Background: This study tested the hypothesis that microstructural white matter abnormalities in frontostriatal-limbic tracts are associated with poor response inhibition on the Stroop task in depressed elders. Method: Fifty-one elders with major depression participated in a 12-week escitalopram trial. Diffusion tensor imaging was used to determine fractional anisotropy (FA) in white matter regions. Executive function (response inhibition) was assessed with the Stroop task. Voxelwise correlational analysis was used to examine the relationship between Stroop performance and fractional anisotropy. Results: Significant associations between FA and Stroop color word interference were evident in multiple frontostriatal-limbic regions, including white matter lateral to the anterior and posterior cingulate cortex and white matter in prefrontal, insular, and parahippocampal regions. Conclusions: These findings suggest that microstructural white matter abnormalities of frontostriatal-limbic networks are associated with executive dysfunction of late-life depression. This observation provides the rationale for examination of specific frontostriatal-limbic pathways in the pathophysiology of geriatric depression.
Bibliographical noteFunding Information:
This work was supported by National Institute of Mental Health Grants RO1 MH65653 (GSA), K23 MH067702 (CFM), P30 MH68638 (GSA), and K23 MH074818 (FMG-D) and by the Sanchez Foundation. Dr. Alexopoulos has received research grants by Forest Pharmaceuticals, Inc. and Cephalon and participated in scientific advisory board meetings of Forest Pharmaceuticals. He has given lectures supported by Forest, Cephalon, Bristol Meyers, Janssen, Pfizer, and Lilly and has received support by Comprehensive Neuroscience, Inc. for the development of treatment guidelines in late-life psychiatric disorders.
- executive function