Did I win? Assessing anhedonia related whole-brain connectivity changes in depression using the newly developed toolbox network-gppi

Anhedonia is a debilitating facet of major depressive disorder (MDD) linked to worse treatment outcomes. To investigate anhedonia-related alteration, an adaptation of the widely used gPPI toolbox was developed, which allows modelling of whole-brain functional connectivity between an unlimited number of regions. Using this network-gppi toolbox, connectivities between all 246 regions of the Brainnetome atlas were estimated for the fMRI data of 99 patients with MDD and 28 healthy controls acquired during a monetary incentive delay task. Resulting components, i.e., interlinked structures of thresholded connections ( p < .001), were statistically evaluated using network-based statistic (NBS). For reward consumption, both groups did not differ significantly ( p NBS = .082). However, the comparison with a subset of 54 anhedonic patients was significant ( p NBS = .017). Interestingly, anhedonic patients were found to have increased connectivities between the left lateral orbitofrontal cortex and multiple regions of the dorsal striatum, potentially indicating a more negative evaluation of the gained rewards. A trend was observed for the correlation between reward consumption connectivities and an anhedonic subscale of the Beck Depression Inventory-II (p NBS = .068). Most noteworthy, symptoms correlated positively with stronger connectivities between the caudate and dorsomedial prefrontal cortex. Given the role of the latter in rumination, this could possibly reflect an increased impact of negative self-related cognitions. Similar analyses for reward anticipation connectivities were not significant. Overall, the results could indicate that anhedonic patients might devaluate winning trials, so they are not too incongruent with existing negative self-related beliefs.