習得年齡對語言處理有相當影響，但其成因及作用階段至今仍無定案，根據以知的行為研究成果及假說，結合事件相關電位技術，及雙重選擇按鍵與否典範，我們將嘗試找出習得年齡在言語產出中的作用階段。假定不欲按鍵則無側化動作準備電位，且側化準備電位起始時間取決於，何時取得用以決定反應手的訊息，我們請受試者根據圖片刺激的兩種語言屬性做出正確反應。 在實驗一中，語意屬性（人造或非人造）決定反應手，圖片名稱第一音節的語音屬性(一、三聲或二、四聲)決定按鍵與否。若習得年齡影響語意處理，我們預期在按鍵情形下，習得年齡早晚兩組的側化準備電位起始時間將有所不同；而不按鍵情形下的側化準備電位持續時間，將反映習得年齡對語音處理的影響。實驗二中，圖片經更嚴格挑選，以控制所有變項，且語言屬性與反應類別間的兩種對應都被測試。 實驗一和實驗二都發現不按鍵時，若反應手非由語意屬性決定，則側化準備電位不會出現。這個結果符合文獻記載，並暗示語意處理早於語音處理。實驗一中，早習得圖片的唸名反應時間、圖片分類反應時間、及側化準備電位起始時間都較短，支持習得年齡越早，語意提取速度越快。但實驗二中，習得年齡對側化準備電位起始時間沒有顯著影響，儘管前測顯示早習得圖片的唸名反應時間較短，其分類反應時間卻較長，。實驗三進一步肯定，習得年齡對唸名及圖片分類作業有相反效果，以及習得年齡對圖片分類作業的效果不因重複練習而喪失。 根據完整語音理論 (Brown & Watson, 1987)，我們認為當作業要求完整的語音訊息，則習得年齡越早，提取速度越快，唸名作業如是；當作業要求片段的語音訊息，則習得年齡越早，提取速度越慢，額外時間用於解構完整語音訊息，我們的圖片判斷作業如是。實驗二中因少數圖片重複出現，習得年齡對語意處理的正面作用減少，習得年齡對片段語音處理的負面作用卻維持，使得習得年齡組別間，側化準備電位沒有顯著差異，且早習得組圖片分類反應時間反而較長。 總而言之，本研究支持概念/詞目競爭理論的說法，亦即習得年齡越早，語意提取速度越快。我們的資料也間接反映，習得年齡越早，語音提取速度越慢，但此推論仍需未來研究進一步支持。 / Age-of-acquisition (AoA) is one of the most robust variables for language processing. But its cause and locus during the processing are still under debate. Based on previous behavioral studies and established hypotheses, this study aims to find electrophysiological evidence for the locus of AoA effect during speech production. The continuous measure of speech production is approached by event-related potential (ERP) in conjunction with a manual, dual choice Go/Nogo paradigm. In this paradigm, participants need to choose the correct response according to two linguistic attributes of the target picture. The presumption of this paradigm is that the lateralized readiness potential (LRP), a motor preparation related component, would be absent once the Nogo decision has been made, and its onset marks the time point at which critical information for hand selection is available. In Experiment 1, which hand to respond depends on the target picture’s semantic attribute (artifact or non-artifact), to respond or not relies on its phonological attribute (the tone value of its first syllable). It is expected that if AoA influences lexical/semantic processing, LRP onset latency would be different under early and late AoA condition. AoA effect on phonological stage would be reflected on the duration of Nogo LRP. In Experiment 2 the reverse mapping between linguistic attribute and response types was also tested and variables other than AoA were more strictly controlled. Both experiments replicate previous finding in that Nogo LRP only occurs when response hand is contingent on semantic information, which indicates that semantic stage precedes phonological stage. In Experiment 1, naming latency, picture classification RT (reaction time), and LRP onset latency were shorter for the early AoA group, indicating accelerated lexical/semantic retrieval. However, in Experiment 2, AoA effect on LRP onset latency was not found. And for items with early AoA, picture classification RT is significantly longer, despite that their naming latency is shorter in the pretest. Experiment 3 further validates the coexistence of the positive AoA effect on naming and negative AoA effect on tone classification and the resistance of the negative AoA effect to repetition. Following the phonological completeness hypothesis (Brown & Watson, 1987), we suggest that when the unitary phonological form is demanded, as in the naming task, the early learned words has advantage. When a fraction of the unitary form is demanded, as in the tone classification task, extra time is needed to decompose the retrieved unitary form. The positive AoA effect on semantic stage is larger in Experiment 1 due to material selection and number of repetition. Thus in Experiment 1, the positive AoA effect on semantic stage remains, but in Experiment 2, it is overpowered by the negative AoA effect on fractional phonological extraction, resulting in the absence of AoA effect on LRP pattern and longer picture classification RT under early AoA condition. In sum, results of this study indicate that semantic feature can be retrieved faster under early AoA condition, which is in line with concept/lemma competition hypothesis. Our results also imply slower tone retrieval under early AoA condition, which need to be further testified by future studies.

研究目的 失眠的過度激發假說是目前最廣為接受的失眠病因之一，失眠者通常可觀察到具有身心過度激發的狀態，其中認知神經過度激發假說更由中樞神經的角度探討失眠者的過度激發現象，且已有許多證據支持此觀點。然而過度激發因素在失眠病程上的影響仍不明確，不論在前置因子或是持續因子的層面，激發因素皆經常被提及與討論。本研究以未失眠但具有高睡眠脆弱特質之族群作為研究對象，企圖模擬失眠者在失眠初發之前的狀態，另加入睡前及早晨的自主神經系統與主觀激發狀態之測量，比較其與低睡眠脆弱特質組在有無壓力誘發狀態下，兩組的睡眠中訊息處理程度、睡前及早晨的自主神經系統激發程度與主觀激發狀態，藉以了解（1）壓力是否會引發個體進入較高的主、客觀激發狀態；(2)睡眠脆弱特質在不同的激發程度下，是否會對於個體的睡前、睡眠中及早晨的激發程度造成影響，以初步推論激發狀態因素在失眠病程中所扮演之角色。 方法 以壓力下失眠反應量表（Ford Insomnia Response to Stress Test, FIRST）區分出高睡眠脆弱特質組（HV）13位（6男、7女）、低睡眠脆弱特質組（LV）14位（6男、8女），年齡為19-32歲之健康成人。每位受試者均需在睡眠實驗室進行3個夜晚之夜間睡眠記錄，包含第一晚的PSG測量以排除個案有其他睡眠疾患，並讓受試者習慣實驗環境；第二晚及第三晚則交互平衡操弄基礎情境或壓力情境，在壓力情境下，受試者被告知將進行即席演講，需在睡前抽出演講題目，並於隔天早晨喚醒後10分鐘內發表一篇內容充實、呼應主題之演說，隨後測量心跳變異率（heart rate variability，HRV）、平均心跳間距（r-r interval，RRI）、主觀身心激發狀態（Pre sleep arousal scale，PSAS）等主客觀激發程度，入睡後進行整夜的ERP（事件相關電位[Event-related potential，ERP]）測量，誘發ERPs之實驗流程以oddball典範為主，並於早晨起床後再次進行HRV、RRI及PSAS之測量。 結果 以2（組別）x 2（情境）之混和設計二因子變異數分析比較各組在不同情境下的主客觀激發程度指標是否有所不同。結果顯示壓力確實能引發受試者進入較高的主客觀激發狀態，包含睡前及早晨有較快的平均心跳速率、較高的主觀身心激發程度，而在NREM睡眠中可發現HV在有壓力的情境下，對外界的訊息處理程度顯著較LV組增加，包含較快的N1與較慢的N350出現，但HV在壓力下亦有較快的P2與較強的P900，顯示對外界訊息的抑制功能上升，且隨著睡眠更深，進入慢波睡眠時，P2及P900亦顯著較LV強，表現出更多的抑制外界訊息能力。 結論 本研究探討睡眠脆弱特質在不同激發狀態下對於睡眠的影響，結果顯示壓力能引發個體較高的激發狀態，然而在未失眠族群中，高睡眠脆弱特質對於認知激發狀態下的睡眠中訊息處理程度雖有提高，但可發現高睡眠脆弱特質組亦有較高的抑制外界訊息能力，而不致於使得激發狀態過度影響其睡眠，此結果部分支持失眠的認知神經過度激發假說，過度激發因素可能在持續因子的部分影響性較大，造成個體產生對睡眠的抱怨。另一方面，本研究結果亦彰顯失眠的高危險群的及早介入預防之重要性。 / Introduction: Conditioned hyperarousal has been theorized to be a major etiological factor in chronic insomnia patients. It has been suggested that insomniacs showed more arousal than non-insomniacs in many psychological and physiological measures, including enhanced information processing during sleep as measured by NREM ERPs. However, the role of hyperarousal on the course of development of insomnia remained unclear, it has been considered as a predisposing trait and/or perpetuating factor in the cause of insomnia. The present study compared arousal levels around sleep onset, during sleep and in the morning between non-insomniac individuals with low and high vulnerability to stress-related sleep disturbance, as high vulnerable individuals were proposed to be predisposed to chronic insomnia. The objectives of the study are therefore to investigate: 1) the effect of an acute stressor on arousal level prior, after, and during sleep, and 2) the differences in stress reactivity between individual with high and low vulnerability to stress-related sleep disturbances. Method: Fourteen healthy individuals scoring low (LV) and thirteen healthy individuals scoring high (HV) on the Ford Insomnia Response to Stress Test (FIRST) were studied. All subjects had to sleep in the lab for three nights: a screening/ adaptation night, then a baseline night and a stress night. The sequences of the later two nights were counterbalanced across subjects. During the stress night, subjects were informed that they would be required to give a speech immediately after waking up. Heart rate variability (HRV), r-r interval (RRI) of EKG and subjective arousal level (Pre sleep arousal scale, [PSAS]) was accessed before lights off and in the morning. Then sleep ERP was recorded during the night. An odd-ball paradigm was conducted to evoke ERPs throughout the night. Result: Mixed two-way ANOVAs were used to compare the differences between vulnerabilities and conditions. Both HV ans LV showed higher subjective arousal level and smaller RRI under the stress condition than the baseline condition. During NREM sleep, HV showed increased information processing under stress condition than LV as shown by faster N1, slower N350. Also, HV showed increased inhibition under stress condition than LV, with faster P2 and higher P900. Stronger P2 and P900 were also observed in HV when reached slow-wave sleep stage, comparing to LV. Conclusion: Both groups showed more arousal under stress condition than baseline condition, indicating an acute stress can lead to a higher arousal level. Moreover, high vulnerable individuals showed increased information processing during NREM sleep than low vulnerable individuals, but also showed more inhibition to prevent sleep from being disturbed by external stimulus. The results suggest that increased information processing in reacting to stress may be a predisposing trait for sleep disturbances. However, sleep may be protected by a compensatory inhibitory process in those who have not developed a long-term insomnia.