Can the behaviour abnormalities induced by gestational stress in rats be prevented or reversed?

Gestational stress increases circulating maternal hormones that produce changes in behaviour and impair the feedback regulation of the hypothalamic pituitary adrenal axis of the offspring. Prenatally-stressed (PS) rats also release more corticotropin-releasing hormone (CRH) in the limbic system in response to stimulation than controls. This contributes to their exaggerated fear of intimidating situations and depressive-like behaviour. By using different treatments given to the pregnant mother, to neonatal or adult offspring, it has been possible to learn more about the mechanisms underlying the behavioural abnormalities induced by gestational stress. Many of these treatments were also able to prevent or reverse the abnormalities. They included maternal adrenalectomy and replacement of her basal hormone levels to avoid the prolonged elevation of plasma corticosterone, administration of anti-anxiety agents to reduce her reactions to the stress and continuous blockade of opioid receptors to prevent down-regulation of the foetal opioid system and subsequent alterations in behaviour. Hyperanxiety in the adult PS offspring could also be avoided if, as neonates, they were handled daily for 10 days, or given an antidepressant, amitriptyline for 4-5 weeks in the prepubertal period. Increased fear of novelty in adult PS rats could also be abolished by the intracerebro-ventricular administration of a CRH antagonist. This suggests that the new non-peptide CRH1 receptor antagonists that enter the brain might provide an effective treatment for the behaviour abnormalities in the offspring arising as a result of gestational stress.     

Language, space, and the development of cognitive flexibility in humans: the case of two spatial memory tasks

Prior experiments have shown that young children, like adult rats, rely mainly on information about the macroscopic shape of the environment to reorient themselves, whereas human adults rely more flexibly on combinations of spatial and non-spatial landmark information. Adult rats have also been shown to exhibit a striking limitation in another spatial memory task, movable object search, again a limitation not shown by human adults. The present experiments explored the developmental change in humans leading to more flexible, human adult-like performance on these two tasks. Experiment 1 identified the age range of 5-7 years as the time the developmental change for reorientation occurs. Experiment 2 employed a multiple regression approach to determine that among several candidate measures, only a specific language production measure, the production of phrases specifying exactly the information needed to solve the task like adults, correlated with the reorientation performance of children in this age range. Experiment 3 revealed that similar language production abilities were associated with more flexible moving object search task performance. These results, in combination with findings with human adults, suggest that language production skills play a causal role in allowing older humans to construct novel representations rapidly, which can then be used to transcend the limits of phylogenetically older cognitive processes.     

发展性障碍儿童的脑发育特点及干预

随着发展认知神经科学的兴起, 研究者借助脑成像等技术探讨了发展性障碍儿童的脑结构发育特点, 发展缺陷与脑功能损伤的关系以及障碍干预和脑功能改善的机制等, 这为揭示发展性障碍儿童异常神经机制的共性和特异性, 进而为早期诊断和干预提供了重要的生物学标记。针对儿童期常见的发展性障碍, 从脑结构损伤、脑激活异常、脑网络连接和脑功能康复等方面对相关研究进行了总结, 指出未来研究应拓展角度, 注重揭示各发展性障碍之间异常脑发育特点的共性和特异性的具体表现、病理机制及基因基础等; 临床工作者应注重将脑发育的异常和功能改善用于辅助各类障碍的早期识别和干预效果评估。     

Prevention science and neighborhood influences on low-income children's development: theoretical and methodological issues

Despite the rapid growth of research on neighborhood influences on children, little of this research may be useful to prevention scientists. Most studies have ignored processes by which neighborhood conditions influence individual outcomes. To encourage neighborhood research that can better guide the development of preventive interventions, we propose a model that focuses attention on mediating and moderating processes, is appropriate for studies interested in individual differences in outcomes, acknowledges the transactions between residents and neighborhoods, and is sensitive to how neighborhood influences may differ for children at different developmental stages. Furthermore, we argue that greater attention to several methodological issues also can make neighborhood research more useful for the next generation of prevention programs to help low-income urban families and children cope successfully with the challenges posed by their neighborhoods.     

Hormonal and behavioural abnormalities induced by stress in utero: an animal model for depression

Prenatal stress in rats can exert profound influence on the off spring's development, inducing abnormalities such as increased "anxiety", "emotionality" or "depression-like" behaviours.Prenatal stress has long-term effects on the development of the hypothalamo-pituitary-adrenal(HPA) axis and forebrain cholinergic systems. These long-term neuroendocrinological effects are mediated, at least in part, by stress-induced maternal corticosterone increase during pregnancy and stress-induced maternal anxiety during the postnatal period. We have shown a significant phase advance in the circadian rhythms of corticosterone secretion and locomotor activity in prenatally-stressed (PNS) rats. When subjected to an abrupt shift in the light-dark(LD) cycle, PNS rats resynchronized their activity rhythm more slowly than control rats. In view of the data suggesting abnormalities in the circadian timing system in these animals, we have investigated the effects of prenatal stress on the sleep-wake cycle in adult male rats. PNS rats exhibited various changes in sleep-wake parameters, including a dramatic increase in the amount of paradoxical sleep. Taken together, our results indicate that prenatal stress can induce increased responses to stress and abnormal circadian rhythms and sleep in adult rats.Various clinical observations in humans suggest a possible pathophysiological link between depression and disturbances in circadian rhythmicity. Circadian abnormalities in depression can be related to those found in PNS rats. Interestingly, we have recently shown that the increased immobility in the forced swimming test observed in PNS rats can be corrected by chronic treatment with the antidepressant tianeptine, or with melatonin or S23478, a melatonin agonist. Those results reinforce the idea of the usefulness of PNS rats as an appropriate animal model to study human depression and support a new antidepressant-like effect of melatonin and the melatonin agonist S23478.     

Cardiovascular responses to open-field stress in rats: sex differences and effects of gonadal hormones

We studied sex differences in cardiovascular responses to stress using a new radio-telemetry model in which freely-moving Spontaneously Hypertensive rats (SHR) are exposed to open-field novelty stress. This model allowed simultaneous assessment of cardiovascular and behavioural responses to psychological stress. Female SHR in the diestrous stage of their estrous cycle had markedly greater pressor and tachycardic responses to open-field exposure when compared to either female rats not in diestrous or male SHR. Treatment of ovariectomized SHR with estrogen alone had no significant effect on cardiovascular reactivity, while a combined treatment of estrogen and progesterone slightly, but significantly attenuated their pressor response to open-field stress. In addition, treatment of castrated male rats with testosterone significantly enhanced their pressor responses to stress when compared to values obtained before treatment. None of the hormone treatments had any significant effect on heart rate responses to stress. Neither at different stages of the estrous cycle nor after hormone treatments were there any marked changes in behavioural responses in the open-field, making it unlikely that the differences in cardiovascular stress responses were caused by changes in behavioural activity. These data demonstrate differences in cardiovascular stress responses that seem to be dependent on the stage of the estrous cycle. They suggest that particularly androgens, such as testosterone, may enhance pressor responses to stress. On the other hand, a combination of estrogen and progesterone, rather than estrogen alone, may have a small attenuating effect on cardiovascular reactivity.     

Maternal stress in pregnancy and its effect on the human foetus: an overview of research findings

There is evidence from human studies that anxiety or stress during pregnancy can affect birth outcome, causing babies to be born earlier and possibly smaller for gestational age. There is also some suggestive evidence for longer-term behavioural problems. Animal studies indicate that antenatal stress does have a long-term effect on the behaviour of the offspring, including a hyper-responsive hypothalamo-pituitary -adrenal axis. The human foetus can mount an independent stress response from mid-gestation. Two possible mechanisms have been demonstrated by which maternal stress or anxiety may affect the human foetus, the passage of cortisol across the placenta, and an impairment of blood flow through the maternal uterine arteries.     

Language Development and Assessment in the Preschool Period

Most young children make significant progress in learning language during the first 4?years of life. Delays or differences in patterns of language acquisition are sensitive indicators of developmental problems. The dynamic, complex nature of language and the variability in the timing of its acquisition poses a number of challenges for the assessment of young children. This paper summarises the key developmental milestones of language development in the preschool years, providing a backdrop for understanding difficulties with language learning. Children with specific language impairment (SLI) are characterised illustrating the types of language difficulties they exhibit. Genetic evidence for language impairment suggests complex interactions among multiple genes of small effect. There are few consistent neurobiological abnormalities and currently there is no identified neurobiological signature for language difficulties. The assessment of young children??s language skills thus focuses on the evaluation of their performances in comparison to typically developing peers. Assessment of language abilities in preschool children should involve an evaluation of both expressive and receptive skills and should include an evaluation of more than one dimension of language. The use of a single measure of a language component, such as vocabulary, is considered inadequate for determining whether preschool children have typical language or language impairment. Available evidence supports the inclusion of measures of phonological short-term memory in the assessment of the language abilities of preschool children. Further study of genetic, neurobiological and early behavioural correlates of language impairments in preschool children is needed.     

Functional neuroimaging of autistic disorders

Functional neuroimaging methods hold promise for elucidating the neurobiology of autistic disorders, yet they present difficult practical and scientific challenges when applied to these complex and heterogeneous syndromes. Single-state studies of brain metabolism and blood flow thus far have failed to yield consistent findings, but suggest considerable variability in regional patterns of cerebral synaptic activity. Patients with idiopathic autism are less likely to show abnormalities than are patients with comorbid illness or epilepsy. Activation studies have begun to suggest alterations in brain organization for language and cognition. Neurotransmitter studies using positron emission tomography (PET) suggest abnormalities of serotonergic and dopaminergic function. Studies using magnetic resonance spectroscopy (MRS) have begun to document metabolic deficits in the frontal cortex and cerebellum. A single study using magnetoencephalography suggests a high incidence of epileptiform activity in children with autistic regression. Research needs include well-controlled developmental studies, particularly of young subjects and relatively homogeneous subgroups, which balance scientific rigor with ethical constraints. Investigations of the serotonergic and dopaminergic systems, limbic-based memory and emotional systems, and the role of epileptiform activity in autism represent priorities for future research.     

Antenatal determinants of early childhood talking delay and behavioural difficulties

The determinants of talking delay alone or its comorbidity with behavioural difficulties was examined in 5768 two-year-old members of the Growing Up in New Zealand longitudinal study. Using the MacArthur-Bates Communicative Development inventories and the total difficulties score from the preschool Strengths and Difficulties Questionnaire, a composite measure was created so that children were categorised as showing no language or behavioural concerns (72.5%), behavioural only difficulties (6.1%), language only difficulties (18.1%), and comorbid language and behavioural difficulties (3.3%). Analyses revealed that antenatal factors such as maternal perceived stress, inadequate folate intake, vitamin intake, alcohol consumption during the first trimester and maternal smoking all had a significant effect on child outcomes. In particular, low multivitamin intake and perceived stress during pregnancy were associated with coexisting language and behavioural difficulties. These findings support international research in showing that maternal factors during pregnancy are associated with developmental outcomes in the early childhood period, and demonstrate these associations within a NZ context. Interventions which address maternal stress management and health behaviours during pregnancy could be beneficial to offspring development.     

Parenting programmes for parents of children and young people with behavioural difficulties

Children and young people exhibiting behavioural difficulties present a major challenge not only to parents but also to education and health professionals and to society as a whole. In this paper, I shall address some key issues regarding these parenting programmes, based particularly on a programme of research over 13 years in the Centre for Educational Development, Appraisal and Research at the University of Warwick. This has comprised large‐scale studies across all areas of England, both programmes targeted at parents whose children are presenting or at risk of developing behavioural difficulties: the Parenting Early Intervention Pathfinder and Parenting Early Intervention Programme; and universal programmes aimed at all parents, as a positive contribution to behavioural development across the population: the CANparent trial. All were funded by the Department for Education plus the continuation of the CANparent trial was funded by the Department of Health. In addition, I consider studies that have built on this research to examine the use of parenting programmes with parents of children and young people with special educational needs; and also the effectiveness of programmes during sustained implementation, beyond formal trials and similar research initiatives, that is, as day‐to‐day practice. I show that well‐constructed parenting programmes that are acceptable to parents are effective, that these positive effects on parents can remain over time, and also that the positive effects found in well‐organised trials can be maintained when programmes are delivered by community services as part of their normal practice.     

The role of media in road safety education for young children

This study compares the effectiveness of two videotaped traffic safety messages, both concerning crossing the road in the vicinity of parked cars. In the ‘instructional’ version the message was presented according to the principles generally used in media presentations for children. The ‘modelling’ version closely followed social learning principles. Both versions were presented to subjects 5 years of age. The subjects were pre-tested and post-tested on crossing the road and their comprehension of the film content was tested after presentation. The ‘modelling’ version resulted in a significant increase in the children's capacity to demonstrate the crossing behaviour, whereas the ‘instructional’ version did not. The comprehension test demonstrated that children exposed to the ‘modelling’ version also showed a significantly higher level of understanding. The conclusion is drawn that traditional media presentations are not successful in effectuating behavioural change in young children. Presentations which follow ‘modelling’ principals and are adapted to the developmental characteristics of the audience can improve young children's behaviour capabilities and can as such be an important part of educational programmes such as road safety which aim at causing behavioural change in young children.     

Family transitions following the birth of a sibling: an empirical review of changes in the firstborn's adjustment

Nearly 80% of children in the United States have at least 1 sibling, indicating that the birth of a baby sibling is a normative ecological transition for most children. Many clinicians and theoreticians believe the transition is stressful, constituting a developmental crisis for most children. Yet, a comprehensive review of the empirical literature on children's adjustment over the transition to siblinghood (TTS) has not been done for several decades. The current review summarizes research examining change in first borns' adjustment to determine whether there is evidence that the TTS is disruptive for most children. Thirty studies addressing the TTS were found, and of those studies, the evidence did not support a crisis model of developmental transitions, nor was there overwhelming evidence of consistent changes in firstborn adjustment. Although there were decreases in children's affection and responsiveness toward mothers, the results were more equivocal for many other behaviors (e.g., sleep problems, anxiety, aggression, regression). An inspection of the scientific literature indicated there are large individual differences in children's adjustment and that the TTS can be a time of disruption, an occasion for developmental advances, or a period of quiescence with no noticeable changes. The TTS may be a developmental turning point for some children that portends future psychopathology or growth depending on the transactions between children and the changes in the ecological context over time. A developmental ecological systems framework guided the discussion of how child, parent, and contextual factors may contribute to the prediction of firstborn children's successful adaptation to the birth of a sibling.     

Childhood Epilepsy and Autism Spectrum Disorders: Psychiatric Problems, Phenotypic Expression, and Anticonvulsants

Epilepsy and autism spectrum disorders (ASDs) frequently co-occur during childhood, however, the characteristics of psychiatric or behavioural problems in these children remains largely unknown. This article contributes to these discussions by reporting on the prevalence and presentation of psychiatric or behavioural problems in children with epilepsy and ASDs, as well as on the use of anticonvulsants in these children. The current evidence suggests that children with epilepsy and ASDs may present with a distinct clinical profile, with a greater number of developmental difficulties, and a more severe expression of the ASD phenotype that can not solely be accounted for by level of intellectual functioning. Positive effects of anticonvulsants on behavioural symptoms associated with ASDs were also reported, though pharmacoresistance and a lack of clear treatment guidelines may contribute to an elevated risk of adverse side effects. In relation to clinical presentation and management there is a need for careful consideration of potential interaction effects between disorder specific factors (e.g., age of seizure onset/ASD diagnosis), cognitive characteristics (e.g., intellectual functioning, memory), and psychosocial variables (e.g., coping strategies). Ultimately however, many conclusions are tentative and this review highlights the need for more empirically validated research on children with epilepsy and ASDs.     

The impact of emotional expressions on children’s trust judgments

Research on the development of selective trust has shown that young children do not indiscriminately trust all potential informants. They are likely to seek and endorse information from individuals who have proven competent or benign in the past. However, research on trust among adults raises the possibility that children might also be influenced by the emotions expressed by potential informants. In particular, they might trust individuals expressing more positive emotion. Indeed, young children’s trust in particular informants based on their past behaviour might be undermined by their currently expressed emotions. To examine this possibility, we tested the selective trust of fifty 4- and 5-year-olds in two steps. We first confirmed that children are likely to invest more trust in individuals expressing more positive emotion. We then showed that even if children have already formed an impression of two potential informants based on their behavioural record, their choices about whose claims to trust are markedly influenced by the degree of positive emotion currently expressed by the two informants. By implication, the facial emotions expressed by potential informants can undermine young children’s selective trust based on the behavioural record of those informants.     

Children with Specific Language Impairment are not impaired in the acquisition and retention of Pavlovian delay and trace conditioning of the eyeblink response

Three converging lines of evidence have suggested that cerebellar abnormality is implicated in developmental language and literacy problems. First, some brain imaging studies have linked abnormalities in cerebellar grey matter to dyslexia and specific language impairment (SLI). Second, theoretical accounts of both dyslexia and SLI have postulated impairments of procedural learning and automatisation of skills, functions that are known to be mediated by the cerebellum. Third, motor learning has been shown to be abnormal in some studies of both disorders. We assessed the integrity of face related regions of the cerebellum using Pavlovian eyeblink conditioning in 7–11 year-old children with SLI. We found no relationship between oral language skills or literacy skills with either delay or trace conditioning in the children. We conclude that this elementary form of associative learning is intact in children with impaired language or literacy development.     

国外儿童词汇识别发展眼动研究的新进展

近年来,国外儿童阅读发展的眼动研究已逐渐成为阅读研究热点领域。本文就国外儿童阅读的眼动研究成果进行概述,从儿童阅读眼动研究的基本问题、字词、句子、篇章和相关理论等方面对儿童的阅读过程进行考察,总结其阅读发展的一般规律和特点。最后,文章从阅读材料、统计方法以及研究设计几个方面对儿童阅读研究的方法性问题进行展望,以期为中文阅读发展的眼动研究提供借鉴     

Behavioural Problems in Children with Headache and Maternal Stress: Is Children's Attachment Security a Protective Factor?

Headache is a potentially disabling condition involving enduring pain that negatively influences the quality of family life. Behavioural problems are more common in children with headache and are potentially associated with higher levels of parental stress. The aim of this study was to evaluate the extent to which children's behavioural problems were associated with maternal stress and how the child's perception of security in the maternal attachment relationship moderates this association. Seventy‐one school‐aged children with headache (headache group (HG), age M = 9.8 years old, SD = 1.3) and 71 children from a low‐risk normative population (control group (CG), age M = 9.2 years old, SD = 1) and their mothers were involved in the study. Mothers' reports of children's behavioural problems were associated with higher maternal stress in the caring task both in the HG and in the CG. Results also showed that the HG was more at risk for behavioural problems, whereas no difference between groups was detected for parenting stress and for attachment insecurity. In children with headache, perception of attachment security decreased the strength of the association between maternal stress and externalizing behavioural problems. Secure attachment may provide children with headache and their parents with support in managing the negative emotions that arise in the context of significant health issues. Implications for practice are discussed. Copyright © 2015 John Wiley & Sons, Ltd.     

Epileptic encephalopathies and their relationship to developmental disorders: do spikes cause autism?

Epileptic encephalopathies are progressive clinical and electroencephalographic syndromes where deterioration is thought to be caused by frequent seizures and abundant EEG epileptiform activity. Seizures occur in approximately 10-15% of children with pervasive developmental disorders (PDD) and 8-10% have epileptiform EEG abnormalities without seizures. Thirty percent of children with PDD have regression of social behavior and language at 2-3 years of age. Some authors speculate that the regression is caused by epileptiform activity even in the absence of overt clinical seizures ("autism with epileptic regression") and suggest that elimination of the epileptiform activity, either medically or surgically, should lead to improvement in behavior. This review examines the data showing that interictal epileptiform discharges are associated with transient clinical dysfunction and discusses the implications of these observations for autistic behavioral abnormalities. The results of resective surgery, vagal nerve stimulation, and multiple subpial transaction on children with autism and epileptiform EEG abnormalities are also discussed. I conclude that there is no evidence that interictal discharges per se cause (or contribute to) the complex behavioral phenotype of autism. There is no justification to support the use of anticonvulsant medication or surgery in children with PDD without seizures; that is, there is no evidence that treatment to eliminate EEG spikes will have a therapeutic effect on the behavioral abnormalities of PDD and autism.