Year: 2018
Type: article
Study design: Observational Study
Abstract: BACKGROUND: Diffusion tensor imaging (DTI) studies report reduced fractional anisotropy (FA) in major depressive disorder (MDD). However, whether FA covaries with key depressive symptoms, such as anhedonia, is unclear. METHODS: Magnetic resonance imaging data were acquired from 38 unmedicated adults with MDD and 52 healthy controls. DTI metrics were extracted from regions of interest that have consistently shown reduced FA in MDD. Analyses focused first on identifying group differences, and then determining whether reduced FA in depressed adults was related to individual differences in anhedonia and depressive severity. To establish specificity to depression, these analyses controlled for symptoms of anxiety. RESULTS: Relative to controls, depressed adults showed reduced FA in the genu of the corpus callosum, the anterior limb of the internal capsule (ALIC), the cingulum bundle near the anterior cingulate cortex, and the uncinate fasciculus (UF). In the depressed group, anhedonia negatively correlated with FA in the genu, cingulum, and UF, but positively correlated with radial diffusivity (RD)-a metric previously linked to demyelination-in the genu and ALIC. Depressive severity positively correlated with RD in the ALIC. These relationships remained significant after accounting for anxiety. CONCLUSION: Anhedonia was positively correlated with reduced FA and increased RD in white matter pathways that connect regions critical for value coding, representing stimulus-reward associations, and guiding value-based action selection. Thus, a cardinal symptom of MDD-anhedonia-was lawfully related to abnormalities in reward network connectivity.
Source: Depression and Anxiety
DOI: 10.1002/da.22734
Institutions: Harvard University, McLean Hospital
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
Awards: Neuroscience of Reward-Related Learning and Memory in Depression, Neuroscience of Reward-Related Learning and Memory in Depression, Multi level Analysis of Positive Valence Systems Across Mood Disorders, Neuroimaging Studies of Reward Processing in Depression, Emotion regulation in depression: neural bases of reappraisal, Neuroimaging Studies of Reward Processing in Depression
OpenAlex ID: W2791507165