Effects of Acute Stress or Centrally Injected Interleukin-1beta on Neuropeptide Expression in the Immune System

Acute stress stimulates the expression and release of corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) from the hypothalamus, and the pro-opiomelanocortin products beta-endorphin and ACTH from the anterior pituitary. These neuropeptides are also expressed in immune tissues, and it has been proposed that they may modulate immune responses to stress through paracrine mechanisms. We subjected rats to restraint stress or central injection of interleukin (IL)-1beta to determine whether these acute stimuli can alter the expression of neuropeptides in the spleen and thymus. Restraint stress significantly increased the contents of all these neuropeptides in thymic, but not splenic, extracts. A single icv injection of IL-1beta increased contents of CRH, AVP, ACTH and beta-endorphin in the spleens of both sham-operated and adrenalectomised (ADX) rats. IL-1beta increased thymic contents of CRH and ACTH in sham-operated rats but these increases were not observed in ADX rats. These results suggest that the effects of IL-1beta on neuropeptide expression in the spleen are independent of glucocorticoids, whereas IL-1beta stimulation of neuropeptide expression in the thymus is dependent on circulating glucocorticoids. There were significant correlations between increases in CRH, ACTH and beta-endorphin in the spleen, and between CRH and ACTH in the thymus, consistent with the suggestion that IL-1beta-induced increases in ACTH and beta-endorphin may be mediated through CRH. These results provide evidence that stressors can directly influence neuropeptide expression in immune tissues. Thus stress may influence immune functions through paracrine mechanisms involving locally synthesised neuropeptides as well as through activation of the hypothalamo-pituitary-adrenal axis.     

Confidence judgments in event recall: developmental progression in the impact of question format

Two studies were conducted to examine developmental progression in children's and adults' ability to adequately monitor their own attempts to recall event details as well as the dependence of such metamemorial competencies on question formats. Eight and 10-year-old children as well as adults (Study 1, N=116; Study 2, N=60) rated their confidence when responding to specific questions about an observed event. Confirming most recent results, children and adults gave higher confidence ratings after correct than after incorrect answers. This ability, however, was limited to an unbiased question format. When being asked misleading questions, children's ability to differentiate was undermined, as reflected in equally high confidence judgments after correct and incorrect answers, even when the interview contained a mix of misleading and unbiased questions. When the interviewer "bombarded" the children with an uninterrupted series of misleading questions, children's difficulties appeared to be even more pronounced. These findings highlight the importance of the way in which questions are asked, and point to age-related progression in the relative impact of questioning style.     

The Role of Executive Control of Attention and Selective Encoding for Preschoolers' Learning

Selectivity in encoding, aspects of attentional control and their contribution to learning performance were explored in a sample of preschoolers. While the children are performing a learning task, their encoding of relevant and attention towards irrelevant information was recorded through an eye‐tracking device. Recognition of target items was used as measure of learning outcome, and individual differences in resistance to interference and inhibition of attention to task‐irrelevant stimuli (i.e. distractibility) were used as measures of executive control of attention. Results indicated well‐developed selectivity during encoding in young children. Recognition performance was related to selective encoding and aspects of attentional control, explaining individual differences in learning. Copyright © 2011 John Wiley & Sons, Ltd.     

Age-related qualitative differences in post-error cognitive control adjustments

Detecting an error signals the need for increased cognitive control and behavioural adjustments. Considerable development in performance monitoring and cognitive control is evidenced by lower error rates and faster response times in multi-trial executive function tasks with age. Besides these quantitative changes, we were interested in whether qualitative changes in balancing accuracy and speed contribute to developmental progression during elementary school years. We conducted two studies investigating the temporal and developmental trajectories of post-error slowing in three prominent cognitive conflict tasks (Stroop, Simon, and flanker). We instructed children (8-, 10-, and 12-year-old) and adults to respond as fast and as accurately as possible and measured their response times on four trials after correct and incorrect responses to a cognitive conflict. Results revealed that all age groups had longer response times on post-error versus post-correct trials, reflecting post-error slowing. Critically, slowing on the first post-error trial declined with age, suggesting an age-related reduction in the orienting response towards errors. This age effect diminished on subsequent trials, suggesting more fine-tuned cognitive control adjustments with age. Overall, the consistent pattern across tasks suggests an age-related change from a relatively strong orienting response to more balanced cognitive control adaptations.     

"It's magic!" The effects of presentation modality on children's event memory, suggestibility, and confidence judgments

The current study investigated the influence of presentation modality (live, video, and slide show) on children's memory, suggestibility, recognition, and metamemorial monitoring processes. A total of 270 children in three age groups (5- and 6-year-olds, 7- and 8-year-olds, and 9- and 10-year-olds) watched a magic show and were questioned about it 1 week later. The live show yielded more correct answers to nonleading questions, higher resistance to misleading questions, and better recognition memory than did the video condition, which in turn resulted in better performance than did the slide show. Although presentation modality raised the general level of memory performance, the effects were equally strong in all age groups and did not affect memory phenomena such as the size of the misinformation effect and confidence judgments.     

Improving executive functions in 5‐ and 6‐year‐olds: Evaluation of a small group intervention in prekindergarten and kindergarten children

Research suggests a central role of executive functions for children's cognitive and social development during preschool years, especially in promoting school readiness. Interventions aiming to improve executive functions are therefore being called for. The present study examined the effect of a small group intervention implemented in kindergarten settings focusing on basic components of executive functions, i.e., working memory, interference control and cognitive flexibility. A total of 135 children enrolled in Swiss prekindergarten (5‐year‐olds) and kindergarten (6‐year‐olds) were involved. Results revealed that the small group intervention promoted gains in all three included components of executive functions: prekindergarten children substantially improved their working memory and cognitive flexibility processes, whereas significant training effects were found for the kindergarten children in interference control. Implications of these findings for early intervention programs and for tailoring preschool curricula are discussed, particularly with respect to children's school readiness. Copyright © 2011 John Wiley & Sons, Ltd.     

Sensory Discrimination,Working Memory and Intelligence in 9‐Year‐Old and 11‐Year‐Old Children

More than a century ago, Galton and Spearman suggested that there was a functional relationship between sensory discrimination ability and intelligence. Studies have since been able to confirm a close relationship between general discrimination ability (GDA) and IQ. The aim of the present study was to assess whether this strong relationship between GDA and IQ could be due to working memory (WM) demands of GDA tasks. A sample of 140 children (seventy 9‐year‐olds and seventy 11‐year‐olds) was studied. Results showed that there was a significant overlap between WM, GDA and fluid intelligence. Furthermore, results also revealed that WM could not explain the relationship between GDA and fluid intelligence as such, but that it acted as a bottleneck of information processing, limiting the influence of GDA on the prediction of fluid intelligence. Specifically, GDA's influence on the prediction of intelligence was only visible when WM capacity was above a certain level. Copyright © 2013 John Wiley & Sons, Ltd.     

Children's knowledge acquisition through film: influence of programme characteristics

Several characteristics of educational programmes for children are discussed to influence learning of content. In the present study, positive effects of a preview and inserted summaries in educational films for learning are examined. A total of 127 6‐and 8‐year‐old participating children watched one of the four educational film versions: The original film (without preview and summaries), a version with a preview, with inserted summaries or with a verbal ‘preview’. One week later, children's recollection of facts was tested in a memory interview. Results show that previews and summaries in educational films can enhance learning, and that visual scene repetition appears to further boost knowledge acquisition. Formal and content characteristics of educational programmes are discussed in terms of the underlying mechanisms influencing children's cognitive processing and learning. Copyright © 2008 John Wiley & Sons, Ltd.     

Motor and cognitive control in a normative sample of 7‐year‐olds

The aim of the present study was to explore the relationship between cognitive and motor control by correlating individual performance on a variety of complex tasks in a normative sample of over 100 7‐year‐olds. While there are a few studies including children with specific developmental disorders (i.e. ADHD and DCD) showing that they share similar comorbid deficits, it is still unclear whether control processes share variance in normative samples. Results presented here reveal on the one hand that some aspects of cognitive and motor control are significantly interrelated, even when controlling for age. On the other hand, individuals’ ability to efficiently respond to the speed and accuracy demands of any of the included tasks appeared to constitute an important aspect of executive functioning.     

Hypothalamo-Pituitary-Adrenocortical Regulation Following Lesions of the Central Nucleus of the Amygdala

Previous reports indicate that the central nucleus of the amygdala (CeA) stimulates adrenocorticotropin and corticosterone secretion, suggesting a role for this region in central hypothalamo-pituitary-adrenocortical (HPA) stress regulation. To evaluate this hypothesis, this study assessed the impact of CeA lesion on the response of hypophysiotrophic paraventricular nucleus (PVN) neurons to acute restraint and chronic unpredictable stress exposure. In contrast to previous reports, CeA lesions did not affect corticosterone or ACTH secretion induced by acute stress. Acute restraint increased PVN corticotropin releasing hormone (CRH) mRNA expression, increased the number of parvocellular PVN neurons expressing the co-secretagogue arginine vasopressin (AVP), and induced cFOS mRNA expression in the parvocellular PVN. However, there was no additional effect of CeA lesion on any measure of PVN activation. Chronic unpredictable stress exposure induced long-term activation of the HPA axis, noted by thymic involution, adrenal hypertrophy and increased PVN CRH mRNA expression. Stress-induced changes in thymus and adrenal weights were not affected by CeA lesion. Further, CeA lesion rats did not differ from controls in post-stress CRH mRNA expression. However, basal CRH mRNA expression was increased in the PVN of CeA rats, suggesting that the CeA plays a role in long-term inhibition of the PVN. The results of these studies are not consistent with the hypothesis that the CeA is necessary for stress-induced pituitary-adrenocortical activation. Rather, this region may play a stressor-specific modulatory role in regulation of HPA function.