Kaskan Peter M, Lu Haidong D, Dillenburger Barbara C, Roe Anna W, Kaas Jon H
Department of Psychology, Vanderbilt University, Nashville, TN, USA.
Front Neurosci. 2007 Oct 15;1(1):67-75. doi: 10.3389/neuro.01.1.1.005.2007.
A significant concept in neuroscience is that sensory areas of the neocortex have evolved the remarkable ability to represent a number of stimulus features within the confines of a global map of the sensory periphery. Modularity, the term often used to describe the inhomogeneous nature of the neocortex, is without a doubt an important organizational principle of early sensory areas, such as the primary visual cortex (V1). Ocular dominance columns, one type of module in V1, are found in many primate species as well as in carnivores. Yet, their variable presence in some New World monkey species and complete absence in other species has been enigmatic. Here, we demonstrate that optical imaging reveals the presence of ocular dominance columns in the superficial layers of V1 of owl monkeys (Aotus trivirgatus), even though the geniculate inputs related to each eye are highly overlapping in layer 4. The ocular dominance columns in owl monkeys revealed by optical imaging are circular in appearance. The distance between left eye centers and right eye centers is approximately 650 mum. We find no relationship between ocular dominance centers and other modular organizational features such as orientation pinwheels or the centers of the cytochrome oxidase blobs. These results are significant because they suggest that functional columns may exist in the absence of obvious differences in the distributions of activating inputs and ocular dominance columns may be more widely distributed across mammalian taxa than commonly suggested.
神经科学中的一个重要概念是，新皮层的感觉区域已经进化出非凡的能力，能够在感觉外周的全局图谱范围内表征多种刺激特征。模块化，这个常被用来描述新皮层不均匀性质的术语，无疑是早期感觉区域（如初级视觉皮层V1）的一个重要组织原则。眼优势柱是V1中的一种模块类型，在许多灵长类物种以及食肉动物中都能发现。然而，它们在一些新大陆猴物种中的存在情况不一，而在其他物种中则完全不存在，这一直是个谜。在这里，我们证明，光学成像显示夜猴（Aotus trivirgatus）V1浅层存在眼优势柱，尽管与每只眼睛相关的膝状体输入在第4层高度重叠。光学成像显示的夜猴眼优势柱外观呈圆形。左眼中心和右眼中心之间的距离约为650微米。我们发现眼优势中心与其他模块化组织特征（如方向风车或细胞色素氧化酶斑的中心）之间没有关系。这些结果意义重大，因为它们表明，在激活输入分布没有明显差异的情况下，功能柱可能存在，而且眼优势柱在哺乳动物类群中的分布可能比通常认为的更广泛。
