Role of the default-mode network during narrative integration in major depressive disorder
Abstract
How brain activity is synchronized across individuals during narrative comprehension has previously been characterized by functional magnetic resonance imaging (fMRI) in healthy and patient populations. To our knowledge, there has been limited investigation as to how it is affected by major depressive disorder (MDD). We addressed this issue with fMRI through examination of inter-subject synchronization in the default mode network (DMN), brain structures which have previously been implicated in MDD pathology. Twenty-two patients with MDD and 20 matched control participants listened to Intact versus Scrambled versions of an auditory narrative; these experimental conditions differed in the degree of temporal integration they demanded. Across conditions, we found a significant increase in synchrony within DMN for intact narratives. As compared to controls, patients demonstrated a significant increase in synchrony across multiple DMN regions, some specific for intact narratives. Our findings highlight the impact of brain abnormalities in MDD on an ecologically relevant cognitive function.