Researchers have reported sex-differentiated maturation of white matter (WM) during puberty. It is not clear, however, whether such distinctions contribute to documented sex differences in sensitivity to reward and punishment during adolescence. Given the role of the orbitofrontal cortex (OFC) and nucleus accumbens (NAcc) in reward and punishment-related behaviors, we tested in a cross-sectional study whether males and females (N=156, 89 females; ages 9-14 years) differ in the association between pubertal stage and fixel-based morphometry of WM fibers connecting the OFC and NAcc (i.e., the fronto-accumbal tract). Further, we examined whether males and females differ in associations between fronto-accumbal WM measures and self-reported sensitivity to reward and punishment. Pubertal stage was positively associated with fronto-accumbal fiber density and cross-section (FDC) in males, but not in females. Consistent with previous reports, males reported higher reward sensitivity than did females, although fronto-accumbal combined FDC was not related to reward sensitivity in either sex. Meanwhile, only males showed a negative association between fronto-accumbal tract FDC and sensitivity to punishment. Follow-up analyses revealed that fiber cross-section, but not density, was related to pubertal stage and punishment sensitivity in males, as well as to reward sensitivity in all participants. Our findings suggest there are sex differences in puberty-related maturation of the fronto-accumbal tract, and this tract is related to lower punishment sensitivity in adolescent males compared to females.

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青春期关联的性别差异与额伏白质形态测量：理解对奖励和惩罚的敏感性的意义

研究人员报告了青春期白质 (WM) 的性别分化成熟。然而，尚不清楚这些区别是否有助于记录在案的青春期奖励和惩罚敏感性方面的性别差异。鉴于眶额皮质 (OFC) 和伏隔核 (NAcc) 在奖惩相关行为中的作用，我们在一项横断面研究中测试了男性和女性（N=156，89 名女性；年龄 9-14 岁）青春期阶段和连接 OFC 和 NAcc（即额伏侧束）的 WM 纤维的基于固定素的形态测量之间的关联不同。此外，我们检查了男性和女性在额伏前额 WM 测量与自我报告的奖励和惩罚敏感性之间的关联方面是否存在差异。青春期阶段与男性的额伏侧纤维密度和横截面 (FDC) 呈正相关，但与女性无关。与之前的报告一致，男性报告的奖励敏感性高于女性，尽管额伏侧联合 FDC 与两种性别的奖励敏感性无关。同时，只有男性在额伏侧束 FDC 和对惩罚的敏感性之间显示出负相关。后续分析显示，纤维横截面，而不是密度，与男性的青春期阶段和惩罚敏感性有关，也与所有参与者的奖励敏感性有关。我们的研究结果表明，与青春期相关的额伏束成熟度存在性别差异，与女性相比，青春期男性与青春期男性的惩罚敏感性较低有关。