The effects of threatened social evaluation of the physique on cortisol activity

Social self preservation theory asserts that situations high in social-evaluative threat elicit increases in cortisol, a hormone released by the hypothalamic-pituitary-adrenal axis. Most tests of the theory have examined threats associated with social evaluation of a performance. Two experiments examined the effects of threatened social evaluation of one's physique. In Experiments 1 (n?=?50) and 2 (n?=?40), participants allocated to an experimental (threat) condition had significantly higher post-manipulation cortisol than participants in a control (no threat) condition. In Experiment 1, perceptions of social-evaluative threat were significantly correlated with post-manipulation cortisol levels. These results suggest that the threatened social evaluation of one's body can activate the cortisol response. Women who frequently experience such threats may be at increased risk for a variety of health conditions associated with chronic cortisol exposure.     

Fibromyalgia and childhood abuse: Exploration of stress reactivity as a developmental mediator

The purpose of this paper is to explore whether the human body’s stress reactivity in response to trauma may be a possible developmental mediator between childhood abuse and the development of fibromyalgia (FM). Four points are emphasized in this article. First, studies that have examined the prevalence of childhood physical, emotional, and sexual abuse in FM patients are evaluated. Second, health and neuroendocrine differences between abused and non-abused FM patients are examined. Third, studies that tested the association between childhood abuse and stress reactivity characterized by neurobiological abnormalities are reviewed. Fourth, studies that have investigated the association between stress reactivity and FM are analyzed. The results of the reviews showed significant associations between childhood abuse and FM, childhood abuse and stress reactivity, and stress reactivity and FM, indicating that childhood abuse may be one of the etiological factors that could lead to abnormal brain development, affecting stress reactivity, and ultimately lead to the development of FM.     

Foetal programming and cortisol secretion in early childhood: A meta-analysis of different programming variables

It is widely recognized that different events may take place in the intrauterine environment that may influence later developmental outcome. Scholars have long postulated that maternal prenatal stress, alcohol or drug use, and cigarette smoking may impact foetal formation of the hypothalamus–pituitary–adrenal (HPA) axis, which may later influence different aspects of early childhood socioemotional and cognitive development. However, results linking each of these factors with child cortisol secretion have been mixed. The current meta-analysis examined the relation between each of these programming variables and child cortisol secretion in studies conducted up to December 31st, 2012. Studies were included if they were conducted prior to child age 60 months, and if they reported an index of effect size linking either maternal prenatal stress, alcohol or drug use, or cigarette smoking with an index of child cortisol secretion. In total, 19 studies (N = 2260) revealed an average effect size of d = .36 (p < .001). Moderator analyses revealed that greater effect sizes could be traced to maternal alcohol use, to the use of retrospective research methodology, where mothers are questioned after childbirth regarding programming variables, and to the use of baseline measures of cortisol secretion, as opposed to recovery measures. Discussion focuses on processes that link the environment to foetal development and how both are linked to later adaptation.     

The cortisol awakening response and the big five personality dimensions

The present study investigated the association between the big five personality dimensions and the cortisol awakening response (CAR), a physiological parameter reflective of HPA axis activity. One hundred and seven participants completed the big five inventory (BFI; John, Donahue, & Kentle, 1991) and collected salivary cortisol samples at 0, 30, and 60 min after awakening on a weekday morning. The cortisol awakening response under the curve (CARauc) and the cortisol awakening response with respect to increase (CARi) were used as outcome variables in the statistical analyses. Hierarchical linear regression analyses were conducted using the data of 92 participants. Gender and age were included as covariates in block one of the regressions, followed by the personality dimensions in block two. Extraversion emerged as a significant predictor of CARauc. No other personality dimensions were significantly predictive of CARauc or CARi. Interestingly, gender emerged as the strongest predictor in the CARauc, with females exhibiting greater cortisol release across the awakening period than males. Our results suggest that extraversion and gender may be particularly important variables to consider in the regulation of the HPA axis.     

Discrimination of faces and houses by rhesus monkeys: the role of stimulus expertise and rotation angle

The face inversion effect, or impaired recognition of upside down compared to upright faces, is used as a marker for the configural processing of faces in primates. The inversion effect in humans and chimpanzees is strongest for categories of stimuli for which subjects have considerable expertise, primarily conspecifics’ faces. Moreover, discrimination performance decreases linearly as faces are incrementally rotated from upright to inverted. This suggests that rotated faces must be transformed, or normalized back into their most typical viewpoint before configural processing can ensue, and the greater the required normalization, the greater the likelihood of errors resulting. Previous studies in our lab have demonstrated a general face inversion effect in rhesus monkeys that was not influenced by expertise. Therefore, the present study examined the influence of rotation angle on the visual perception of face and nonface stimuli that varied in their level of expertise to further delineate the processes underlying the inversion effect in rhesus monkeys. Five subjects discriminated images in five orientation angles. Results showed significant linear impairments for all stimulus categories, including houses. However, compared to the upright images, only rhesus faces resulted in worse performance at rotation angles greater than 45°, suggesting stronger configural processing for stimuli for which subjects had the greatest expertise.     

创伤后应激障碍患者的HPA轴功能变化的时间序列特征

已知创伤后应激障碍(posttraumatic stress disorder, PTSD)患者表现出HPA轴(hypothalamic-pituitary- adrenocortical axis)功能异常, 而皮质醇是反映PTSD患者HPA轴功能的重要生物标记。近期的研究结果提示, PTSD患者的皮质醇水平变化可能有明显的时间序列特征, 即应激事件发生后先升高, 后下降至正常水平之下。这一特征受到生物标记的时间特性, 患者病程, 应激源类型和强度, 伴生疾病等因素的干扰和掩蔽。未来研究应进一步采用长期追踪设计, 控制干扰因素的影响, 结合急性应激和慢性应激生物标记来综合验证PTSD患者皮质醇水平变化的时间序列特征|并利用该特征预测PTSD的发生、发展, 以便及时进行干预|考虑皮质醇的代谢、拮抗等机制, 结合多种生物标记综合评估、诊断PTSD患者的HPA轴功能活性。     

A psychology of the human brain–gut–microbiome axis

In recent years, we have seen increasing research within neuroscience and biopsychology on the interactions between the brain, the gastrointestinal tract, the bacteria within the gastrointestinal tract, and the bidirectional relationship between these systems: the brain–gut–microbiome axis. Although research has demonstrated that the gut microbiota can impact upon cognition and a variety of stress‐related behaviours, including those relevant to anxiety and depression, we still do not know how this occurs. A deeper understanding of how psychological development as well as social and cultural factors impact upon the brain–gut–microbiome axis will contextualise the role of the axis in humans and inform psychological interventions that improve health within the brain–gut–microbiome axis. Interventions ostensibly aimed at ameliorating disorders in one part of the brain–gut–microbiome axis (e.g., psychotherapy for depression) may nonetheless impact upon other parts of the axis (e.g., microbiome composition and function), and functional gastrointestinal disorders such as irritable bowel syndrome represent a disorder of the axis, rather than an isolated problem either of psychology or of gastrointestinal function. The discipline of psychology needs to be cognisant of these interactions and can help to inform the future research agenda in this emerging field of research. In this review, we outline the role psychology has to play in understanding the brain–gut–microbiome axis, with a focus on human psychology and the use of research in laboratory animals to model human psychology.     

Selective activation of lower leg muscles during maximum voluntary isometric contractions

The pronators and supinators play a key role in the medio-lateral stability of the ankle joint complex (i.e. talo-crural and subtalar joints). We hypothesized that each shank muscle has a specific activation pattern determined by its anatomical course around the axes of the subtalar and talo-crural joints. A secondary objective was to examine the effect of foot posture on these activation patterns. Forty-nine young adults (25 normal-arched feet, 24 flat-arched feet) performed maximum voluntary isometric contractions against manual resistance in four movement directions: plantarflexion (PF), dorsiflexion (DF), pronation (PRO) and supination (SUP). Electromyographic activity was recorded from tibialis posterior (TP) and peroneus longus (PL) with intramuscular electrodes, and gastrocnemius medialis (GM) and tibialis anterior (TA) with surface electrodes. When compared to their agonist function, all muscles were co-activated at significantly lower levels in their synergistic function (GM: 23% during SUP, TA: 72% during SUP; TP: 42% during PF, PL: 52% during PF) (p < 0.001). A significant interaction between foot posture and contraction type was evident for TA. During isometric contractions, the electromyographic activity of the shank muscles is geared to their biomechanical advantage according to their position relative to the subtalar and talo-crural joint axes.     

急性应激影响工作记忆的生理心理机制

急性应激是机体面对外界环境变化所产生的一系列生理和心理反应, 对认知加工, 尤其是核心的工作记忆能力产生深远影响, 然而以往的研究存在大量不一致的结果。从应激诱发方式、工作记忆加工子成分、个体差异等三个方面系统阐释应激影响工作记忆的生理心理机制, 并结合认知神经机制的框架, 可以更好地理解以往的结果。未来研究应综合考虑应激诱发、认知任务和响应个体等方面的差异对应激带来的影响, 并关注急性应激负面影响的干预与调控。     

细胞因子和抑郁症

在心理神经免疫学领域,越来越多的证据表明神经和免疫之间存在双向交流通路,免疫系统可能在一些心理精神障碍中具有重要作用。“抑郁症的细胞因子假说”认为细胞因子作为神经调质,可能在抑郁症的病因和病理过程中具有重要作用。这个假说得到了很多证据的支持。而在动物身上应用前炎性细胞因子也能够引起与人类抑郁症行为症状非常类似的“病态行为”。研究认为外周细胞因子通过信号传导进入脑内与中枢产生的细胞因子共同作用于下丘脑－垂体－肾上腺轴和5－羟色胺系统,从而导致抑郁症。细胞因子的中枢效应可以解释很多抑郁症状,“抑郁症的细胞因子假说”为探讨抑郁症状的机制和治疗抑郁症提供了一个新的视角