Sleep EEG changes during adolescence: An index of a fundamental brain reorganization

Delta (1–4 Hz) EEG power in non-rapid eye movement (NREM) sleep declines massively during adolescence. This observation stimulated the hypothesis that during adolescence the human brain undergoes an extensive reorganization driven by synaptic elimination. The parallel declines in synaptic density, delta wave amplitude and cortical metabolic rate during adolescence further support this model. These late brain changes probably represent the final ontogenetic manifestation of nature’s strategy for constructing nervous systems: an initial overproduction of neural elements followed by elimination. Errors in adolescent brain reorganization may cause mental illness; this could explain the typical age of onset of schizophrenia. Longitudinal studies of sleep EEG are enhancing our knowledge of adolescent brain maturation. Our longitudinal study of sleep EEG changes in adolescence showed that delta power, which may reflect frontal cortex maturation, begins its decline between ages 11 and 12 years and falls by 65% by age 17 years. In contrast, NREM theta power begins its decline much earlier. Delta and theta EEG frequencies are important to sleep theory because they behave homeostatically. Surprisingly, these brain changes are unrelated to pubertal maturation but are strongly linked to age. In addition to these (and other) maturational EEG changes, sleep schedules in adolescence change in response to a complex interaction of circadian, social and other influences. Our data demonstrate that the daytime sleepiness that emerges in adolescence is related to the decline in NREM delta as well as to altered sleep schedules. These longitudinal sleep data provide guideposts for studying cognitive and behavioral correlates of adolescent brain reorganization.     

压力反应、压力应对与睡眠质量关系述评

压力反应是个体应对应激源作用时所产生的非特异性表现, 而压力应对是个体社会生活中一种综合的压力适应过程。压力反应及其应对是压力与睡眠质量之间的重要变量。生理、认知、情绪和行为等方面的压力反应与睡眠质量有直接的交互作用, 而认知调节、情绪调节、应对方式、社会支持和人格倾向等压力应对因素则能够改变压力与睡眠之间相互作用的强度、持续时间以及最终结果。     

判断框架对时序知觉位置启动效应的影响

研究采用包含两种判断框架（判断刺激出现的先后次序）的时序判断任务探讨了决策偏向对时序知觉位置启动效应的影响。实验结果表明,时序知觉中存在着位置启动效应,而且在两个靶刺激出现时间间隔不同时,被试在“哪个靶刺激先出现”和“哪个靶刺激后出现”两种判断框架下的正确率存在显著差异,但在两个靶刺激同时出现时并没有出现显著的判断框架效应。因此,本研究推测时序知觉位置启动效应的作用机制不仅包括知觉增强加工过程,而且也与认知决策有关,这为反应偏向理论提供了新的支持证据。     

4-6岁儿童在小模型旋转任务中的线索学习与位置学习*

以90名4-6岁儿童为被试,探讨了儿童在小模型旋转任务中利用线索学习和位置学习表征空间位置的年龄特点。研究结果表明:(1)儿童对线索学习的利用要优于对位置学习的利用;(2)4岁儿童已经可以使用线索学习的方式表征空间位置,但到6岁左右才开始能够使用基于方向的位置学习;(3)线索特征对于儿童的线索学习有显著影响,明显、突出的线索有利于儿童的线索学习。     

改革公立医院的一点思考

当前的看病难、看病贵不仅与政府的医疗投入不足有关,更与公立医院之间、公立医院与民营医院之间的无序竞争有关,导致了患者的过度医疗和超前医疗的畸形消费。重新界定一批公立医院,政府的全额资金投入和政策的约束与支持,才能从根本上解决看病难与看病贵的问题。     

旋转任务中3～5岁儿童空间物体位置编码的研究

本实验探讨3~5岁儿童在对空间物体位置进行编码时,能否有效采用心理旋转策略或根据物体"位置关系"来判断物体方位。实验采用3×4混合设计,在旋转条件下研究上述问题。结果表明:(1)在策略方面,儿童对心理旋转的使用要显著优于利用位置关系进行判断;(2)随着年龄增长,心理旋转的能力不断提高,5岁时进步尤其明显;(3)3~5岁儿童均不能自动利用位置关系对物体位置进行编码,但5岁儿童经提示后可采用此策略。     

A multiple-criteria decision-making approach for the evaluation of retail location

This study proposes an ANP-based evaluation of retail locations. Authors acted as decision analysts and interacted with professionals in Turkish apparel retailing sector for acquiring their knowledge and expertise. As a result, evaluation criteria of the study were identified. These criteria are clustered into five groups: store, other retailers, shopping centre/business district, accessibility, and environmental. The relationship among criteria were assessed and a network was formed. ANP approach was then utilized in order to evaluate possible retail locations for the apparel stores. Besides global preferences of these alternatives, relative importance of the criteria was also revealed. Copyright © 2007 John Wiley & Sons, Ltd.     

位置提示下视觉注意范围的调控机制

研究视觉空间注意中不同注意范围引起脑内加工时程的动态变化。使用固定位置的、三种不同直径的线圈作为注意范围的位置性提示,祛除空间定位因素的影响,记录反应时和事件相关电位（ERP）数据。结果显示：在同等注意范围时,随着刺激位置远离视野中心,反应时延长,靶刺激诱发的P1、N1不受刺激位置的影响,而其前部N2的波幅明显受到刺激位置的影响;在靶刺激位置相同时,随着注意范围的扩大,反应时缩短,靶刺激诱发的P1、N1不受提示范围大小的影响,而其前部P2的波幅明显受到注意范围的影响。结果说明：①视觉注意范围信息加工与靶刺激诱发的P2成分相关;②视觉注意诱发的P1、N1成分,主要与注意方位相关,而与注意范围大小无关;③注意范围变化引起注意集中度的调节是在一定范围内进行的。