Anhedonia is a complex symptom of Major Depressive Disorder (MDD) that presents itself through multiple behavioral phenotypes of diminished reward processing. In order to better understand this deficit, we aim to look at a marker of reward that is sensitive to information content and valence, the Reward Positivity (RewP). The source of this signal is, however, up for debate. This study used concurrent EEG and MEG to establish the source of the RewP as a distributed network involving ventromedial prefrontal cortex (vmPFC), anterior midcingulate cortex (aMCC), and insulae. Additionally, only vmPFC showed a deficit in MDD. fMRI resting state functional connectivity analysis of these regions showed that these areas are all highly correlated with each other and with the nucleus accumbens (NAcc), a known, subcortical center of reward processing. Group comparisons of functional connectivity showed no differences between the MEG-derived regions and NAcc. Functional connectivity between vmPFC and aMCC was found to anticorrelate with MASQ – General Depression scores within the MDD+ group, but not MASQ – Anhedonia scores. These findings suggest that while vmPFC activation in response to reward may be diminished in MDD, the resting state network involved remains largely intact, perhaps with the exception of those with extreme symptom severity.
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Major Depressive Disorder, Reward Positivity, Reward Processing, Anhedonia, Magnetoencephalography, Functional Magnetic Resonance Imaging
Pirrung, Christopher J.H.. "Source Estimation of the Reward Positivity and Related Resting State Network Activity in Major Depressive Disorder." (2022). https://digitalrepository.unm.edu/psy_etds/383