Department of Radiology, Washington University, St. Louis, MO 63110, USA.
Proc Natl Acad Sci U S A. 2011 Jul 5;108(27):11241-5. doi: 10.1073/pnas.1108241108. Epub 2011 Jun 27.
Teenagers are often impulsive. In some cases this is a phase of normal development; in other cases impulsivity contributes to criminal behavior. Using functional magnetic resonance imaging, we examined resting-state functional connectivity among brain systems and behavioral measures of impulsivity in 107 juveniles incarcerated in a high-security facility. In less-impulsive juveniles and normal controls, motor planning regions were correlated with brain networks associated with spatial attention and executive control. In more-impulsive juveniles, these same regions correlated with the default-mode network, a constellation of brain areas associated with spontaneous, unconstrained, self-referential cognition. The strength of these brain-behavior relationships was sufficient to predict impulsivity scores at the individual level. Our data suggest that increased functional connectivity of motor-planning regions with networks subserving unconstrained, self-referential cognition, rather than those subserving executive control, heightens the predisposition to impulsive behavior in juvenile offenders. To further explore the relationship between impulsivity and neural development, we studied functional connectivity in the same motor-planning regions in 95 typically developing individuals across a wide age span. The change in functional connectivity with age mirrored that of impulsivity: younger subjects tended to exhibit functional connectivity similar to the more-impulsive incarcerated juveniles, whereas older subjects exhibited a less-impulsive pattern. This observation suggests that impulsivity in the offender population is a consequence of a delay in typical development, rather than a distinct abnormality.
青少年往往容易冲动。在某些情况下，这是正常发育的一个阶段；在其他情况下，冲动会导致犯罪行为。我们使用功能磁共振成像，研究了 107 名被监禁在高度安全设施中的青少年的大脑系统静息状态功能连接与冲动行为的关系。在冲动程度较低的青少年和正常对照组中，运动规划区域与与空间注意力和执行控制相关的大脑网络相关。在冲动程度较高的青少年中，这些相同的区域与默认模式网络相关，默认模式网络是与自发、不受约束、自我参照认知相关的一系列大脑区域。这些大脑-行为关系的强度足以在个体水平上预测冲动得分。我们的数据表明，运动规划区域与支持不受约束、自我参照认知的网络的功能连接增加，而不是与执行控制相关的网络，增加了青少年罪犯冲动行为的倾向。为了进一步探索冲动和神经发育之间的关系，我们在广泛的年龄范围内研究了 95 名正常发育个体的相同运动规划区域的功能连接。功能连接随年龄的变化与冲动的变化相似：年轻的受试者往往表现出与冲动程度较高的被监禁青少年相似的功能连接，而年龄较大的受试者则表现出冲动程度较低的模式。这一观察结果表明，犯罪人群中的冲动是典型发育延迟的结果，而不是明显的异常。
