臺灣博碩士論文加值系統

大腦是人體非常重要的器官之一，非侵入式的腦電圖（electroencephalography, EEG）及功能性磁振造影（functional Magnetic Resonance Image, fMRI）近年來已普遍運用在腦功能的研究。EEG是直接量測神經活動電訊號，fMRI則是透過量測因神經細胞活化所造成的區域血液氧化程度變化間接得知神經活動狀態，有研究指出功能性磁振造影訊號會受血碳酸過多影響，但造成影響的原因是由血液動力學方面或是根本上神經訊號的改變仍未被徹底探究，因此血碳酸過多與神經活化之間的關係仍有待了解。因此我們希望藉著記錄EEG訊號，從神經活動電訊號的角度了解在血碳酸的過多的狀態下視覺誘發電位（Visual Evoked Potential, VEP）的變化狀況。本實驗包含六名健康受測者，每次實驗包含血碳酸過多前、血碳酸過多、血碳酸過多後三個階段，在血碳酸過多階段透過讓受測者吸入不同濃度二氧化碳混合氣體（室內空氣、3%、5%、7%）產生不同程度的血碳酸過多，在三個階段中各給予閃光刺激以誘發VEP，並紀錄在不同血碳酸過多環境下誘發波形變化。將血碳酸過多前與血碳酸過多階段VEP波形進行比較，實驗結果顯示不論暫態視覺誘發電位實驗中波峰II-III振幅或穩態視覺誘發電位實驗中峰對峰振幅皆隨著吸入二氧化碳的濃度提高而變小，在3%時改變並不明顯（Wilcoxon, P>0.05）但在5%及7%二氧化碳時較顯著(Wilcoxon, P<0.01)。但暫態視覺誘發電位實驗中VEP波形延遲時間不受血碳酸過多的影響（Friedman, P>0.05）。VEP波形改變反應了腦細胞活化程度的變化，因此在臨床上腦功能檢查時，應考量血碳酸過多造成的影響。

The cerebrum is one of important organs for human. Recently there are many studies to discover brain function by traditional EEG and novel functional MRI (fMRI). The electrical signal of neural activity can directly recorded by EEG, but fMRI only measure the local blood oxygen level that effect by neural activity. A lot of researches point out the activated signal could be influenced by hypercapnia in fMRI study, due to the change of local blood flow during hypercapina. According our best knowledge, the relationship between hypercapnia and neural activity has not been fully investigated in human. In this study, we estimate the relationship by the change of visual evoked potential (VEP) under multi-level carbon dioxide concentration. Six healthy volunteers were recruited, each undergoing 4 separate experiments by inhaling gas mixtures with different fractions of CO2 (room air, 3%,5%, and 7%). Visual stimulation was given in each experiment contained 3 phases, prehypercapnic, hypercapnic, and posthypercapnic via a LED flashing. After comparing the results in different phases, we found the decreased amplitude of VEP with increase of inhaled CO2 fractions. It is not significantly different when inhaling 3% CO2 gas (Wilcoxon, P>0.05) but in 5% and 7% (Wilcoxon, P<0.01). However, the latency of VEP is not affected by hypercapnia in the experiment of transient visual evoked potential （Friedman, P>0.05）. Because the amplitude and latency reflect the neural activity, we suggest the effect of hypercapnia is necessary to be sufficient consideration in clinical cerebral functional research.

中文摘要 i
Abstract ii
目錄 iii
圖目錄 v
表目錄 vii
第一章 緒論 1
1.1研究背景 1
1.2研究目的與其重要性 2
1.3文獻回顧 3
第二章 研究理論 5
2.1大腦組織構造 5
2.2血碳酸過多（Hypercapnia） 7
2.3腦電圖（electroencephalograph, EEG） 7
2.3.1EEG簡介 7
2.3.2EEG頻段劃分及其生理意義 8
2.4誘發電位（Evoked Potentials, EPs） 10
2.5視覺誘發電位（Visual Evoked Potential, VEP） 12
2.5.1暫態視覺誘發電位（Transient Visual Evoked Potential） 13
2.5.2穩態視覺誘發電位（Steady-State Visual Evoked Potential, SSVEP） 14
第三章 實驗流程與方法 16
3.1實驗對象 16
3.2氣體準備與生理參數監測 16
3.3EEG及視覺刺激實驗設備 18
3.3.1EEG放大濾波系統 18
3.3.2電極帽 19
3.3.3視覺刺激單元 21
3.3.4個人電腦 21
3.4實驗流程 22
3.5資料分析 23
第四章 結果與討論 25
4.1潮氣末二氧化碳濃度量測結果 25
4.2暫態視覺誘發電位實驗結果與討論 27
4.2.1暫態視覺誘發電位實驗結果 27
4.2.2暫態視覺誘發電位實驗結果討論 32
4.3穩態視覺誘發電位實驗結果與討論 34
4.3.1穩態視覺誘發電位實驗結果 34
4.3.2穩態視覺誘發電位實驗結果討論 37
第五章 結論與未來展望 38
5.1結論 38
5.2未來展望 39
參考文獻 40

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