Reep R L, Finlay B L, Darlington R B
Department of Physiological Sciences and McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
Brain Behav Evol. 2007;70(1):57-70. doi: 10.1159/000101491. Epub 2007 Apr 4.
Previous accounts of mammalian brain allometry have relied largely on data from primates, insectivores and bats. Here we examine scaling of brain structures in carnivores, ungulates, xenarthrans and sirenians, taxa chosen to maximize potential olfactory and limbic system variability. The data were compared to known scaling of the same structures in bats, insectivores and primates. Fundamental patterns in brain scaling were similar across all taxa. Marine mammals with reduced olfactory bulbs also had reduced limbic systems overall, particularly in those structures receiving direct olfactory input. In all species, a limbic factor with olfactory and non-olfactory components was observed. Primates, insectivores, ungulate and marine mammals collectively demonstrate an inverse relationship between isocortex and limbic volumes, but terrestrial carnivores have high relative volumes of both, and bats low relative volumes of both. We discuss developmental processes that may provide the mechanistic bases for understanding these findings.
以往关于哺乳动物脑异速生长的描述主要依赖于灵长类动物、食虫动物和蝙蝠的数据。在此，我们研究了食肉动物、有蹄类动物、贫齿目动物和海牛目动物脑结构的异速生长情况，选择这些分类群是为了使潜在的嗅觉和边缘系统变异性最大化。将这些数据与蝙蝠、食虫动物和灵长类动物相同结构的已知异速生长情况进行了比较。所有分类群的脑异速生长基本模式相似。嗅球缩小的海洋哺乳动物其边缘系统总体上也缩小，尤其是在那些接受直接嗅觉输入的结构中。在所有物种中，均观察到一个具有嗅觉和非嗅觉成分的边缘因子。灵长类动物、食虫动物、有蹄类动物和海洋哺乳动物共同表现出同型皮质与边缘系统体积之间的负相关关系，但陆生食肉动物两者的相对体积都很高，而蝙蝠两者的相对体积都很低。我们讨论了可能为理解这些发现提供机制基础的发育过程。
