BMRMI Reduces Depressive Rumination Possibly through Improving Abnormal FC of Dorsal ACC.

Rumination is a common symptom of major depressive disorder (MDD) and has been characterized as a vulnerability factor for the onset or recurrence of MDD. However, the neurobiological mechanisms underlying rumination and appropriate treatment strategies remain unclear. In the current study, we used resting-state functional magnetic resonance imaging to investigate the effects of body-mind relaxation meditation induction (BMRMI) intervention in MDD with rumination. To this aim, we have recruited 25 MDD and 24 healthy controls (HCs). Changes in functional connectivity (FC) of the anterior cingulate cortex (ACC) subregion and the scores of clinical measurements were examined using correlation analysis. At baseline, MDD showed stronger FC between the right dorsal ACC (dACC) and right superior frontal gyrus than did the HC group. Compared to baseline, the HC group showed a significantly enhanced FC between the right dACC and right superior frontal gyrus, and the MDD group demonstrated a significantly weaker FC between the left dACC and right middle frontal gyrus (MFG) after the intervention. Furthermore, the FC between the right dACC and right superior frontal gyrus was positively associated with rumination scores across all participants at baseline. The above results indicate that BMRMI may regulate self-referential processing and cognitive function through modulating FC of the dACC in MDD with rumination.

Transcutaneous Auricular Vagus Nerve Stimulation Modulating the Brain Topological Architecture of Functional Network in Major Depressive Disorder: An fMRI Study.

BACKGROUND: Transcutaneous auricular vagus nerve stimulation (taVNS) is effective in regulating mood and high-level cognition in patients with major depressive disorder (MDD). This study aimed to investigate the efficacy of taVNS treatment in patients with MDD and an altered brain topological organization of functional networks. METHODS: Nineteen patients with MDD were enrolled in this study. Patients with MDD underwent 4 weeks of taVNS treatments; resting-state functional magnetic resonance imaging (rs-fMRI) data of the patients were collected before and after taVNS treatment. The graph theory method and network-based statistics (NBS) analysis were used to detect abnormal topological organizations of functional networks in patients with MDD before and after taVNS treatment. A correlation analysis was performed to characterize the relationship between altered network properties and neuropsychological scores. RESULTS: After 4 weeks of taVNS treatment, patients with MDD had increased global efficiency and decreased characteristic path length (Lp). Additionally, patients with MDD exhibited increased nodal efficiency (NE) and degree centrality (DC) in the left angular gyrus. NBS results showed that patients with MDD exhibited reduced connectivity between default mode network (DMN)-frontoparietal network (FPN), DMN-cingulo-opercular network (CON), and FPN-CON. Furthermore, changes in Lp and DC were correlated with changes in Hamilton depression scores. CONCLUSIONS: These findings demonstrated that taVNS may be an effective method for reducing the severity of depressive symptoms in patients with MDD, mainly through modulating the brain's topological organization. Our study may offer insights into the underlying neural mechanism of taVNS treatment in patients with MDD.

Effect and neural mechanisms of the transcutaneous vagus nerve stimulation for relapse prevention in patients with remitted major depressive disorder: protocol for a longitudinal study.

INTRODUCTION: After the first episode, patients with remitted major depressive disorder (MDD) have a 60% chance of experiencing a second episode. There are currently no accepted, effective methods to prevent the recurrence of MDD in remission. Transcutaneous vagus nerve stimulation (taVNS) is a non-invasive, safe and economical approach based on the efficacy of VNS in improving clinical depression symptoms. This clinical trial will study the efficacy of taVNS in preventing MDD relapse and investigate the underlying mechanisms of this. METHODS AND ANALYSIS: We will conduct a multicentre, randomised, patient-blinded and evaluators double-blinded trial. We will randomise 90 eligible participants with recurrent MDD in remission in a 1:1 ratio into a real or sham taVNS group. All participants will be given six biopsychosocial assessments: proinflammatory cytokines, serum monoamine neurotransmitters, cognition, affective neuropsychology, multimodal neuroimaging and endocrinology. After the baseline measurements, all participants will be given corresponding interference for 6 months and then complete a 1-year follow-up. The assessments will be performed three times: at baseline, post-treatment and at the end of 1-year follow-up (except for multimodal MRI scanning, which will be conducted at the first two assessments only). Change in 17-item Hamilton Depression Rating Scale scores for MDD is the primary outcome parameter. ETHICS AND DISSEMINATION: The study protocol was approved by the Medical Ethical Committee of Beijing Hospital of Traditional Chinese Medicine on 18 January 2019 (2018BL-076). The trial results will be published in peer-reviewed journals and at conferences. TRIAL REGISTRATION NUMBER: ChiCTR1900022618.

Enhanced functional connectivity between insular subregions correlates with the efficacy of music and instruction-guided relaxation in depression.

Music and instruction-guided relaxation (MIGR) is a complementary therapeutic tool used in the treatment of the major depressive disorder (MDD). However, the neural mechanism that underlies the effect of MIGR on MDD patients is not known. Twenty-three right-handed MDD patients and 23 age-, sex-, handedness-, and educational level-matched healthy controls were enrolled. Resting-state functional MRI data were acquired from patients before and after MIGR and from healthy controls. The relationships between insular subregion-based functional connectivity and Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale (HAM-A), Automatic Thoughts Questionnaire, and Ruminative Responses Scale scores were examined. One-way analysis of variance exhibited significant differences among the three groups in functional connectivity between the left dorsal anterior insula (dAI) and left superior medial frontal gyrus (SMFG), left dAI and left precuneus, left posterior insula and left gyrus rectus, right ventral anterior insula (vAI) and left posterior cingulate cortex (PCC), right vAI and right inferior frontal gyrus (R-IFG). Further comparisons in regions of interest showed that MDD patients before MIGR showed decreased functional connectivity between the left dAI and left SMFG, left dAI and left precuneus, left posterior insula, and left gyrus rectus, right vAI and left PCC, right vAI and R-IFG relative to those in healthy controls. The strength of functional connectivity between the right dAI and left putamen also exhibited a negative correlation with the HAM-A score in MDD cases before MIGR. MIGR may result in enhanced functional connectivity in insular subregions, thereby potentially increasing the regulatory influence of cognitive reappraisal.

Abnormal spontaneous neural activity in the anterior insular and anterior cingulate cortices in anxious depression.

OBJECTIVE: Anxious depression is a distinct clinical subtype of major depressive disorder (MDD) characterized by palpitations, somatic complaints, altered interoceptive awareness, high risk of suicide, and poor response to pharmacotherapy. However, the neural mechanisms of anxious depression are still not well understood. In this study we investigated changes in neural oscillation during the resting-state of patients with anxious depression by measuring differences in the amplitude of low-frequency fluctuation (ALFF). METHODS: Resting-state functional magnetic resonance imaging was acquired in 31 patients with anxious depression, 18 patients with remitted depression, as well as 68 gender- and age-matched healthy participants. We compared the differences both in the ALFF and fractional ALFF (fALFF) among the three groups. We also examined the correlation between the ALFF/fALFF and the severity of anxiety as well as depression. RESULTS: Anxious depression patients showed increased ALFF/fALFF in the right dorsal anterior insular cortex and decreased ALFF/fALFF in the bilateral lingual gyrus relative to remitted depression patients and healthy controls. The increased ALFF in the dorsal anterior insula was also positively correlated with stronger anxiety in the anxious depression group. Anxious depression patients also displayed increased fALFF in the right ventral anterior cingulate cortex (ACC) compared to remitted depression patients and healthy controls. CONCLUSIONS: Our results suggest that alterations of the cortico-limbic networks, including the right dorsal anterior insula and right ventral ACC, may play a critical role in the physiopathology of anxious depression.