多巴胺接受器受藥物刺激下對大鼠腦內局部場電位同步關係之研究

Abstract

在腦神經科學研究中，腦部神經震盪訊號代表了腦部的活動情形。藉由不同區塊的腦部神經震盪訊號記錄，研究者得以開始探討腦部網路中連結關係與腦區間影響關係。不同區塊的腦部的震盪訊號已被證實在腦部網路中會交互影響，訊號間的同步性探討是了解腦部中運作機制的一個重要方法。在疾病影響或是外部刺激影響下，腦部內線性與非線性的訊號同步關係開始被廣泛探討。然而不同腦部區塊的震盪訊號彼此之間相互影響的關係須要被進一步探討，以了解腦部網路中的運作情形，是本研究要探討的主要方向。 本研究目標在對於大鼠多巴胺接受器刺激下探討腦部訊號間的線性與非線性關係，經由記錄大鼠腦內紋狀體與運動皮質區的局部場電位訊號(LFP)，施與多巴胺D2接受器促進劑與拮抗劑影響正常大鼠的多巴胺系統，以單一頻段連貫性與跨頻段雙相位鎖定方式，比較在正常狀態與在藥物刺激影響下，腦部紋狀體與運動皮質區間局部場電位訊號震盪同步關係。由實驗結果得知，在多巴胺促進劑與拮抗劑影響之下，低頻段德塔(δ),西塔(θ)的震盪訊號會明顯的出現因刺激而導致的相同頻帶間同步性加強與減弱現象。而藥物的刺激同時也會改變跨頻帶間並帶有特定方向性的同步關係。本研究說明了多巴胺藥物刺激下不僅改變特定腦部間的能量變化，同時也會影響腦區間神經震盪訊號的同步性關係，為與多巴胺系統相關的腦部神經訊號運作情形提供了更進一步的了解與分析。

Neural oscillation represent the neural activity in nervous system, by recording neural oscillation connectivity and interactions within brain networks could be investigated in an effective measure. A wealth of research have suggested that electrophysiological signals in brain networks would interact with each other, and synchronization between distinct areas has been implied the mechanism for brain interaction. With disease influence or external stimulation, the neural oscillation induce linear and non-linear interaction. However, the neural oscillation interaction originated from different brain areas need more investigation to realize the operation in brain networks. Therefore, the aim of this thesis attempts to explore the non-linear interaction with cross-frequency coupling in brain network during the stimulation of dopamine receptors. We record local field potential (LFP) in rats from striatum and motor cortex, giving stimulation on dopamine D2 receptors with dopamine receptor agonist and antagonist. Analysis with coherence and bispectral analysis discuss LFP synchronization between striatum and motor cortex that changes with drug stimulations, discussing the interaction between brain areas with and without drug stimulations. Results demonstrate that oscillations between striatum and motor cortex at delta and theta bands appear significant inverse synchrony changes in identical frequency band with different stimulations. Meanwhile, different stimulations induce cross-frequency bands synchronized or interferential synchrony fluctuations in brain with direction specificity, providing a further investigation and a special point of view in intracerebral neural oscillations interaction in neural network when dopamine receptors stimulated by drugs.