Luo Yuanjun, Fujita Hirofumi, Nedelescu Hermina, Biswas Mohammad Shahangir, Sato Chika, Ying Sarah, Takahashi Mayu, Akita Keiichi, Higashi Tatsuya, Aoki Ichio, Sugihara Izumi
Department of Systems Neurophysiology, Tokyo Medical and Dental University Graduate School, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave., Baltimore, MD, 21205, USA.
Brain Struct Funct. 2017 Aug;222(6):2449-2472. doi: 10.1007/s00429-017-1436-9. Epub 2017 May 15.
Comparative neuroanatomy provides insights into the evolutionary functional adaptation of specific mammalian cerebellar lobules, in which the lobulation pattern and functional localization are conserved. However, accurate identification of homologous lobules among mammalian species is challenging. In this review, we discuss the inter-species homology of crus I and II lobules which occupy a large volume in the posterior cerebellar hemisphere, particularly in humans. Both crus I/II in humans are homologous to crus I/II in non-human primates, according to Paxinos and colleagues; however, this area has been defined as crus I alone in non-human primates, according to Larsell and Brodal. Our neuroanatomical analyses in humans, macaques, marmosets, rats, and mice demonstrate that both crus I/II in humans are homologous to crus I/II or crus I alone in non-human primates, depending on previous definitions, and to crus I alone in rodents. Here, we refer to the region homologous to human crus I/II lobules as "ansiform area (AA)" across animals. Our results show that the AA's olivocerebellar climbing fiber and Purkinje cell projections as well as aldolase C gene expression patterns are both distinct and conserved in marmosets and rodents. The relative size of the AA, as represented by the AA volume fraction in the whole cerebellum was 0.34 in human, 0.19 in macaque, and approximately 0.1 in marmoset and rodents. These results indicate that the AA reflects an evolutionarily conserved structure in the mammalian cerebellum, which is characterized by distinct connectivity from neighboring lobules and a massive expansion in skillful primates.
比较神经解剖学有助于深入了解特定哺乳动物小脑小叶的进化功能适应性，其中小叶模式和功能定位是保守的。然而，准确识别哺乳动物物种间的同源小叶具有挑战性。在本综述中，我们讨论了占据小脑后半球很大体积的Ⅰ、Ⅱ脚小叶的种间同源性，尤其是在人类中。根据帕西诺斯及其同事的研究，人类的Ⅰ、Ⅱ脚小叶均与非人类灵长类动物的Ⅰ、Ⅱ脚小叶同源；然而，根据拉塞尔和布罗达尔的研究，在非人类灵长类动物中，该区域仅被定义为Ⅰ脚。我们对人类、猕猴、狨猴、大鼠和小鼠的神经解剖学分析表明，人类的Ⅰ、Ⅱ脚小叶根据先前的定义，与非人类灵长类动物的Ⅰ、Ⅱ脚小叶或仅Ⅰ脚同源，而与啮齿动物的仅Ⅰ脚同源。在此，我们将与人类Ⅰ、Ⅱ脚小叶同源的区域在所有动物中称为“袢状区（AA）”。我们的结果表明，袢状区的橄榄小脑攀缘纤维和浦肯野细胞投射以及醛缩酶C基因表达模式在狨猴和啮齿动物中既独特又保守。以袢状区在整个小脑中的体积分数表示的袢状区相对大小，在人类中为0.34，在猕猴中为0.19，在狨猴和啮齿动物中约为0.1。这些结果表明，袢状区反映了哺乳动物小脑中一种进化上保守的结构，其特征是与相邻小叶的连接不同，并且在熟练的灵长类动物中大量扩展。
