Undergraduate and postgraduate dental students''reflection on learning'': a qualitative study

The aim of this study was to explore undergraduate and postgraduate dental students' understanding of a good learning experience by using 'reflection on learning' as described by Schon. Four groups of Year 4 BDS students and one group of postgraduate students in dental public health took part in a series of focus group discussions. The responses were grouped into four broad themes (a) active, practical and positive learning; (b) interactive/together learning; (c) personal learning; (d) theory into practice. Six educational models of good learning proposed by the students are described.     

Orthodontic undergraduate education: developments in a modern curriculum.

This paper explores some modern concepts of teaching and learning, including cognitive theory, the zone of proximal development, constructivism, andragogy and learning styles and describes how they have informed the development of an undergraduate orthodontic curriculum. The changes described include student-centred learning, guided self-learning, and the incorporation of problem-based learning concepts. The details of the problem-based learning programme are described together with results of student feedback on the change in teaching and learning style.     

Effects of exercise on neurogenesis in the dentate gyrus and ability of learning and memory after hippocampus lesion in adult rats

Objective To explore the effects of exercise on dentate gyrus (DG) neurogenesis and the ability of learning and memory in hippocampus-lesioned adult rats. Methods Hippocampus lesion was produced by intrahippocampal microinjection of kainic acid (KA). Bromodeoxyuridine (BrdU) was used to label dividing cells. Y maze test was used to evaluate the ability of learning and memory. Exercise was conducted in the form of forced running in a motor-driven running wheel. The speed of wheel revolution was regulated at 3 kinds of intensity: lightly running, moderately running, or heavily running. Results Hippocampus lesion could increase the number of BrdU-labeled DG cells, moderately running after lesion could further enhance the number of BrdU-labeled cells and decrease the error number (EN) in Y maze test, while neither lightly running, nor heavily running had such effects. There was a negative correlation between the number of DG BrdU-labeled cells and the EN in the Y maze test after running. Conclusion Moderate exercise could enhance the DG neurogenesis and ameliorate the ability of learning and memory in hippocampus-lesioned rats.     

Evidence for NMDA receptor involvement in environmentally induced dentate gyrus plasticity.

Research has demonstrated environmentally induced plasticity of hippocampal dentate gyrus-evoked potentials. Other research has shown a role of the NMDA receptor in dentate gyrus long-term potentiation (LTP). The authors tested the role of the NMDA receptor in one form of environmentally induced plasticity, in which transferring animals from their home cages to another environment results in significant excitatory postsynaptic potential (EPSP) enhancement and concomitant depression of the population spike. Rats were chronically implanted with stimulating electrodes in the perforant path and recording electrodes in the dentate gyrus bilaterally. Evoked potentials were recorded from freely behaving rats for four 20-minute sessions (1/wk), which took place immediately following an environmental transfer. Rats received 0.00, 0.05, 0.08, or 0.10 mg/kg MK-801 s.c. 30 minutes prior to recording sessions in either an ascending- or descending-dose series. Results showed that MK-801 produced a reduction of the EPSP enhancement, which takes place over the 20-minute session. The effects of MK-801 on spike depression varied as a function of dose series and time within a session, suggesting a long-term effect of MK-801 on spike depression. There was no detected effect of MK-801 on behavior. Results suggest a role of the NMDA receptor in this form of environmentally induced plasticity with different effects of NMDA receptor antagonism on EPSP enhancement and spike depression.     

Electrophysiological Signs of Neurocognitive Deficits in Long-Term Leukemia Survivors

The long-term effects of disease and treatment on electrophysiologicalmeasures of neurocognitive function were studied in childrenwho had survived acute lymphoblastic leukemia (ALL) for at least4 years and were currently in remission. We report here changesin cognitive processing time as shown by the latency of theP3 wave of the auditory event-related EEG potential (ERP). P3latency was significantly prolonged in long-term ALL surivors,as well as in patients successfully trreated for solid tumors(ST)outside the CNS who received similar chemotherapy but did notreceive prophylactic treatment to the CNS. P3 latencies werestrongly correlated with measures of school performance andIQ in these individuals. The similarity in P3 latency betweenthe ALL and ST groups suggests that the treatments used on thesepateints produce changes in electrophysiological responses thatare associated with mild, but significant, cognitive deficits.     

The locus coeruleus, norepinephrine, and memory in newborns

Use of learned odor cues by newborn rats is critical for pup survival. Rat pups acquire approach responses to maternal odors through an associative conditioning mechanism. This learned behavioral response is accompanied by a modification of olfactory bulb neural response patterns to the learned odor. Both the behavioral and neural reponse changes involved and require norepinephrine release in the olfactory bulb. The source of this norepinephrine is the locus coeruleus. It is proposed that the unique response properties of the locus coeruleus during the early postnatal period in the rat may facilitate acquisition of these critical early memories.     

欧美达系列麻醉机应用中的常见故障及原因分析

目的探讨欧美达(OHMEDA)系列麻醉机临床应用中常见故障发生的原因及预防措施。方法对我院近年来OHMEDA系列麻醉机应用过程中发生的一些故障进行分析。结果常见故障主要有:屏幕显示呼出气体反流;误将螺纹管接于氧气转换阀处接口;呼吸环路内压力异常升高等。结论其发生原因有的与麻醉机部件损坏有关,有的则与使用不当有关。     

非特异性言语学习障碍的遗传学研究进展

非特异性言语学习障碍是具有明显的遗传倾向和遗传异质性的一类神经心理疾病,患者通常仅具有言语发育障碍这一认知缺陷.研究非特异性言语学习障碍的遗传易感位点和候选基因功能不仅可以从分子角度去认识和理解非特异性言语学习障碍的遗传和病理生理机制,同时也推动了神经心理学和认知遗传学等相关学科的发展.本文就目前常见非特异性言语学习障碍遗传易感位点和候选基因的研究现状及该研究领域所存在和面临的问题,以及发展前景作一综述.     

图片学习测验在识别老年人轻微认知功能损害中的作用

目的　分析图片学习测验在识别老年人轻微认知功能损害 (MCI)中的作用。方法　选择符合MCI诊断标准的老年人 4 8例与正常对照组 5 6名完成图片学习测验、简易智能状态检查、听觉词语学习测验及多种非记忆测验。结果　图片学习测验的 3个记忆指标 (图片短时记忆、延迟记忆和学习记忆 )在MCI与正常对照组之间有非常显著的差异。已经给出这三个图片记忆指标区分MCI与正常老年人的划界分、敏感性和特异性。结论　图片记忆操作简便、信度和效度好 ,可以作为临床医师筛选MCI的有效工具     

Transmitter Release Associated with Long-term Synaptic Depression in Rat Corticostriatal Slices

Using a corticostriatal slice preparation, we have recently shown that tetanic stimulation of the corticostriatal pathway produces long-term depression (LTD) of striatal excitatory synaptic transmission. In the present study we have analysed the relationship between LTD and the striatal release of different endogenous transmitters. Samples of perfusate were collected via a small cannula placed just above the surface of the striatal slice close to the recording electrode, and were analysed by HPLC. The high-frequency stimulation (100 Hz, three trains, 3 s duration, 20 s intervals) used to induce LTD caused a significant but transient increase in the release of both excitatory (aspartate and glutamate) and inhibitory (glycine and GABA) amino acid transmitters. Tetanic stimulation also produced a significant, but transient increase in the release of endogenous dopamine. We conclude that the tetanic stimulation of the corticostriatal pathway is able to induce a large but transient release of excitatory amino acids and of dopamine, whose participation in the induction of striatal LTD has been demonstrated previously. Moreover, the maintenance of this form of synaptic plasticity does not seem to require a sustained change in transmitter release.