arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1306.2808q-bio.NC
收藏

视网膜神经节细胞偶极子能否在视觉皮层中引发等取向域?

Can retinal ganglion cell dipoles seed iso-orientation domains in the visual cortex?

Manuel Schottdorf, Stephen J. Eglen, Fred Wolf, Wolfgang Keil

AI总结:

本研究检验统计连接模型中RGC马赛克偶极子角度相关性是否足以引发皮层等取向域,发现猫和灵长类数据中无空间相关,并引入新点过程证明弱相关极不可能,结论是马赛克缺乏所需空间结构。

摘要:

已有观点认为,食肉动物和灵长类初级视觉皮层(V1)中大致周期性的取向偏好图(OPMs)的出现可以用所谓的统计连接模型来解释。该模型假设,V1神经元的输入主要来自一小群视网膜神经节细胞(RGCs)的前馈投射。相邻偏好相同取向的皮层取向柱之间的典型间距,则通过六边形ON/OFF RGC马赛克之间的莫尔干涉产生。虽然这种莫尔干涉关键依赖于RGC马赛克内的长程六边形有序性,但最近对RGC感受野位置的统计分析未发现此类长程位置有序性的证据。六边形有序性可能只是统计连接模型中获得空间重复OPMs的多种方式之一。在此,我们研究RGC马赛克空间结构的一个更一般性要求,该要求能够引发空间重复的皮层OPMs的出现,即所谓的RGC偶极子之间的角度相关性表现出类似于OPM自相关函数的空间结构。在猫的β细胞马赛克和灵长类的伞状感受野马赛克中,我们都发现RGC偶极子角度在空间上是不相关的。为了帮助评估这些相关性的水平,我们引入了一种新颖的点过程,该过程生成具有现实最近邻统计量和可调偶极子角度空间相关程度的马赛克。利用该过程,我们表明,鉴于现有数据集的大小,数据中即使存在微弱的角度相关性也非常不可能。我们得出结论,ON/OFF神经节细胞马赛克的布局缺乏在初级视觉皮层中引发等取向域所需的空间结构。

英文摘要:

It has been argued that the emergence of roughly periodic orientation preference maps (OPMs) in the primary visual cortex (V1) of carnivores and primates can be explained by a so-called statistical connectivity model. This model assumes that input to V1 neurons is dominated by feed-forward projections originating from a small set of retinal ganglion cells (RGCs). The typical spacing between adjacent cortical orientation columns preferring the same orientation then arises via Moiré-Interference between hexagonal ON/OFF RGC mosaics. While this Moiré-Interference critically depends on long-range hexagonal order within the RGC mosaics, a recent statistical analysis of RGC receptive field positions found no evidence for such long-range positional order. Hexagonal order may be only one of several ways to obtain spatially repetitive OPMs in the statistical connectivity model. Here, we investigate a more general requirement on the spatial structure of RGC mosaics that can seed the emergence of spatially repetitive cortical OPMs, namely that angular correlations between so-called RGC dipoles exhibit a spatial structure similar to that of OPM autocorrelation functions. Both in cat beta cell mosaics as well as primate parasol receptive field mosaics we find that RGC dipole angles are spatially uncorrelated. To help assess the level of these correlations, we introduce a novel point process that generates mosaics with realistic nearest neighbor statistics and a tunable degree of spatial correlations of dipole angles. Using this process, we show that given the size of available data sets, the presence of even weak angular correlations in the data is very unlikely. We conclude that the layout of ON/OFF ganglion cell mosaics lacks the spatial structure necessary to seed iso-orientation domains in the primary visual cortex.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑