不少家长担心，孩子进入青春期，交友不慎会学坏。美国一项研究显示，随着年龄增长，少年的大脑会提升“防御”功能，帮助抵御坏朋友的影响。
对比研究
俄勒冈大学研究人员找来同为10岁的24名女孩和14名男孩，让他们看印有不同面部表情的图片，同时用磁共振成像仪（MRI）扫描他们的大脑。图片上的表情包括中性、生气、恐惧、欢乐和悲伤。
扫描完成后，研究人员让这些孩子填写调查问卷，回答是否能抗拒同龄人影响、是否有过冒险行为等问题。
三年后，这些孩子开始进入青春期，再次参加先前的实验。
研究人员对比两次实验结果后发现，孩子大脑中腹侧纹状体、即与愉悦和情感控制相关区域的活动明显增强。
能力提升
研究人员认为，少年腹侧纹状体活动增强，表明抵御外界影响的能力增加，控制自己情绪的能力提高。
俄勒冈大学社会神经科学实验室负责人珍妮弗·普法伊费尔说：“人们通常认为处于青春期的少年容易受同龄人影响，情况的确如此。不过，他们抗拒影响的能力也不断提升。”
她说，青春期的孩子花更多时间与同龄人而非家人在一起，受同龄人影响更多。所以，增强抵御影响的能力是好事。
这一研究结果由最新一期《神经元》月刊发表。
掌握技巧
普法伊费尔说：“少年越能控制对同龄人引诱自己堕落的情感反应，可能越不容易受外界影响。”
她说，这项研究为后续研究打下基础。人们对大脑发育仍有不少领域需要探索。
另外，他说，研究表明，少年适当掌握调节情绪的技巧十分必要，可以让他们少受同龄人的负面影响，在成长道路上避免做出冒险行为。
先前英国研究人员对少年大脑所作研究显示，少年大脑处于发育阶段，存在大量灰质细胞，即参与信息传输和处理的细胞，导致处于发育阶段的头脑思维混乱。（生物谷Bioon.com）
生物谷推荐原始出处：
Neuron doi：10.1016/j.neuron.2011.02.019
Entering Adolescence: Resistance to Peer Influence, Risky Behavior, and Neural Changes in Emotion Reactivity
Jennifer H. Pfeifer, Carrie L. Masten, William E. Moore, Tasha M. Oswald, John C. Mazziotta, Marco Iacoboni, Mirella Dapretto
Highlights
Longitudinal MRI reveals development of neural reactivity to emotion from ages 10-13
Responsivity increased in ventral striatum (VS), ventromedial PFC, and amygdala
Increased VS activity linked with less susceptibility to peer influence, risk-taking
VS showed more negative functional connectivity with amygdala in early adolescence
Summary
Adolescence is often described as a period of heightened reactivity to emotions paired with reduced regulatory capacities, a combination suggested to contribute to risk-taking and susceptibility to peer influence during puberty. However, no longitudinal research has definitively linked these behavioral changes to underlying neural development. Here, 38 neurotypical participants underwent two fMRI sessions across the transition from late childhood (10 years) to early adolescence (13 years). Responses to affective facial displays exhibited a combination of general and emotion-specific changes in ventral striatum (VS), ventromedial PFC, amygdala, and temporal pole. Furthermore, VS activity increases correlated with decreases in susceptibility to peer influence and risky behavior. VS and amygdala responses were also significantly more negatively coupled in early adolescence than in late childhood while processing sad and happy versus neutral faces. Together, these results suggest that VS responses to viewing emotions may play a regulatory role that is critical to adolescent interpersonal functioning.
