Beyond the cortex: implications of white matter connectivity for depression, cognition, and vascular disease

The current study investigates the effects of vascular disease on white matter health by comparing participants with atherosclerotic vascular disease (AVD) to healthy control participants (HC). The comparison between groups will help elucidate the differences between early-stage mild vascular disease and normal aging processes in terms of their effects on white matter health as measured by diffusion tensor imaging (DTI). Relationships between white matter health and depression, attention, and processing speed are studied by the application of a variety of DTI neuroimaging techniques, which will allow investigation of these relationships at the levels of global, lobe-wise, and subregional analysis. The specific subregion of interest in the depression study is Brodmann Area 25, which has shown significant relationships with depressive symptomatology in patients with treatment refractory depression, but has not been studied in the context of aging, vascular disease, or subthreshold depressive symptoms. Results indicate that there are significant differences between AVD and HC participants in global and regional FA measures. Within the AVD group, significant relationships of FA with depressive symptoms and attentional function have been observed in the current study. Several unexpected findings emerged, most important of which was the observation that there is a significant relationship between FA in Brodmann Area 25 and depressive symptoms in AVD participants which is specific to the right hemisphere. These findings have implications for the treatment of depressive symptoms in older adults and participants with vascular disease.