一项研究发现了冲动行为的一个可能的神经基础。和智慧一样，自我控制也常常被认为随着年龄而增长，但是自我控制的病理性丧失可能导致犯罪倾向。Benjamin J. Shannon及其同事进行了一个功能磁共振成像（fMRI）实验，用于比较一个看守严密的机构里的100多个青少年罪犯与7到31岁的典型发育的人的大脑功能连接情况。
这组作者在受试者安静休息的时候扫描了他们的大脑。这组作者报告说，在较少冲动的青少年罪犯中，大脑所谓的“运动规划”区域（它们参与了规划运动）展现了与参与注意和认知控制的大脑区域一致的活动。然而，对于更冲动的罪犯，运动规划区域的活动与大脑的所谓“默认模式”的网络的活动相关，后者参与了无意识的、不受约束的认知。在典型发育的人中间，运动规划区域活动的模式随着年龄而变化。较年轻的人的大脑活动类似于更冲动的罪犯的活动，而年龄较大的人的活动类似于较少冲动的罪犯的活动。这组作者提出，这些发现可能有助于解释为什么冲动的人的行动可能是受瞬间的满足而不是受长期后果驱动的。（生物谷Bioon.com）
生物谷推荐原文出处：
Proceedings of the National Academy of Sciences DOI： 10.1073/pnas.1108241108
Premotor functional connectivity predicts impulsivity in juvenile offenders
Shannon, Benjamin J.; Raichle, Marcus E.; Snyder, Abraham Z.; Fair, Damien A.; Mills, Kathryn L.; Zhang, Dongyang; Bache, Kevin; Calhoun, Vince D.; Nigg, Joel T.; Nagel, Bonnie J.; Stevens, Alexander A.; Kiehl, Kent A.
Teenagers are often impulsive. In some cases this is a phase of normal development; in other cases impulsivity contributesto criminal behavior. Using functional magnetic resonance imaging, we examined resting-state functional connectivity amongbrain systems and behavioral measures of impulsivity in 107 juveniles incarcerated in a high-security facility. In less-impulsivejuveniles and normal controls, motor planning regions were correlated with brain networks associated with spatial attentionand executive control. In more-impulsive juveniles, these same regions correlated with the default-mode network, a constellationof brain areas associated with spontaneous, unconstrained, self-referential cognition. The strength of these brain–behaviorrelationships was sufficient to predict impulsivity scores at the individual level. Our data suggest that increased functionalconnectivity of motor-planning regions with networks subserving unconstrained, self-referential cognition, rather than thosesubserving executive control, heightens the predisposition to impulsive behavior in juvenile offenders. To further explorethe relationship between impulsivity and neural development, we studied functional connectivity in the same motor-planningregions in 95 typically developing individuals across a wide age span. The change in functional connectivity with age mirroredthat of impulsivity: younger subjects tended to exhibit functional connectivity similar to the more-impulsive incarceratedjuveniles, whereas older subjects exhibited a less-impulsive pattern. This observation suggests that impulsivity in the offenderpopulation is a consequence of a delay in typical development, rather than a distinct abnormality.
