Highly ordered arrangement of single neurons in orientation pinwheels
Highly ordered arrangement of single neurons in orientation pinwheels
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DOI：
10.1038/nature05019
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发表时间：
2006-08-24
期刊：
影响因子：
64.8
通讯作者：
Reid, R. Clay
中科院分区：
文献类型：
--
作者：
Ohki, Kenichi;Chung, Sooyoung;Reid, R. Clay
在高等哺乳动物的视觉皮层中，神经元排列在皮层表面，形成一个有序的偏好刺激方向图（1,2）。这张地图包含了“方向风车”，这种结构像车轮的辐条一样排列，这样方向就会围绕一个中心不断变化。传统的光学成像（3,4）首先展示了这些风车（3,5），但该技术缺乏空间分辨率，无法确定风车中心附近细胞的响应特性和排列。电生理记录后来证明了风车中心附近的神经元具有明显的选择性（6,7），但仍不清楚它们是随机排列还是有序排列。在这里，我们使用体内双光子钙成像（8-12）以单细胞分辨率确定猫视觉皮层风车中心的微观结构。我们发现风车中心是高度有序的：选择不同方向的神经元即使在中心也是明显分离的。因此，风车中心确实代表了皮层地图上的奇点。这种在单细胞水平上的高度有序的排列表明，在定向选择性的基础上，皮层回路的发育非常精确。
In the visual cortex of higher mammals, neurons are arranged across the cortical surface in an orderly map of preferred stimulus orientations(1,2). This map contains 'orientation pinwheels', structures that are arranged like the spokes of a wheel such that orientation changes continuously around a centre. Conventional optical imaging(3,4) first demonstrated these pinwheels(3,5), but the technique lacked the spatial resolution to determine the response properties and arrangement of cells near pinwheel centres. Electrophysiological recordings later demonstrated sharply selective neurons near pinwheel centres(6,7), but it remained unclear whether they were arranged randomly or in an orderly fashion. Here we use two-photon calcium imaging in vivo(8-12) to determine the microstructure of pinwheel centres in cat visual cortex with single-cell resolution. We find that pinwheel centres are highly ordered: neurons selective to different orientations are clearly segregated even in the very centre. Thus, pinwheel centres truly represent singularities in the cortical map. This highly ordered arrangement at the level of single cells suggests great precision in the development of cortical circuits underlying orientation selectivity.