Nicotinic cholinergic synaptic mechanisms in the ventral tegmental area contribute to nicotine addiction

Tobacco use is a major health problem that is estimated to cause 4 million deaths a year worldwide. Nicotine is the main addictive component of tobacco. It acts as an agonist to activate and desensitize nicotinic acetylcholine receptors (nAChRs). A component of nicotine's addictive power is attributable to actions on the mesolimbic dopaminergic system, which serves a fundamental role in the acquisition of behaviors that are inappropriately reinforced by addictive drugs. Here we show that nicotine, in the same concentration and time ranges as obtained from tobacco, has three main actions that regulate the activity of midbrain dopamine (DA) neurons. Nicotine first activates and then desensitizes nAChRs on the DA neurons. This process directly excites the DA neurons for a short period of time before the nAChRs desensitize. Nicotine also enhances glutamatergic excitation and decreases GABAergic inhibition onto DA neurons. These events increase the probability for synaptic plasticity, such as long-term potentiation. The short-lived direct excitation of the DA neurons coupled with the enhanced glutamatergic afferent activity provides the presynaptic and postsynaptic coincidence necessary to initiate synaptic potentiation. In total, these synaptic events lead to a relatively long-lasting heightened activity of midbrain DA neurons. Consistent with other summarized studies, this work indicates that the synaptic changes normally associated with learning and memory can be influenced and commandeered during the nicotine addiction process.     

汉语转折复句的命题表征项目互换效应研究

采用句子一图画验证任务(sentence-picture verification task)探讨了汉语转折复句的命题表征项目互换效应。结果表明,汉语倒装转折复句的项目表达顺序为“(但是)B→虽然A”,命题表征中项目存在着互换的倾向,所形成的命题表征为“虽然A→但是B”。本研究结果初步表明,读者理解汉语转折复句可能是一个按照“虽然A(事实让步)→但是B(转折)”固定方向进行系列认知加工的过程。     

Preserved spatial memory over brief intervals in older adults

Two studies compared young and older adults' memory for location information after brief intervals. Experiment 1 found that accuracy of intentional spatial memory for individual locations was similar in young and older participants for set sizes of 3 and 6. Both groups also encoded individual locations in relation to the larger configuration of locations. Experiment 2 showed that like young adults, older adults' latency to respond to a test probe in a letter working memory task was negatively influenced by spatial information that was irrelevant to the task. This interference effect indicated preserved incidental memory for spatial information in older adults. Together, these data suggest that initial encoding of spatial information for relatively small numbers of items is largely preserved in healthy older adults and that representations of spatial information persist over short intervals.     

外表真实区别、表征变化和错误信念的任务分析

自20世纪80年代以来,“心理理论”已成为发展心理学的研究热点和最活跃、最多产的领域。为了分析和比较“心理理论”的实验任务,该研究以济南市3所幼儿园中的233名3—6岁儿童为有效被试。进行了“意外转移。和“欺骗外表”两种心理理论实验任务。得出如下主要结论：(1)意外转移任务中内隐错误信念显著难于标准错误信念,易化错误信念与标准错误信念的难度不存在显著差异。(2)欺骗外表任务中外表真实区别难度显著低于表征变化和错误信念。(3)意外转移任务的错误信念显著难于欺骗外表任务的错误信念。     

攻击行为儿童大脑半球某些认知特点的研究

为了解攻击行为儿童大脑两半球的认知活动特点,采用侧视野速示呈现技术,对径“同伴提名量表”筛选的１７名攻南 儿童和１６名正常儿童进行了比较研究。     

整体与部分的关系对汉字的知觉分离影响的研究

采用命名技术探讨了整体与部分的关系对汉字知觉分离的影响。实验一探讨了在由相同构字部件组成的汉字整体中部件从整体中分离出来的情况。结果表明,在由相同构字部件组成的整体中,部件同整体分离的难易与部件数有关,在部件少的整体当中,部件反而更难同整体分离,部件之间结合得更紧密,当命名部件时,整体更难被忽视。实验二探讨了部件从由不同构字部件组成的汉字整体中分离出来的情况,结果表明：（１）部件同整体分离的难易取     

想象空间中物体搜索的方位效应和注意效应

该工作提出,在故事阅读产生的想象场景中,位于其中的观察者对身体四周物体的搜索应分为两个阶段：第一阶段是目标方位的判断,认知加工时间的模式是前后〈后〈左＝右;第二阶段是注意指出目标方位,从而辩别目标物体,认知加工时间的模式是注意点〈注意对面〈注意点左侧＝注意点右侧。     

微生物与人类进化

根据现代分子生物学知识和微生物知识,认为基因重组方式可能是人类进化的一种主要方式;并认为微生物能通过基因重组有效介导自身基因和各种生物基因流向人类;从原核生物到真核生物中广泛存在的转座作用可能是微生物介导的基因重组的一种重要方式;高等生物是由低等生物进化而来的,而微生物是进化上最早最低级的生命体。据此,认为微生物可能在人类进化和物种进化中起到了极其重要的作用,甚至可能是一种源泉的作用。其可能方式是     

肿瘤具有两面性吗

对于患者本身而言,肿瘤往往具有极大的危害性。但是正如砒霜,这昔日毒物品的代表,其提取物三氧化二砷已成功地用来治疗白血病,显示了大自然的一个规律－事物是具有两两性的。那私肿瘤,在其严重影响人类健康的同时,是否也具有可被加以利用的一面呢？初步探讨了这种可能性,并探讨了其应用前景、可能的一些应用领域及注意事项。     

人类会继续进化吗

从猿到人的进化经历了漫长的过程,但是今天的人类是青少年,还是已迈入老年？未来的命运将怎样？至今仍无答案。一个关于人类生命历程的假说回答了上述问题,并探讨发展进程中人类的生物学变化。结论：目前的人类正处在成熟（青少年）期,可能经较长的时间发展后进入稳定期,最终逐渐衰老