创伤后应激障碍的动物模型及其神经生物学机制

创伤后应激障碍是指个体由于经历对生命具有威胁的事件或严重的创伤,导致症状长期持续的精神障碍。研究创伤后应激障碍的主要动物模型为条件性恐惧和应激敏感化模型。研究表明,创伤后应激障碍中长时程留存的恐惧性记忆、高唤醒等症状与大脑杏仁核、内侧前额叶皮层和海马三个脑区及下丘脑-垂体-肾上腺轴负反馈功能增强密切相关。其中杏仁核活动增强是条件性恐惧记忆获得、保持和表达的关键神经基础。内侧前额叶皮层对杏仁核的去抑制及海马向杏仁核传递的威胁性环境信息,促进创伤后应激障碍症状的出现。在经历创伤应激后糖皮质激素受体的上调及多巴胺活动的增强是创伤后应激障碍产生的主要神经基础。对创伤后应激障碍的药物治疗研究证明多巴胺D2受体在改善患者症状中的作用比较重要,但仍需作更深入的探索     

Choice behavior in a discrete-trial concurrent VI-VR: A test of maximizing theories of matching

Rats were trained on a discrete-trial procedure in which one alternative (VR) was correlated with a constant probability of reinforcement while the other was correlated with a VI schedule which ran during the intertrial intervals and held the scheduled reinforcer until they were obtained by the next VI response. Relative reinforcement rate was varied in series of conditions in which the VR schedule was varied and in series in which the VI was varied. Choice behavior was described well by the generalized matching law, although moderate undermatching occurred for all subjects. Contrary to the predictions of molar maximizing (optimality) theories, there was no consistent bias in favor of the ratio alternative, and the sensitivity to reinforcement allocation was not systematically affected by whether the ratio or interval schedule was varied. The results were also contrary to momentary maximizing accounts, as there was no correspondence between the probability of a changeover to the VI behavior and the time since the last response to the VI alternative. Neither variety of maximizing theory appears to provide a general explanation of matching in concurrent schedules.     

社会阶层与大学生网络利他行为:一个有调节的中介模型

采用问卷法对813名大学生进行调查,探讨社会阶层、公正世界信念、网络社会支持与大学生网络利他行为之间的关系及内在作用机制。结果发现：（1）客观社会阶层不能显著预测网络利他行为,主观社会阶层能正向预测网络利他行为;（2）公正世界信念在主观社会阶层与网络利他行为的关系中起部分中介作用;（3）网络社会支持调节了公正世界信念的中介作用。对于高网络社会支持个体,公正世界信念起部分中介作用;而对于低网络社会支持个体,公正世界信念的中介效应不显著,主观社会阶层对网络利他行为只有直接效应。     

Selecting University Lecturers: What is and Should be Done

This paper presents a survey designed to identify the procedures used by British university departments when selecting academic staff and compare them with typical practice in other UK organizations. The results indicate that, compared with other large organizations, university departments make much less use of psychometric tests or assessment centres, relying heavily on the application form, a single interview and a presentation. There were no differences between academic departments of English, Biology or Psychology and the level of academic appointment only affected the composition of the interview panel. Possible reasons for the failure to use modern objective methods of selection are considered. It is argued that universities should apply more objective selection methods based on a full analysis of the competencies required of the higher education lecturer.     

Muscle tension in human operant heart rate conditioning

The physiological mechanism involved in human operant heart rate conditioning is not known. If skeletal muscle tension is a mediator, it should be possible to generate significant heart rate increases by inconspicuous voluntary muscle tension. Eleven subjects were instructed to generate inconspicuous muscle tension for 90-second periods. No gross muscle movements were observed, but average heart rate during the trials was over 13 beats-per-minute greater than pre-trial base lines. Respiratory pattern changes and surface electromyogram changes did not reliably correlate with heart rate increases. Inconspicuous muscle tension could be a mediator in human operant heart rate conditioning, and cannot be ruled out by absence of change in respiratory pattern or electromyogram.     

Detection of increments in noise intensity by monkeys

Monkeys were trained to detect 100-msec increments in the intensity of continuous white noise. A response on one of two bars was reinforced with some probability if it conformed to the presence or absence of the increment on that trial. Stimulus parameters of background intensity, increment size, and probability of increment presentation were varied, and response probabilities and latencies were recorded. The task was analogous to the "yes-no" task used in human psychophysics. Data analysis within the context of signal-detection theory revealed response biasing toward one bar or the other to be related to the probability of increment presentation, whereas sensitivity depended on the combination of increment size and background noise intensity. Weber's law was found to hold for a large range of background intensities in that the sensitivity to relative intensity increments varied little. Performance was compared to that of an ideal observer that uses samples of the envelope of the noise waveform on which to base its responses.     

High-speed memory retrieval with auditorily presented stimuli

Two groups of 8 Ss memorized three lists of consonental phonemes. The length of the memorized lists (M) was one, two, and four phonemes. Test words were presented, and reaction time (RT) for S to say whether or not the word started with a member of the memorized list was measured. RT increased with M. In one group, the phonemes comprising the memorized sets were dissimilar. RT increased linearly with M for that group. In the other group, the phonemes comprising the sets were similar. The function relating RT to M appeared to deviate from linearity. Even after extended practice, all the evidence was consistent with a somewhat modified serial model of memory retrieval.     

Choice reactions with a null stimulus event

A procedure for producing a null stimulus (S₀) in a CRT task is described. The S₀ produced is shown to elicit reactions that have characteristics of responses given to stimuli (S₁) that appear in regular CRT tasks. It was also discovered that, in this procedure, the initiation of S₀ sampling comes earlier than that of S₁ when S₀ and S₁ appear in the same CRT task. The nature of S₀ as well as the apparent reasons for its early sampling are discussed.