A computational framework for topographies of cortical areas.
A computational framework for topographies of cortical areas.
复制标题
皮质区域地形的计算框架。
DOI：
10.1007/s00422-009-0294-9
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发表时间：
2009
影响因子：
1.9
通讯作者：
Barbour,DennisL
中科院分区：
文献类型：
--
作者：
Watkins,PaulV;Chen,ThomasL;Barbour,DennisL
自组织特征图 (SOFM) 代表一种降维算法，已用于复制在初级视觉皮层 (V1) 中实验观察到的特征拓扑。我们使用 SOFM 算法对包含最多五个任意生理特征的通用感觉皮层区域的可能拓扑进行建模。这项研究探讨了这些多特征 SOFM 包含两个单调映射并相互正交对齐的特征（即“全局正交”）的条件，以及一个特征的图与建模皮质区域的最长解剖尺寸对齐的条件（即“主导”）。在具有两个以上特征的单个 SOFM 中，我们从未观察到超过一个主导特征，也没有观察到两个全局正交特征在发生主导特征的同一张图中，是否发生主导性或全局正交性取决于特征相对于彼此的权重大小。因此，我们的结果表明，在具有二维感觉上皮的感觉形态的初级皮层区域中，这两个特征可能是全局正交的。然而，在具有一维感觉上皮的感觉形态的初级皮质区域中，这一特征可能占主导地位，并且没有两个特征可能在全局上彼此正交地组织，因为听觉系统沿耳蜗的整个长度传递单个刺激特征（即频率），所以这些发现可能与初级听觉皮层的地形图特别相关。
Self-organizing feature maps (SOFMs) represent a dimensionality-reduction algorithm that has been used to replicate feature topographies observed experimentally in primary visual cortex (V1). We used the SOFM algorithm to model possible topographies of generic sensory cortical areas containing up to five arbitrary physiological features. This study explored the conditions under which these multi-feature SOFMs contained two features that were mapped monotonically and aligned orthogonally with one another (i.e., “globally orthogonal”, as well as the conditions under which the map of one feature aligned with the longest anatomical dimension of the modeled cortical area (i.e., “dominant”. In a single SOFM with more than two features, we never observed more than one dominant feature, nor did we observe two globally orthogonal features in the same map in which a dominant feature occurred. Whether dominance or global orthogonality occurred depended upon how heavily weighted the features were relative to one another. The most heavily weighted features are likely to correspond to those physical stimulus properties transduced directly by the sensory epithelium of a particular sensory modality. Our results imply, therefore, that in the primary cortical area of sensory modalities with a two-dimensional sensory epithelium, these two features are likely to be organized globally orthogonally to one another, and neither feature is likely to be dominant. In the primary cortical area of sensory modalities with a one-dimensional sensory epithelium, however, this feature is likely to be dominant, and no two features are likely to be organized globally orthogonally to one another. Because the auditory system transduces a single stimulus feature (i.e., frequency) along the entire length of the cochlea, these findings may have particular relevance for topographic maps of primary auditory cortex.