Altered topological properties of functional brain networks in patients with first episode, late-life depression before and after antidepressant treatment

Abstract

ObjectivesTo preliminarily explore the functional activity and information integration of the brains under resting state based on graph theory in patients with first-episode, late-life depression (LLD) before and after antidepressant treatment.MethodsA total of 50 patients with first-episode LLD and 40 non-depressed controls (NCs) were recruited for the present research. Participants underwent the RBANS test, the 17-item Hamilton depression rating scale (HAMD-17) test, and resting-state functional MRI scans (rs-fMRI). The RBANS test consists of 12 sub-tests that contribute to a total score and index scores across the five domains: immediate memory, visuospatial/constructional, language, attention, and delayed memory. Escitalopram or sertraline was adopted for treating depression, and the dosage of the drug was adjusted by the experienced psychiatrists. Of the 50 LLD patients, 27 cases who completed 6-month follow-ups and 27 NCs matched with age, sex, and education level were included for the final statistical analysis.ResultsThere were significant differences in RBANS total score, immediate memory, visuospatial/constructional, language, attention, and delayed memory between LLD baseline group and NCs group (P < 0.05). Considering the global attribute indicators, the clustering coefficient of global indicators was lower in the LLD baseline group than in the NCs group, and the small-world attribute of functional brain networks existed in all three groups. The degree centrality and node efficiency of some brains were lower in the LLD baseline group than in the NCs group. After 6 months of antidepressant therapy, the scores of HAMD-17, immediate memory, language, and delayed memory in the LLD follow-up group were higher than those in the LLD baseline group. Compared with the LLD baseline group, the degree centrality and node efficiency of some brains in the cognitive control network were decreased in the LLD follow-up group.ConclusionsThe ability to integrate and divide labor of functional brain networks declines in LLD patients and linked with the depression severity. After the relief of depressive symptoms, the small-world attribute of functional brain networks in LLD patients persists. However, the information transmission efficiency and centrality of some brain regions continue to decline over time, perhaps related to their progressive cognitive impairment.

Executive function deficits in patients with the first episode of late‐life depression before and after SSRI treatment: A pilot fMRI study

“…In this study, after a 6-month of antidepressant treatment, the results of the TMT and Stroop task test indicated no statistically significant difference between the LLD baseline group and the LLD follow-up group. This finding aligned with our previous study, 34 which demonstrated that the LLD follow-up group exhibited enhanced performance in immediate memory, delayed memory, and speech function compared to the LLD baseline group. However, there was no significant alteration observed in visual space and attention ability.…”

“…After 6 months of SSRIs treatment, compared with the LLD baseline group, the congruency between word color and word meaning led to enhanced activation of the left middle cingulate gyrus in the LLD follow‐up group. Similarly, we recently found that after 6 months of SSRIs treatment, patients in the LLD follow‐up group had an increased degree centrality (DC) value in the left median cingulate and paracingulate gyrus compared to the LLD baseline group 34 . In graph theory, DC refers to the degree of each node in the network in the node attribute index, and the higher the value, the more likely the node is to become a hub in the network, the higher the value, the more likely the node is to become a hub in the network 44 .…”

“…Similarly, we recently found that after 6 months of SSRIs treatment, patients in the LLD follow-up group had an increased degree centrality (DC) value in the left median cingulate and paracingulate gyrus compared to the LLD baseline group. 34 In graph theory, DC refers to the degree of each node in the network in the node attribute index, and the higher the value, the more likely the node is to become a hub in the network, the higher the value, the more likely the node is to become a hub in the network. 44 Previous research has indicated that the posterior cingulate cortex has the capacity to receive…”

“…The head was tightly fastened using foam pads and straps to avoid the effect of head movement to the maximum extent. We initially captured the T1 images (excluding intracranial organic diseases preliminary, such as tumor‐like lesions or absence followed by ts‐fMRI (around 4 min) 34 . When collecting T1 images, each participant was asked to relax with eyes closed, lie still, and keep awake.…”

“…We initially captured the T1 images (excluding intracranial organic diseases preliminary, such as tumor-like lesions or absence followed by ts-fMRI (around 4 min). 34 When collecting T1 images, each participant was asked to relax with eyes closed, lie still, and keep awake. The T1 images were collected with the T1-weighted sagittal 3D magnetization-prepared rapid…”