Heart rate--QT relationships during baroreceptor stimulation with diminished autonomic influence on the ventricles. Ventricular autonomic tone and QT interval.

The shortening of the QT interval of the electrocardiogram coincident with acceleration of heart rate and vice versa has been accepted for many years as evidence that the action potential duration and hence QT are necessarily dependent on heart rate. Exceptions to this rule have been attributed to the intervention of counteracting autonomic effects. In order to test this assumption, 26 conscious dogs divided into three groups were tested during baroreceptor stimulation by a bolus injection of phenylephrine. Seventeen dogs had been used in earlier studies in which they had undergone an experimental anterior myocardial infarction with apparent full recovery. A group of those dogs underwent beta-adrenergic blockade by intravenous atenolol 30 min prior to the baroreceptor activation. To test the intactness of the baroreceptor responses in the previously infarcted dogs, a third group of nine dogs that had had no prior myocardial infarction was included. All dogs were adapted to the laboratory environment and were not sedated during experiments. Simultaneous recordings of RR, QT interval, and phasic arterial pressure were made in all dogs before and during baroreceptor stimulation. In the normal group, and the previously infarcted group that received no atenolol, baroreceptor stimulation elicited a small (8/msec), but significant prolongation of the QT associated with a nearly 50% reduction in heart rate. The QT interval of the atenolol-treated dogs, although significantly more prolonged before stimulation, remained unchanged during the reflex. The data indicate that withdrawal of ventricular sympathetic tone may prolong the QT interval, thereby confirming the role of sympathetic innervation in the control of QT.(ABSTRACT TRUNCATED AT 250 WORDS)     

Resource scarcity aggravates ingroup bias: Neural mechanisms and cross-scenario validation

Previous studies examining the relationship between ingroup bias and resource scarcity have produced heterogeneous findings, possibly due to their focus on the allocation of positive resources (e.g. money). This study aims to investigate whether ingroup bias would be amplified or eliminated when perceived survival resources for counteracting negative stimuli are scarce. For this purpose, we exposed the participants and another confederate of the experimenters (ingroup/outgroup member) to a potential threat of unpleasant noise. Participants received some ‘relieving resources’ to counteract noise administration, the amount of which may or may not be enough for them and the confederate in different conditions (i.e. abundance vs. scarcity). First, a behavioural experiment demonstrated that intergroup discrimination manifested only in the scarcity condition; in contrast, the participants allocated similar amounts of resource to ingroup and outgroup members in the abundance condition, indicating a context-dependent allocation strategy. This behavioural pattern was replicated in a follow-up neuroimaging experiment, which further revealed that when contrasting scarcity with abundance, there was higher activation in the anterior cingulate cortex (ACC) as well as stronger functional connectivity of the ACC with the empathy network (including the temporoparietal junction and medial prefrontal cortex) for ingroup compared to outgroup members. We suggest that ACC activation reflects the mentalizing process toward ingroup over outgroup members in the scarcity condition. Finally, the ACC activation level significantly predicted the influence of resource scarcity on ingroup bias in hypothetical real-life situations according to a follow-up examination.     

Teacher stress and guidance work in Hong Kong secondary school teachers

Major sources of stress in Hong Kong teachers were investigated, with specific reference to guidance work as a potential source of stress. A survey of 415 secondary school teachers revealed that guidance-related aspects of work constituted a major dimension of stress, with guidance teachers, female teachers, younger teachers and junior teachers perceiving more stress than their counterparts in this dimension. Workload and time pressure were perceived as the most stressful aspects of work for all teachers. Results also showed an association between stress and job satisfaction, and biographical variables. Implications of the findings for teachers doing guidance work in Hong Kong and internationally are discussed.     

侧脑室注射东莨菪碱对条件反射及对海马神经元自发放电的影响

本工作采用食物性运动,条件反射方法和慢性微电极记录技术。条件反射实验在9只兔上进行,海马自发放电的实验在22只兔上进行。在9次实验中,30μg的东莨菪碱注入一侧脑室后,条件反射均受到抑制,而吃食则不受影响。注射剂量为45μg时,注射后3—5分,条件反射完全消失,而吃食行为在了次实验中不受影响,在2次实验中稍有减弱,注射后20分钟左右条件反射开始恢复;侧脑室注射40μg的东莨菪碱后,海马神经元的自发活动无明显改变。文中并对抗胆碱药作用于海马抑制条件反射的可能方式进行了讨论。     

Transfer of reaction inhibition

A serious challenge to Hull's (1943) theory of reminiscence and intertrial-interval effects is posed by the current contention that reactive inhibition (In) must be task-specific since it does not seem to transfer from one task to another. This notion was examined within the framework of a practice-rest paradigm in which three control groups were given 20 1-min trials on a principal task with intertrial intervals of 0, 5, and 70 sec, respectively, while two experimental groups practiced alternately on the principal task and a secondary task known to produce evidence for I(R). The two secondary tasks varied in their similarities to the principal task. Additional control groups were used to assess the magnitude of habit transfer effects. The total sample consisted of 70 males and 70 females whose modal age was 18 yr. With habit transfer effects controlled, results showed clearly that work effects transferred from the alternate tasks to the main task without regard for differences in similarity. Thus, the task-specificity hypothesis was not supported.     

从"历史先天"来看福柯的知识考古学

该文试图考察福柯的自律的话语理论并反思考古学的症结。文章从“历史先天”这一关键词出发,阐述福柯的知识考古学如何将对话语的实证描述和探索话语构成的先天规则结合起来,从而保证其在对话语的形式分析的同时,超越传统哲学深陷其中的三对矛盾：“经验-先验”、“我思-未思”、“本源的隐退-回归”。围绕着“陈述”的三个特性,我们可以看到福柯为此所做的努力,即打通共时与历时之隔,经验与先验之分,实现结构主义和实证主义的联姻。文章最后指出这种自律的话语理论的症结所在,认为福柯并没有如愿以偿地跳出“有限性解析”的窠臼。     

高级职业经理人胜任特质评定探索

为了方便企业甄选所需要的高级管理人才,本文就“高级职业经理人胜任特质评定量表”的编制过程及其量表的结构分析做一报告。该量表分为认知基质、组织协调、领导力、个性倾向和自我调节五个纬度和一个测谎的分量表。本研究立足于中国本土文化,采用小组中心访谈和多种统计分析技术对中国的高级职业经理人的胜任特质进行测评,结果显示总量表和各纬度上的项目具有较高的同质性信度和结构效度,具有较好的鉴别力。     

应当关注时间心理无意识的研究

随着心理无意识研究在记忆、学习和思维等领域的兴起,内隐时间认知也逐步成为时间心理学中的一个研究热点。本文分析了探究内隐时间认知的四种方法:分离范式、序列学习范式、表征动量范式和计时分布相关范式,指出内隐时间认知实验范式在无意识时间人格与社会心理学中的研究也是有相当前景的。     

Age-related enhancement of a protein synthesis-dependent late phase of LTP induced by low frequency paired-pulse stimulation in hippocampus

Protein synthesis-dependent late phase of LTP (L-LTP) is typically induced by repeated high-frequency stimulation (HFS). This form of L-LTP is reduced in the aged animal and is positively correlated with age-related memory loss. Here we report a novel form of protein synthesis-dependent late phase of LTP in the CA1 region of hippocampus induced by a brief 1-Hz paired-pulse stimulation (PP-1 Hz, 1 min). In contrast to L-LTP induced by HFS, the late phase of PP-1 Hz LTP does not exist in young adult animals. Rather, it emerges and becomes enhanced in an age-related way. Thus, in 1.5- to 2-mo-old mice, a brief PP-1 Hz stimulation induces only a short lasting LTP, decaying to baseline in about 90 min. By contrast, PP-1 Hz stimulation induces an enduring and protein synthesis dependent LTP in 12- to 18-mo-old mice. The PP-1 Hz-induced L-LTP is dependent on NMDA receptor activation, requires voltage-dependent calcium channels, and is modulated by dopamine D1/D5 receptors. Because memory ability declines with aging, the age-related enhancement of L-LTP induced by PP-1 Hz stimulation indicates that this form of L-LTP appears to be inversely correlated with memory ability.