近日，國(guó)際著名雜志《自然—神經(jīng)科學(xué)》Nature Neuroscience在線刊登的一項(xiàng)報(bào)告中指出,，相似沖動(dòng)行為牽涉不同大腦區(qū)域,。雖然注意力缺失過(guò)動(dòng)癥（ADHD）和藥物濫用都一直被認(rèn)為和沖動(dòng)行為有關(guān)，但未成年人的ADHD和藥物濫用卻分別牽涉到不同的大腦網(wǎng)絡(luò),。
Robert Whelan等人使用功能性磁共振成像對(duì)近2000名未成年人的大腦活動(dòng)進(jìn)行追蹤,，監(jiān)控他們?cè)谕蝗唤邮盏?ldquo;停止”指令時(shí)，大腦是如何下令停止某個(gè)動(dòng)作的,?？傮w來(lái)說(shuō)，較沖動(dòng)的人會(huì)認(rèn)為這樣的指令比較有難度,，藥物濫用者和ADHD患者面對(duì)“停止”指令的反應(yīng)時(shí)間也會(huì)比較長(zhǎng),。研究人員發(fā)現(xiàn)那些ADHD癥狀的未成年患者和有過(guò)藥物濫用、酗酒的未成年人均能同樣完成指令,，但對(duì)于后者而言,，其大腦的眼窩前額皮層區(qū)域中心的活動(dòng)會(huì)降低。
與此形成對(duì)比的是，只有非法藥物濫用才能對(duì)大腦右下額葉皮層的活動(dòng)產(chǎn)生影響,，而且該區(qū)域活動(dòng)的變化又和藥物的濫用頻率有關(guān),，這意味著這種變化可能是由類似藥物的重復(fù)使用所導(dǎo)致的，而并不是先天存在的,。
這些研究發(fā)現(xiàn)表明,，一些看上去相同的行為對(duì)應(yīng)在大腦中的活動(dòng)區(qū)域可能有很大的不同。（生物谷Bioon.com）
doi:10.1038/nn.3092
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Adolescent impulsivity phenotypes characterized by distinct brain networks
Robert Whelan, Patricia J Conrod, Jean-Baptiste Poline, Anbarasu Lourdusamy, Tobias Banaschewski, Gareth J Barker, Mark A Bellgrove, Christian Büchel, Mark Byrne, Tarrant D R Cummins, Mira Fauth-Bühler, Herta Flor, Jürgen Gallinat, Andreas Heinz, Bernd Ittermann, Karl Mann, Jean-Luc Martinot, Edmund C Lalor, Mark Lathrop, Eva Loth, Frauke Nees, Tomas Paus, Marcella Rietschel, Michael N Smolka, Rainer Spanagel et al.
The impulsive behavior that is often characteristic of adolescence may reflect underlying neurodevelopmental processes. Moreover, impulsivity is a multi-dimensional construct, and it is plausible that distinct brain networks contribute to its different cognitive, clinical and behavioral aspects. As these networks have not yet been described, we identified distinct cortical and subcortical networks underlying successful inhibitions and inhibition failures in a large sample (n = 1,896) of 14-year-old adolescents. Different networks were associated with drug use (n = 1,593) and attention-deficit hyperactivity disorder symptoms (n = 342). Hypofunctioning of a specific orbitofrontal cortical network was associated with likelihood of initiating drug use in early adolescence. Right inferior frontal activity was related to the speed of the inhibition process (n = 826) and use of illegal substances and associated with genetic variation in a norepinephrine transporter gene (n = 819). Our results indicate that both neural endophenotypes and genetic variation give rise to the various manifestations of impulsive behavior.
