Abstract
ObjectivesLate-life depression (LLD) has negative impacts on somatic, emotional and cognitive domains of the lives of patients. Elucidating the abnormality in the brain networks of LLD patients could help to strengthen the understanding of LLD pathophysiology, however, the studies exploring the spontaneous brain activity in LLD during the resting state remain limited. This study aimed at identifying the voxel-level whole-brain functional connectivity changes in LLD patients.MethodsFifty patients with late-life depression (LLD) and 33 healthy controls were recruited. All participants underwent a resting-state functional magnetic resonance imaging scan to assess the voxel-wise degree centrality (DC) changes in the patients. Furthermore, DC was compared between two patient subgroups, the late-onset depression (LOD) and the early-onset depression (EOD).ResultsCompared with the healthy controls, LLD patients showed increased DC in the inferior parietal lobule, parahippocampal gyrus, brainstem and cerebellum (p < 0.05, AlphaSim-corrected). LLD patients also showed decreased DC in the somatosensory and motor cortices and cerebellum (p < 0.05, AlphaSim-corrected). Compared with EOD patients, LOD patients showed increased centrality in the superior and middle temporal gyrus and decreased centrality in the occipital region (p < 0.05, AlphaSim-corrected). No significant correlation was found between the DC value and the symptom severity or disease duration in the patients after the correction for multiple comparisons.ConclusionsThese findings indicate that the intrinsic abnormality of network centrality exists in a wide range of brain areas in LLD patients. LOD patients differ with EOD patients in cortical network centrality. Our study might help to strengthen the understanding of the pathophysiology of LLD and the potential neural substrates underlie related emotional and cognitive impairments observed in the patients.
Highlights
Depression refers to a mental disorder characterized by low mood present across most situations for at least two weeks
To explore the alterations of functional centrality in Latelife depression (LLD) patients, we examined the difference in voxel-wise degree centrality (DC) between the LLD patients and healthy controls (HCs)
To determine the abnormality in core brain hub architecture as reflected by DC in the LLD patient group, we identified the clusters with DC difference between the LLD patients and HCs, using two-sample t-test with gender, age, education level, score of Mini-Mental State Examination (MMSE) and framewise displacement regressed out
Summary
Depression refers to a mental disorder characterized by low mood present across most situations for at least two weeks. Aside from the emotional and somatic burdens associated with depression, such as insomnia, anorexia and fatigue [1], elderly depressive patients may show impairment in various cognitive domains including attention [2], memory [3, 4], information processing speed [5, 6], and executive functions [4, 7]. LLD patients exhibited abnormal local synchronization in various brain areas, as revealed by the measure of regional homogeneity [14] These observations suggest that the brain activities in the resting state have extensive cortical and subcortical abnormalities in LLD patients, which might be associated with clinical manifestations such as emotional disturbance and cognitive deficits observed in the patients
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