喜歡富于內(nèi)省,，緘默謹(jǐn)慎，靜如止水的林黛玉,；還是長于交際,，活潑開朗，動(dòng)如脫兔的史湘云,？內(nèi)向和外向作為一個(gè)人穩(wěn)定而統(tǒng)一的人格品質(zhì),，長久以來得到心理學(xué)家的重視。西南大學(xué)心理學(xué)部雷旭副教授帶領(lǐng)的研究小組發(fā)現(xiàn)該特質(zhì)與休息時(shí)大腦的活動(dòng)有關(guān),。他們發(fā)現(xiàn),，大腦中一個(gè)叫默認(rèn)模式網(wǎng)絡(luò)的系統(tǒng)實(shí)質(zhì)負(fù)責(zé)了內(nèi)外向的編碼：越內(nèi)向的人默認(rèn)模式網(wǎng)絡(luò)的波動(dòng)越有記憶性。目前,，本項(xiàng)研究已在線發(fā)表于神經(jīng)影像學(xué)期刊《神經(jīng)成像》(NeuroImage)上,。
在這項(xiàng)名為"默認(rèn)模式網(wǎng)絡(luò)編碼外向人格特質(zhì)"的研究中，研究生趙治瀛邀請到20位西南大學(xué)在校學(xué)生參與功能磁共振掃描,。一個(gè)叫默認(rèn)模式網(wǎng)絡(luò)的活動(dòng)引起了他的注意,。該網(wǎng)絡(luò)正如其名，即使在人處于休息狀態(tài)(默認(rèn))時(shí),，它仍在持續(xù)不斷的激活,。已有研究表明，默認(rèn)模式網(wǎng)絡(luò)的異?？赡軐?dǎo)致從阿爾茨海默病到精神分裂癥的各種疾病,。應(yīng)用信號長時(shí)記憶指數(shù)(Hurst)，趙治瀛進(jìn)一步發(fā)現(xiàn)外向的人長時(shí)記憶指數(shù)都比較小,。而內(nèi)向的人長時(shí)記憶指數(shù)越大,，表明大腦活動(dòng)更多地受到過去狀態(tài)的影響。
該研究認(rèn)為,，默認(rèn)模式網(wǎng)絡(luò)活動(dòng)的長時(shí)記憶性在一定意義上體現(xiàn)了大腦自我參考的刷新和處理能力,。信號記憶性越小的被試具有更好的在線信息處理能力，能夠支持他們活潑好動(dòng),，思維敏捷的需要,，表現(xiàn)出外向性。反之則會(huì)使人更多的將興趣指向自身內(nèi)部,，表現(xiàn)出自我反想,、深思熟慮、疑慮困惑等特點(diǎn)。下一步,，該小組希望深入探討盡責(zé)性,、隨和性等其他人格特質(zhì)是否也與休息時(shí)大腦特定區(qū)域的活動(dòng)有關(guān)。想知道自己的人格特質(zhì)是怎么樣的嗎,？快來做個(gè)五分鐘的功能磁共振掃描吧,，答案就在你大腦活動(dòng)的軌跡中。
本研究得到國家自然科學(xué)基金(31200857,31170981)和教育部人文社會(huì)科學(xué)研究青年基金(12YJC190015)的支持,。（生物谷Bioon.com）
DOI: 10.1016/j.neuroimage.2013.02.020
Extraversion is encoded by scale-free dynamics of default mode network
Xu Lei, Zhiying Zhao, Hong Chen
Resting-state functional Magnetic Resonance Imaging (rsfMRI) is a powerful tool to investigate neurological and psychiatric diseases. Recently, the evidences linking the scaling properties of resting-state activity and the personality have been accumulated. However, it remains unknown whether personality is associated with the scale-free dynamics of default mode network (DMN) - the most widely studied network in the rsfMRI literatures. To investigate this question, we estimated the Hurst exponent, quantifying long memory of a time-series, in DMN of rsfMRI in 20 healthy individuals. The Hurst exponent in DMN, whether extracted by independent component analysis (ICA) or region of interest (ROI), was significantly associated with the extraversion score of the revised Eysenck Personality Questionnaire. Specifically, longer memory in DMN corresponded to lower extraversion. We provide evidence for an association between individual differences in personality and scaling dynamics in DMN, whose alteration has been previously linked with introspective cognition. This association might arise from the efficient in online information processing. Our results suggest that personality trait may be reflected by the scaling property of resting-state networks.
