Barton R A, Dean P
Department of Anthropology, University of Durham, U.K.
Proc Biol Sci. 1993 Oct 22;254(1339):63-8. doi: 10.1098/rspb.1993.0127.
The evolution of cognitive and sensory specializations must involve concomitant modifications of neural substrates. Ecological correlates of species differences in brain structure are intriguing sources of evidence about such evolutionary specialization but, to date, these have been identified only for gross parameters, such as overall brain size and the size of major brain regions. Here we show that a behavioural specialization in mammals, predation, is associated with species differences in the fine structure of a single neural pathway, the tectospinal tract. Both the relative number of neurons in this pathway and the relative size of their cell bodies were greater in more predatory species than in their less predatory counterparts within each of four separate mammalian orders. Expansion of these analyses to consider comparisons between taxa at a variety of taxonomic levels gave further support to the idea of a relation between predatory habits and the evolution of the tectospinal tract. In addition, within the primates, the number of neurons in the tectospinal tract was significantly correlated with the proportion of prey in the diet. These results therefore appear to provide an example of correlated evolution between a specific neural system and behaviour which applies generally within the mammals. They also help to unify findings from physiological and anatomical studies on a wider range of vertebrate taxa, including reptiles and amphibians.
认知和感官特化的进化必然涉及神经基质的相应改变。脑结构物种差异的生态关联是有关此类进化特化的有趣证据来源，但迄今为止，这些关联仅在诸如脑总体大小和主要脑区大小等粗略参数方面得到确认。在此我们表明，哺乳动物的一种行为特化——捕食，与单一神经通路（顶盖脊髓束）精细结构的物种差异相关。在四个不同的哺乳动物目中，每个目内捕食性更强的物种相比于捕食性较弱的物种，该通路中的神经元相对数量及其细胞体的相对大小都更大。将这些分析扩展至考虑不同分类水平的类群之间的比较，进一步支持了捕食习性与顶盖脊髓束进化之间存在关联的观点。此外，在灵长类动物中，顶盖脊髓束中的神经元数量与饮食中猎物的比例显著相关。因此，这些结果似乎提供了一个特定神经系统与行为之间协同进化的例子，这种协同进化在哺乳动物中普遍存在。它们还有助于整合来自更广泛脊椎动物类群（包括爬行动物和两栖动物）的生理学和解剖学研究结果。
