Altered resting-state functional connectivity in late-life depression: A cross-sectional study

Abstract

Background Disrupted brain connectivity is implicated in the pathophysiology of late-life depression (LLD). There are few studies in this area using resting-state functional magnetic resonance imaging (rs-fMRI). In this pilot case-control study, we compare rs-fMRI data between age-matched depressed and non-depressed older adults. Methods Older participants (≥ 55 years) with current major depressive disorder (MDD) were recruited to participate in an ongoing study of LLD, and were compared to the age-matched, non-depressed controls. Rs-fMRI data were collected using a 3-Tesla MRI system. In this study, a data-driven approach was chosen and an independent component analysis (ICA) was performed. Results Seventeen subjects with MDD were compared to 31 controls. The depressed group showed increased connectivity in three main networks compared to the controls (p(corr) < 0.05), including connectivity between the default mode network (DMN) and the posterior superior temporal sulcus (pSTS). Increased connectivity was also observed within the visual network in the medial, lateral and ventral regions of the occipital lobes, and within the auditory network throughout the right superior temporal cortex. Conclusion This data-driven, pilot study finds patterns of increased connectivity that may be unique to LLD in the DMN, as well as visual and auditory networks. The functional implications of this aberrant connectivity remains to be determined. These findings should be further explored in larger samples.

A difference degree test for comparing brain networks

“…The results from the real data analysis suggest that the DDT appropriately identifies problematic brain regions in major depressive disorder. The existence of differential connectivity between nodes in the AUD and VIS networks (Figure ) has previously been observed (Eyre et al, ). Further, multivariate pattern analyses have suggested that the most discriminative FC patterns lie within and across the VIS network, DMN, and affective network (Zeng et al, ).…”

Depressive Symptoms and Tau Accumulation in the Inferior Temporal Lobe and Entorhinal Cortex in Cognitively Normal Older Adults: A Pilot Study

“…Future work will involve investigation of the relationships among depressive symptoms, AD proteinopathies, and medical and cerebrovascular illness burden, as well as those between depression and cognitive function. Furthermore, given the role of disruption of network structure and function in depressive illness and AD [51–55], future work investigating tau and amyloid accumulation in the context of both neuronal network structure and functional connectivity may provide a more thorough understanding of the pathophysiology of these symptoms in the context of other age-related brain changes.…”

Intrinsic inter-network brain dysfunction correlates with symptom dimensions in late-life depression

“…Enhanced DMN Fc is demonstrated in LLD (Alexopoulos et al, 2012; Eyre et al, 2016; Wu et al, 2011), which may be due to aging-related brain changes (Smith, G.S. et al, 2009; Wu et al, 2011).…”

“…Using seed-based resting-state functional connectivity magnetic resonance imaging (R-fcMRI) technique, diminished functional connectivity (Fc) within the ECN is observed in LLD and is predictive of poor treatment response, persistent depressive symptoms and executive dysfunction (Alexopoulos et al, 2012). LLD is also associated with enhanced DMN Fc in symptomatic (Alexopoulos et al, 2012; Eyre et al, 2016) but not remitted (Sexton et al, 2012) patients. Intrinsic ECN and DMN Fc changes differ based on antidepressant response, and could serve as early markers of treatment response variability in LLD (Karim et al, 2016).…”