Rosa Marcello G P, Tweedale Rowan
Department of Physiology, Monash University Centre for Brain and Behaviour, Monash University, Clayton, VIC 3800, Australia.
Philos Trans R Soc Lond B Biol Sci. 2005 Apr 29;360(1456):665-91. doi: 10.1098/rstb.2005.1626.
In this paper, we review evidence from comparative studies of primate cortical organization, highlighting recent findings and hypotheses that may help us to understand the rules governing evolutionary changes of the cortical map and the process of formation of areas during development. We argue that clear unequivocal views of cortical areas and their homologies are more likely to emerge for "core" fields, including the primary sensory areas, which are specified early in development by precise molecular identification steps. In primates, the middle temporal area is probably one of these primordial cortical fields. Areas that form at progressively later stages of development correspond to progressively more recent evolutionary events, their development being less firmly anchored in molecular specification. The certainty with which areal boundaries can be delimited, and likely homologies can be assigned, becomes increasingly blurred in parallel with this evolutionary/developmental sequence. For example, while current concepts for the definition of cortical areas have been vindicated in allowing a clarification of the organization of the New World monkey "third tier" visual cortex (the third and dorsomedial areas, V3 and DM), our analyses suggest that more flexible mapping criteria may be needed to unravel the organization of higher-order visual association and polysensory areas.
在本文中，我们回顾了来自灵长类动物皮质组织比较研究的证据，重点介绍了近期的研究发现和假说，这些发现和假说可能有助于我们理解支配皮质图谱进化变化的规则以及发育过程中区域形成的过程。我们认为，对于“核心”区域，包括初级感觉区域，更有可能出现关于皮质区域及其同源性的清晰明确的观点，这些区域在发育早期通过精确的分子识别步骤得以确定。在灵长类动物中，颞中区可能就是这些原始皮质区域之一。在发育后期逐渐形成的区域对应于逐渐更新的进化事件，它们的发育在分子特化方面的锚定作用较弱。随着这种进化/发育序列的推进，能够界定区域边界并确定可能的同源性的确定性变得越来越模糊。例如，虽然目前关于皮质区域定义的概念在澄清新大陆猴“第三层”视觉皮质（第三区和背内侧区，V3和DM）的组织方面得到了证实，但我们的分析表明，可能需要更灵活的图谱绘制标准来阐明高阶视觉联合区和多感觉区的组织。
