神經(jīng)元保持沉默，行動(dòng)力得以改善

Article Date: 07 Nov 2011 - 0:00 PST

發(fā)表于2011年11月7日

To be able to focus on the world, we need to turn a part of ourselves off for a short while, and this is precisely what our brain does. 

我們?yōu)榱司劢惯@個(gè)世界，需要身體暫時(shí)停止某些部位的活動(dòng)，而這正是大腦的所作所為。

They demonstrate more specifically that when we need to concentrate, this network disrupts the activation of other specialized neurones when it is not deactivated enough. The results have just been published in the Journal of Neuroscience. 

這一結(jié)論剛剛發(fā)表在《神經(jīng)系統(tǒng)科學(xué)雜志》上，文章說(shuō)當(dāng)我們需要集中注意力時(shí)，如果某些神經(jīng)元不夠安靜的話，大腦網(wǎng)絡(luò)就會(huì)干擾特定神經(jīng)元的活性。

When we focus on the things around us, certain parts of the brain are activated: this network, well known to neurobiologists, is called the attention network. Other parts of the brain, however, cease their activity at the same time, as if they generally prevented our attention from being focused on the outside world. These parts of the brain form a network that is extensively studied in neurobiology, and commonly known as the "default-mode network", because, for a long time, it was believed that it activated itself when the brain had nothing in particular to do. This interpretation was refined through ten years of neuroimaging research that concluded by associating this mysterious network ("the brain's dark energy" as it was called by one of its discoverers, Marcus Raichle) with a host of intimate and private phenomena of our mental life: self-perception, recollections, imagination, thoughts... 

當(dāng)我們將注意力集中于身邊某事時(shí)，大腦中特定區(qū)域?qū)⒈患せ睿哼@個(gè)特殊區(qū)域呈網(wǎng)狀，正是為神經(jīng)生物學(xué)家們所熟知的“注意力網(wǎng)狀結(jié)構(gòu)”。而大腦的其他部分則同時(shí)停止了活動(dòng)，就好像它們一起在阻止我們的注意力不被外部世界所吸引。大腦的這些部分形成了一個(gè)網(wǎng)絡(luò)，通常它被稱為“靜息狀態(tài)網(wǎng)絡(luò)”——正被神經(jīng)生物學(xué)家們進(jìn)行著廣泛的研究。原因是，長(zhǎng)期以來(lái)，人們認(rèn)為當(dāng)大腦無(wú)事可做時(shí)這個(gè)結(jié)構(gòu)會(huì)進(jìn)行自我激活。

這種說(shuō)法在過(guò)去的10年間通過(guò)神經(jīng)成像技術(shù)不停地被加以精煉，成像學(xué)將這個(gè)神秘網(wǎng)絡(luò)和許多私密的精神現(xiàn)象聯(lián)系在一起，而得出了這一結(jié)論。比如人的自我認(rèn)知、回憶、想像、思想等……它們與靜息狀態(tài)網(wǎng)絡(luò)進(jìn)行著聯(lián)結(jié)（這個(gè)也被稱做“大腦暗物質(zhì)”，這是說(shuō)法是發(fā)現(xiàn)者之一的馬庫(kù)斯最先叫起來(lái)的）。

A study carried out by a team at the Centre de Recherche en Neurosciences de Lyon (led by Tomas Ossandon and managed by Jean-Philippe Lachaux, Research Director at Inserm and Karim Jerbi, Research Leader at Inserm) has just revealed how this network interferes with our ability to pay attention, by assessing the activity of the human brain's default-mode network neurones on a millisecond scale for the first time ever, in collaboration with Philippe Kahane's epilepsy department in Grenoble. 

法國(guó)國(guó)家健康科學(xué)研究院的一個(gè)科研小組聯(lián)合在格勒諾布爾（法國(guó)南部城市）的菲利普癲癇病研究所首次在毫秒水平上，對(duì)大腦中這個(gè)網(wǎng)絡(luò)是如何影響我們的行為進(jìn)行了研究：比如如何集中注意力，如何評(píng)估大腦靜息狀態(tài)網(wǎng)絡(luò)聯(lián)結(jié)的神經(jīng)元活動(dòng)。

The results unambiguously illustrate that whenever we look for an object in the area around us, the neurones of this default-mode network stop their activity. Yet, this interruption only lasts for the amount of time required to find the object: in less than a tenth of a second, after the object has been found, the default-mode network resumes its activity as before. And if our default-mode network is not sufficiently deactivated, then we will need more time to find the object. These results show that there is fierce competition for our attentional resources inside our brain which, when they are not used to actively analyse our sensorial environment, are instantaneously redirected towards more internal mental processes. The brain hates emptiness and never stays idle, even for a tenth of a second.

結(jié)論明白地揭示出：無(wú)論何時(shí)，只要我們?cè)谥車鷮ふ乙粋€(gè)目標(biāo)時(shí)，大腦中靜息狀態(tài)網(wǎng)絡(luò)的神經(jīng)元就會(huì)停止活動(dòng)。當(dāng)然這個(gè)中斷只會(huì)持續(xù)到我們找到目標(biāo)時(shí)為止，而這個(gè)時(shí)長(zhǎng)還不到十分之一秒。當(dāng)目標(biāo)被找到，靜息狀態(tài)網(wǎng)絡(luò)將立即恢復(fù)其之前的活動(dòng)。如果我們的靜息狀態(tài)網(wǎng)絡(luò)不能充分地去活，那么我們就需要更多的時(shí)間來(lái)尋找目標(biāo)。

這些結(jié)論顯示：在大腦中，為注意力源存在著相當(dāng)激烈的競(jìng)爭(zhēng)活動(dòng)，如果神經(jīng)元不是被活躍地用來(lái)分析感知周圍環(huán)境，則會(huì)立即轉(zhuǎn)向更為內(nèi)化的精神活動(dòng)。我們的大腦憎恨空虛，而且從不吃閑飯，就算只有不到十分之一秒。