個體間的預設神經網絡功能性連結隨不同任務的變化

Abstract

近年來的研究建議預設神經網絡的活性以及功能性連結也許可以做為一些心智相關疾病如精神分裂症、與老化有關的認知退化、失智症等的臨床生物標記。但是，正常人面對不同任務像是與自我相關、非自我相關、休息任務時擁有不同的心理狀態下，而預設神經網絡的功能性連結在正常人不同心理狀態下的一致性仍不清楚。因此，本研究探討預設神經網絡的功能性連結在正常人是穩固不變的或者會因為任務的要求及任務的順序而改變。43位參與者 (平均年齡 (標準差) = 24.2 (2.4) 歲;其中23位為女性) 在磁振照影儀器內完成四項不同的任務 (記憶、詞語判斷、自我評價、休息)。我們的結果顯示楔前葉-顳頂葉交界的功能性連結與內側顳葉-腦島的功能性連結會受任務的調控而改變。本研究揭露部分預設神經網絡的功能性連結在同個體內會隨任務要求而改變。因此使用預設神經網絡的功能性連結作為個體認知狀態的指標時，至少需要提供參與者在掃描腦影像之前與掃描腦影像當下做了哪些心智活動。

It has been suggested that default mode network activity and functional connectivity (FC) may have application as a clinical biomarker for various mental disorders such as schizophrenia, age-related cognitive declines, and Alzheimer’s Disease. However, the consistency of default mode network FC within a normal individual under different psychological states when engaging in self and non-self tasks, and during resting-state situations is unclear. In this study, we evaluated the extent to which default mode network FC within an individual is robust or sensitive to task demands (including resting-state) and task order. 43 right-handed participants (mean age (SD) = 24.2 (2.4) yrs old; 23 female) completed four different tasks (memory, lexical decision, self judgment, rest) in this functional magnetic resonance imaging (fMRI) study. We found that precuneus - temporoparietal junction FC and medial temporal lobe - insula FC were significantly different across these tasks. Thus, default mode network FCs are sensitive to task demands in a within-subjects manner. These results suggest that the use of default mode network FC to index cognitive status in individuals should be qualified perhaps by reports of what mental activities subjects are engaged in during or prior to the scan.