Sakai Tomoko, Mikami Akichika, Suzuki Juri, Miyabe-Nishiwaki Takako, Matsui Mie, Tomonaga Masaki, Hamada Yuzuru, Matsuzawa Tetsuro, Okano Hideyuki, Oishi Kenichi
The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
Department of Physiology, Keio University School of Medicine, Tokyo, Japan.
PLoS One. 2017 Jun 27;12(6):e0179624. doi: 10.1371/journal.pone.0179624. eCollection 2017.
How brains develop during early life is one of the most important topics in neuroscience because it underpins the neuronal functions that mature during this period. A comparison of the neurodevelopmental patterns among humans and nonhuman primates is essential to infer evolutional changes in neuroanatomy that account for higher-order brain functions, especially those specific to humans. The corpus callosum (CC) is the major white matter bundle that connects the cerebral hemispheres, and therefore, relates to a wide variety of neuronal functions. In humans, the CC area rapidly expands during infancy, followed by relatively slow changes. In chimpanzees, based on a cross-sectional study, slow changes in the CC area during the juvenile stage and later have also been reported. However, little is known about the developmental changes during infancy. A longitudinal study is also required to validate the previous cross-sectional observations about the chimpanzee CC. The present longitudinal study of magnetic resonance imaging scans demonstrates that the CC development in chimpanzees and humans is characterized by a rapid increase during infancy, followed by gradual increase during the juvenile stage. Several differences between the two species were also identified. First, there was a tendency toward a greater increase in the CC areas during infancy in humans. Second, there was a tendency toward a greater increase in the rostrum during the juvenile stage in chimpanzees. The rostral body is known to carry fibers between the bilateral prefrontal and premotor cortices, and is involved in behavior planning and control, verbal working memory, and number conception. The rostrum is known to carry fibers between the prefrontal cortices, and is involved in attention control. The interspecies differences in the developmental trajectories of the rostral body and the rostrum might be related to evolutional changes in the brain systems.
大脑在生命早期如何发育是神经科学中最重要的课题之一，因为它支撑着在此期间成熟的神经元功能。比较人类和非人类灵长类动物的神经发育模式对于推断神经解剖学的进化变化至关重要，这些变化构成了高阶脑功能，尤其是人类特有的功能。胼胝体（CC）是连接大脑半球的主要白质束，因此与多种神经元功能相关。在人类中，CC区域在婴儿期迅速扩张，随后变化相对缓慢。在黑猩猩中，基于一项横断面研究，也有报道称幼年及以后阶段CC区域变化缓慢。然而，关于婴儿期的发育变化知之甚少。还需要进行纵向研究来验证之前关于黑猩猩CC的横断面观察结果。目前这项磁共振成像扫描的纵向研究表明，黑猩猩和人类的CC发育特征是在婴儿期迅速增加，随后在幼年阶段逐渐增加。还发现了两个物种之间的一些差异。首先，人类婴儿期CC区域有更大增加的趋势。其次，黑猩猩在幼年阶段胼胝体嘴部有更大增加的趋势。胼胝体嘴部已知携带双侧前额叶和运动前皮质之间的纤维，并参与行为规划和控制、言语工作记忆和数字概念。胼胝体膝部已知携带前额叶皮质之间的纤维，并参与注意力控制。胼胝体嘴部和膝部发育轨迹的种间差异可能与脑系统的进化变化有关。
