Ablation of cerebellar nuclei prevents H-reflex down-conditioning in rats

While studies of cerebellar involvement in learning and memory have described plasticity within the cerebellum, its role in acquisition of plasticity elsewhere in the CNS is largely unexplored. This study set out to determine whether the cerebellum is needed for acquisition of the spinal cord plasticity that underlies operantly conditioned decrease in the H-reflex, the electrical analog of the spinal stretch reflex. Rats in which the cerebellar output nuclei dentate and interpositus (DIN) had been ablated were exposed for 50 d to the H-reflex down-conditioning protocol. DIN ablation, which in itself had no significant long-term effect on H-reflex size, entirely prevented acquisition of a smaller H-reflex. Since previous studies show that corticospinal tract (CST) transection also prevents down-conditioning while transection of the rubrospinal tract and other major descending tracts does not, this result implies that DIN output that affects cortex is essential for generation of the CST activity that induces the spinal cord plasticity, which is, in turn, directly responsible for the smaller H-reflex. The result extends the role of the cerebellum in learning and memory to include participation in induction of plasticity elsewhere in the CNS, specifically in the spinal cord. The cerebellum might simply support processes in sensorimotor cortex or elsewhere that change the spinal cord, or the cerebellum itself might undergo plasticity similar to that occurring with vestibulo-ocular reflex (VOR) or eyeblink conditioning.     

Medical students' involvement in patient care

In a recent issue of The Journal of Clinical Ethics, Peter A. Ubel and Ari Silver-Isenstadt reported on patients' willingness to participate in medical education. Their findings and other data they refer to suggest that patients are generally willing to interact with medical students, but that this willingness may vary depending upon the clinical setting. The authors concluded that patients hold a right to information regarding students' participation in their care and that openness in this regard is valuable. The Council on Ethical and Judicial Affairs (CEJA) of the American Medical Association (AMA) recently developed a policy that addresses the issues that were investigated by Ubel and Silver-Isenstadt.     

6～14岁儿童对想象物的文字与图画描述

本研究采用开放式问卷法,通过调查810名6-14岁儿童头脑中想象物的文字与图画描述,考察了儿童想象发展的特点。结果发现：(1)儿童对想象物的文字与图画描述可以分划分为3种水平：表象的记忆水平、表象的再造水平和表象创造水平。其中,对想象物的文字描述水平,年龄发展趋势明显,从小学一至二年级之间和四到五年级之间的发展变化最大;而对想象物的图画描述水平,年龄发展趋势不明显。(2)根据儿童对想象物的文字描述和图画描述的发展的匹配程度,可以把儿童的想象发展分为3种类型：文字与图形符号均衡发展型、文字符号型和图形符号型。     

从面孔模块到马赛克──视觉特异性加工的脑机制

“脑功能的模块性”是视觉乃至整个认知神经科学的研究热点。特异性的面孔加工模块被当作是认知模块假说的最好证据。但综述跨学科的正反两方面实验证据表明,视觉加工存在特异性,并没有普遍的模块式的亚单元,而是“马赛克”镶嵌式的组构。     

对学生学习成绩与社会行为的交叉滞后分析

采用二元交叉滞后回归分析法考察小学四、五年级学生和初中一、二年级学生在21个月中的学校适应与学习成绩之间的关系。结果发现,在同时性测量中,由教师评价获得的中小学生的社交领导能力、定向耐挫能力、果敢性社交技能得分和同伴积极提名分数与他们的学习成绩之间均存在正相关关系,而他们的攻击破坏得分、学习适应不良得分以及小学生的同伴消极提名分均与他们的学习成绩有显著的负相关关系。二元交叉滞后回归分析结果表明,小学生在前测中的社交领导能力得分、攻击破坏得分、定向耐挫得分、学习适应不良得分、果敢性社交技能得分同伴积极和消极提名得分均可以预测21个月后的学习成绩。对中学生来说,这种预测关系只在攻击破坏行为、定向耐挫行为中存在。中小学生的害羞抑制得分和焦虑抑郁得分与他们的学习成绩之间既没有同时性的相关关系,也没有滞后性的预测关系。     

言语表情标记在儿童寓言故事理解中的作用

运用听读理解测验的方法探讨言语表情标记对6～8岁儿童寓言故事理解的影响。结果表明。言语表情标记能促进各年龄组儿童对故事的理解,这种促进作用在6、7岁儿童身上表现得非常显著。男、女儿童对有、无言语表情标记的故事的理解不存在显著差异。     

家庭居住与机构居住老年人社会支持的比较研究

以65位家庭居住和92位机构居住的老年人为样本,采用Sherbourne和Stewart的MOS社会支持问卷和自编社会支持问卷调查了老年人的社会支持现状,比较了家庭居住与机构居住老年人社会支持的不同特点。结果发现：（1）家庭居住和机构居住老年人在社会支持维度上存在显著差异：在心理支持、行为支持、活动支持等维度上,机构居住的老年人显著高于家庭居住的老年人;而在感情支持维度上家庭居住的老年人显著高于机构居住的老年人。（2）社会支持对老年人的身心健康具有显著影响。（3）性别,年龄,教育水平,职业状况,婚姻状况,子女数量,健在兄弟姐妹数量等人口统计变量对不同居住背景老年人的社会支持有显著影响。