Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, 235 E. Cameron Ave., Chapel Hill, NC 27516, USA.
Soc Cogn Affect Neurosci. 2018 Sep 11;13(9):977-988. doi: 10.1093/scan/nsy063.
Sibling relationships have been linked to adolescent externalizing behaviors, but the neurobiological factors that underlie this association have not been identified. This study investigated sibling closeness and birth order as a predictor of adolescent externalizing behavior via differences in neural processes during safe decision-making. A total of 77 adolescents (range = 12-15 years, Mage = 13.45 years, 40 females) completed a computerized driving task during a functional MRI scan. Results showed that adolescents' perceptions of sibling closeness were associated with greater neural activation in the anterior insula, ventral striatum and left ventrolateral prefrontal cortex when making safe decisions, suggesting that the quality of sibling relationships modulates adolescent neurocognition even without being present. Furthermore, moderated mediation analyses revealed that higher sibling closeness was associated with lower externalizing behavior via left anterior insula activation during safe decision-making, but only for adolescents without older siblings (i.e. eldest children) compared to adolescents who had multiple older siblings. Importantly, these findings persisted above and beyond parental and peer closeness and sibling characteristics (i.e. sex, relatedness, birth order), highlighting the significant influence of sibling relationships on adolescent externalizing behavior through the brain.
兄弟姐妹关系与青少年的外化行为有关，但这一关联背后的神经生物学因素尚未确定。本研究通过安全决策过程中神经过程的差异，调查了兄弟姐妹之间的亲密程度和出生顺序对青少年外化行为的预测作用。共有 77 名青少年（年龄范围为 12-15 岁，Mage=13.45 岁，40 名女性）在 fMRI 扫描期间完成了一项计算机驾驶任务。结果表明，青少年对兄弟姐妹关系的感知与在做出安全决策时前岛叶、腹侧纹状体和左侧腹外侧前额叶皮层的神经激活有关，这表明兄弟姐妹关系的质量即使不在场也能调节青少年的神经认知。此外，中介调节分析显示，在安全决策过程中，较高的兄弟姐妹亲密程度与较低的外化行为有关，而这种关系仅存在于没有年长兄弟姐妹（即老大）的青少年中，而不存在于有多个年长兄弟姐妹的青少年中。重要的是，这些发现超过了父母和同伴亲密程度以及兄弟姐妹特征（即性别、亲缘关系、出生顺序）的影响，突出了兄弟姐妹关系对青少年外化行为的重要影响。
