Introdução: A perda auditiva na infância, mesmo perdas auditivas mínimas, pode dificultar ou atrasar a aquisição de linguagem da criança. Quanto mais tardio for o diagnóstico e o início da intervenção, maiores serão os efeitos da privação sensorial na via auditiva. Em crianças usuárias de aparelho de amplificação sonora individual (AASI), a utilização dos Potenciais Evocados Auditivos de Longa Latência (PEALL) torna-se uma ferramenta de verificação capaz de mensurar a maturação do sistema nervoso auditivo central (SNAC) ao longo do tempo de uso da amplificação. Objetivo: Caracterizar os potenciais evocados auditivos de longa latência (PEALL) em crianças com perda auditiva neurossensorial pré e pós-adaptação do aparelho de amplificação sonora individual (AASI). Metodologia: Estudo longitudinal constituído por 32 sujeitos e dividido em dois grupos: grupo estudo e grupo controle. O grupo estudo foi composto por 18 crianças, sendo cinco do gênero feminino e 13 do gênero masculino, com idade entre sete e 12 anos (média de idade: 9 anos e 2 meses), com perda auditiva neurossensorial bilateral simétrica de grau leve a moderado, sem experiência prévia com qualquer tipo de amplificação. Todas as crianças foram adaptadas com AASI bilateral após a primeira avaliação eletrofisiológica para a captação dos PEALL (componentes P1, N1, P2, N2 e P300) com estímulo de fala e estímulo tone burst, sendo que esta avaliação se repetiu 3 meses e 9 meses após o uso do AASI. O grupo controle foi composto por 14 crianças, sendo seis do gênero feminino e 8 do gênero masculino, com idade entre sete e 12 anos (média de idade: 9 anos e 8 meses). Todas as crianças deste grupo apresentaram audição normal e a avaliação para obtenção dos PEALL foi realizada respeitando o mesmo intervalo de tempo do grupo estudo: M0 - avaliação inicial; M3 e M9 - avaliação após três e nove meses da avaliação inicial. Resultados: Na comparação dos valores de latência e amplitude com o estímulo tone-burst no GE (condição sem AASI), observou-se diferença estatisticamente significante entre os três momentos de avaliação (M0xM3xM9) para a latência do P1 na orelha esquerda (OE) e latência do P300 na orelha direita (OD), com diminuição da latência ao longo do tempo. Na comparação dos momentos de avaliação dois a dois, para o componente P1 a diferença significante deu-se entre os momentos M0xM9 (p-valor=0,022), e para o componente P300 entre M0xM3 (p-valor=0,013). Com relação ao estímulo de fala pode-se observar uma diminuição estatisticamente significante nas latências dos componentes P2 (p-valor=0,010) e N2 (p-valor=0,007) (OE) entre os momentos M3 e M9. Quanto à presença e ausência dos componentes dos PEALL com estímulo de fala, verificou-se ausência dos componentes P1 e N1 no momento M3 assim como para N1, P2 e P300 no momento M9. Com estímulo tone burst observou-se ausência de respostas para os componentes N1 e P2, nos diferentes momentos de avaliação. No que diz respeito à correlação entre o tempo de privação sensorial e os componentes do PEALL obtidos com estímulo tone-burst na OD (condição com AASI) observou-se correlação estatisticamente significante entre tempo de privação sensorial e amplitude do P300 (p-valor=0,006), sendo que quanto maior o tempo de privação sensorial, menor a amplitude do P300 (r=-0,655). Com relação à correlação entre a frequência de uso do AASI e os componentes dos PEALL observou-se correlação estatisticamente significante entre frequência de uso do AASI e amplitude P2-N2 (p-valor=0,033) para o estímulo de fala na condição com AASI na OE. Conclusão: O PEALL demonstrou ser uma ferramenta clínica viável na avaliação de crianças usuárias de AASI, permitindo monitorar e mensurar a plasticidade neuronal do Sistema Nervoso Auditivo Central após um período de estimulação auditiva / Introduction: Hearing loss in childhood, even when very small, can hinder or even delay the process of language acquisition. The effects of sensory deprivation in the auditory pathway worsen, as diagnosis and the beginning of intervention are delayed. The use of Long Latency Auditory Evoked Potentials (LLAEP) in children that use individual hearing aids becomes a scanning tool capable of measuring the central auditory nervous system\'s (CANS) maturation throughout the period of use of the hearing aid. Purpose: To characterize the long latency auditory evoked potentials (LLAEP) in children with sensorineural hearing loss before and after fitting of hearing aids. Methodology: Longitudinal study composed of 32 subjects and divided into 2 groups: study group and control group. The study group was composed of 18 children, of these 5 were female and 13 were male, with ages between 7 and 12 years (age average: 9 years and 2 months), with mild to moderate bilateral symmetrical sensorineural hearing loss, with no previous experience using any kind of hearing aid. All of the children were fitted with bilateral hearing aids after the first electrophysiological assessment in order to record the LLAEP (components P1, N1, P2, N2 and P300), with speech and tone-burst stimuli; this assessment was repeated 3 and 9 months after the fitting of the hearing aids. The control group was composed of 14 children, of these 6 were female and 8 were male, with ages between 7 and 12 years (age average 9 years and 8 months). All of the children in this group showed normal hearing and the assessments to record the LLAEP were carried out in the same intervals of time as the study group: A0 - initial assessment; A3 and A9 - assessments 3 and 9 months after the initial assessment. Results: When comparing the latency and amplitude results with the tone-burst stimulus in the study group (SG) (without hearing aids), a statistically significant difference between the 3 assessments (A0xA3xA9) was observed for the P1 latency in the left ear (LE) and the P300 latency in the right ear (RE), with a decrease in latency with the passing of time. When comparing the assessments two by two, for the P1 component, the significant difference was recorded between A0xA9 (p-value=0,022), and for the P300 component, the significant difference was recorded between A0xA3 (p-value=0,013). Regarding the speech stimulus, a statistically significant decrease can be observed in the latency of the components P2 (p-value=0,010) and N2 (p-value=0,007) (LE) between A3 and A9. As for the presence and absence of the LLAEP components with the speech stimulus, an absence of the components P1 and N1 at A3 was observed, as well as for N1, P2 and P300 at A9. An absence of response was observed with the tone-burst stimulus for the N1 and P2 components, at the different times of assessment. As for the correlation between the period of sensory deprivation and the LLAEP components obtained from the tone-burst stimulus in the RE (with hearing aids), a statistically significant correlation was observed between the period of sensory deprivation and the amplitude of the P300 (p-value=0,006) - where there was a higher sensory deprivation time, the amplitude of the P300 was lower (r=-0,655). As for the correlation between the frequency of the use of hearing aids and the components of the LLAEP, a statistically significant relationship was observed between the frequency of use of hearing aids and the P2-N2 amplitude (p-value=0,033) for the speech stimulus when using hearing aids in the LE. Conclusion: The LLAEP proved to be a viable clinical tool in the assessment of children using hearing aids, allowing for the monitoring and measuring of the neural plasticity of the Central Auditory Nervous System after a period of hearing stimulation

O estímulo pela atividade física pode mediar a ação do IGF-1 sobre a indução à neuroplasticidade, modular o neurometabolismo e influenciar a memória e a ansiedade. Entretanto, a atividade física também pode induzir à hipoglicemia, condição que pode ser revertida com a administração de rápida fonte de glicose provinda da alimentação. Assim como a atividade física, a dieta exerce forte influência nos processos moleculares, celulares e comportamentais e estudos analisando o efeito exclusivo de dietas ricas em açúcar revelam prejuízos sobre a memória e favorecimento à ansiedade. Portanto, analisar os efeitos moleculares e comportamentais num protocolo que contemple atividade física e dieta não exclusiva de xarope de milho podem corroborar ou discordar das pesquisas que analisam os mecanismos de uma dieta exclusiva. O objetivo desse trabalho foi verificar os efeitos da administração de xarope de glicose do milho a 15% após atividade física aguda forçada em esteira sobre a memória, a ansiedade, a atividade locomotora, a neuroplasticidade e a morte celular de camundongos machos. Foram formados 4 grupos, sendo sedentário controle (SED), treinado controle (TRE), sedentário administrado (SED15%) e treinado administrado (TRE15%). O regime de treinamento consistiu em atividade física forçada em esteira por 40 min a 0,7km/h por 5 dias. A administração de 15% do xarope de milho se deu sempre após atividade física por período de 1½h. Para avaliação de memória aversiva foi utilizado a esquiva passiva no 4º e 6º dias e para avaliação do comportamento relacionado à ansiedade foi utilizado o labirinto em cruz elevado. Para análise de morte celular foi utilizado kit TUNEL que identifica fragmentação do DNA. Os dados comportamentais foram avaliados estatisticamente através do software Prisma e os demais qualitativamente. Houve influência da administração sobre o menor consumo para o grupo TRE15%, prejuízos à memória aversiva para ambos os grupos, indução ao comportamento relacionado à ansiedade nos animais do grupo SED15%, maior exposição às situações de risco para o grupo TRE15%, incidência considerável e difusa de morte celular na amígdala e importante expressão de IGF-1 nos grupos. A administração de 15% de xarope de glicose do milho posterior à exposição na esteira desencadearam importante expressão de IGF-1, mas não suficiente para proporcionar neuroproteção causando consideráveis e difusos pontos de morte celular na amígdala, prejuízos à memória aversiva, medo induzindo comportamento relacionado à ansiedade para SED15% e significativa maior exposição às situações de risco para TRE15% após protocolo agudo de 5 dias / The stimulation by physical activity can mediate the action of IGF-1 on the induction of neuroplasticity, modulating neural energetic metabolism and influencing memory and anxiety behavior. However, physical activity can also to lead to hypoglycemia, a condition that can be reversed by the administration of glucose. As physical activity, diet has a strong influence on molecular, cellular and behavioral processes and studies analyzing exclusively the effects of high-sugar diets reveal prejudices on memory and favors anxiety. Therefore, analyze the molecular and behavioral effects in a protocol that includes physical activity and non-exclusive diet of corn syrup can corroborate or disagree with the studies that analyze the mechanisms of an exclusive diet. The aim of this work was to investigate the effects of 15% of glucose corn-syrup administration after treadmill training on memory, anxiety, neuronal plasticity and cell death in male mice. Sedentary control (SED), Trained control (TRE), Sedentary administrated (SED15%) and Trained administered (TRE15%) were the 4 groups formed randomly. The training regimen consisted on a treadmill training for 40 min at 0.7km/h during 5 days. The administration of the 15% corn syrup were always given after a 1½h period after physical activity. For evaluation of aversive memory the passive avoidance was used in day 4 and day 6 and for assessment of anxiety-related behavior was used the elevated plus maze. For cell death analysis TUNEL kit that identifies DNA fragmentation was used and immunohistochemistry was applied to analyze IGF-1 expression on amygdala. Behavioral data were evaluated statistically using Prisma software and cell death and IFG-1 expression were analyzed qualitatively. Results: There was influence of administration on the lowest feed consumption to TRE15%, losses to aversive memory for both groups, inducing behavior related to anxiety in SED15%, greater exposure to risk situations for TRE15%, considerable incidence and diffuse cell death the amygdala and important expression of IGF-1 in the groups. The administration of 15% glucose corn syrup after treadmill training triggered an important expression of IGF-1, but not enough to provide neuronal protection causing considerable and diffuse points of cell death in the amygdala, losses to aversive memory, fear inducing behavior related to anxiety to SED15% and significantly greater exposure to risk situations for TRE15% after acute protocol 5 days

Os receptores glutamatérgicos metabotrópicos (mGluRs) estão envolvidos nos processos de plasticidade, neurodegeneração e neuroproteção. Avaliamos a expressão de mGluRs no sistema visual de ratos e pintos em diferentes tempos após enucleação ocular. Os animais foram avaliados pelo método de imuno-histoquímica, immunoblotting e RT-PCR, para detecção dos receptores mGluR1,2/3,5 e 7. Foi observado aumento da imunorreatividade (IR) de mGluR1, 5 e 7 no colículo superior, porém não foi observada diferença no núcleo geniculado lateral. Houve aumento na expressão protéica para mGluR1, 5 e 7 e aumento da expressão gênica para mGluR1,5 e 7; por outro lado, ocorreu uma diminuição de mGluR3. No TeO, foi observado aumento da IR para mGluR1 e 5 e diminuição para mGluR2/3. As análises de immunoblotting confirmaram o aumento observado de mGluR1 e diminuição de mGluR2/3. Os resultados indicam uma modulação diferencial na expressão gênica e protéica dos mGluRs, sugerindo a participação desses receptores em processos plásticos decorrentes de lesões no sistema visual adulto. / The metabotropic glutamate receptors (mGluRs) are involved in neuronal plasticity and neuroprotection. We analyzed the expression of mGluRs in the visual system of rats and chicks in several periods after ocular enucleation. The localization and expression of mGluR1, 5, 2/3 and 7 receptors were evaluated by standard immunoperoxidase, immunoblotting and real-time PCR protocols. The immunorreativity, protein and gene expression of mGluR1, 5 and 7 receptors in the superior colliculus showed an increase, whereas no changes were seen in the lateral geniculate nucleus. For mGluR3, gene expression was decreased. In the TeO, mGluR1 and 5 increased for all survival periods analyzed. Immunoblotting analyses confirmed the increases for mGluR1 and 5, decreases for mGluR2/3. These results indicate that the expression of mGluRs is regulated by the glutamatergic retinal input, and add data on a possible role of these receptors in neuroplasticity in adult animals.

O exercício físico traz inúmeros benefícios para o sistema nervoso, dentre eles a melhora da memória e cognição, além de um efeito protetor em relação ao declínio mental decorrente do envelhecimento e de lesões do sistema nervoso. Este estudo teve como objetivo observar os efeitos plásticos do exercício moderado de curta duração no hipocampo e em regiões motoras do encéfalo de ratos, frequentemente afetadas por lesões ou doenças neurodegenerativas. As metodologias empregadas nestas análises foram a imuno-histoquímica, o Western blotting,o PCR em tempo real, avaliação dos níveis de neurogênese pela injeção de BrdU e imageamento de Ca2+ de astrócitos corticais. Os resultados encontrados mostram que o exercício moderado de curta duração promoveu alterações plásticas específicas em todas as regiões estudadas, variando na dependência do marcador utilizado e do decurso temporal do exercício. Acreditamos que este é suficiente para promover plasticidade difusa no sistema nervoso, que pode ser parte do substrato do efeito benéfico do exercício no sistema nervoso. / Evidence shows that physical exercise is neuroprotective and enhances brain function by improving cognition, learning and memory. It has also been associated with structural changes such as angiogenesis, synaptogenesis and neurogenesis. The aim of this study was to observe the effects of a moderate, short-term exercise protocol on the hippocampus and brain regions related to motor function, commonly affected by neurodegenerative diseases. The methods used for these analyses were immunohistochemistry, Western blotting, real-time PCR, evaluation of the levels of hippocampal neurogenesis with injections of BrdU and Ca2+ imaging of cortical astrocytes. Our results show that short-term moderate physical exercise induced specific plastic changes in all regions studied, which varied depending on the marker and time course of exercise and is enough to modulate synaptic and structural elements of neurons as well as astrocytes, playing an important role in the diffuse exercise-dependent plasticity which may underlie the beneficial effects of exercise in the brain.

阻塞性睡眠呼吸暂停（OSA）是一种常见的睡眠障碍，睡眠过程中反复发作的气道阻塞，导致间歇性低氧血症。OSA 中的間歇性缺氧（IH）一直被视為一個主要致病因素。會影響神經認知功能，包括記憶障礙，遲鈍的反應和其它。以前的研究提示氧化应激产物（ROS）和细胞凋亡是間歇性缺氧引起的认知功能障碍的主要機制之一。然而，确切的机制仍然知之甚少，并没有得到解决。我们基于間隙性缺氧 （IH）的动物模型的实验结果首次发现，即在IH 模型中海馬長時程增強（LTP）的降低，以及腦源性神經營養因子（BDNF）的表达减少。同時我們發現，大脑内注射BDNF 可以有效地恢复LTP 的幅度。因此，我们的研究提供了一种新的可能机制，即在缺乏脑源性神经营养因子可能是阻塞性睡眠呼吸暂停導致的伴有脑功能障碍一个关键因素。 / Ampakine 是一種AMPA 受體調節劑，更重要的是可以增加腦內BDNF 的表達。在这项研究中，我們在不同缺氧時間處理的動物模型中通过腹部注射ampakine 來觀察其效應。我們使用了四组成年雄性小鼠，其中組接受7 天IH处理，另外两组接受14 天缺氧处理。所有四组均分别接受腹腔ampakine 和对照生理盐水注射。 IH 模式仍然是氧含量在90 秒内从21 降到10%，再回复到21%。缺氧时间是每天8 小時周期。从整个IH /正常氧环境的第一天开始，八臂放射迷宮被用来研究参考记忆和工作记忆的表现。然后，我们对脑源性神经营养因子，活性氧和细胞凋亡的分子标记和海马的树突棘形态的表达进行了检查， 海馬突触可塑性的表現，包括E-LTP，L-LTP 也都被檢測。 / Western blot 分析显示，ampakine 注射有效恢复了IH 導致的海马BDNF 水平下降。同时， 我們也發現在ampakine 注射組中ROS 的表达减少，细胞凋亡的减轻，其中包括内质网应激诱导的细胞凋亡。树突棘被認為是海马突触可塑性的结构基础之一。高尔基体染色也表明， ampakine 注射IH 成功回復了7 天IH 導致的較大的，成熟树突棘的減少。 / 此外，八臂放射迷宮的结果表明，无论是参考记忆和工作记忆在7 天IH和14 天IH 均有受損表現。但是，ampkine 的使用同樣挽救了IH 引起的這些记忆障碍。 / 最後，通過研究AMPA 受體調節劑（ampakines）對IH-誘導的神經認知功能障礙及長時程增強障礙影響，我們發現進一步的闡明BDNF 在OSA 所起的重要作用。這些結果也將探索新的藥物治療的OSA 了新的思路。 / 阿爾茨海默病（AD），也叫老年癡呆癥，在65 歲的人的失憶症中，是最常見的原因，也是最常見的神經退行性疾病。 AD 的原因並不清楚，其起病也並不明顯。它的特點是逐漸喪失記憶，語言障礙及其他認知功能障礙，這些症狀可能會變得明顯。在AD 中，兩種蛋白質聚集體的參與和特點的AD 病理澱粉樣斑塊，由澱粉樣蛋白-β 肽，並導致細胞外病變和tau 蛋白纏結，這是由過度磷酸化的絲微管相關蛋白tau，並導致細胞內的病變。 / 鐵是最豐富的微量金屬，在大腦中參與範圍廣泛的細胞過程的運作。然而，鐵臭名昭著的另一方面是其強大的氧化催化性能。事實上，失調的鐵已被發現與細胞老化和各種各樣的神經退行性疾病有牽連。鐵在突觸功能的重要性是對突觸的影響，例如其可以順行軸突運輸突觸功能區域，這也是阿爾茨海默病中的澱粉樣蛋白斑的沉積的起始部位。然而，到現在，鐵的積累是如何影響突觸功能以及更普及的大腦功能很少被研究。 / 為了調查是否高鐵食有任何正常或阿爾茨海默氏病的影響，我們在實驗中引入了APPswe/ps1 轉基因小鼠，這是一個經典的老年癡呆症的疾病的動物模型。研究中，我們使用四組動物模型，即野生型（WT）和APPswe/ps1 小鼠（TG），每組給予至少10 個月正常（ctrl）的食和高鐵（HI）食。 / 海馬LTP 記錄表明，野生小鼠與正常食（WT-HI）的海馬長時程增強下降。 Tg-ctrl 組也相比wt-ctrl 組顯示LTP 水準下降，包括E-LTP 和L-LTP。引人注目的是，高鐵食下的APPswe/ps1 下顯示了被提高和恢復的海馬長時程突觸可塑性。 / 八臂放射迷宮的結果還表明，與高鐵食的野生型以及正常食的APPswe/ps1，無論是在參考記憶體或工作記憶，比野生型與正常食組有較差的記憶水準。同樣，我們驚訝地發現，和APPswe/ps1 正常食的小鼠相比，給予高鐵食的APPswe/ps1 組的迷宮成績要好得多,几乎回复到和野生型对照组一样的水平。 / 這些結果表明，鐵在阿爾茨海默病的功能是非常複雜的，可能會對其神經可塑性顯示雙相調節作用特性。詳細機制有待進一步探討。 / Obstructive sleep apnea (OSA) is a common sleep disorder, characterized by repeated episodes of airway obstruction during sleep resulting in intermittent hypoxemia. Previous studies proposed that reactive oxygen species (ROS) and apoptosis caused by intermittent hypoxia (IH) contributed to cognitive deficits. However, the exact mechanism is still poorly understood and not settled. Our recent studies, for the first time, showed that there is decreased expression of brain-derived neurotrophic factor (BDNF) in the hippocampus and impairment in long-term potentiation (LTP). Intra-brain injection of BDNF can effectively restore the magnitude of LTP. Thus, our study provides a novel mechanism and insight in the etiology of OSA-induced brain dysfunction in that lacking BDNF could be a critical factor. / In this study, ampakine application was used as “BDNF raiser“ during 7-day IH and 14-day IH treatment by intraperitoneal (i.p.) injection. Four groups of adult male mice were used, two of them exposed to 7-day IH and two of them exposed to 14-day IH, each received either vehicle or ampakine i.p. injection. The paradigm of IH consisted of cycles of oxygen levels between 10% and 21% every 90s during the daytime for 8 hrs. Radial arm maze was used to investigate the performance of reference memory and working memory during the whole IH/ normoxia treatment from the first day. After that, expression of BDNF, ROS and molecular markers of apoptosis and morphology of hippocampal dendritic spines were examined, together with the investigation of both hippocamal synaptic plasticity, including early phase LTP (E-LTP) and late phase L-LTP (L-LTP). / Ampakine treatment restored the decreased level of hippocampal BDNF in the IH-treated group, as revealed by Western blot. Meanwhile, decreased ROS expression and alleviated cell death, including ER stress induced-apoptosis are all found in those ampakine injected groups. Golgi staining also showed that ampakine injection IH treatment rescued the decrease of mature dendritc spines, which is the structural basis of hippocampal synaptic plasticity, under 7-day IH treatment. Hippocampal long-term synaptic plasticity, which underlies the proposed mechanism of memory, was also found reversed in those ampakine injected groups, compared with groups under IH treatment. / Furthermore, results of radial arm maze showed that both the reference memory and working memory are impaired by 7-day IH treatment or 14-day IH treatment. However, the application of ampakine rescued IH-induced memory deficits. / Finally, by studying the effects of the ampakines on IH-induced neurocognitive dysfunction and LTP impairment, the role played by BDNF in OSA was further elucidated. These results were shed new lights on the exploration of novel pharmacological treatments in the OSA. / Alzheimer’s disease is the most common cause of dementia among aged people. The causes of AD are not clear and onset of the disease is also not obvious. Iron is the most abundant trace metal in the brain and dysregulation of iron has been implicated in cell aging and a wide variety of neurodegenerative diseases including Alzheimer disease. However, up to now, very little is known about how iron accumulation is involved in Alzheimer disease. / To investigate whether high iron diet has any effects on normal or Alzheimer’s disease, we introduced APPswe/ps1 transgenic mice, an Alzheimer’s disease animal model, and used four groups in our study, namely wild type (wt) and APPswe/ps1 mice (tg), each with normal (ctrl) diets and high iron (HI) diet for at least 10 months. / Hippocampal LTP recording showed that wild type with high iron diet (wt-HI) decreased than that of wt-ctrl group. Tg-ctrl group also displayed decreased LTP level, including E-LTP and L-LTP, than that of wt-ctrl group. Strikingly, that of APPswe/ps1 under HI diets rescued the impaired hippocampal long-term synaptic plasticity than that of APPswe/ps1 mice under normal diets. / Results from radial arm maze also showed that both APPswe/ps1 with normal diet and wild type with HI diet had worse performance, either in reference memory or working memory, than those of wild type with normal diets. Again, it is surprised to find that performances of tg-HI group were much better than APPswe/ps1 mice under normal diet. / These results showed that the function of iron are very complicated, may have different effects on neural function of normal and AD objects. The detailed mechanisms needs to be further explored. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Xie, Hui. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 200-225). / Abstracts also in Chinese. / Declaration --- p.II / ABSTRACT OF THESIS ENTITLED --- p.III / 中文摘要 --- p.VII / Acknowledgements --- p.XI / List of abbreviations --- p.XIII / List of publications --- p.XVI / Chapter CHAPTER 1 --- INTRODUCTION --- p.4 / Chapter 1.1 --- Overview of the study --- p.4 / Chapter 1.2 --- Obstructive sleep apnea --- p.7 / Chapter 1.2.1 --- Epidemiology --- p.8 / Chapter 1.2.2 --- Pathogenesis --- p.10 / Chapter 1.2.3 --- Pathophysiologic Consequences --- p.11 / Chapter 1.2.4 --- Diagnosis --- p.14 / Chapter 1.2.5 --- Treatment --- p.15 / Chapter 1.3 --- Memory and long-term potentiation --- p.17 / Chapter 1.3.1 --- Memory --- p.17 / Chapter 1.3.2 --- Hippocampal Synaptic plasticity --- p.19 / Chapter 1.3.3 --- Dendritic Spines --- p.23 / Chapter 1.4 --- Brain-derived neurotrophic factor --- p.35 / Chapter 1.4.1 --- Introduction of BDNF --- p.35 / Chapter 1.4.2 --- BDNF and synaptic plasticity --- p.36 / Chapter 1.5 --- Intermittent hypoxia impaired memory and neuroplasticity --- p.38 / Chapter 1.5.1 --- Clinical and basic studies on IH-induced neurological dysfunction --- p.38 / Chapter 1.5.2 --- Current mechanisms of IH-induced neurological dysfunction --- p.39 / Chapter 1.5.3 --- ROS generation and intermittent hypoxia --- p.41 / Chapter 1.5.4 --- Critical role of decreased BDNF expression in chronic intermittent hypoxia --- p..46 / Chapter 1.6 --- Ampakine --- p.48 / Chapter 1.6.1 --- Effects of ampakine on receptor activities --- p.49 / Chapter 1.6.2 --- Effects of ampakine on synaptic transmission --- p.50 / Chapter 1.6.3 --- Effects of ampakine on long-term potentiation --- p.52 / Chapter 1.6.4 --- Ampakine, BDNF and neurological disease --- p.53 / Chapter CHAPTER 2 --- METHODS --- p.61 / Chapter 2.1 --- Experimental procedure --- p.61 / Chapter 2.1 --- Animal model of Obstructive Sleep Apnea --- p.62 / Chapter 2.1.1 --- Chronic Intermittent Hypoxia --- p.62 / Chapter 2.1.2 --- Oxygen saturation measurement under normoxia and intermittent hypoxia --- p.64 / Chapter 2.1.3 --- Body weight during hypoxia treatment --- p.64 / Chapter 2.2 --- Western Blot Analysis --- p.65 / Chapter 2.3 --- ROS measurement --- p.67 / Chapter 2.4 --- Golgi staining --- p.67 / Chapter 2.4.1 --- Analysis of spine density --- p.68 / Chapter 2.4.2 --- Measurement of dendritic spines --- p.68 / Chapter 2.5 --- Electrophysiological Experiments --- p.69 / Chapter 2.5.1 --- Brain Slice Preparation --- p.69 / Chapter 2.5.2 --- Multi-electrode Recording Setup (MED64) --- p.70 / Chapter 2.5.3 --- Slice Superfusion --- p.72 / Chapter 2.5.4 --- Field Potential Recordings --- p.73 / Chapter 2.5.5 --- LTP Induction Protocol --- p.74 / Chapter 2.6 --- Radial arm maze --- p.76 / Chapter CHAPTER 3 --- RESULTS --- p.91 / Chapter 3.1 --- Molecular detection under IH treatment and ampakine injection --- p.91 / Chapter 3.1.1 --- BDNF expression under IH treatment and ampakine injection --- p.91 / Chapter 3.1.2 --- ROS measurement under IH treatment and ampakine injection --- p.92 / Chapter 3.1.3 --- Involvement of ER stress during IH treatment --- p.93 / Chapter 3.2 --- Changes of dendritic spines under IH treatment and ampakine injection --- p.100 / Chapter 3.2.1 --- Changes of total dendritic spine density under IH treatment and ampakine injection --- p.100 / Chapter 3.2.2 --- Changes of different dendritic spine density under IH treatment and ampakine injection --- p.101 / Chapter 3.2.3 --- Changes of dendritic spine morphology under IH treatment and ampakine injection --- p.103 / Chapter 3.3 --- IH-induced impairment in hippocampal synaptic plasticity --- p.110 / Chapter 3.3.1 --- E-LTP measurement of 7-day intermittent hypoxia treatment in long-term synaptic plasticity --- p.110 / Chapter 3.3.2 --- L-LTP measurement of 7-day intermittent hypoxia treatment in long-term synaptic plasticity --- p.111 / Chapter 3.3.3 --- E-LTP measurement of 14-day intermittent hypoxia treatment in long-term synaptic plasticity --- p.112 / Chapter 3.3.4 --- L-LTP measurement of 14-day intermittent hypoxia treatment in long-term synaptic plasticity --- p.113 / Chapter 3.4 --- Behavioral studies under IH treatment and ampakine injection --- p.119 / Chapter 3.4.1 --- Reference memory test under IH treatment and ampakine injection --- p.119 / Chapter 3.4.2 --- Working memory measurement under IH treatment and ampakine injection --- p..122 / Chapter CHAPTER 4 --- DISCUSSION --- p.140 / Chapter 4.1 --- Molecular changes under IH treatment and ampakine application --- p.140 / Chapter 4.1.1 --- Intermittent hypoxia down regulate BDNF expression in hippocampus while ampakine injection rescued IH-induced decreased BDNF level --- p.140 / Chapter 4.1.2 --- Ampakine injection against ROS and apoptosis --- p.143 / Chapter 4.1.3 --- Involvement of ER stress-induced apoptosis during IH treatment --- p.145 / Chapter 4.2 --- Changes of spine morphology and density under IH treatment and ampakine injection --- p.146 / Chapter 4.3 --- Ampakine rescued hippocampal synaptic plasticity --- p.152 / Chapter 4.4 --- IH impaired reference memory and working memory --- p.156 / Chapter 4.5 --- Summary --- p.160 / Chapter Chapter 5 --- Effects of High-iron diet in Alzheimer’s Disease --- p..164 / Chapter 5.1 --- Overview of the study --- p.164 / Chapter 5.2 --- Introduction --- p.166 / Chapter 5.2.1 --- Alzheimer's disease --- p.166 / Chapter 5.2.2 --- Function of iron in brain --- p.167 / Chapter 5.2.3 --- Involvement of iron in oxidative damage --- p.168 / Chapter 5.2.4 --- Role of iron in neurodegeneration diseases --- p.168 / Chapter 5.2.5 --- Role of iron in Alzheimer's disease --- p.169 / Chapter 5.2.6 --- Deleterious effects of iron in memory function --- p.171 / Chapter 5.3 --- Methods --- p.172 / Chapter 5.3.1 --- Experimental design --- p.172 / Chapter 5.3.2 --- T-maze --- p.172 / Chapter 5.4 --- Results --- p.174 / Chapter 5.4.1 --- Validation of animal model of Alzheimer's disease --- p.174 / Chapter 5.4.2 --- Examination of normal and high iron diet on body weight --- p.174 / Chapter 5.4.3 --- Effects of Aβ accumulation and high-iron diet on hippocampal synaptic plasticity --- p.175 / Chapter 5.4.4 --- Effects of Aβ accumulation and high-iron diet on spatial memory measured by T-maze --- p.177 / Chapter 5.4.5 --- Effects of Aβ accumulation and high-iron diet on reference memory and working memory measured by radial arm maze --- p.178 / Chapter 5.5 --- Discussion --- p.180 / Chapter Chapter 6 --- General discussion --- p.195 / Reference --- p.200

Introdução: O implante coclear (IC) é um dos adventos tecnológicos na área da saúde mais importantes dos últimos anos. Mesmo com todo avanço tecnológico, os pacientes ainda apresentam queixas quanto ao rendimento do IC. O treinamento auditivo é o procedimento que pode proporcionar a melhora do desempenho das habilidades auditivas do indivíduo. Uma das possibilidades de treinamento auditivo é a musicoterapia. Objetivos: Verificar a influência da musicoterapia na compreensão da linguagem oral em pacientes pós linguais usuários de implante coclear, além disso, verificar a influência do efeito placebo; o desempenho das habilidades de percepção musical; verificar o desempenho das habilidades auditivas temporais de resolução e ordenação pré e pós musicoterapia em pacientes pós linguais usuários de implante coclear; e descrever os hábitos musicais nesses pacientes. Método: Participaram do estudo 11 indivíduos (média idade: 47,64 anos), pós linguais implantados, que foram submetidos a 10 sessões de musicoterapia, sendo uma por semana. Para a avaliação auditiva foram utilizados o teste Gap in Noise (GIN), o Montreal Battery Evaluation of Amusia, o teste de padrão de frequência (TPF), o teste de compreensão de sentenças, e o questionário de Munich Music Questionnaire. Todos os participantes passaram por um momento placebo antes da musicoterapia, e foram avaliados em três momentos distintos. Resultados: Foi observado melhora significativa no teste de sentenças de compreensão de fala, bem como nas habilidades musicais de contorno e melodia após musicoterapia. Não foi observado efeito placebo e nem diferença do TPF após a musicoterapia. Foi observado um desempenho ruim entre os participantes no teste GIN. Além disso, foi observado a redução do hábito de escutar música após IC. Conclusões: A musicoterapia foi uma ferramenta útil para melhorar as habilidades auditivas e compreensão de fala em indivíduos adultos pós-linguais usuários de IC, além de melhorar a frequência de escuta musical entre os participantes / Introduction: Cochlear implants (CI) represent one of the most important technological innovations in the health care sector in recent years. Despite the technological advance, patients continue to complain about CI performance. Auditory training constitutes the procedure most capable of improving the performance of individual hearing skills. One possibility for auditory training is music therapy. Objectives: To verify the influence of music therapy on the understanding of spoken language by postlingual users of cochlear implants. In addition, verify the influence of the placebo effect; the performance of musical perception skills; verify the performance of temporal auditory resolution and ordering skills of pre- and post-music therapy patients with cochlear implants. Method: A total of 11 individual postlingual implant users participated in the study (average age: 47.64 years), consisting of 10 weekly sessions of music therapy. For purposes of the respective hearing evaluations, the Gap in Noise (GIN) test, Montreal Battery Evaluation of Amusia test, Frequency Pattern Test (FPT), sentence comprehension test, and Munich Music Questionnaire were applied. All participants were submitted to a placebo condition prior to music therapy and were evaluated at three different points. Results: A significant improvement was observed in the spoken sentence comprehension test, as well as enhanced musical contour and melody skills, following music therapy. No placebo effect was observed, nor any difference in FPT after music therapy. The participants registered poor performance on the GIN test. In addition, a reduction was observed in music listening habits after CI. Conclusions: Music therapy was a useful tool to improve hearing and speech comprehension skills in adult postlingual users of CI and to improve the frequency of music listening among participants

Les réseaux périneuronaux (PNN) sont des régulateurs clé de la plasticité et de la régénération des neurones au niveau du système nerveux central chez l’adulte. Le PNN est une matrice extracellulaire hautement organisée, qui entoure des populations spécifiques de neurones, enrichie en protéoglycanes à chondroïtine sulfate (CSPG). La chondroïtine sulfate (CS) est un polysaccharide linéaire, appartenant à la famille des glycosaminoglycanes (GAG), qui peut être sulfaté à différentes positions et donner lieu à plusieurs isoformes. Ces isoformes interagissent de manière spécifique avec de nombreuses molécules de signalisation dont la semaphorine 3A (Sema3A). Sema3A est une protéine secrétée, qui interagit avec les CS et s’accumule ainsi dans les PNN. Elle est impliquée dans la guidance des neurones sur lesquels elle agit par chemorepulsion. Les aspects structuraux et fonctionnels de l’ interaction entre Sema3A et CS sont encore mal connus, mais celle-ci pourrait être requise pour renforcer la liaison de la Sema3A avec ses récepteurs et déclencher une voie de signalisation qui aboutit à l’inhibition de la plasticité synaptique. Le but du projet est donc de caractériser biochimiquement l’interface d’interaction Sema3A-CS. Il a pour perspective d’élaborer des molécules interférant avec cette interaction qui pourraient permettre une amélioration de la plasticité neuronale après une maladie neurodégénérative ou une lésion de la moelle épinière.Pour ce faire, la Sema3A est exprimée dans un système hétérologue de cellules eucaryotes pour être purifiée. Deux formes ont été purifiées: une forme complète de 90 kDa qui reste accrochée à la surface cellulaire et une forme clivée de 65 kDa secrétée dans le milieu de culture. La Sema3A-90 interagit d’une manière sélective et avec une très haute affinité avec la CS-E (chondroitine disulfatée en position 4 et 6) et l’héparane sulfate,alors que, la forme clivée n’interagit avec aucun GAG, comme observé par résonance plasmonique de surface (SPR). Quatre sites, situés dans le domaine C-terminal de la protéine, susceptibles d’interagir avec les GAG ont été identifiés et analysés par mutagenèse. Deux d’entre eux sont impliqués dans la reconnaissance des GAG et sont nécessaires à la Sema3A pour inhiber la croissance de neurites sur des cultures de neurones issus de ganglion de la racine dorsale de rats. En parallèle, nos travaux montrent qu’un tetrasaccharide de CS-E est la taille minimale requise pour l’interaction avec la Sema 3A. Enfin, des analyses réalisées en utilisant une microbalance à cristal de quartz avec dissipation ont montré que la Sema3A pourrait réticuler les chaines de GAGs, participant ainsi à la stabilisation du réseau périneuronal. / Perineuronal nets (PNNs) are the key regulators of neuronal plasticity and regeneration in the mature central nervous system (CNS). They are a unique and highly organised extracellular matrix (ECM) structure, found around sub-population of neurons, composed mainly of chondroitin sulfate proteoglycan (CSPG). Chondroitin sulfate (CS) is a linear polysaccharide belonging to glycosaminoglycans (GAGs) family. The sulphation pattern defines different types of CS, which interact with different signalling proteins including those regulating axonal outgrowth and guidance such as semaphorin 3A (Sema3A). Sema3A is a secreted chemorepulsive protein found accumulated in the PNNs through its interaction with CS. This process is believed to potentiate Sema3A signalling through plexin A1 (PlxnA1) and Neuropilin 1 (Nrp1) and regulate plasticity and regeneration. The aim of the thesis project is to characterise the interface of Sema3A- CS interaction.For this purpose, Sema3A is expressed in eukaryote cells and purified. Interestingly, two major forms were obtained: a full length Sema3A (90 kDa) which remains attached to the cell surface GAGs and a truncated form without the C-ter part (65 kDa) which is released to the culture medium. With the use of surface plasmon resonance (SPR), we observed that full length Sema3A binds selectively to CS-E (4,6-disulfated chondroitin) and heparan sulfate with a high affinity (KD in the sub pM range), while the truncated Sema3A does not bind to any GAG. Four putative GAG binding sequences were identified in the C-ter of Sema3A and mutated using site directed mutagenesis. SPR analysis then revealed that two out of these four sites are required for the binding to CS-E. The importance of these GAG-binding sequences in inhibition of neurites outgrowth of dorsal root ganglion neurons in culture was also reported, indicating thus the importance of GAG-binding in Sema3A signalling. In parallel, the minimal required sequence of Sema3A-binding of CS-E was determined as being a tetrasaccharide. The Sema3A-CS interface was thus characterized. Furthermore, quartz crystal microbalance with dissipation monitoring analysis suggested that Sema3A could crosslink GAG chains. This suggests Sema3A could be involved in stabilising the PNN network and induces mechanical changes on neuronal surface.The detail characterization of Sema3A-CS interaction may enable the design of new strategies aiming at enhancing plasticity and regeneration for neurodegenerative diseases or spinal cord injury.

Morphologic and metabolic change is a known property of the adult brain. A number of behavioural tasks alter local cerebral blood flow and glucose utilisation. The expression of the glucose transporter 1 (GLUT1), which allows the entry of glucose to the brain, also has been shown to change in response to long-lasting neuronal activation. However, little is known about the effect of acute neuronal activation on GLUT1 expression. Using immunohistochemistry and Western blot, we investigated cerebral GLUT1 expression and vasculature density in mice undergoing a 48-hour voluntary wheel running period. The results showed that the striatum was the main region where GLUT1 protein was up-regulated: There was a trend for GLUT1 expression and blood vessels density to be associated with the distance run during the experiment. These results indicate that short-term increased neuronal activation is associated with rapid changes in glucose transport and possibly vascular remodelling.

Morphologic and metabolic change is a known property of the adult brain. A number of behavioural tasks alter local cerebral blood flow and glucose utilisation. The expression of the glucose transporter 1 (GLUT1), which allows the entry of glucose to the brain, also has been shown to change in response to long-lasting neuronal activation. However, little is known about the effect of acute neuronal activation on GLUT1 expression. Using immunohistochemistry and Western blot, we investigated cerebral GLUT1 expression and vasculature density in mice undergoing a 48-hour voluntary wheel running period. The results showed that the striatum was the main region where GLUT1 protein was up-regulated: There was a trend for GLUT1 expression and blood vessels density to be associated with the distance run during the experiment. These results indicate that short-term increased neuronal activation is associated with rapid changes in glucose transport and possibly vascular remodelling.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 105-135).