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.     

Establishing a Diversity Program is Not Enough: Exploring the Determinants of Diversity Climate

Purpose  

This study provides an organizational level investigation of the determinants of perceptions of diversity climate among employees.     

Multiple resources in divided attention: a cross-modal test of the independence of hemispheric resources

Dual-task methodology was used to assess a multiple-resources account of information processing in which each cerebral hemisphere is assumed to have access to its own finite amount of attentional resources. A visually presented verbal memory task was paired with an auditory tone memory task, and subjects were paid to emphasize one task more than the other. When subjects were trying to remember tones presented to the right ear, they could trade performance between tasks as a function of the emphasis condition, whereas on left-ear trials they could not. In addition, a control session indicated that stimuli presented to the unattended ear demanded processing resources, even when it was to the detriment of performance. The data support the assumption of independence between the hemispheres' resource supplies.     

Empathy, theory of mind, and individual differences in the appropriation bias among 4- and 5-year-olds

Evidence that young children often claim ownership of their partner’s contributions to an earlier collaborative activity, the appropriation bias, has been attributed to shared intentionality (Cognitive Development (1998) 13, 91–108). The current investigation explored this notion by examining individual differences in the bias among 4- and 5-year-olds as a function of empathy and theory of mind. On two occasions, children joined an adult and two dolls (with each doll being operated by one of the humans) in a picture matching board game before being asked to remember who placed each picture. Children showed a robust appropriation bias despite excellent recognition memory for the studied pictures (Study 1) and particularly in relation to the human sources (Study 2). Whereas higher levels of self-reported empathy were associated with a greater frequency of appropriation errors and fewer correct attributions for pictures placed by the adult and her doll partner, the opposite pattern emerged for theory of mind. Moreover, the positive relations between theory of mind and source monitoring accuracy remained robust after controlling for general ability and inhibitory skills. We consider the implications of these findings for understanding the processes driving the appropriation bias.     

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.     

Object-based attention and cognitive tunneling

Simulator-based research has shown that pilots cognitively tunnel their attention on head-up displays (HUDs). Cognitive tunneling has been linked to object-based visual attention on the assumption that HUD symbology is perceptually grouped into an object that is perceived and attended separately from the external scene. The present research strengthens the link between cognitive tunneling and object-based attention by showing that (a) elements of a visual display that share a common fate are grouped into a perceptual object and that this grouping is sufficient to sustain object-based attention, (b) object-based attention and thereby cognitive tunneling is affected by strategic focusing of attention, and (c) object-based attention is primarily inhibitory in nature.     

The Institute of Medicine's report on non-heart-beating organ transplantation

In December 1997, the Institute of Medicine (IOM) released a report on medical and ethical issues in the procurement of non-heart-beating organ donors. This report had been requested in May 1997 by the Department of Health and Human Services (DHHS). We will here describe the genesis of the IOM report, the medical and moral concerns that led the DHHS to sponsor it, the process of producing it, and its conclusions. The analyses, findings, and recommendations of the report are also reviewed, in particular the central issues that led to suggestions for policy changes.     

Attentional demands of visual word recognition

Becker's (1976, 1979, 1980, 1985; Becker & Killion, 1977; Eisenberg & Becker, 1982) verification model was used as a framework to investigate the attentional demands of word recognition. In two experiments, a lexical decision task and an auditory probe task were performed in single- and dual-task conditions. Responses to probes were divided into detection and movement measures that indexed the demands of recognition and response output, respectively. In Experiment 1, single- to dual-task decrements in probe detection performance were larger during low-frequency as compared with high-frequency trials. This finding indicates that the attentional demands of word recognition vary with word frequency. These findings were replicated in Experiment 2, which was designed to separate a response compatibility and a capacity interpretation of the results. The findings are interpreted within Becker's verification model.     

Gender role conflict scale: validation for a sample of gay men and lesbian women

This study tested the oblique four-factor model of the Gender Role Conflict Scale for a sample of gay men and lesbian women residing in the United States. 400 gay men and 292 lesbian women recruited from university and college gay, lesbian, bisexual, and transgender LISTSERVs participated. The internal consistency reliability of the Gender Role Conflict Scale scores was high, but low means on the expressive dimension of gender role conflict were noted. The results of two separate sets of confirmatory factor analyses indicated that the four-factor model's fit to the data could be enhanced for both groups by applying item parceling to lower the number of indicators per factor, suggesting that the actual structural validity of the Gender Role Conflict Scale may be better than suggested by the reported fit indices.