Abstract
Background: Major depressive disorder (MDD) patients face an increased risk of developing cognitive impairments. One of the prominent cognitive impairments in MDD patients is verbal fluency deficit. Nonetheless, it is not clear which vulnerable brain region in MDD is interactively linked to verbal fluency deficit. It is important to gain an improved understanding for verbal fluency deficit in MDD.Methods: Thirty-four MDD patients and 34 normal controls (NCs) completed resting-state fMRI (rs-fMRI) scan and a set of verbal fluency tests (semantic VFT and phonemic VFT). Fourteen brain regions from five brain networks/systems (central executive network, default mode network, salience network, limbic system, cerebellum) based on their vital role in MDD neuropathology were selected as seeds for functional connectivity (FC) analyses with the voxels in the whole brain. Finally, correlations between the z-score of the FCs from clusters showing significant between-group difference and z-score of the VFTs were calculated using Pearson correlation analyses.Results: Increased FCs in MDD patients vs. NCs were identified between the bilateral posterior cingulate cortex (PCC) and the right inferior frontal gyrus (triangular part), in which the increased FC between the right PCC and the right inferior frontal gyrus (triangular part) was positively correlated with the z score of phonemic VFT in the MDD patients. Moreover, decreased FCs were identified between the right hippocampal gyrus and PCC, as well as left cerebellum Crus II and right parahippocampal gyrus in MDD patients vs. NCs.Conclusions: The MDD patients have altered FCs among key brain regions in the default mode network, the central executive network, the limbic system, and the cerebellum. The increased FC between the right PCC and the right inferior frontal gyrus (triangular part) may be useful to better characterize pathophysiology of MDD and functional correlates of the phonemic verbal fluency deficit in MDD.
Highlights
Major depressive disorder (MDD) is one of the most common and costly psychiatric disorders [1]
They indicated that semantic verbal fluency was more related to semantic knowledge, semantic memory retrieval, language production, and strategy formation, while phonemic verbal fluency was more related to vocabulary, language production, memory retrieval, and strategy formation
The normal controls (NCs) were all volunteers who were physically healthy based on their self-reported medical history and mentally healthy according to the Mini-International Neuropsychiatric Interview (MINI) [34] as applied by two psychologists
Summary
Major depressive disorder (MDD) is one of the most common and costly psychiatric disorders [1]. Only small improvements in cognitive impairments were found during the treatment of depression, verbal fluency was the most sensitive to improve in the treatment when compared to other cognitive domains [5]. In light of these findings, it is important to gain a better understanding and find a potential biomarker for verbal fluency deficit in MDD, which could be of great clinical importance in terms of allowing early and accurate diagnosis [6]. The above results indicated a deficit of verbal fluency in MDD patients; the underlying brain functional alteration has not been fully revealed yet. Major depressive disorder (MDD) patients face an increased risk of developing cognitive impairments. It is important to gain an improved understanding for verbal fluency deficit in MDD
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call