Functional imaging with cellular resolution reveals precise micro-architecture in visual cortex
Functional imaging with cellular resolution reveals precise micro-architecture in visual cortex
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DOI：
10.1038/nature03274
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发表时间：
2005-02-10
期刊：
影响因子：
64.8
通讯作者：
Reid, RC
中科院分区：
文献类型：
--
作者：
Ohki, K;Chung, S;Reid, RC
大脑皮层中的神经元被组织成解剖学上的柱状物，从表面到白色物质排列着细胞的集合体。在一个列中，神经元通常具有相同的功能特性，例如对刺激方向的选择性;具有不同特性的列，例如不同的偏好方向，以有序的模式平铺皮质表面。这种功能结构是通过微电极记录的相对稀疏的采样发现的。膜电压或代谢活性的光学成像阐明了功能图的整体几何结构，但在许多细胞上取平均值（分辨率> 100 μ m）。因此，功能域的纯度和它们之间边界的精确性无法解决。在这里，我们用钙敏感指示剂在体内标记了数千个视觉皮层的神经元。然后，我们用双光子显微镜以单细胞分辨率成像神经元群体的活动，深度达400 μ m。在大鼠初级视皮层，神经元具有强大的方向选择性，但没有明显的局部结构，相邻的神经元往往对不同的方向作出反应。在猫视皮层18区，功能图以精细的尺度组织。对刺激方向有相反偏好的神经元在三维空间中以非凡的空间精度分离，柱状边界为一到两个细胞宽。这些结果表明，皮层地图可以建立与单细胞精度。
Neurons in the cerebral cortex are organized into anatomical columns, with ensembles of cells arranged from the surface to the white matter. Within a column, neurons often share functional properties, such as selectivity for stimulus orientation; columns with distinct properties, such as different preferred orientations, tile the cortical surface in orderly patterns. This functional architecture was discovered with the relatively sparse sampling of microelectrode recordings. Optical imaging of membrane voltage or metabolic activity elucidated the overall geometry of functional maps, but is averaged over many cells ( resolution > 100 mum). Consequently, the purity of functional domains and the precision of the borders between them could not be resolved. Here, we labelled thousands of neurons of the visual cortex with a calcium- sensitive indicator in vivo. We then imaged the activity of neuronal populations at single- cell resolution with two- photon microscopy up to a depth of 400 mum. In rat primary visual cortex, neurons had robust orientation selectivity but there was no discernible local structure; neighbouring neurons often responded to different orientations. In area 18 of cat visual cortex, functional maps were organized at a fine scale. Neurons with opposite preferences for stimulus direction were segregated with extraordinary spatial precision in three dimensions, with columnar borders one to two cells wide. These results indicate that cortical maps can be built with single- cell precision.