Dopamine and serotonin systems modify environmental effects on human behavior: A review

The relative influences of genetic and environmental factors in the development of human behavior have been a long‐term topic for an intense debate. Recent behavioral genetic studies suggest focusing on the joint effect of genes and environment, and especially on the life‐course developmental interplay between nature and nurture. Vulnerability to environmental adversities and sensitivity to its benefits may be conditional on genetic background, and regarding psychological outcomes, these kinds of gene × environment interactions may be of higher importance than direct gene–trait associations. In our recent series of studies, we have shown that different variants of serotonergic and dopaminergic genes may moderate the influence of environmental conditions on a range of psychological outcomes, i.e. temperament, depression, hostility, and educational attainment. These studies suggest that depending on their genotype, people may be differentially sensitive to the environmental conditions they encounter. In the light of these results it seems highly plausible that the effects of genes may become evident only when studied in the context of environmental factors.     

Risk factors for eating disorders

The authors review research on risk factors for eating disorders, restricting their focus to studies in which clear precedence of the hypothesized risk factor over onset of the disorder is established. They illustrate how studies of sociocultural risk factors and biological factors have progressed on parallel tracks and propose that major advances in understanding the etiology of eating disorders require a new generation of studies that integrate these domains. They discuss how more sophisticated and novel conceptualizations of risk and causal processes may inform both nosology and intervention efforts.     

儿童发展的环境敏感性模型：一种整合的观点

儿童发展的环境敏感性模型是在整合素质-压力模型、差别易感性模型、优势敏感性模型、情境生物敏感性模型以及感觉加工敏感性模型理论观点的基础上提出来的一个关于个体与环境因素如何交互影响儿童发展的元理论框架。该模型认为儿童的环境敏感性即儿童感知和加工周围环境刺激信息的能力不同,其发展受到环境影响的大小就不同,高环境敏感性儿童受到环境影响大,低环境敏感性儿童受到环境影响小。儿童的环境敏感性是儿童携带的敏感基因与早期环境交互作用的结果,敏感基因与早期环境共同塑造了中枢神经系统功能的敏感性,从而导致儿童对环境刺激的心理、生理与行为反应不同。大量实证研究表明,存在基因多态性、神经生理与气质等不同的潜在环境敏感性因子。儿童发展的环境敏感性模型的提出,为从基因-神经生理-环境三项交互作用系统探讨儿童发展的多样性提供了理论框架。     

Individual Resiliency Factors from a Genetic Perspective: Results from a Twin Study

This article is part of the Twin Mother's Study, a study that examines influences on maternal adjustment. A number of studies have investigated the importance of genetic factors for mental health, but few of these examine how genes and the environment influence resiliency/salutogenic factors. This article investigates the relative importance of genetic and environmental influences on resiliency/salutogenic factors. This study includes 326 twin pairs (150 monozygotic and 176 dizygotic) who are mothers, who are living with their spouse, and who are part of the Swedish twin register. Using self‐report structured questionnaires, we assessed salutogenic factors, depression, and quality of life; however, we analyzed the questionnaires completed by the mothers. Statistical analyses were conducted using structural equation modeling. We conclude that nonshared environmental components were of principal importance in individual resiliency/salutogenic factors in a genetically informative design, but we also noted that genetic influences were important. The shared environment had mainly no effect.     

抑郁的多基因遗传基础

抑郁具有复杂的、非孟德尔式的多基因遗传模式, 但是目前多数抑郁的遗传研究集中于考察单个候选基因, 不能全面揭示遗传因素的作用机制。近年来, 多基因遗传得分研究和基因−基因交互研究分别为抑郁的多基因累加效应和交互效应提供了新的证据。多基因不仅直接影响抑郁, 还通过与环境因素的交互作用影响抑郁的发生发展, 并且这一复杂交互作用存在性别差异。抑郁的内表型研究发现多基因可能通过认知因素、人格、压力荷尔蒙等间接影响个体的抑郁水平。未来研究应更加关注多基因与多种环境因素如何相互作用影响抑郁, 探索多基因遗传机制的性别差异, 考察多基因对抑郁影响随年龄的发展动态变化。     

An organizing framework for collective identity: articulation and significance of multidimensionality

The authors offer a framework for conceptualizing collective identity that aims to clarify and make distinctions among dimensions of identification that have not always been clearly articulated. Elements of collective identification included in this framework are self-categorization, evaluation, importance, attachment and sense of interdependence, social embeddedness, behavioral involvement, and content and meaning. For each element, the authors take note of different labels that have been used to identify what appear to be conceptually equivalent constructs, provide examples of studies that illustrate the concept, and suggest measurement approaches. Further, they discuss the potential links between elements and outcomes and how context moderates these relationships. The authors illustrate the utility of the multidimensional organizing framework by analyzing the different configuration of elements in 4 major theories of identification.     

Prospective memory: The relative effects of encoding,retrieval, and the match between encoding and retrieval

Previous prospective memory studies have revealed some important features of encoding, retrieval, and the match between the encoding and the retrieval that contribute to prospective memory performance. However, these studies have not provided evidence concerning the relative importance of these three factors because no study has investigated all three in a single design. We developed a laboratory-based paradigm that allowed us to manipulate different characteristics of encoding, retrieval, and the match between encoding and retrieval simultaneously in a single experiment. The results of eight experiments showed that all three factors have an influence on prospective memory performance, but that the match between encoding and retrieval has a significantly larger influence than either encoding or retrieval factors.     

Prospective memory: the relative effects of encoding, retrieval, and the match between encoding and retrieval

Previous prospective memory studies have revealed some important features of encoding, retrieval, and the match between the encoding and the retrieval that contribute to prospective memory performance. However, these studies have not provided evidence concerning the relative importance of these three factors because no study has investigated all three in a single design. We developed a laboratory-based paradigm that allowed us to manipulate different characteristics of encoding, retrieval, and the match between encoding and retrieval simultaneously in a single experiment. The results of eight experiments showed that all three factors have an influence on prospective memory performance, but that the match between encoding and retrieval has a significantly larger influence than either encoding or retrieval factors.     

抑郁症的影像遗传学研究:探索基因与环境的交互作用

抑郁症具有中等的遗传度。通过影像遗传学方法探讨抑郁相关基因的多态性对神经活动的影响,发现编码五羟色胺、促肾上腺素释放激素受体、多巴胺等神经递质或受体的基因多态性会影响杏仁核、前扣带等情绪加工脑区的功能或结构,且多数基因与压力生活经历发生交互作用。表明基因与环境的交互作用在抑郁症发病机理中扮演重要角色。未来的研究应拓展遗传和神经影像分析方法,重视环境因素的测量,通过整合遗传、神经影像及环境变量构建抑郁病理模型。     

The impact of task-irrelevant emotional stimuli on attention in three domains

Whether task-irrelevant emotional stimuli facilitate or disrupt attention performance may depend on a range of factors, such as emotion type, task difficulty, and stimulus duration. Few studies, however, have systematically examined the influence of these factors on attention performance. Sixty-three adults, scoring within a normative range for mood and anxiety symptoms, completed either an easy or difficult version of an attention task measuring three aspects of attention performance: alerting, orienting, and executive attention. Results showed that in the easy task only, threatening versus nonthreatening task-irrelevant emotional faces facilitated orienting regardless of stimulus duration. These effects were no longer significant during the difficult condition. When the easy and difficult conditions were examined together, duration effects emerged such that stimuli of longer durations lead to greater interference, although effects were nonlinear. Findings illustrate that threat-relevant emotional stimuli facilitate attention during tasks with low cognitive load, but underscore the importance of considering a range of task parameters. Results are discussed in the context of adaptive and maladaptive emotion-attention interactions.     

Communication in preterm infants: Why is it different?

The present paper selectively reviews the literature which compares full-term and preterm infants' communication with their mothers in the first year of life. The review is focused not only on what differences are found between full-term and preterm infants, but also why such differences exist. Particular emphasis is placed on the importance of interpreting the findings in the light of the developmental phase of the infants, the heterogeneity of the preterm population and the situation in which communication is studied. Most studies were not designed to consider these issues in any detail. Differences with respect to these factors can be found between studies, however, which may have contributed to the often contradictory findings. Consequently, comparisons between these studies provide clues about the effects of these factors on communicative development. The ultimate goal of this review is to point to important directions for future research on early communication in preterm infants.     

Association of polymorphisms in BDNF, MTHFR, and genes involved in the dopaminergic pathway with memory in a healthy Chinese population

The contribution of genetic factors to the memory is widely acknowledged. Research suggests that these factors include genes involved in the dopaminergic pathway, as well as the genes for brain-derived neurotrophic factor (BDNF) and methylenetetrahydrofolate reductase (MTHFR). The activity of the products of these genes is affected by single nucleotide polymorphisms (SNPs) within the genes. This study investigates the association between memory and SNPs in genes involved in the dopaminergic pathway, as well as in the BDNF and MTHFR genes, in a sample of healthy individuals. The sample includes 134 Taiwanese undergraduate volunteers of similar cognitive ability. The Chinese versions of the Wechsler Memory Scale (WMS-III) and Wechsler Adult Intelligence Scale (WAIS-III) were employed. Our findings indicate that the BDNF Met66Val polymorphism and dopamine receptor D3 (DRD3) Ser9Gly polymorphism are associated significantly with long-term auditory memory. Further analysis detects no significant associations in the other polymorphisms and indices. Future replicated studies with larger sample sizes, and studies that consider different ethnic groups, are encouraged.     

Progress in the Molecular-Genetic Study of Intelligence

ABSTRACT— The past decade has seen a major shift in the genetic study of human intelligence; where classic studies aimed to quantify the heritability of intelligence, current studies aim to dissect this heritability into its molecular-genetic components. Five whole-genome linkage scans have been published in the past year, converging on several chromosomal (or genomic) regions important to intelligence. A handful of candidate genes, some of which lie in these genomic regions, have shown significant association to intelligence and the associations have been replicated in independent samples. Finding genes brings us closer to an understanding of the neurophysiological basis of human cognition. Furthermore, when genes are no longer latent factors in our models but can actually be measured, it becomes feasible to identify those environmental factors that interact and correlate with genetic makeup. This will supplant the long nature–nurture debate with actual understanding.     

MTHFR and ACE gene polymorphisms and risk of vascular and degenerative dementias in the elderly

Focal lacunar infarctions due to cerebral small vessel atherosclerosis or single/multiple large cortical infarcts lead to vascular dementia, and different genes and environmental factors have been implicated in causation or aggravation of the disease. Previous reports suggest that some of the risk factors may be common to both vascular as well as degenerative dementia. Among genetic factors, role of angiotensin converting enzyme (ACE) and methylene-tetrahydrofolate reductase (MTHFR) genes as putative risk factors has been examined but the outcome of these studies remain inconclusive. Present study attempted to see the importance of ACE alu insertion/deletion and MTHFR C677T polymorphisms as genetic predisposers to dementia. The study comprised of 80 vascular dementia patients, 90 degenerative dementia patients and 170 age matched controls. All were genotyped for ACE, MTHFR and APOE polymorphisms using PCR-RFLP method. Frequency of ACE D allele was seemingly high in dementia cases (26.7%) when compared to controls (11.2%). However, after adjusting for age and APOE E4^*, none of the ACE alleles showed good correlation. MTHFR genotypes or alleles also did not show any correlation. Our study suggests no true correlation of ACE or MTHR genes with dementia in elderly.     

MTHFR and ACE gene polymorphisms and risk of vascular and degenerative dementias in the elderly

Focal lacunar infarctions due to cerebral small vessel atherosclerosis or single/multiple large cortical infarcts lead to vascular dementia, and different genes and environmental factors have been implicated in causation or aggravation of the disease. Previous reports suggest that some of the risk factors may be common to both vascular as well as degenerative dementia. Among genetic factors, role of angiotensin converting enzyme (ACE) and methylene-tetrahydrofolate reductase (MTHFR) genes as putative risk factors has been examined but the outcome of these studies remain inconclusive. Present study attempted to see the importance of ACE alu insertion/deletion and MTHFR C677T polymorphisms as genetic predisposers to dementia. The study comprised of 80 vascular dementia patients, 90 degenerative dementia patients and 170 age matched controls. All were genotyped for ACE, MTHFR and APOE polymorphisms using PCR-RFLP method. Frequency of ACE D allele was seemingly high in dementia cases (26.7%) when compared to controls (11.2%). However, after adjusting for age and APOE E4^*, none of the ACE alleles showed good correlation. MTHFR genotypes or alleles also did not show any correlation. Our study suggests no true correlation of ACE or MTHR genes with dementia in elderly.     

多巴胺相关基因甲基化、家庭环境与创造力的关系

“遗传与环境”的争论一直是创造力研究的核心问题, 但目前对于环境以及遗传与环境交互作用对创造力影响的分子生物机制还未有研究涉及。近年来, 随着表观遗传学的兴起, 揭示影响心理行为的表观遗传机制现已成为心理学研究的热点。作为环境与基因组之间的纽带, 表观遗传学研究为揭示环境以及遗传与环境交互作用对创造力影响的分子生物机制提供了机遇。本研究以多巴胺相关基因、家庭环境以及两者对于创造力的交互作用为切入点, 对影响创造力的表观遗传机制进行考察, 并在此基础之上, 对环境以及遗传与环境交互作用对创造力影响的分子生物机制进行探索。具体研究内容包括：(1)通过对多巴胺相关基因甲基化模式与创造力关系的系统考察, 筛选出甲基化模式与创造力有关的基因; (2)对筛选出的基因, 进一步考察其甲基化模式在家庭环境及其遗传多态性与家庭环境交互作用对创造力影响中的中介作用。本研究有助于揭示创造力的表观遗传机制, 深化关于遗传与环境对创造力影响的作用机制的理解。     

Don't Get Too Excited: Assessing Individual Differences in the Down-Regulation of Positive Emotions

A voluminous literature has documented the importance of emotion regulation for health and well-being. The studies in this literature, however, have generally focused on the down-regulation of negative affect. Few studies have examined the down-regulation of positive affect. In Study 1, we constructed a scale, the revised Regulatory Emotional Self-Efficacy Scale (r–RESE), which assesses both the down- and up-regulation of positive affect, in addition to the traditional down-regulation of negative affect. In Study 2, we conducted an extensive validation of the r–RESE scale, using a multimethod approach with informant ratings, to illustrate that the down-regulation of positive affect represents a process independent of each of the other forms of emotion regulation. In Study 3, we provided evidence that the ability to down-regulate positive emotions provides added predictive utility when predicting indexes of impulsivity and adjustment. Across the studies, we illustrate the potential importance of the down-regulation of positive emotions as a topic of study for the field of emotion regulation.     

Complexities in International Organizational Socialization

The growing number of expatriates highlights the importance of organizational socialization as these people strive to adjust to a new work environment in a foreign country. Research hypotheses presented by Feldman (1997) are reviewed for their impact on future research. The complexities of organizational socialization or work adjustment within an international context are believed to transcend the bounds of simple linear relationships. Five of the hypotheses are discussed to illustrate these complexities and to offer new ideas for future research.     

Tangled webs: tracing the connections between genes and cognition

The rise of molecular genetics is having a pervasive influence in a wide variety of fields, including research into neurodevelopmental disorders like dyslexia, speech and language impairments, and autism. There are many studies underway which are attempting to determine the roles of genetic factors in the aetiology of these disorders. Beyond the obvious implications for diagnosis, treatment and understanding, success in these efforts promises to shed light on the links between genes and aspects of cognition and behaviour. However, the deceptive simplicity of finding correlations between genetic and phenotypic variation has led to a common misconception that there exist straightforward linear relationships between specific genes and particular behavioural and/or cognitive outputs. The problem is exacerbated by the adoption of an abstract view of the nature of the gene, without consideration of molecular, developmental or ontogenetic frameworks. To illustrate the limitations of this perspective, I select two cases from recent research into the genetic underpinnings of neurodevelopmental disorders. First, I discuss the proposal that dyslexia can be dissected into distinct components specified by different genes. Second, I review the story of the FOXP2 gene and its role in human speech and language. In both cases, adoption of an abstract concept of the gene can lead to erroneous conclusions, which are incompatible with current knowledge of molecular and developmental systems. Genes do not specify behaviours or cognitive processes; they make regulatory factors, signalling molecules, receptors, enzymes, and so on, that interact in highly complex networks, modulated by environmental influences, in order to build and maintain the brain. I propose that it is necessary for us to fully embrace the complexity of biological systems, if we are ever to untangle the webs that link genes to cognition.