Modulatory interactions of resting-state brain functional connectivity in major depressive disorder

Abstract

BackgroundMajor depressive disorder (MDD) is mediated by chronic dysregulation of complex neural circuits, particularly the specific neurotransmitters or other neural substrates. Recently, both increases and decreases in resting-state functional connectivity have been observed in patients with MDD. However, previous research has only assessed the functional connectivity within a specific network or some regions of interests, without considering the modulatory effects of the entire brain regions. To fill in the research gap, this study employed PPI (physiophysiological interaction) to investigate the functional connectivity in the entire brain regions. Apart from the traditional PPI used for cognitive research, current PPI analysis is more suitable for exploring the neural mechanism in MDD patients. Besides, this PPI method does not require a new cognitive estimation task and can assess the modulatory effects on different part of brain without prior setting of regions of interest.MethodsFirst, we recruited 76 outpatients with major depressive disorder, and conducted MRI scan to acquire structural and functional images. As referred to the previous study of resting-state networks, we identified eight well-defined intrinsic resting-state networks by using independent component analysis. Subsequently, we explored the regions that exhibited synchronous modulatory interactions within the network by executing PPI analysis.ResultsOur findings indicated that the modulatory effects between healthy crowed and patient are different. By using PPI analysis in neuroimaging can help us to understand the mechanisms of neural disruptions in MDD patients. In addition, this study provides new insight into the complicated relationships between three or more regions of brain, as well as different brain networks functions in external and internal.ConclusionFurthermore, the functional connectivity may deepen our knowledge regarding the complex brain functions in MDD patients and suggest a new multimodality treatment for MDD including targeted therapy and transcranial magnetic stimulation.

Altered cerebral activities and functional connectivity in depression: a systematic review of fMRI studies

“…Decreased VMHC was found in STG, the insula, and the precuneus [28]. In ICA studies, abnormally increased functional connectivity was found between the precuneus/posterior cingulate cortex (PCC) and the left lateral parietal cortex (LPC), and the abnormally decreased coupling was found between the bilateral anterior portion of dlPFC [26,38]. In the seed‐based analysis, the most common region of interest (ROI) is the amygdala.…”

“…Fourteen studies reported abnormal functional connectivity in the resting state (Tab 328], and two performed the independent component analysis (ICA) [26,38].…”

“…As for studies with multiple ROIs across brain networks, abnormally increased connectivity within the reward network and the default mode network (DMN) as well as between DMN and the executive control network was reported [32,43,48]. Meanwhile, abnormally decreased within DMN connectivity, within-network superior occipital and superior temporal connectivity, and between-network hippocampal connectivity was reported [37,42,43,59].…”

A Treatment-Response Comparison Study of Resting-State Functional Magnetic Resonance Imaging Between Standard Treatment of SSRI and Standard Treatment of SSRI Plus Non-dominant Hand-Writing Task in Patients With Major Depressive Disorder

“…Another result is decreased connectivity between the right IC and left pTFus C. Insular connectivity changes in MDD give contradictory results (32,33). A study showed a positive correlation between the severity of hopelessness in MDD and right ventral ACC and right insular ReHo (34).…”