Thompson K G, Leventhal A G, Zhou Y, Liu D
Department of Anatomy, University of Utah, School of Medicine, Salt Lake City 84132.
Vis Neurosci. 1994 Sep-Oct;11(5):939-51. doi: 10.1017/s0952523800003898.
The cortical contribution to the orientation and direction sensitivity of LGNd relay cells was investigated by recording the responses of relay cells to drifting sinusoidal gratings of varying spatial frequencies, moving bars, and moving spots in cats in which the visual cortex (areas 17, 18, 19, and LS) was ablated. For comparison, the spatial-frequency dependence of orientation and direction tuning of striate cortical cells was investigated employing the same quantitative techniques used to test LGNd cells. There are no significant differences in the orientation and direction tuning to relay cells in the LGNd of normal and decorticate cats. The orientation and direction sensitivities of cortical cells are dependent on stimulus parameters in a fashion qualitatively similar to that of LGNd cells. The differences in the spatial-frequency bandwidths of LGNd cells and cortical cells may explain many of their differences in orientation and direction tuning. Although factors beyond narrowness of spatial-frequency tuning must exist to account for the much stronger orientation and direction preferences of cells in area 17 when compared to LGNd cells, the evidence suggests that the orientation and direction biases present in the afferents to the visual cortex may contribute to the orientation and direction selectivities found in cortical cells.
通过记录猫的外侧膝状体核（LGNd）中继细胞对不同空间频率的漂移正弦光栅、移动条纹和移动光斑的反应，研究了皮质对LGNd中继细胞方向和方向敏感性的贡献。这些猫的视觉皮质（17、18、19区和LS区）已被切除。为了进行比较，采用与测试LGNd细胞相同的定量技术，研究了纹状皮质细胞方向和方向调谐的空间频率依赖性。正常猫和去皮质猫LGNd中的中继细胞在方向和方向调谐方面没有显著差异。皮质细胞的方向和方向敏感性以一种与LGNd细胞定性相似的方式依赖于刺激参数。LGNd细胞和皮质细胞在空间频率带宽上的差异可能解释了它们在方向和方向调谐上的许多差异。尽管与LGNd细胞相比，17区细胞更强得多的方向和方向偏好肯定存在除空间频率调谐狭窄之外的因素，但证据表明，传入视觉皮质的纤维中存在的方向和方向偏差可能有助于皮质细胞中发现的方向和方向选择性。
