CORTICOFUGAL FEEDBACK INFLUENCES THE GENERATION OF LENGTH TUNING IN THE VISUAL PATHWAY
CORTICOFUGAL FEEDBACK INFLUENCES THE GENERATION OF LENGTH TUNING IN THE VISUAL PATHWAY
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DOI：
10.1038/329727a0
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发表时间：
1987-10-22
期刊：
影响因子：
64.8
通讯作者：
SILLITO, AM
中科院分区：
文献类型：
--
作者：
MURPHY, PC;SILLITO, AM
在猫科动物的视觉系统中，首先在皮层中观察到对移动轮廓长度表现出敏感性的神经元1，2，并将其描述为“超复杂细胞”。在这些细胞中，超过最佳值的刺激长度的增加导致反应的快速下降。这种下降归因于皮质内抑制性输入1，这可能是由具有非常长的感受野3的第VI层细胞驱动的。然而，现在很清楚的是，在背外侧膝状体核（dLGN）的细胞，表现出一定程度的长度调谐类似于皮质的“超复杂细胞”4，5，这表明这种响应特性可以产生subcortically。或者，由于dLGN从视觉皮层中的第VI层细胞接收大量的离皮质投射6，因此这种输入可能具有在dLGN中产生长度调谐的功能。我们已经调查了这个问题，通过比较的dLGN细胞的长度调谐与无离皮质反馈。这些数据表明，离皮质反馈对dLGN细胞的长度调谐做出了非常显著的贡献。这就提出了一种可能性，即长度调谐是膝状体-皮层回路的一种新特性。
In the feline visual system, neurons exhibiting sensitivity to the length of a moving contour were first observed in the cortex1,2and described as 'hypercomplex' cells'. In these cells an increase in stimulus length beyond an optimal value leads to a rapid decline in response. This decline has been attributed to an intracortical inhibitory input1which may be driven by layer VI cells with very long receptive fields3. It is now clear, however, that cells in the dorsal lateral geniculate nucleus (dLGN), exhibit a degree of length tuning similar to that of cortical 'hypercomplex cells'4,5, suggesting that this response property could be generated subcortically. Alternatively, as the dLGN receives a massive corticofugal projection from layer VI cells in the visual cortex6, it is possible that this input has a function in generating length tuning in the dLGN. We have investigated this issue by comparing the length tuning of dLGN cells with and without corticofugal feedback. The data show that corticofugal feedback makes a highly significant contribution to the length tuning of dLGN cells. This raises the possibility that length tuning is an emergent property of the geniculo-cortical loop.