- 學位論文
探討記憶固化時間相依特性：比較延遲及立即干擾
Time-Dependent Nature of Memory Consolidation: Contrasting Delayed with Immediate Intervention
摘要
記憶固化為學習後記憶隨著時間逐漸穩固化的心理歷程，即學習內容愈趨不受外界干擾如新資訊或是腦傷所影響。根據標準系統層次記憶固化理論，處理記憶的腦區網絡逐漸重組，隨著皮質區內部的聯結增強，相關腦區網絡將逐漸獨立於海馬迴。本研究藉由比較立即干擾組（學習後立即介入干擾）及延遲干擾組（學習後一小時介入干擾）並結合功能性磁振造影技術探討記憶固化時間相依特性。本研究結果顯示（1）立即干擾組從第一天到第二天的記憶表現下滑幅度大於延遲干擾組；（2）立即干擾組在提取時海馬迴和皮質區（左上顳葉迴及楔狀葉）之間的功能性連結強度從第一天到第二天明顯上升；（3）立即干擾組於學習後的靜息態影像結果未呈現功能性連結上的變化，而在延遲干擾組發現學習後一小時到一天間其海馬迴與皮質區（楔狀葉）之間的功能性連結強度顯著下降。本研究結果表示由於記憶固化時間相依的特性，干擾介入的不同時間點將產生行為和神經機制上的差異，在相對不穩定時受到干擾將嚴重影響記憶表現且神經機制將相對依賴海馬迴。
並列摘要
Memory consolidation refers to progressive stabilization of memory after learning. It features the time-dependent nature revealing memory becoming less susceptible to interference such as new information or brain injury. According to the standard systems consolidation theory, consolidation involves gradual reorganization of brain regions that support memory formation. As the connections among the related cortical regions are strengthened, neural basis of memories shows gradual independence of the hippocampus. This study investigates the time-dependent nature of memory consolidation by contrasting the immediate intervention condition (interference immediately after learning) with the delayed intervention condition (interference after 1 hour), using functional magnetic resonance imaging (fMRI). The results show: (1) Greater detrimental effect on memory performance of the immediate intervention group than that of the delayed intervention group; (2) Significant increase in the hippocampal-cortical (left superior temporal gyrus and cuneus) connectivity for the immediate intervention group; (3) No significant change in the resting-state hippocampal-cortical connectivity from 1 hour to 1 day after learning, but a significant decrease in the hippocampal-cortical (cuneus) connectivity for the delayed intervention group. These results suggest that due to the time-dependent nature of memory consolidation, interferences at different time points lead to significant differences in behavior and brain activity. When interference appears in a relatively unstable state, memory performance will be severely impaired and the neural operation will be more dependent on the hippocampus.