領導實施這項研究的不列顛哥倫比亞大學心理學教授卡琳娜·克里斯托夫（Kalina Christoff）表示：“思緒飄揚一般同懶散或精力不集中等負面事情有關。但是，這項研究卻表明我們走神時大腦活動反而更為活躍，活躍程度甚至超過我們專心從事一些日常工作的時候�！�
在研究中，志愿者躺在fMRI掃描儀里面，當數字出現在屏幕上時進行按鍵等簡單活動。研究人員可以通過大腦掃描、志愿者的主動報告以及追蹤志愿者的成績來調查他們的瞬間注意力。研究結果發現，走神(最多可以占據我們清醒狀態下三分之一的時間)是一種重要的認知狀態，在這種狀態下，我們可能在不知不覺中將注意力從當前的工作轉向梳理日常生活中的重要問題。
在此之前，科學家認為大腦的“默認網絡”是走神時大腦中唯一活躍的區域。大腦“默認網絡”同日常輕松的智力活動有關，包括內側前額葉皮質、后扣帶回皮質和顳頂聯合區(temporoparietal junction)。但是，這項研究卻發現，大腦的“執行網絡”在我們走神時也會被激活。大腦“執行網絡”負責解決高度復雜的問題，由側面前額葉皮質和背面后扣帶回皮質構成。
克里斯托夫說：“這是一項驚人發現，兩個大腦網絡可以被同時激活。在此之前，科學家一直認為它們在一個被激活時，另一個處于休眠狀態�！敝驹刚咴揭庾R不到他們的思緒飄蕩，兩個大腦網絡越能被激活。
大腦活動的數量和質量表明，嘗試解決復雜問題的人應該先停下來，轉而從事更為簡單的工作，讓思緒自由飄蕩�？死锼雇蟹蛘f：“你在走神的時候，可能并沒有取得直接目標——比如在課堂上讀書或集中注意力聽講，但思緒可能利用這一時間去解決你人生中更為重要的問題，比如事業發展或個人關系�！�
PNAS May 11, 2009, doi: 10.1073/pnas.0900234106
Experience sampling during fMRI reveals default network and executive system contributions to mind wandering
Kalina Christoffa,1, Alan M. Gordonb, Jonathan Smallwoodc, Rachelle Smitha and Jonathan W. Schoolerc
Although mind wandering occupies a large proportion of our waking life, its neural basis and relation to ongoing behavior remain controversial. We report an fMRI study that used experience sampling to provide an online measure of mind wandering during a concurrent task. Analyses focused on the interval of time immediately preceding experience sampling probes demonstrate activation of default network regions during mind wandering, a finding consistent with theoretical accounts of default network functions. Activation in medial prefrontal default network regions was observed both in association with subjective self-reports of mind wandering and an independent behavioral measure (performance errors on the concurrent task). In addition to default network activation, mind wandering was associated with executive network recruitment, a finding predicted by behavioral theories of off-task thought and its relation to executive resources. Finally, neural recruitment in both default and executive network regions was strongest when subjects were unaware of their own mind wandering, suggesting that mind wandering is most pronounced when it lacks meta-awareness. The observed parallel recruitment of executive and default network regions—two brain systems that so far have been assumed to work in opposition—suggests that mind wandering may evoke a unique mental state that may allow otherwise opposing networks to work in cooperation. The ability of this study to reveal a number of crucial aspects of the neural recruitment associated with mind wandering underscores the value of combining subjective self-reports with online measures of brain function for advancing our understanding of the neurophenomenology of subjective experience.
（譯文及原文源自不知哪里。）
本文來自：快速記憶法 http://www.885221.com/dp-bbsthread-7652.html
