Farris Sarah M
Department of Biology, West Virginia University, Morgantown, WV 26506, USA.
Brain Behav Evol. 2013;82(1):9-18. doi: 10.1159/000352057. Epub 2013 Aug 21.
Large, complex higher brain centers have evolved many times independently within the vertebrates, but the selective pressures driving these acquisitions have been difficult to pinpoint. It is well established that sensory brain centers become larger and more structurally complex to accommodate processing of a particularly important sensory modality. When higher brain centers such as the cerebral cortex become greatly expanded in a particular lineage, it is likely to support the coordination and execution of more complex behaviors, such as those that require flexibility, learning, and social interaction, in response to selective pressures that made these new behaviors advantageous. Vertebrate studies have established a link between complex behaviors, particularly those associated with sociality, and evolutionary expansions of telencephalic higher brain centers. Enlarged higher brain centers have convergently evolved in groups such as the insects, in which multimodal integration and learning and memory centers called the mushroom bodies have become greatly elaborated in at least four independent lineages. Is it possible that similar selective pressures acting on equivalent behavioral outputs drove the evolution of large higher brain centers in all bilaterians? Sociality has greatly impacted brain evolution in vertebrates such as primates, but it has not been a major driver of higher brain center enlargement in insects. However, feeding behaviors requiring flexibility and learning are associated with large higher brain centers in both phyla. Selection for the ability to support behavioral flexibility appears to be a common thread underlying the evolution of large higher brain centers, but the precise nature of these computations and behaviors may vary.
大型、复杂的高等脑中枢在脊椎动物中已经多次独立进化，但推动这些进化的选择压力却很难确定。众所周知，感觉脑中枢会变得更大且结构更复杂，以适应对一种特别重要的感觉模态的处理。当诸如大脑皮层这样的高等脑中枢在某一特定谱系中大幅扩展时，很可能是为了支持更复杂行为的协调和执行，比如那些需要灵活性、学习能力和社交互动的行为，以应对使这些新行为具有优势的选择压力。脊椎动物研究已经在复杂行为，特别是与社会性相关的行为，与端脑高等脑中枢的进化扩展之间建立了联系。在昆虫等类群中，高等脑中枢也独立进化出了增大的情况，在这些昆虫中，被称为蘑菇体的多模态整合以及学习和记忆中枢在至少四个独立谱系中得到了极大的发展。作用于等效行为输出的类似选择压力是否有可能驱动了所有两侧对称动物中大型高等脑中枢的进化呢？社会性对灵长类等脊椎动物的大脑进化产生了重大影响，但它并不是昆虫中高等脑中枢增大的主要驱动力。然而，需要灵活性和学习能力的取食行为在这两个门类中都与大型高等脑中枢相关。对支持行为灵活性能力的选择似乎是大型高等脑中枢进化背后的一个共同线索，但这些计算和行为的确切性质可能有所不同。
