that prospective memory is negatively affected by PD, but whether the deficits originate from pathways that support attention, retrospective memory, working memory, and/or motor control has not yet been determined. For the current study, the goal is to estimate the structural integrity of these pathways by using diffusion-imaging analysis to then correlate these estimates with prospective memory performance within a standard event-based task. Two participant data sets were reported in the current study and compared with the global and target fractional anisotropy as well as seed connectivity. All the results reported here are preliminary.