Opposing and emotion-specific associations between frontal activation with depression and anxiety symptoms during facial emotion processing in generalized anxiety and depression

Oral oxytocin blurs sex differences in amygdala responses to emotional scenes

BACKGROUND

The sex differences were co-shaped by innate biological differences and social environment, and were frequently observed in human emotional neural responses. Oral administration of oxytocin, as an alternative and noninvasive intake method, has been demonstrated to produce sex-dependent effects on emotional face processing. However, it is unclear whether oral oxytocin produces similar sex-dependent effects on processing continuous emotional scenes.

METHODS

Current randomized, double-blind, placebo-controlled neuro-psychopharmacological fMRI experiment was conducted in 147 healthy participants (oxytocin=74, male/female=37/37; placebo=73, male/female=36/37) to examine the oral oxytocin effect on plasma oxytocin concentrations and neural response to emotional scenes in both sexes.

RESULTS

At the neuroendocrine level, females showed lower endogenous oxytocin concentrations than males, but oral oxytocin equally increased the oxytocin concentrations in both sexes. Regarding neural activity, emotional scenes evoked opposite valence-independent effects on right amygdala activation (females>males) and its functional connectivity with the insula (males>females) in two sexes in the placebo group. This sex difference were either attenuated (amygdala response) or even completely eliminated (amygdala-insula functional connectivity) in the oxytocin group. The multivariate pattern analysis confirmed these findings by developing an accurate sex-predictive neural pattern that including the amygdala and the insula under the placebo but not oxytocin condition.

CONCLUSION

Present study suggests a pronounced sex-difference in neural responses to emotional scenes which is abolished by oral oxytocin, with it having opposite modulatory effects in two sexes. Possibly this may reflect oral OXT enhancing emotional regulation to continuous emotional stimuli in both sexes by facilitating appropriate changes in sex-specific amygdala-insula circuitry.

Modulating the default mode network: Antidepressant efficacy of transcutaneous electrical cranial-auricular acupoints stimulation targeting the insula

BACKGROUND

Transcutaneous electrical cranial-auricular acupoint stimulation (TECAS) is a novel non-invasive therapy for major depressive disorder (MDD) that stimulates acupoints innervated by the trigeminal and auricular vagus nerves. However, there are few neuroimaging studies involving the TECAS for the treatment of MDD. Therefore, this study aimed to investigate the treatment response and neurological effects of TECAS using resting-state functional magnetic resonance imaging (rs-fMRI).

METHOD

A total of 34 patients with mild-to-moderate MDD and 34 demographically matched healthy controls (HCs) were recruited. After an eight-week treatment the primary outcome was clinical response, defined as a baseline-to-endpoint ≥ 50 % reduction in the 17-item Hamilton Depression Rating Scale (HAMD-17). The low-frequency fluctuations (ALFF) method were used to investigate the brain abnormalities of MDD patients and HCs, and altered brain networks were analyzed between pre- and post-treatment using seed-based functional connectivity (FC) analysis.

RESULTS

We found no significant differences in terms of gender, age, and years of education between the two groups. After treatment, the response rate was 58.82 %. Compared to HCs, MDD patients showed lower ALFF values in the left insula(t = -4.298,P < 0.005), the insula-based FC revealed in the right middle frontal gyrus (MFG)/ right superior frontal gyrus, orbital part (ORBsupmed) (t = -5.29,P < 0.005) and the right anterior cingulate gyrus (ACC)were decreased (t = -6.08,P < 0.005). Furthermore, Compared to pre-treatment, abnormal FC values in the ACC /orbital superior frontal gyrus (SFG) (t = 3.42,P < 0.005) and left superior frontal gyrus (SFG)/ supplement motor area (SMA) were enhanced (t = 3.34,P < 0.005).

CONCLUSION

TECAS exhibits antidepressant efficacy, particularly influencing the insula-based functional connections within the Default Mode Network (DMN) related to emotion processing in individuals with MDD.

Longitudinal Relationships Between Depressive Symptoms and Generalized Anxiety Symptoms in Adolescents: A Cross-Lagged Network Analysis

The comorbidity of depression and generalized anxiety have raised questions about the existing classification system. Based on the perspective of network analysis, the developmental relationship between psychological symptoms can be explored more clearly. The current study aimed to explore the longitudinal network association of depressive symptoms and generalized anxiety symptoms in non-clinical adolescents. The sample contained 1,947 Chinese adolescents (Mage = 13.93, SD = 1.71; 48.5% girls). Their depression (PHQ-9) and generalized anxiety (GAD-7) symptoms were assessed at baseline (T1) and 6-month follow-up (T2). Data was analyzed using a cross-lagged network analysis. Depressive symptoms and generalized anxiety symptoms were closely related and did not appear to be distinct categories in adolescence. More generalized anxiety symptoms predicted depressive symptoms rather than vice versa. After controlling for gender, and age, "Difficulty relaxing" presented the highest out-expected influence (out-EI) in the network, while "trouble concentrating", and "suicidal ideation" showed the lowest in expected influence (in-EI). Findings suggested that interventions for generalized anxiety symptoms may help reduce depressive symptoms among Chinese adolescents. Specifically, alleviating "difficulty relaxing" may improve overall mental health.

Shared and distinctive dysconnectivity patterns underlying pure generalized anxiety disorder (GAD) and comorbid GAD and depressive symptoms

The resting-state connectivity features underlying pure generalized anxiety disorder (GAD, G1) and comorbid GAD and depressive symptoms (G2) have not been directly compared. Furthermore, it is unclear whether these features might serve as potential prognostic biomarkers and change with treatment. Degree centrality (DC) in G1 (40 subjects), G2 (58 subjects), and healthy controls (HCs, 54 subjects) was compared before treatment, and the DC of G1 or G2 at baseline was compared with that after 4 weeks of paroxetine treatment. Using support vector regression (SVR), voxel-wise DC across the entire brain and abnormal DC at baseline were employed to predict treatment response. At baseline, G1 and G2 exhibited lower DC in the left mid-cingulate cortex and vermis IV/V compared to HCs. Additionally, compared to HCs, G1 had lower DC in the left middle temporal gyrus, while G2 showed higher DC in the right inferior temporal/fusiform gyrus. However, there was no significant difference in DC between G1 and G2. The SVR based on abnormal DC at baseline could successfully predict treatment response in responders in G2 or in G1 and G2. Notably, the predictive performance based on abnormal DC at baseline surpassed that based on DC across the entire brain. After treatment, G2 responders showed lower DC in the right medial orbital frontal gyrus, while no change in DC was identified in G1 responders. The G1 and G2 showed common and distinct dysconnectivity patterns and they could potentially serve as prognostic biomarkers. Furthermore, DC in patients with GAD could change with treatment.

Abnormal multi-layered dynamic cortico-subcortical functional connectivity in major depressive disorder and generalized anxiety disorder

Comorbidity has been frequently observed between generalized anxiety disorder (GAD) and major depressive disorder (MDD), however, common and distinguishable alterations in the topological organization of functional brain networks remain poorly understood. We sought to determine a robust and sensitive functional connectivity marker for diagnostic classification and symptom severity prediction. Multi-layered dynamic functional connectivity including whole brain, network-node and node-node layers via graph theory and gradient analyses were applied to functional MRI resting-state data obtained from 31 unmedicated GAD and 34 unmedicated MDD patients as well as 33 age and education matched healthy controls (HC). GAD and MDD symptoms were assessed using Penn State Worry Questionnaire and Beck Depression Inventory II, respectively. Three network measures including global properties (i.e., global efficiency, characteristic path length), regional nodal property (i.e., degree) and connectivity gradients were computed. Results showed that both patient groups exhibited abnormal dynamic cortico-subcortical topological organization compared to healthy controls, with MDD > GAD > HC in degree of randomization. Furthermore, our multi-layered dynamic functional connectivity network model reached 77% diagnostic accuracy between GAD and MDD and was highly predictive of symptom severity, respectively. Gradients of functional connectivity for superior frontal cortex-subcortical regions, middle temporal gyrus-subcortical regions and amygdala-cortical regions contributed more in this model compared to other gradients. We found shared and distinct cortico-subcortical connectivity features in dynamic functional brain networks between GAD and MDD, which together can promote the understanding of common and disorder-specific topological organization dysregulations and facilitate early neuroimaging-based diagnosis.