Local sleep and learning

Human sleep is a global state whose functions remain unclear. During much of sleep, cortical neurons undergo slow oscillations in membrane potential, which appear in electroencephalograms as slow wave activity (SWA) of <4 Hz. The amount of SWA is homeostatically regulated, increasing after wakefulness and returning to baseline during sleep. It has been suggested that SWA homeostasis may reflect synaptic changes underlying a cellular need for sleep. If this were so, inducing local synaptic changes should induce local SWA changes, and these should benefit neural function. Here we show that sleep homeostasis indeed has a local component, which can be triggered by a learning task involving specific brain regions. Furthermore, we show that the local increase in SWA after learning correlates with improved performance of the task after sleep. Thus, sleep homeostasis can be induced on a local level and can benefit performance.     

深度学习的睡眠脑电特征波检测

回顾了深度学习（deep learning,DL）技术在睡眠脑电检测上的应用．以睡眠脑电过程中的纺锤波检测问题为例,探讨了睡眠脑电检测的各类方法,以及相较于传统信号处理算法,DL算法在睡眠脑电纺锤波检测问题上具有精度较高、对数据适应性更强的特点．针对进一步提高网络检测性能与硬件适用性需求,提出特征融合与脉冲神经2种改进型网络,并获得较高的检测性能,进一步阐释了DL技术在睡眠脑电特征波检测方面的应用潜力．      

不同足地界面对人体三维步态的影响

为了解足地界面对人体下肢运动学、动力学的影响,从实验的角度对受试者在光足、穿球鞋和穿7 cm高跟鞋时的三维步态进行了测试。结果表明在运动学方面:足地界面对踝、膝和髋关节运动均有影响,而且在冠状面内的影响程度远大于矢状面。在动力学方面:穿高跟鞋后,膝关节和踝关节内收力矩峰值增大,踝关节和髋关节弯曲伸展力矩均有变化;沿股骨和胫骨轴向,分别作用于膝关节和踝关节的力增加,沿步行前后方向膝关节和髋关节的力增加。这些变化加剧了关节的磨损,长期积累会造成关节损伤和病变。     

如何降低雷害对铁路信号设备影响的探讨

根据雷害对铁路信号设备的影响,对产生雷害的原因进行了具体分析,针对雷害的特点提出了具体的解决方案,并对在实施过程中应注意的问题进行了探讨.     

Consolidation during sleep of perceptual learning of spoken language

Memory consolidation resulting from sleep has been seen broadly: in verbal list learning, spatial learning, and skill acquisition in visual and motor tasks. These tasks do not generalize across spatial locations or motor sequences, or to different stimuli in the same location. Although episodic rote learning constitutes a large part of any organism's learning, generalization is a hallmark of adaptive behaviour. In speech, the same phoneme often has different acoustic patterns depending on context. Training on a small set of words improves performance on novel words using the same phonemes but with different acoustic patterns, demonstrating perceptual generalization. Here we show a role of sleep in the consolidation of a naturalistic spoken-language learning task that produces generalization of phonological categories across different acoustic patterns. Recognition performance immediately after training showed a significant improvement that subsequently degraded over the span of a day's retention interval, but completely recovered following sleep. Thus, sleep facilitates the recovery and subsequent retention of material learned opportunistically at any time throughout the day. Performance recovery indicates that representations and mappings associated with generalization are refined and stabilized during sleep.     

Altered brain response to verbal learning following sleep deprivation

The effects of sleep deprivation on the neural substrates of cognition are poorly understood. Here we used functional magnetic resonance imaging to measure the effects of 35 hours of sleep deprivation on cerebral activation during verbal learning in normal young volunteers. On the basis of a previous hypothesis, we predicted that the prefrontal cortex (PFC) would be less responsive to cognitive demands following sleep deprivation. Contrary to our expectations, however, the PFC was more responsive after one night of sleep deprivation than after normal sleep. Increased subjective sleepiness in sleep-deprived subjects correlated significantly with activation of the PFC. The temporal lobe was activated after normal sleep but not after sleep deprivation; in contrast, the parietal lobes were not activated after normal sleep but were activated after sleep deprivation. Although sleep deprivation significantly impaired free recall compared with the rested state, better free recall in sleep-deprived subjects was associated with greater parietal lobe activation. These findings show that there are dynamic, compensatory changes in cerebral activation during verbal learning after sleep deprivation and implicate the PFC and parietal lobes in this compensation.     

Projection neurons within a vocal motor pathway are born during song learning in zebra finches

Many birds learn song during a restricted 'sensitive' period. Juveniles memorize a song model, and then learn the pattern of muscle contractions necessary to reproduce the song. Of the neural changes accompanying avian song learning, perhaps the most remarkable is the production of new neurons which are inserted into the hyperstriatum ventralis pars caudalis (HVc), a region critical for song production. We report here that in young male zebra finches many of the new neurons incorporated into the HVc innervate the robust nucleus of the archistriatum (RA) which projects to motor neurons controlling the vocal musculature. Furthermore, far fewer of these new neurons are incorporated into the HVc of either adult males that are beyond the sensitive learning period, or young females (who do not develop song). Thus, a major portion of the vocal motor pathway is actually created during song learning. This may enable early sensory experience and vocal practice to not only modify existing neuronal circuits, but also shape the insertion and initial synaptic contacts of neurons controlling adult song.     

如何使电路原理学习更加生动

《电路原理》是一门重要的技术基础课，具有理论严密、逻辑性强的特点，很多学生学习起来感到枯燥乏味。结合多年的教学实践就如何活跃课堂气氛、提高学生学习的兴趣提出了一些看法。     

听,荆棘鸟在歌唱——论《荆棘鸟》的爱情悲剧

考琳·麦卡洛的家世小说《荆棘鸟》畅销多年,是中国读者最为熟知的澳大利亚小说之一。它展现了宗教、权力、金钱、野心、自然等各种主题,但其中拉尔夫和麦琪痛苦而绝望的爱情故事同样深深吸引着读者。本文试图梳理麦琪和拉尔夫的情感故事以及背后隐藏的寓意。     

三十年代歌词的历史反思

在 2 0世纪三十年代的烽火中诞生的歌词是用血泪凝聚而成的战时文艺 ,无论其激昂、悲壮 ,还是凝重、舒婉 ,都能激起人们普遍而久远的心灵回声 ,然而那些以宣传代替艺术 ,口号式的振喊、公式化的演绎、概念化的图解 ,时间很快证明了它们艺术魅力与审美效应的短暂与苍白。历史使命意识与历史局限性 ,共同构成了三十年代歌词的历史具体性     

谈民歌《茉莉花》的流变

《茉莉花》是我国民歌的经典之作,是中国文化的一个标志性符号。它从起源到现在,有着各种各样的变体和版本,经过各地人民的改编创作,加之当地的方言、曲调、演唱风格,展现了中国音乐文化的博大精深,洋溢着独特的东方神韵,在受到国人喜欢的同时,也深受世界人民的喜爱。     

歌曲创作的高潮布局和处理

歌曲创作中的高潮布局和处理,既是千变万化的,又是循规蹈矩的,可以通过旋律、节奏、转调、和声等手段加以处理。     

聋鸟模型的制作

鸟是自然界除人类之外最具复杂发声行为的动物，鸟类语言与人类语言在很多方面都有相似之处，尤其是发声学习的听觉反馈，聋鸟模型的制作可以为其研究鸟类的发声与听觉反馈的关系提供理想的动物模型，本文采用链霉素肌肉注射的方法对鸟进行了致聋试验，结果发现肌肉注射链霉素每日60mg／kg以下为鸟的安全剂量，每日90mg／kg-210mg／kg为鸟的有毒剂量，每日240mg／kg以上为鸟的致死剂量，为聋鸟模型的制作摸索出了一套有效的方法。     

外语教学中如何激发学生的学习动机

描述了学习动机的几种分类,论述了外语教学中动机对教学双方的影响,指出激发学生的学习动机特别是内在动机和融合型动机是非常重要的,因为它可以激发教师的教学热情及责任心,加强学生的学习自主性,从而更好地搞好教学.同时还提出了激发学生学习动机的几条建议.     

鸣禽脑的性别分化与鸣叫行为

鸣禽的鸣叫行为具有明显雄雌差异,一些鸣禽只有雄性可以鸣叫,而雌性却不能,这种行为上的差异是由中枢神经系统的双态性所决定的,鸣禽鸣转系统性别分化的方式与经典的性别分化方式不同,雌激素起重要作用,结合近年来国内外的研究进展,介绍了脑性别分化与鸣叫行为的若干控制因素。     

宋代田制思想

土地关系问题是封建经济研究中的核心之一，宋代实施“不立田制”的土地政策，引发了一系列的社会问题，促进了立田制思想的兴起。