Inhibition of the LH Surge by Restraint Stress in Cyclic Rats: Studies on the Role of GABAA and GABAB Receptors

There is evidence that stress can alter the activity in the brain of gamma-aminobutyricacid (GABA), a neurotransmitter that has been implicated in the regulation of LH secretion. In the present study the role of GABA in the restraint stress-induced inhibition of the LH surge was investigated in the intact cyclic rat. Intracerebroventricular (icv) administration of the GABAA receptor agonist muscimol (0.1, 0.5 or 1 μg) 5 min before the presumed onset of the pro-oestrous LH surge (at 0900 h) caused a dose dependent suppression of the surge. A single dose of the GABAB receptor agonist baclofen (1 μg; icv) injected at 0855 h postponed the onset of the LH surge, and repeated injections at 0855 and 1130 h suppressed the surge. These data indicate that GABA-ergic activity in the brain can inhibit the LH surge in the cyclic rat via GABAA and GABAB receptors. Pro-oestrous rats were subjected to 5 hrs of restraint starting at 0855 h. Pretreatment with the GABAA receptor antagonist bicuculine (1 μg; icv) at 0840, 0940 and 1040 h or pretreatment with the GABAB receptor antagonist phaclofen (10 μg; icv) at 0840 h were ineffective in preventing the restraint-induced inhibition of the LH surge. The results suggest that GABAA and GABAB receptors are not involved in the inhibitory effect of restraint stress on the LH surge.     

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.     

Does echoic memory develop?

A series of experiments is reported on the stimulus suffix effect with the primary variables being age of the subject (7 and 11 years), rate of presentation, and list length. While the suffix effect was larger for younger subjects at a slow rate of presentation, the effect was nearly identical across age groups with a fast presentation rate. It was concluded that when the contaminating effects of more central processes are reduced, there is no developmental change in the capacity of echoic memory. An interesting effect of rate of presentation is reported with younger subjects performing better at faster rates of presentation and adults performing better at slower rates.     

Mediation analysis of the association between use of NRT for smoking reduction and attempts to stop smoking

Objectives: Use of nicotine replacement therapy (NRT) for smoking reduction (SR) is linked to higher quit attempt rates than SR without NRT. This study aimed to assess the possible mediating roles of confidence in ability to quit, enjoyment of smoking and motivation to quit in this association.

Design: Cross-sectional survey.

Main outcome measures: Smokers were asked if they were currently attempting SR, and if they were, whether they were using NRT. Motivation to stop, enjoyment of smoking, confidence in ability to stop, and previous quit attempts, were also assessed.

Results: There was no evidence that confidence in ability to quit or enjoyment of smoking mediated the association between the use of NRT for SR and attempts to quit. Only motivation to stop partially mediated between the use of NRT for SR and attempts to stop (indirect effect: odds ratio 1.08, p?<?0.001).

Conclusion: Although this study is limited by its cross-sectional design, the findings point towards the possibility that the use of NRT to aid SR may promote attempts to stop through increasing motivation to quit but not by increasing confidence or by reducing enjoyment of smoking. Longitudinal studies are required to draw firmer conclusions about the possible mediating effects of motivation to quit.     

大学二年级学生人际宽恕与报复心理及其与抑郁的关系研究

采用沉思量表、报复动机量表、宽恕倾向量表、宽恕态度量表和流调中心用抑郁量表对236名大二学生进行问卷调查,综合探讨大学生人际宽恕和报复心理及其与抑郁的关系。研究发现:(1)男大学生的报复倾向显著高于女大学生。(2)宽恕倾向与报复倾向及对侵犯的沉思程度显著负相关。沉思程度和抑郁显著正相关。(3)沉思程度和宽恕倾向对抑郁分别具有显著的正向和负向的预测作用。(4)大学生的宽恕倾向和宽恕态度的相互作用以及宽恕倾向和报复倾向之间的交互作用对抑郁均没有显著预测作用。     

Memory for frequency of hearing popular songs

In two experiments college students were asked to provide situational frequency estimates of 10-s excerpts from rock songs. In both experiments familiarity of the musical selections heard one, two, three, or four times was varied. In Experiment 2 the nature of instructions given to subjects prior to presentation of the musical excerpts was also manipulated. Across both experiments subjects' estimates were less accurate for unfamiliar than for familiar rock music. In Experiment 2 instructions to remember frequency, as well as general memory instructions, resulted in better memory for presentation frequency than did instructions to "ignore" music while working on math problems. Memory for situational frequency was also related to knowledge of rock music as defined by subjects' ability to identify the titles and artists of the presented songs. The present pattern of results with popular music is viewed as similar to that obtained in experiments investigating memory for frequency of verbal stimuli. Although providing support for an automatic processing view of frequency encoding, the results also implicate meaningful elaboration of stimuli as an important determinant of memory for frequency of events.     

Researchers misunderstand confidence intervals and standard error bars

Little is known about researchers' understanding of confidence intervals (CIs) and standard error (SE) bars. Authors of journal articles in psychology, behavioral neuroscience, and medicine were invited to visit a Web site where they adjusted a figure until they judged 2 means, with error bars, to be just statistically significantly different (p < .05). Results from 473 respondents suggest that many leading researchers have severe misconceptions about how error bars relate to statistical significance, do not adequately distinguish CIs and SE bars, and do not appreciate the importance of whether the 2 means are independent or come from a repeated measures design. Better guidelines for researchers and less ambiguous graphical conventions are needed before the advantages of CIs for research communication can be realized.     

Education and children with Down syndrome: neuroscience, development, and intervention

Of the recent advances in education-related research in Down syndrome, the characterization of the Down syndrome behavioral phenotype has become a potentially critical tool for shaping education and intervention in this population. This article briefly reviews the literature on brain-behavior connections in Down syndrome and identifies aspects of the Down syndrome behavioral phenotype that are potentially relevant to educators. Potential challenges to etiologically informed educational planning are discussed.