http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/83229 Sat, 04 Apr 2026 22:39:31 GMT 2026-04-04T22:39:31Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/83236 標題: 預測處理功能於年輕與老年神經迴路之研究; Evaluation of predictive processing in younger and older neural circuits 作者: 蘇煜翔; Yu-Shiang Su 摘要: 人類大腦反應外界訊息的過程可以貝氏推理的方法來呈現。這個方法是先利用既有的先驗信念來解讀資料，之後將概度整合以形塑成事後推論，而這兩個步驟是適應變化中環境的重要認知歷程。在這個研究中，我們假設年齡會改變大腦的神 經迴路，而這樣的變化使得年輕人與老年人以不同的能力來適應不斷變化的環境。 34 位年輕人(年齡 = 22.66 ± 2.58 歲，20 位女性)與 32 位老年人(年齡= 70.64 ± 5.60 歲， 17 位女性)參與我們的功能性磁振造影實驗。實驗任務會使用的三個箱子包含紅、藍、黃三種顏色的球，實驗參與者在實驗任務之前將會學習不同顏色的球的出現機率。在正式實驗任務中，三顆球將會從其中一個被選定的箱子中抽 出，而實驗參與者需要猜測待會抽出的三顆球是哪一個顏色比較多，之後會將抽出的三顆球呈現給參與者，並按照結果給予獎賞。參與者需結合自己的抽球前的先驗信念搭配抽球結果的概度來得出事後推論，才能準確判斷哪一個箱子才是被選定的箱子，而正確的推論能準確地預測抽球結果，並獲得更多的分數。實驗中，被選定的箱子將在一段時間之後更換為另一個箱子，所以參與者必須留心抽球結 果，並在準確地在正確的時間轉換先驗信念到另一個箱子。我們以貝氏修正 (Bayesian updating)的計算模型來適配參與者的行為資料，老年人相對於年輕人有比較低的機率保留原本的先驗信念(Cohen’s d = 0.86, 95%可靠區間 = [0.34, 1.38])，表示老年人的信念較不穩固，不顧抽球結果的概度就頻繁地更改心中對箱子的信念。而且，在整合抽球結果的概度上，並沒有發現統計上顯著的年齡差 異(Cohen’s d = -0.35, 95%可靠區間 = [-0.89, 0.20])。在功能性大腦影像資料中，我們因嚴重的頭動狀況排除一位年輕人與一位老年人，而剩餘的 33 位年輕人(年齡 = 22.72 ± 2.60 歲，19 位女性)與 31 位老年人(年齡 = 70.70 ± 5.68 歲，17 位 女性)以表徵相似分析(representational similarity analysis，RSA)與模型為基的單 變量廣義線性模型(model-based univariate generalized linear model)進行分析。 相對於年輕人，老年人功能性影像的右側頂下葉(inferior parietal lobe; 54, -42, 51)與楔前葉(precuneus; 0, -48, 45)的多變項神經模式(multivariate neural patterns)與後驗信念有比較差的關聯性，表示信念在大腦的神經表徵與老年人的 決策行為有不一致的狀況。另外，年輕人在腹內側前額葉(ventral medial prefrontal cortex; 0, 48, -15)與海馬迴(hippocampus; -33, -30, -15)的活化程度 與信念的信心有正相關，但在老年人的大腦上沒有這樣的正相關。總體來說，我們在行為上發現老年人的信念較不穩定，而這能反映在頂下葉與楔前葉有比較差 的神經表徵。相對應地，老年人減少腹內側前額葉與海馬迴的活化來維持信念的 信心。另外，在本論文中，我們結合預測性編碼(predictive coding)的理論架構來建立假說，我們預測大腦在低階層腦區或高階層腦區若遭受影響，將分別導致信念修正上比較頑固死板或比較反覆無常。我們的發現支持後者的假設，老年人後側頂葉的神經處理的失序使得在表徵高層次的抽象信念遇到問題，反映在決策行為上，與我們觀察到老年人有不穩定信念的結果一致。; Human brains respond to incoming external information in a manner that can be formulated as Bayesian inference. Exploiting internal prior beliefs to make inferences about incoming information and then integrating likelihoods to form posterior inferences are two critical cognitive processes facilitating compliance with the changing environment. We postulated that age alters the neural circuits that reflect different abilities to adapt to changing environments in younger and older adults. In a functional magnetic resonance imaging (fMRI) experiment, we recruited 34 younger adults (age = 22.66 ± 2.58, 20 female) and 32 older adults (age = 70.64 ± 5.60, 17 female). Participants first learned about different proportions of red, blue, or yellow balls contained within three boxes. At test, participants were told that sets of three balls would be drawn from one of the boxes and they had to guess the majority color of the balls drawn with the source box hidden from participants. Outcomes of the drawn ball colors were then provided with correct guesses rewarded. Thus, participants had to update their posterior beliefs about which was the source box by integrating prior beliefs about the box and the likelihood of the drawn colors. Critically, source boxes were intermittently switched so that participants had to notice the outcome changes and transition to new beliefs. Computational model fitting with Bayesian updating showed older adults had lower probabilities to stay in the same belief (Cohen’s d = 0.86, 95% credible interval: [0.34, 1.38]), indicating less stable beliefs that frequently transitioned from trial to trial regardless of outcome likelihoods. However, we found no evidence of age-related difference in updating beliefs from outcome likelihoods (Cohen’s d = -0.35, 95% credible interval = [-0.89, 0.20]). We excluded one younger adult and one older adult for the functional brain data because of severe head motion during scanning. Functional brain imaging from the remaining 33 younger adults (age = 22.72 ± 2.60, 19 female) and 31 older adults (age = 70.70 ± 5.68, 17 female) were submitted to representational similarity analysis (RSA) and model-based univariate generalized linear modeling. Compared to younger adults, older adults showed reduced association between multivariate patterns and trial-wise posterior beliefs in the right inferior parietal lobe (IPL; 54, -42, 51) and precuneus (0, -48, 45), suggesting a behavioral disjoint with neural representations of belief in older adults. In younger adults, belief confidence also modulated activation in ventral medial prefrontal cortex (vmPFC; 0, 48, -15) and hippocampus (-33, -30, -15), which was not seen in older adults. Overall, we show that older adults have less stable beliefs. This is reflected by reduced neural representations of posterior beliefs in IPL and precuneus in older. Correspondingly, older adults showed reduced recruitment of VMPFC and hippocampus to maintain confident beliefs. Furthermore, in this dissertation, we incorporated a theoretical framework based on predictive coding and hypothesized that the disruption in brain regions at lower-level or higher-level hierarchies results in rigid or unstable beliefs, respectively. Our findings support the later speculation that older adults have disordered posterior parietal cortex (PPC) engagement in representing higher-level abstract beliefs which is associated with stochastic beliefs exemplified in decision behavior. Sat, 01 Jan 2022 00:00:00 GMT http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/83236 2022-01-01T00:00:00Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/95479 標題: 藉由觀察活體視交叉上核解析近日週期相反應曲線神經網路之研究; In Vivo Observation of the Suprachiasmatic Nucleus Reveals Bi-Stable Network for Circadian Phase Responses 作者: 葉柏廷; Po-Ting Yeh 摘要: 地球上的生物必須適應和預測日夜週期性變化，以促進它們的生存和適應性，因此能夠受環境光變化調控的內源性生理時鐘至關重要。這些生理時鐘能夠通過根據接收的時鐘刺激來調整其時鐘相位延遲或提前，以與環境協調。這種時鐘相位延遲或提前依賴於時鐘時間接收刺激的特性，被描述為相位響應曲線（phase response curve, PRC）。在哺乳動物中，位於下視丘底部的視交叉上核（suprachiasmatic nucleus, SCN）負責主要的生理時鐘，並整合經視下丘胞束傳遞的環境光信號，觸發生理時鐘的光節律。然而，SCN如何計算PRC仍然不清楚。為了闡明這一問題，我們使用通過梯度折射光纖內窺鏡中繼的螢光基因編碼的鈣指示劑，在未麻醉的小鼠中觀察SCN的急性光響應，這使得可以在不同條件下重複觀察SCN中的相同一組神經元。結果顯示，不同的時鐘時區具有不同的神經元活動模式，包括相位延遲區、相位提前區和行為無反應區。此外，神經元活動與光敏感神經元的組成之間的相關性在不同的時鐘時區之間也發生了變化。與傳統的SCN信息流的簡單階層模型不同，我們的研究結果表明，SCN在早期和晚期主觀夜晚分別處理光信號的雙模式網絡。; Creatures on the earth have to adapt and predict the periodic changes of day and night to facilitate their survival and fitness, which endogenous circadian clocks that can be entrained by the environmental light changes are critical. The clocks can harmonize with the environment by shifting their circadian phase delay or advance dependent on the circadian time receiving stimuli. The circadian time-dependent response function is described as the phase response curve (PRC). In mammals, the suprachiasmatic nucleus (SCN) located in the bottom of the hypothalamus is in charge of the master circadian oscillator and integrating environmental light signals transmitted through the retinohypothalamic tract that trigger photoentrainment of circadian rhythms. However, how the SCN computes PRC remains unclear. To elucidate it, we observe acute light responses of SCN in unanesthetized mice using fluorescent genetically encoded calcium indicators relayed through gradient-index endoscopes, enabling repeated observation of the same set of neurons in the SCN under various conditions. The results showed distinct neuron activity patterns at different circadian time zones, including phase delay zone, phase advance zone, and the behaviorally irresponsive dead zone. Moreover, the correlation between neuron activities and the composition of light-responsive neurons is changed between circadian time zones. Instead of conventional simple hierarchical models of SCN information flow, our findings suggest that SCN employed a bimodal network to process light signals separately in the early and late subjective night. Mon, 01 Jan 2024 00:00:00 GMT http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/95479 2024-01-01T00:00:00Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/92322 標題: 研究漸凍人症中富含精胺酸之二胜肽重複序列的毒理機制以及潛在的治療藥物; Investigating toxicity mechanisms and potential therapeutics of arginine-rich dipeptide repeats in amyotrophic lateral sclerosis (ALS) 作者: 張育仁; Yu-Jen Chang 摘要: 額顳葉失智症(frontotemporal lobar dementia, FTLD)和肌萎縮側索硬化症(amyotrophic lateral sclerosis, ALS)中最常見的突變是C9ORF72基因非編碼區域中的六核苷酸GGGGCC (簡稱G4C2)的重複擴增。FTLD是一種具有額顳葉型神經退化、行為能力缺陷和逐漸產生失語症為特徵的神經退化性疾病。而ALS則是一種上下運動神經元兩者皆受影響的運動神經元疾病，ALS惡化極為快速，確診後病人平均剩下二至五年的壽命。而這兩種看似差異極大的疾病卻擁有相當多共同的病理特徵和基因突變。 與C9ORF72突變相關的病理機制包括C9ORF72蛋白質功能的喪失和涉及RNA和蛋白質增益毒性。由於核苷酸重複所導致非ATG啟動的蛋白質轉譯機制(RAN)作用，在C9ORF72的六核苷酸重複擴增可以產生五種雙胜肽重複，包括了聚甘胺酸-丙胺酸、聚甘胺酸-精胺酸、聚甘胺酸-脯胺酸、聚脯胺酸-精胺酸和聚脯胺酸-丙胺酸。這些雙胜肽重複序列可源自於正義和反義RNA，而在FTLD或ALS患者的海馬迴、額葉和運動皮質層、脊髓和小腦中，都可鑑定出這些雙胜肽重複序列。 在這些雙胜肽重複序列中，聚甘胺酸-精胺酸和聚脯胺酸-精胺酸，這兩種富含精胺酸的雙胜肽重複序列，被認為是最具毒性的兩種。關於聚甘胺酸-精胺酸和聚脯胺酸-精胺酸的毒性機制目前仍在積極研究中。提出的機制包括引起核仁壓力、阻塞核仁孔的運輸、破壞核糖體與RNA的合成、降低粒線體功能和抑制蛋白質轉譯。雖然所有雙胜肽重複序列都可在細胞質包含體中觀察到，但聚甘胺酸-丙胺酸含量是最豐富的，並且可以錯誤堆積成具神經毒性的類澱粉沉積物。此外，聚甘胺酸-丙胺酸被認為會影響蛋白酶體的功能並誘導另一病理蛋白TDP-43的錯誤定位和聚集。另一方面，目前沒有文獻指出聚甘胺酸-脯胺酸和聚脯胺酸-丙胺酸具有毒性。 在正常人基因中的G4C2重複次數從2到24次皆有可能，而在ALS患者中，它的範圍則從30擴增至數百甚至上千次不等。關於精確會造成病理現象以及產生雙胜肽重複胜肽鏈的G4C2重複次數仍不清楚。在以下這個對聚甘胺酸-精胺酸和聚脯胺酸-精胺酸病理機制進行的研究中，我們使用化學合成的聚甘胺酸-精胺酸和聚脯胺酸-精胺酸來檢驗要產生細胞毒性所需的最小長度。並且利用圓二色譜光譜和小角度X射線散射結合分子模擬，我們提供了聚甘胺酸-精胺酸/聚脯胺酸-精胺酸的可能結構。並且利用脂質體泄漏和鈣流入實驗我們測試了聚甘胺酸-精胺酸和聚脯胺酸-精胺酸對於生物膜的破壞。並且在聚甘胺酸-精胺酸肽鏈中置換多個脯胺酸來進一步檢驗與螺旋構型相關的細胞毒性。我們還使用了等溫量熱法來評估聚甘胺酸-精胺酸/聚脯胺酸-精胺酸與核苷酸的結合與交互作用。此外，我們也進一步研究了聚甘胺酸-精胺酸/聚脯胺酸-精胺酸對DNA複製、RNA轉錄或蛋白質轉譯的抑制以及在細胞中核質運輸的破壞。最後，利用糖分子庫我們篩選出了一種具硫酸化的雙糖可以逆轉上述提到的毒性。利用ALS病人身上取得的多功能幹細胞分化而成的運動神經元，我們發現這個雙糖分子還可以增加此類神經元存活率，並且在聚甘胺酸-精胺酸/聚脯胺酸-精胺酸基因轉殖的果蠅模型上，我們發現這個雙糖分子可以延長其壽命和改善其運動功能。最後，若我們在小鼠腦部運動皮層注射聚甘胺酸-精胺酸會看到其運動功能的退化，利用這個雙糖分子我們亦可以反轉這個現象，為日後藥物的發展找尋契機。; The most prevalent mutation in frontotemporal lobar dementia (FTLD) and amyotrophic lateral sclerosis (ALS) is the expansion of the hexanucleotide GGGGCC, G4C2, repeat in the non-coding region of the C9ORF72 gene. FTLD is a neurodegenerative disease characterized by frontotemporal dementia, behavioral deficits, and progressive aphasia. ALS, on the other hand, is a motor neuron disease affecting both upper and lower motor neurons, leading to paralysis with an average survival time of two to five years. These two disorders share common pathologies and gene mutations. The pathological mechanisms associated with the C9ORF72 mutation include both loss of function and gain of function, involving reported RNA and protein toxicity. Repeat-associated non-ATG (RAN) initiated translation generates five dipeptide repeats (DPRs) from the hexanucleotide repeat expansion: poly-glycine-alanine (GA), poly-glycine-arginine (GR), poly-glycine-proline (GP), poly-proline-arginine (PR), and poly-proline-alanine (PA). These DPRs, originating from both sense and antisense RNA, are identified in the hippocampus, frontal and motor cortices, spinal cord, and cerebellum of FTLD or ALS patients. Among the DPRs, poly-GR and poly-PR, which are arginine-rich, have been observed as the most toxic species. The mechanisms of toxicity for poly-GR and poly-PR are still under intensive investigation. Proposed pathways include causing nucleolar stress, blocking nuclear pore transportation, compromising ribosomal RNA biogenesis, reducing mitochondrial function, and inhibiting protein translation. While all DPRs are observed in cytoplasmic inclusions, poly-GA is the most abundant and can fibrillize into neurotoxic amyloids. Additionally, poly-GA impairs proteasome function and induces TDP-43 mis-localization and aggregation. In contrast, the toxicities of poly-GP and poly-PA have not been reported. The G4C2 repeat number for healthy individuals ranges from 2 to 24 repeats, while in patients, it varies from over ~30 to hundreds or even thousands. The precise pathological threshold for G4C2 repeat number and the toxicity boundary regarding peptide length of DPRs remain unclear. In my study investigating the disease mechanism of poly-GR/PR, synthetic poly-GR peptides were utilized to examine the minimal length required for poly-GR toxicity. Structural information of poly-GR/PR was provided through circular dichroism (CD) spectroscopy and small angle X-ray scattering (SAXS) combined with molecular simulation. Membrane integrity was assessed through liposome leakage and calcium influx assays following poly-GR/PR treatment. Helix-related cytotoxicity was further examined by introduction of proline residues into poly-GR peptides. Poly-GR/PR interaction with nucleotides was also assessed using isothermal calorimetry. In addition, interference with DNA replication, RNA transcription, or protein translation was further investigated. Besides, compromised nucleocytoplasmic transportation was examined. Finally, a sulfated disaccharide was identified through chemical library screening and reversed most of the toxicities mentioned above. It also rescued poly-GR/PR-induced cytotoxicity in C9-iPS-derived motor neurons, transgenic poly-GR/PR fly models, and a poly-GR-injected mouse model. Mon, 01 Jan 2024 00:00:00 GMT http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/92322 2024-01-01T00:00:00Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/96475 標題: 研究C9ORF72漸凍人症中富含精胺酸雙胜肽所造成的細胞核TDP-43蛋白凝集現象; The study of TDP-43 nuclear condensation under C9ORF72 ALS-associated arginine-rich dipeptides 作者: 迪 莎; Diksha Agnihotri 摘要: 肌萎縮性脊髓側索硬化症（ALS）是一種致命的神經退化性疾病，運動神經元的退化最終會導致癱瘓，患者自疾病發作後的壽命僅剩 3 到 5 年。ALS 的一個重要遺傳原因是 C9ORF72 基因中的六核苷酸重複擴增。C9ORF72 基因中的 GGGGCC 序列擴增會轉譯為五種重複雙肽（DPR），包括甘胺酸-丙胺酸（poly-GA）、脯胺酸-精胺酸（poly-PR）、甘胺酸-精胺酸（poly-GR）。在這五種 DPR 中，富含精胺酸的雙肽被認為是最具毒性的。特別是poly-PR 二肽的毒性與其擾亂無膜胞器液體狀性質的能力高度相關。富含低複雜度區域（LCD）的蛋白質進行的液-液相分離（LLPS）是形成與維持無膜胞器（如核仁與側核斑）的基本機制。與 ALS 相關的蛋白質（如 TDP-43）中的 LLPS 失調被認為與 ALS 的致病機制有關。具體來說，LLPS 的改變可能會導致 TDP-43 在細胞質中凝膠化，並在延長壓力下聚集。然而，poly-PR 壓力對 TDP-43 在細胞核中 LLPS 的影響仍不清楚。 本研究中，我們探討了 poly-PR 壓力對 TDP-43 核凝聚的短期與長期影響。我們的研究結果顯示，暫時 poly-PR 壓力會誘導形成流動性降低的 TDP-43 核凝聚體 (NCs)。值得注意的是，長鏈非編碼 RNA NEAT1 與 HSP70 分子伴護蛋白在短期 poly-PR 壓力下與 TDP-43 核凝聚體顯著共位。藉由 siRNA造成減少，發現 NEAT1 其對於 TDP-43 核凝聚體（NC）形成是必要的。此外，以藥物抑制 HSP70 顯示其維持凝聚體流動性中的作用。在長期 poly-PR 壓力下，NEAT1 繼續作為 TDP-43 核凝聚體形成的支架；然而，HSP70 從這些凝聚體中脫離，導致流動性進一步降低並最終凝膠化。 利用基於螢光壽命的成像顯微鏡結合免疫螢光染色，發現在凝膠狀核凝聚物（NCs）中存在 TDP-43 寡聚物。此外，長期暴露於 poly-PR 壓力下導致了 TDP-43 蛋白病變，其特徵包括 TDP-43 磷酸化、錯位以及 C 末端 TDP-43 片段的出現，並伴隨著細胞毒性的增加。這項研究闡明了poly-PR通過干擾TDP-43核內LLPS以及典型TDP-43蛋白病變可能導致的毒性機制，並揭示了NEAT1和HSP70在這一過程中的作用。; Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease characterized by motor neuron degeneration that leads to paralysis, typically resulting in a life expectancy of 3-5 years after onset. A significant genetic factor in ALS is the hexanucleotide repeat expansion (GGGGCC) in the C9ORF72 gene, which results in the translation of five dipeptide repeats (DPRs). Among these, arginine-rich dipeptides toxicity is highly associated with their ability to disrupt liquid-like properties of membraneless organelles (such as the nucleolus and paraspeckles). Liquid-liquid phase separation (LLPS) of low-complexity domain (LCD)-rich proteins is crucial for the formation of these organelles. Dysregulated LLPS in ALS-related proteins like TAR DNA-binding protein 43 (TDP-43) has been linked to ALS pathogenesis, with alterations in LLPS potentially leading to TDP-43 gelation and aggregation under stress. However, the impact of arginine-rich dipeptides on TDP-43 LLPS in the nucleus is still unclear. In this study, we investigated the transient and prolonged effects of poly-PR and poly-GR dipeptide on TDP-43 nuclear condensation. Our findings indicate that only transient poly-PR stress induces the formation of TDP-43 nuclear condensates (NCs) with decreased fluidity. Of note, the long non-coding RNA NEAT1 and the HSP70 chaperones demonstrated significant colocalization with TDP-43 NCs under transient poly-PR stress. Through siRNA-mediated depletion, NEAT1 was found necessary for TDP-43 NCs formation. In addition, pharmacological inhibition of HSP70 suggested its role in maintaining condensate fluidity. Following prolonged exposure to poly-PR stress, NEAT1 continued to function as a scaffold for TDP-43 NC formation. However, HSP70 delocalized from these condensates, resulting in further reduced fluidity and subsequent gelation. By combining fluorescence lifetime-based imaging microscopy and immunofluorescence staining, the presence of TDP-43 oligomers were detected within gel-like NCs. In addition, prolonged poly-PR stress induced TDP-43 proteinopathy including TDP-43 phosphorylation, mislocalization and C-terminal TDP-43 fragments, along with the increased cytotoxicity. This study elucidates a potential toxicity mechanism of poly-PR dipeptide via perturbation of TDP-43 nuclear LLPS along with canonical TDP-43 proteinopathy, and shedding light on the roles of NEAT1 and HSP70 in the process. Mon, 01 Jan 2024 00:00:00 GMT http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/96475 2024-01-01T00:00:00Z