Distinctive amygdala subregions involved in emotion-modulated Stroop interference

Abnormality of anxious behaviors and functional connectivity between the amygdala and the frontal lobe in maternally deprived monkeys

OBJECTIVE

Anxious behaviors often occur in individuals who have experienced early adversity. Anxious behaviors can bring many hazards, such as social withdrawal, eating disorders, negative self-efficacy, self-injurious thoughts and behaviors, anxiety disorders, and even depression. Abnormal behavior are is closely related to changes in corresponding circuit functions in the brain. This study investigated the relationship between brain circuits and anxious behaviors in maternal-deprived rhesus monkey animal model, which mimic early adversity in human.

METHODS

Twenty-five rhesus monkeys (Macaca mulatta) were grouped by two different rearing conditions: 11 normal control and mother-reared (MR) monkeys and 14 maternally deprived and peer-reared (MD) monkeys. After obtaining images of the brain areas with significant differences in maternal separation and normal control macaque function, the relationship between functional junction intensity and stereotypical behaviors was determined by correlation analysis.

RESULTS

The correlation analysis revealed that stereotypical behaviors were negatively correlated with the coupling between the left lateral amygdala subregion and the left inferior frontal gyrus in both MD and MR macaques.

CONCLUSION

This study suggests that early adversity-induced anxious behaviors are associated with changes in the strength of the amygdala-prefrontal connection. The normalization of the regions involved in the functional connection might reverse the behavioral abnormality. It provides a solid foundation for effective intervention in human early adversity.

SIGNIFICANCE STATEMENT

This study suggests that early adversity-induced anxious behaviors are associated with changes in the strength of the amygdala-prefrontal connection. The higher the amygdala-prefrontal connection strength, the less stereotyped behaviors exhibited by monkeys experiencing early adversity. Thus, in the future, changing the strength of the amygdala-prefrontal connection may reverse the behavioral abnormalities of individuals who experience early adversity. This study provides a solid foundation for effective intervention in humans' early adversity.

The inter-relationships of the neural basis of rumination and inhibitory control: neuroimaging-based meta-analyses

Rumination, as a clinical manifestation and pathogenic factor of depression, has long been the focus of psychological research regarding its causes and ameliorating approaches. Behavioral studies have shown that rumination is related to inhibitory control deficits, which provides ideas for reducing it. However, the neural relationship between them has not been clearly discussed. In this study, we first used multi-level kernel density analysis to conduct two meta-analyses of published functional magnetic resonance imaging studies: one was rumination comprising 17 studies with 180 foci, and the other was inhibitory control comprising 205 studies with 3791 foci. Conjunction analysis was then performed to explore the common brain regions and further decode them through Neurosynth to confirm the cognitive specificity. Results showed that rumination was mainly related to the default mode network (DMN), while inhibitory control was associated with the frontoparietal network (FPN). In addition, the common activation areas were mainly concentrated in the bilateral precuneus, right superior frontal gyrus, bilateral median cingulate, paracingulate gyri, and the left triangular part of inferior frontal gyrus (IFG). Decoding results also revealed they were involved in inhibition, memory retrieval, and self-related processes. Our findings support that rumination is associated with inhibitory control and can be explained neurologically by an antagonistic relationship between the DMN and FPN. In sum, inhibitory control may be related to rumination via inhibiting task-unrelated attention and controlling self-related processing. This research will help us understand and predict rumination from the perspective of inhibitory control and reduce rumination through behavioral training of inhibitory control or the application of neuromodulation techniques to common activation regions.

Dynamic Functional Connectivity Reveals Abnormal Variability in the Amygdala Subregions of Children With Attention-Deficit/Hyperactivity Disorder

Objective: This study investigates whether the dynamic functional connectivity (dFC) of the amygdala subregions is altered in children with attention-deficit/hyperactivity disorder (ADHD).

Methods: The dFC of the amygdala subregions was systematically calculated using a sliding time window method, for 75 children with ADHD and 20 healthy control (HC) children.

Results: Compared with the HC group, the right superficial amygdala exhibited significantly higher dFC with the right prefrontal cortex, the left precuneus, and the left post-central gyrus for children in the ADHD group. The dFC of the amygdala subregions showed a negative association with the cognitive functions of children in the ADHD group.

Conclusion: Functional connectivity of the amygdala subregions is more unstable among children with ADHD. In demonstrating an association between the stability of functional connectivity of the amygdala and cognitive functions, this study may contribute by providing a new direction for investigating the internal mechanism of ADHD.

Integrity of Amygdala Subregion-Based Functional Networks and Emotional Lability in Drug-Naïve Boys With ADHD

Objective: This study evaluated the functional networks of amygdala subregions (basolateral [BLA], centromedial [CMA], and superficial amygdala [SFA]) in ADHD and their association with emotional lability (EL) symptoms. Method: Resting-state functional connectivity (RSFC) of amygdala subregions and their correlations with EL scores were evaluated in 35 drug-naïve boys with ADHD and 30 age-matched healthy controls (HC). Results: Compared with HC, altered RSFC were detected differently for each amygdala subregion in ADHD: altered RSFC of BLA with the thalamus and vermis; aberrant RSFC of CMA with the superior temporal gyrus/pole and insula, precuneus and cerebellum; reduced RSFC of SFA with dorsal frontoparietal cortices. Within ADHD, higher EL scores were associated with reduced negative RSFC of SFA with the dorsolateral prefrontal cortex and inferior parietal lobe. Conclusion: Diffuse alterations of amygdala subregion-based networks are associated with ADHD, and the weaker SFA-frontoparietal networks might be involved in the hypothesized top-down effortful regulation of emotion.

Escitalopram ameliorates differences in neural activity between healthy comparison and major depressive disorder groups on an fMRI Emotional conflict task: A CAN-BIND-1 study

BACKGROUND

Identifying objective biomarkers can assist in predicting remission/non-remission to treatment, improving remission rates, and reducing illness burden in major depressive disorder (MDD).

METHODS

Sixteen MDD 8-week remitters (MDD-8), twelve 16-week remitters (MDD-16), 14 non-remitters (MDD-NR) and 30 healthy comparison participants (HC) completed a functional magnetic resonance imaging emotional conflict task at baseline, prior to treatment with escitalopram, and 8 weeks after treatment initiation. Patients were followed 16 weeks to assess remitter status.

RESULTS

All groups demonstrated emotional Stroop in reaction time (RT) at baseline and Week 8. There were no baseline differences between HC and MDD-8, MDD-16, or MDD-NR in RT or accuracy. By Week 8, MDD-8 demonstrated poorer accuracy compared to HC. Compared to HC, the baseline blood-oxygen level dependent (BOLD) signal was decreased in MDD-8 in brain-stem and thalamus; in MDD-16 in lateral occipital cortex, middle temporal gyrus, and cuneal cortex; in MDD-NR in lingual and occipital fusiform gyri, thalamus, putamen, caudate, cingulate gyrus, insula, cuneal cortex, and middle temporal gyrus. By Week 8, there were no BOLD activity differences between MDD groups and HC.

LIMITATIONS

The Emotional Conflict Task lacks a neutral (non-emotional) condition, restricting interpretation of how mood may influence perception of non-emotionally valenced stimuli.

CONCLUSIONS

The Emotional Conflict Task is not an objective biomarker for remission trajectory in patients with MDD receiving escitalopram treatment. Escitalopram may have influenced emotion recognition in MDD groups in terms of augmented accuracy and BOLD signal in response to an Emotional Conflict Task, following 8 weeks of escitalopram treatment.

Personality Traits and Impulsivity Tasks Among Substance Use Disorder Patients: Their Relations and Links With Retention in Treatment

BACKGROUND

Various authors have described the elements of impulsive approach and inhibitory control in drug users. These two components have been studied in terms of personality traits, performance on tasks that measure impulsive behavior, and neurophysiology. However, few studies have analyzed the association between these constructs. Thus, the aim of the present study is to analyze the associations between personality traits and performance on impulsivity tasks.

METHODS

A follow-up study was conducted with a baseline assessment at the beginning and end of treatment. The sample was composed of 121 patients undergoing treatment in therapeutic communities. Personality domains were evaluated through the PID-5. The impulsivity tasks employed were the Iowa Gambling Task (IGT), Delay Discounting Test (DDT), Go/No-Go and Stroop test.

RESULTS

A correlation was found between DDT scores and the domains of detachment (r = -.315; p<.01), antagonism (r = -.294; p<.01), and disinhibition (r = .215; p<.05). Performance on the Stroop task was significantly associated with psychoticism (r = .232; p<.05) and negative affect (r = .212; p<.05). Multivariate analysis revealed that IGT scores and negative affect predict retention in treatment.

CONCLUSIONS

These findings partially support the hypothesized association between sensation-seeking personality traits and detachment with impulsive choice tasks; and the relationships between negative affect and psychoticism traits with performance on inhibitory control tasks. Further, impulsive choice task scores and negative affect are both shown to predict retention in treatment.

Effective connectivity between Broca's area and amygdala as a mechanism of top-down control in worry

Individuals higher in trait worry exhibit increased activation in Broca's area during inhibitory processing tasks. To identify whether such activity represents an adaptive mechanism supporting top-down control, functional and effective connectivity of Broca's area were investigated during a task of inhibitory control. fMRI data obtained from 106 participants performing an emotion-word Stroop task were examined using psychophysiological interaction and Granger Causality (GC) analyses. Findings revealed greater directed connectivity from Broca's to amygdala in the presence of emotional distraction. Furthermore, a predictive relationship was observed between worry and the asymmetry in effective connectivity, with worriers exhibiting greater directed connectivity from Broca's to amygdala. When performing the task, worriers with greater GC directional asymmetry were more accurate than worriers with less asymmetry. Present findings indicate that individuals with elevated trait worry employ a mechanism of top-down control in which communication from Broca's to amygdala fosters successful compensation for interference effects.

Effects of the experimental administration of oral estrogen on prefrontal functions in healthy young women

17-Beta-estradiol (E2) stimulates neural plasticity and dopaminergic transmission in the prefrontal cortex, which is critically involved in attentional control, working memory, and other executive functions. Studies investigating E2's actions on prefrontally mediated behavior in the course of the menstrual cycle or during hormone replacement therapy are inconclusive, with numerous null findings as well as beneficial and detrimental effects. The current study focused on the effect of E2 on attentional performance, as animal studies indicate that supraphysiological doses (i.e., above estrous cycle levels) of E2 have beneficial effects on measures of attention in female rodents. To translate these findings to humans, we administered 12 mg E2-valerate or placebo orally to 34 naturally cycling women in the low-hormone early follicular phase using a randomized, double-blinded, pre-post design. Behavioral performance was tested twice during baseline and E2 peak, where E2 levels reached mildly supraphysiological levels in the E2 group. Aside from mainly prefrontally mediated tasks of attention, working memory, and other executive functions, we employed tasks of affectively modulated attention, emotion recognition, and verbal memory. E2 administration had a significant, but subtle negative impact on general processing speed and working memory performance. These effects could be related to an overstimulation of dopaminergic transmission. The negative effect of supraphysiological E2 on working memory connects well to animal literature. There were no effects on attentional performance or any other measure. This could be explained by different E2 levels being optimal for changing behavioral performance in specific tasks, which likely depends on the brain regions involved.

Dissociations of cognitive inhibition, response inhibition, and emotional interference: Voxelwise ALE meta-analyses of fMRI studies

Inhibitory control is the stopping of a mental process with or without intention, conceptualized as mental suppression of competing information because of limited cognitive capacity. Inhibitory control dysfunction is a core characteristic of many major psychiatric disorders. Inhibition is generally thought to involve the prefrontal cortex; however, a single inhibitory mechanism is insufficient for interpreting the heterogeneous nature of human cognition. It remains unclear whether different dimensions of inhibitory processes-specifically cognitive inhibition, response inhibition, and emotional interference-rely on dissociated neural systems. We conducted systematic meta-analyses of fMRI studies in the BrainMap database supplemented by PubMed using whole-brain activation likelihood estimation. A total of 66 study experiments including 1,447 participants and 987 foci revealed that while the left anterior insula was concordant in all inhibitory dimensions, cognitive inhibition reliably activated specific dorsal frontal inhibitory system, engaging dorsal anterior cingulate, dorsolateral prefrontal cortex, and parietal areas, whereas emotional interference reliably implicated a ventral inhibitory system, involving the ventral surface of the inferior frontal gyrus and the amygdala. Response inhibition showed concordant clusters in the fronto-striatal system, including the dorsal anterior cingulate region and extended supplementary motor areas, the dorsal and ventral lateral prefrontal cortex, basal ganglia, midbrain regions, and parietal regions. We provide an empirically derived dimensional model of inhibition characterizing neural systems underlying different aspects of inhibitory mechanisms. This study offers a fundamental framework to advance current understanding of inhibition and provides new insights for future clinical research into disorders with different types of inhibition-related dysfunctions.

Disruption of effective connectivity from the dorsolateral prefrontal cortex to the orbitofrontal cortex by negative emotional distraction in obsessive-compulsive disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) has been associated with abnormal cognitive and emotional functions and these dysfunctions may be dependent on the disruption of dynamic interactions within neuronal circuits associated with emotion regulation. Although several studies have shown the aberrant cognitive-affective processing in OCD patients, little is known about how to characterize effective connectivity of the disrupted neural interactions. In the present study, we applied effective connectivity analysis using dynamic causal modeling to explore the disturbed neural interactions in OCD patients.

METHOD

A total of 20 patients and 21 matched healthy controls performed a delayed-response working memory task under emotional or non-emotional distraction while undergoing functional magnetic resonance imaging.

RESULTS

During the delay interval under negative emotional distraction, both groups showed similar patterns of activations in the amygdala. However, under negative emotional distraction, the dorsolateral prefrontal cortex (DLPFC) and the orbitofrontal cortex (OFC) exhibited significant differences between groups. Bayesian model averaging indicated that the connection from the DLPFC to the OFC was negatively modulated by negative emotional distraction in patients, when compared with healthy controls (p < 0.05, Bonferroni-corrected).

CONCLUSIONS

Exaggerated recruitment of the DLPFC may induce the reduction of top-down prefrontal control input over the OFC, leading to abnormal cortico-cortical interaction. This disrupted cortico-cortical interaction under negative emotional distraction may be responsible for dysfunctions of cognitive and emotional processing in OCD patients and may be a component of the pathophysiology associated with OCD.