Abstract
Patients with later-life depression (LLD) show abnormal gray matter (GM) volume, white matter (WM) integrity and functional connectivity in the anterior cingulate cortex (ACC) and posterior superior temporal gyrus (pSTG), but it remains unclear whether these abnormalities persist over time. We examined whether structural and functional abnormalities in these two regions are present within the same subjects during depressed vs. remitted phases. Sixteen patients with LLD and 30 healthy subjects were studied over a period of 1.5 years. Brain images obtained with a 3-Tesla magnetic resonance imaging (MRI) system were analyzed by voxel-based morphometry of the GM volume, and diffusion tensor imaging (DTI) and resting-state functional MRI were used to assess ACC–pSTG connectivity. Patients with LLD in the depressed and remitted phases showed significantly smaller GM volume in the left ACC and left pSTG than healthy subjects. Both patients with LLD in the depressed and remitted phases had significantly higher diffusivities in the WM tract of the left ACC–pSTG than healthy subjects. Remitted patients with LLD showed lower functional ACC–pSTG connectivity compared to healthy subjects. No difference was found in the two regions between depressed and remitted patients in GM volume, structural or functional connectivity. Functional ACC–pSTG connectivity was positively correlated with lower global function during remission. Our preliminary data show that structural and functional abnormalities of the ACC and pSTG occur during LLD remission. Our findings tentatively reveal the brain pathophysiology involved in LLD and may aid in developing neuroanatomical biomarkers for this condition.
Highlights
Accumulated evidence from structural neuroimaging studies suggests that patients with later-life depression (LLD) show abnormal gray matter (GM) and white matter (WM) brain structures
The whole brain analysis demonstrated that depressed patients with LLD showed smaller GM volumes in the left posterior superior temporal gyrus (STG) (pSTG) than healthy subjects
There was no significant difference in the GM volume in the whole brain analysis between remitted patients with LLD and healthy subjects, or between patients with LLD in the depressed and remitted phases
Summary
Accumulated evidence from structural neuroimaging studies suggests that patients with later-life depression (LLD) show abnormal gray matter (GM) and white matter (WM) brain structures. In terms of WM structures, patients with LLD showed abnormal connectivity in the cingulum, uncinate fasciculus (Charlton et al, 2015), temporal lobe (Charlton et al, 2015), superior longitudinal fasciculus, superior frontal gyrus, corpus callosum (Reppermund et al, 2014) and parahippocampal gyrus (Guo et al, 2014). Patients with LLD showed smaller GM volumes in the ACC, posterior STG (pSTG), and orbitofrontal cortex and abnormal WM integrity of the uncinate fasciculus, in comparison to healthy subjects (Harada et al, 2016). It remains unclear whether abnormalities of GM volume and WM connectivity are progressive or consistent over time. That study found no significant differences in the fractional anisotropy of WM tracts between LLD remitters and non-remitters over a 12-week antidepressant-treatment period (Khalaf et al, 2015)
Sign-in/Register to view highlights & summary 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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
