Frontostriatal functional connectivity underlies self-enhancement during social evaluation

Self-enhancement, the tendency to view oneself positively, is a pervasive social motive widely investigated in the psychological sciences. Relatively little is known about the neurocognitive mechanisms underlying this motive, specifically in social-evaluative situations. To investigate whether positive emotion regulation circuitry, circuitry involved in modulating positive affect, relates to the self-enhancement motive in social contexts, we conducted an functional magnetic resonance imaging (fMRI) study in a healthy young adult sample. We hypothesized that self-enhancement indices (state and trait self-esteem) would relate to greater functional connectivity between right ventrolateral prefrontal cortex (RVLPFC), a region implicated in emotion regulation, and the ventral striatum (VS), a region associated with reward-related affect, during a social feedback task. Following social evaluation, participants experienced stable or decreased state self-esteem. Results showed that stable state self-esteem from pre- to post-scan and higher trait self-esteem related to greater RVLPFC–VS connectivity during positive evaluation. Stable-state self-esteem also related to greater RVLPFC–VS connectivity during negative evaluation. Moreover, RVLPFC activation during all types of feedback processing and left VS activation during negative feedback processing was greater for participants with stable-state self-esteem. These findings implicate neurocognitive mechanisms underlying emotion regulation in the self-enhancement motive and highlight a pathway through which self-enhancement may restore feelings of self-worth during threatening situations.     

Altered functional connectivity density and couplings in postpartum depression with and without anxiety

Postpartum depression (PPD) is the most common psychological health issue among women, which often comorbids with anxiety (PPD-A). PPD and PPD-A showed highly overlapping clinical symptoms. Identifying disorder-specific neurophysiological markers of PDD and PPD-A is important for better clinical diagnosis and treatments. Here, we performed functional connectivity density (FCD) and resting-state functional connectivity (rsFC) analyses in 138 participants (45 unmedicated patients with first-episode PPD, 31 PDD-A patients and 62 healthy postnatal women, respectively). FCD mapping revealed specifically weaker long-range FCD in right lingual gyrus (LG.R) for PPD patients and significantly stronger long-range FCD in left ventral striatum (VS.L) for PPD-A patients. The follow-up rsFC analyses further revealed reduced functional connectivity between dorsomedial prefrontal cortex (dmPFC) and VS.L in both PPD and PPD-A. PPD showed specific changes of rsFC between LG.R and dmPFC, right angular gyrus and left precentral gyrus, while PPD-A represented specifically abnormal rsFC between VS.L and left ventrolateral prefrontal cortex. Moreover, the altered FCD and rsFC were closely associated with depression and anxiety symptoms load. Taken together, our study is the first to identify common and disorder-specific neural circuit disruptions in PPD and PPD-A, which may facilitate more effective diagnosis and treatments.     

针刺内关穴与非穴的fMRI脑功能成像研究

目的:观察针刺健康志愿者右侧内关穴和非穴时不同脑区的激活情况,探讨针刺穴位对脑中枢的激活效应。方法:将14例健康志愿者随机分为内关穴组和非穴组,分别针刺右侧内关穴和非穴;同时,运用GE公司1.5T超导核磁共振系统完成脑部fMRI扫描,获得局部脑组织激活与否的试验数据,采用感兴趣区(ROI)法进行处理和分析。结果:针刺内关穴和非穴,对双侧顶叶、额叶、枕叶、颞叶、基底节区、扣带回、小脑、脑桥、脑岛等多个脑区分别有不同程度的激活;从激活几率、激活数量和激活强度上看,针刺右侧内关穴以激活左侧顶叶、额叶、颞叶、枕叶为主,并且特异性激活左侧海马和双侧桥脑;尽管在脑区的激活上,有上述趋势,但是在统计学上无显著性意义(P>0.05)。结论:针刺内关穴和非穴激活的脑区有相对的差异性,针刺外周穴位能特异性的激活脑中枢。     

Effects of age and gender on neural correlates of emotion imagery

Mental imagery is part of people''s own internal processing and plays an important role in everyday life, cognition and pathology. The neural network supporting mental imagery is bottom‐up modulated by the imagery content. Here, we examined the complex associations of gender and age with the neural mechanisms underlying emotion imagery. We assessed the brain circuits involved in emotion mental imagery (vs. action imagery), controlled by a letter detection task on the same stimuli, chosen to ensure attention to the stimuli and to discourage imagery, in 91 men and women aged 14–65 years using fMRI. In women, compared with men, emotion imagery significantly increased activation within the right putamen, which is involved in emotional processing. Increasing age, significantly decreased mental imagery‐related activation in the left insula and cingulate cortex, areas involved in awareness of ones'' internal states, and it significantly decreased emotion verbs‐related activation in the left putamen, which is part of the limbic system. This finding suggests a top‐down mechanism by which gender and age, in interaction with bottom‐up effect of type of stimulus, or directly, can modulate the brain mechanisms underlying mental imagery.     

Neural representation of phonological information during Chinese character reading

Previous studies have revealed that phonological processing of Chinese characters elicited activation in the left prefrontal cortex, bilateral parietal cortex, and occipitotemporal regions. However, it is controversial what role the left middle frontal gyrus plays in Chinese character reading, and whether the core regions (e.g., the left superior temporal gyrus and supramarginal gyrus) for phonological processing of alphabetic languages are also involved in Chinese character reading. To address these questions, the present study used both univariate and multivariate analysis (i.e., representational similarity analysis, RSA) to explore neural representations of phonological information during Chinese character reading. Participants were scanned while performing a reading aloud task. Univariate activation analysis revealed a widely distributed network for word reading, including the bilateral inferior frontal gyrus, middle frontal gyrus, lateral temporal cortex, and occipitotemporal cortex. More importantly, RSA showed that the left prefrontal (i.e., the left middle frontal gyrus and left inferior frontal gyrus) and bilateral occipitotemporal areas (i.e., the left inferior and middle temporal gyrus and bilateral fusiform gyrus) represented phonological information of Chinese characters. These results confirmed the importance of the left middle frontal gyrus and regions in ventral pathway in representing phonological information of Chinese characters.     

针刺治疗慢性疼痛的功能磁共振研究述评＊

目的基于针刺治疗慢性疼痛的功能磁共振(Functional magnetic resonance imaging,fMRI)文献进行述评,为针刺治疗慢性疼痛的机制研究提供思路和借鉴。方法对近10年针刺治疗慢性疼痛的fMRI研究进行回顾,依据病种选择、样本量计算、试验设计、研究结果四方面内容进行述评,分析并总结当前研究现状。结果偏头痛、膝骨关节炎和下腰痛是目前研究中涉及频次最高的3个病种。受试者的疾病亚型、年龄段、利手习惯及fMRI禁忌症在研究中基本都保证了一致性和规范性。但多数研究仍存在样本量计算方式不明确的问题。对照组设置主要包括标准对照、无效对照和安慰对照。针刺效应因素在各研究间存在较大差异。研究中结局指标包括疾病特异性量表、疼痛评分及心理、精神状态的评估。fMRI设计以静息态和单一任务态设计为主,多任务fMRI研究相对较少。研究证实针刺可调节疼痛处理网络的功能连接,有效建立心理物理疼痛稳态。结论运用fMRI探讨针刺治疗慢性疼痛作用机制的研究成果丰硕,未来可通过扩大病种的选择,完善质量控制,关注针刺效应影响因素,丰富数据处理手段,借鉴多学科任务设计方式等方式,促进针刺疗慢性疼痛机制研究的进一步发展。     

足三里穴中枢神经网络作用机制的静息态脑功能磁共振成像研究

目的:应用静息态磁共振成像技术的局部一致性探讨足三里穴的中枢神经网络作用机制。方法:选择12名青年健康志愿者,于针刺足三里前及针刺足三里拔针后25 min分别进行静息态脑功能磁共振成像扫描,应用脑功能成像局部一致性(regional homogeneity,ReHo)方法处理功能磁共振(fMRI)成像数据。结果:针刺拔针后25 min后右侧额中回、左侧额上回、右侧颞上回、后扣带回、右侧中央旁小叶、右侧苍白球、右侧枕中回、左侧额内侧回等脑区的ReHo值较针刺前增高;双侧中央后回、左侧枕中回、左侧颞中回、左侧颞下回、左侧梭状回、左侧中央旁小叶、右侧额内侧回等脑区的ReHo值较针刺前减低(P0.05,K值≥10)。结论:针刺足三里后额叶、颞叶、枕叶、扣带回相关脑区局部一致性发生改变,提示足三里的认知影响、镇痛及胃肠功能调节的中枢神经网络作用机制存在。     

Can we increase the speed and efficacy of antidepressant treatments? Part II. Glutamatergic and RNA interference strategies

In the second part we focus on two treatment strategies that may overcome the main limitations of current antidepressant drugs. First, we review the experimental and clinical evidence supporting the use of glutamatergic drugs as fast-acting antidepressants. Secondly, we review the involvement of microRNAs (miRNAs) in the pathophysiology of major depressive disorder (MDD) and the use of small RNAs (e.g.., small interfering RNAs or siRNAs) to knockdown genes in monoaminergic and non-monoaminergic neurons and induce antidepressant-like responses in experimental animals.The development of glutamatergic agents is a promising venue for antidepressant drug development, given the antidepressant properties of the non-competitive NMDA receptor antagonist ketamine. Its unique properties appear to result from the activation of AMPA receptors by a metabolite [(2 S,6 S;2 R,6 R)-hydroxynorketamine (HNK)] and mTOR signaling. These effects increase synaptogenesis in prefrontal cortical pyramidal neurons and enhance serotonergic neurotransmission via descending inputs to the raphe nuclei. This view is supported by the cancellation of ketamine's antidepressant-like effects by inhibition of serotonin synthesis.We also review existing evidence supporting the involvement of miRNAs in MDD and the preclinical use of RNA interference (RNAi) strategies to target genes involved in antidepressant response. Many miRNAs have been associated to MDD, some of which e.g., miR-135 targets genes involved in antidepressant actions. Likewise, SSRI-conjugated siRNA evokes faster and/or more effective antidepressant-like responses. Intranasal application of sertraline-conjugated siRNAs directed to 5-HT_1A receptors and SERT evoked much faster changes of pre- and postsynaptic antidepressant markers than those produced by fluoxetine.     

Altered resting-state networks in adolescent non-suicidal self-injury—a graph theory analysis

Non-suicidal self-injury (NSSI) is a highly prevalent transdiagnostic symptom and risk marker for mental health problems among adolescents. Research on the neurobiological mechanisms underlying NSSI is needed to clarify the neural correlates associated with the behavior. We examined resting-state functional connectivity in n = 33 female adolescents aged 12–17 years engaging in NSSI, and in n = 29 age-matched healthy controls using graph theory. Mixed linear models were evaluated with the Bayes Factor to determine group differences on global and regional network measures and associations between network measures and clinical characteristics in patients. Adolescents engaging in NSSI demonstrated longer average characteristic path lengths and a smaller number of weighted hubs globally. Regional measures indicated lower efficiency and worse integration in (orbito)frontal regions and higher weighted coreness in the pericalcarine gyrus. In patients, higher orbitofrontal weighted local efficiency was associated with NSSI during the past month while lower pericalcarine nodal efficiency was associated with suicidal thoughts in the past year. Higher right but lower left pericalcarine weighted hubness was associated with more suicide attempts during the past year. Using a graph-based technique to identify functional connectivity networks, this study adds to the growing understanding of the neurobiology of NSSI.     

Meta-analytic activation maps can help identify affective processes captured by contrast-based task fMRI: the case of threat-related facial expressions

Meta-analysis of functional magnetic resonance imaging (fMRI) data is an effective method for capturing the distributed patterns of brain activity supporting discrete cognitive and affective processes. One opportunity presented by the resulting meta-analysis maps (MAMs) is as a reference for better understanding the nature of individual contrast maps (ICMs) derived from specific task fMRI data. Here, we compared MAMs from 148 neuroimaging studies representing emotion categories of fear, anger, disgust, happiness and sadness with ICMs from fearful > neutral and angry > neutral faces from an independent dataset of task fMRI (n = 1263). Analyses revealed that both fear and anger ICMs exhibited the greatest pattern similarity to fear MAMs. As the number of voxels included for the computation of pattern similarity became more selective, the specificity of MAM–ICM correspondence decreased. Notably, amygdala activity long considered critical for processing threat-related facial expressions was neither sufficient nor necessary for detecting MAM–ICM pattern similarity effects. Our analyses suggest that both fearful and angry facial expressions are best captured by distributed patterns of brain activity, a putative neural correlate of threat. More generally, our analyses demonstrate how MAMs can be leveraged to better understand affective processes captured by ICMs in task fMRI data.