Effects of semantic discrimination of Chinese words on N400 component of event-related potentials.

20 subjects' event-related brain potentials were measured during a lexical decision task in which Chinese characters were used in both conditions of related (antonym) and unrelated words. Analysis indicated that the mean reaction time for unrelated words was 130 msec. longer than that elicited by related words. The condition of unrelated words elicited a significant N450, and an obvious P500 was evoked by related words at each of the 17 recording sites. Furthermore, the amplitudes of N210 and N450 were larger in the left hemisphere than in the right hemisphere but the amplitude of P500 was larger in the right hemisphere than in the left hemisphere.     

The effect of mother-infant skin-to-skin contact on plasma cortisol and β-endorphin concentrations in preterm newborns

The aim of this study was to assess the effect of mother-infant skin-to-skin contact on plasma β- endorphin and cortisol concentrations in stable, preterm infants on a newborn intensive care unit. Blood samples were obtained before and at the end of a 20-min period of skin-to-skin contact. Similarly paired samples, obtained at the same times and after the same interval, without skin-to- skin contact, were obtained on another day and served as controls. Both cortisol and β-endorphin concentrations fell significantly after the skin-to-skin session (cortisol: geometric mean change 66%, p=0.008; β-endorphin: geometric mean change 74%, p=0.002). There was also a significant fall in cortisol levels during the control session (geometric mean change 78%, p=0.02), in contrast to β-endorphin levels, in which there was no significant change. Analysis of variance showed that the fall in β-endorphin, but not the fall in cortisol, during the skin-to-skin session was significant when compared with the control session. These results emphasize the hormonal responsiveness of the preterm newborn to relatively minor interventions. We conclude that maternal skin-to-skin contact results in a significant reduction in circulating β-endorphin in the newborn; there was no evidence of any adverse effect.     

Self-focused attention and the placebo effect: Fooling some of the people some of the time

An experiment tested the hypothesis that mirror-induced self-awareness would minimize a “placebo” effect. Some subjects were led to believe that a drug that they were about to ingest would produce arousal symptoms as a side effect. Self-aware subjects in this condition subsequently reported experiencing less arousal from the placebo, and fewer of the side effects ascribed to it, than did less self-aware subjects. Discussion centered on the implications of these findings for placebo research and implications for two common alternative interpretations of self-awareness effects.     

Barriers between mental health services and Mexican Americans: An examination of a paradox

The paradox of underutilization of mental health services by Mexican Americans is critically examined. It is argued that Mexican Americans live under high levels of psychological and environmental stress that would ordinarily lead to mental health problems and an increased utilization of mental health services. A number of barriers to the use of mental health services by Mexican Americans are examined. Included among these barriers are such factors as the relationship between social class and treatment offered, stereotypes concerning Mexican American folk psychiatry, limitations imposed by language differences, and the effects of stereotypes between Anglo Americans and Mexican Americans. Paradoxical findings in some studies which show a positive perception of mental health services by Mexican Americans are seen to further underscore the need for more research on the Mexican American's position. Stereotypes and generalizations about Spanish-speaking and bilingual Mexican American's approaches to psychotherapy are challenged in the light of recent empirical findings. Recommendations for future research directions and for improving the delivery of mental health services are presented.     

负性生活事件、社会支持和创伤后应激障碍症状：对汶川地震后青少年的追踪研究

创伤后应激障碍是灾难后常见的心理病理问题, 灾后继发负性生活事件和社会支持是影响创伤后应激障碍症状的重要因素。该研究采用追踪设计, 历时2年对汶川地震后都江堰地区1573名青少年进行3次测查, 考察震后继发负性生活事件、不同类型社会支持与创伤后应激障碍症状之间的相互作用关系。研究发现：不同类型的社会支持与震后继发负性生活事件、创伤后应激障碍症状存在不同的作用关系; 震后继发负性生活事件不仅直接影响个体的心理健康还对个体的社会支持系统有损害; 震后负性生活事件、主观支持与创伤后应激障碍症状存在联动效应, 即三者中任一方面的变化都可能引起其他方面的变化。     

Working memory selection and competition between target and distractor representations

A working memory selection task combining directed-forgetting and memory-scanning paradigms was used to test the hypothesis that difficulty in selecting target from distractor items in working memory depends on the competition between target and distractor representations, as is commonly assumed in perceptual selection research. Participants memorized two trigrams and were then cued to select one as the new memory set and forget the other. They later saw a test letter and made judgment as to whether the letter was in the selected trigram, i.e., the new memory set. Selection difficulty was examined by manipulating the type of selection cues and the time the cue could be utilized. While re-presenting the targets in the cue display facilitated selection, re-presenting distractors did not impede selection. The results suggest that working memory selection may depend more on the activation from representations of the target than of the distractor.     

患者的自主权及困境

在生命伦理学中,尊重自主性原则是指尊重病人或受试者的自主性,可理解为病人自主原则。自主性的实现涉及到自主性的人与自主性的选择,面对复杂的医疗情境,患者自主权的实施面临着重重困境。从自主、病人自主原则、病人自主的实践三个层面讨论了该原则,并尝试用境遇伦理学原理来解决病人自主原则的实践困境。