Department of Psychobiology, University of California, Irvine.
J Cogn Neurosci. 1990 Winter;2(1):1-17. doi: 10.1162/jocn.1990.2.1.1.
The neocortex is the most characteristic feature of the human brain. On gross inspection, its convoluted surfaces can be seen to have overgrown and covered most other brain structures. In the functional sphere, it is to the neocortex that we attribute those behaviors assumed to be most uniquely human such as cognition and linguistic behavior. This essay is an attempt to understand how this structure expanded during the course of mammalian evolution. At present, any attempt must be more speculative than definitive, but it is offered in the hope that it will generate more discussion on a topic that is central to all neurobiology, as well as a number of allied disciplines. I will proceed by outlining current views on the evolution of the brain, briefly review the organization of the somatosensory cortex in several mammalian forms, and then discuss in some detail ontogenetic mechanisms that may have some bearing on neocortical phylogeny. The primary proposition put forth is that the mammalian neocortex is relatively unspecified by strict genetic means, and that this allowed the neocortex to expand and adapt to a variety of circumstances during the course of phylogeny.
大脑皮层是人类大脑最具特征的部分。在大体检查中，可以看到其褶皱的表面已经过度生长并覆盖了大多数其他大脑结构。在功能领域，我们将认知和语言行为等被认为是最具人类特征的行为归因于大脑皮层。本文试图了解在哺乳动物进化过程中，这个结构是如何扩张的。目前，任何尝试都必须比定论更具推测性，但希望它能激发更多关于这个对所有神经生物学以及许多相关学科都至关重要的主题的讨论。我将通过概述大脑进化的当前观点，简要回顾几种哺乳动物形式的躯体感觉皮层的组织，然后详细讨论可能对新皮层发生有一定影响的个体发生机制。提出的主要主张是，哺乳动物的新皮层相对不受严格的遗传手段的限制，这使得新皮层在进化过程中能够扩张并适应各种情况。
