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.     

Comprehension of the Referential Intent of Looking and Pointing Between 12 and 15 Months

Butler, Caron, & Brooks (2000) tested the gaze following of 14-and 18-month-olds under 3 conditions: (1) when the adult's view of the targets was blocked by barriers, (2) when the barriers contained open windows, and (3) no barriers. Contrary to a nonmentalist "ecological" model (adult turns serve as cues to the location of interesting events), frequency of gaze following by 14-month-olds was not equivalent across the 3 conditions. Contrary to a mentalist model (infant wants to see what the adult is seeing), gaze following was not substantially less in the barrier than in the window and no-barrier conditions (as was the case for 18-month-olds). To examine whether the barriers posed vector projection problems for essentially nonmentalist, or line-of-sight problems for essentially mentalist younger infants, 3 experiments were conducted. In Experiment 1, a 12-month group was tested in the same 3 conditions to determine if, being younger, they might yield a more clearcut nonmentalist pattern. Contrarily, they behaved like Butler et al.'s 14-month-olds. In Experiment 2, a 14-month group was tested in the barrier and window conditions, but now combining pointing with turning. Infants behaved as predicted by the mentalist model: strong responding in the window condition and minimal in the barrier (where many strained to look inside the partitions). In Experiment 3, an attempt was made to differentiate between mentalist and "geometric" (vector projection) interpretations of the results of Experiment 2 by testing another 14-month group with the adult's eyes closed while pointing. Gaze following now dropped precipitously in the window condition as did looking inside the solid barriers, indicating (1) that infants in Experiment 2 had not simply been guided to target by an extended arm, but construed it as part of a referential act that was as much visual as gestural, and (2) that by 14 months, infants may have acquired a mentalistic concept of seeing.     

Further evaluation of latency measures in the assessment and treatment of severe self‐injurious behavior

Recent research has demonstrated the utility of latency measures during the functional analysis of problem behavior; however, few studies have evaluated the utility of latency measures during subsequent treatment analyses. The current study seeks to extend the literature on the use of latency measures during the treatment of severe self‐injurious behavior (SIB). Following a latency‐based functional analysis, a treatment analysis was conducted using a hybrid procedure in which baseline sessions were terminated following the first instance of SIB, and test sessions ended after a fixed length of time. Latency to SIB was compared across conditions, whereas latency and rate measures for both SIB and functional communication responses were compared for the functional communication training condition. Results suggest that latency measures may be too sensitive during treatment analyses and that it is beneficial to use a hybrid procedure that allows for both latency and rate comparisons.     

Discovery algorithms for hierarchical relations

Two algorithms based on a latent class model are presented for discovering hierarchical relations that exist among a set ofK dichotomous items. The two algorithms, stepwise forward selection and backward elimination, incorporate statistical criteria for selecting (or deleting) 0–1 response pattern vectors to form the subset of the total possible 2 ^k vectors that uniquely describe the hierarchy. The performances of the algorithms are compared, using computer-constructed data, with those of three competing deterministic approaches based on ordering theory and the calculation of Phi/Phi-max coefficients. The discovery algorithms are also demonstrated on real data sets investigated in the literature.     

Preliminary investigation of a video-based stimulus preference assessment

Video clips may be an effective format for presenting complex stimuli in preference assessments. In this preliminary study, we evaluated the correspondence between preference hierarchies generated from preference assessments that included either toys or videos of the toys. The top-ranked item corresponded in both assessments for 5 of the 6 participants, and the top- and bottom-ranked items corresponded for 4 participants. The implications of these results for future research on video preference assessments are discussed.     

GRAPH-THEORETIC CONFIRMATION OF RESTRUCTURING DURING INSIGHT

Abstract— The "flash of insight" sometimes observed m problem solving and in scientific discovery has been thought to be due to a sudden cognitive restructuring of the problem situation Direct confirmation of restructuring has been difficult without an independent procedure Graph structures were derived from judgments of concept relatedness made by subjects who had an insight and by several groups who either did not or could not have the insight The graphs of the solvers differed from the graphs of subjects who tried and failed, those who listened to the solvers, and those who were given the solution When other subjects in a subsequent experiment repeatedly judged similarity of pairs of Concepts, there was evidence that those lections critical to the new cognitive order were targeted long before there was the breathtaking cognitive reorganization     

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.