Variation in hypothalamic-pituitary-adrenal axis activity among bullied and non-bullied children

We examined the relationship between being bullied during childhood and activity of the hypothalamic-pituitary-adrenal (HPA) axis as assessed through repeated measures of salivary cortisol. A non-clinical sample of 154 (74 boys) predominantly Caucasian middle-class 12-year-olds each provided detailed information about their experiences with bullying and six saliva samples were standardized across time and day. Children with a history of child maltreatment, diagnosed psychiatric illness, foster care placement, medication use (psychotropic and oral contraception) and aggression directed toward peers and/or family members were excluded. Using multilevel regression and applying orthogonal polynomial contrasts to model the observed circadian pattern in the data, we found that occasional and frequent verbal peer victimization was associated with hyposecretion of cortisol when controlling for sex, pubertal status, age, depression and anxiety. This relation, however, was moderated by sex. For boys, occasional exposure was associated with higher cortisol levels, whereas for girls exposure was associated with lower cortisol levels. The present study highlights the need to consider the plight of peer-victimized children seriously, as it is associated with alterations to the HPA axis that affect males and females differently, and likely diminishes a person's ability to cope with stress, possibly placing them at risk for psychopathology and ill health.     

创伤后应激障碍的动物模型及其神经生物学机制

创伤后应激障碍是指个体由于经历对生命具有威胁的事件或严重的创伤,导致症状长期持续的精神障碍。研究创伤后应激障碍的主要动物模型为条件性恐惧和应激敏感化模型。研究表明,创伤后应激障碍中长时程留存的恐惧性记忆、高唤醒等症状与大脑杏仁核、内侧前额叶皮层和海马三个脑区及下丘脑-垂体-肾上腺轴负反馈功能增强密切相关。其中杏仁核活动增强是条件性恐惧记忆获得、保持和表达的关键神经基础。内侧前额叶皮层对杏仁核的去抑制及海马向杏仁核传递的威胁性环境信息,促进创伤后应激障碍症状的出现。在经历创伤应激后糖皮质激素受体的上调及多巴胺活动的增强是创伤后应激障碍产生的主要神经基础。对创伤后应激障碍的药物治疗研究证明多巴胺D2受体在改善患者症状中的作用比较重要,但仍需作更深入的探索     

Individual differences in cortisol responses to fear and frustration during middle childhood

The purpose of this study was to examine individual differences in the activation and regulation of the hypothalamic-pituitary-adrenal (HPA) axis in prepubertal children after exposure to two different stress modalities and to evaluate the utility of an individual differences approach to the examination of HPA axis functioning. After a 30-min controlled baseline period, 73 7-year-olds (40 boys and 33 girls) were randomly assigned to a validity check condition or one of two experimental tasks designed to elicit fear or frustration. This was followed by a 60-min controlled regulation phase. A total of 17 saliva samples were collected, including 12 poststress samples at 5-min intervals. There was a significant stress modality effect, with children exposed to the fear condition reaching peak cortisol levels at 25 min poststress and those exposed to the frustration condition reaching peak levels at 45 min poststress. There was no difference in peak cortisol levels between the stress modalities. Individual variability across conditions was significant, with participants reaching peak levels as early as 10 min poststress and as late as 60 min poststress. Our data suggest that analysis of individual curves prior to making group-level comparisons may improve the explanatory power of HPA axis behavior models.     

神经质人格的神经生理基础

神经质作为一种人格特质, 核心特征是具有负性情绪体验的倾向。高神经质个体表现出更强的情绪反应、更差的情绪感知和应对, 因而体验到更多的负性情绪, 进而容易形成一系列精神障碍和身体疾病。因此, 神经质成为精神病理学中一个重要的风险因素。来自自主神经系统、神经内分泌系统和脑的证据发现, 高神经质个体心血管灵活性降低、HPA轴基线活动增强、EEG活动增大以及负性情绪引起的杏仁核活动增强, 其中杏仁核的自上而下和自下而上通路可能是整合多方面证据的关键。进一步研究应致力于将遗传学、电生理学、生物化学、脑成像技术等相结合, 构建神经质产生、形成的神经生理模型。     

Daily and trait rumination: diurnal cortisol patterns in adolescent girls

Rumination is a maladaptive form of emotion regulation associated with psychopathology. Research with adults suggests that rumination covaries with diurnal cortisol rhythms, yet this has not been examined among adolescents. Here, we examine the day-to-day covariation between rumination and cortisol, and explore whether trait rumination is associated with alterations in diurnal cortisol rhythms among adolescent girls. Participants (N?=?122) provided saliva samples 3 times per day over 3 days, along with daily reports of stress and rumination, questionnaires assessing trait rumination related to peer stress, and diagnostic interviews assessing depression and anxiety. Greater rumination than usual during the day was associated with lower cortisol awakening responses the following morning, but this effect was not significant after accounting for wake time and an objective measure of adherence to the saliva sampling protocol. Trait rumination was associated with lower average cortisol levels at waking and flatter diurnal slopes, accounting for wake time, protocol compliance, and other factors. These patterns may help to explain why rumination is related to the development of psychopathology.     

精神分裂症肠道微生物与脑影像和临床表征的关系

微生物-肠-脑轴假设在精神分裂症发病机制中的研究受到越来越多的关注。以往研究初步考察了肠道微生物的构成与精神分裂症患者脑影像和临床表征之间的联系,但具体的作用路径尚不明确。当前研究通过总结最新研究进展,并在此基础上提出肠道微生物影响精神分裂症患者大脑结构和功能的机制假设。相关内容对于进一步阐明精神分裂症的病理机制,为将肠道微生物纳入精神分裂症的评估与干预提供理论基础。     

Investigations of HPA function and the enduring consequences of stressors in adolescence in animal models

Developmental differences in hypothalamic–pituitary–adrenal (HPA) axis responsiveness to stressors and ongoing development of glucocorticoid-sensitive brain regions in adolescence suggest that similar to the neonatal period of ontogeny, adolescence may also be a sensitive period for programming effects of stressors on the central nervous system. Although research on this period of life is scarce compared to early life and adulthood, the available research indicates that effects of stress exposure during adolescence differ from, and may be longer-lasting than, effects of the same stress exposure in adulthood. Research progress in animal models in this field is reviewed including HPA function and the enduring effects of stress exposures in adolescence on sensitivity to drugs of abuse, learning and memory, and emotional behaviour in adulthood. The effects of adolescent stress depend on a number of factors, including the age, gender, the duration of stress exposure, the type of stressor, and the time between stress exposure and testing.     

消化系统疾病与精神心理因素的辩证关系

消化系统疾病与精神心理因素相互影响,其相互作用呈现个体化差异,这与个体间的内环境以及外环境差别有关。主要病理生理学机制之一为"脑-肠轴"及"脑肠互动"学说。临床医生需要认识到二者之间辩证关系的普遍性和重要性,及时发现躯体症状背后潜藏的精神心理问题,综合运用各种心理干预和药物治疗手段。     

Effects of Early Maternal Separation on Subsequent Reproductive and Behavioral Outcomes in Male Rats

To investigate effects of maternal separation on reproductive and behavioral outcomes, male Wistar rats were separated from their mothers daily for 3 hr (maternal separation; MS) or 0 hr (control) from postnatal day (PND) 1 to 14. Timing of puberty, reproductive parameters, hormone levels, and aggressive behaviors in juvenile and adult rats were examined. Contrary to expectations, there was no effect of maternal separation on any measure of aggression. However, maternal separation altered peripubertal testosterone secretion and increased mean day of preputial separation. In addition, adult MS males demonstrated less total sexual behavior. There was no difference in sperm counts or testosterone levels at necropsy on PND 56 or in adulthood, but seminal vesicle weights were increased in adult MS rats. These results suggest that early life stress may influence hypothalamic-pituitary-gonadal axis development in males, at least during peripuberty.     

母子依恋与农村儿童焦虑的关系：HPA轴活动的调节作用

本研究考察了母子依恋与农村留守、非留守儿童焦虑的关系以及儿童的HPA轴活动（唾液皮质醇日常节律）对这一关系的调节作用。39名留守儿童和70名非留守儿童完成了母子依恋问卷、儿童焦虑量表和连续三天共6次（上午、下午）的唾液采集。结果发现：（1）母子依恋安全性与留守儿童焦虑的负相关程度高于非留守儿童;（2）伴随皮质醇日常变化节律的提高,母子依恋安全性对留守儿童焦虑的保护作用增强,对非留守儿童焦虑的保护作用减弱。结果表明,HPA轴活动与母子依恋安全性的交互作用模式在农村留守与非留守儿童之间存在差异性。