Bisti S, Clement R, Maffei L, Mecacci L
Exp Brain Res. 1977 Mar 30;27(3-4):335-45. doi: 10.1007/BF00235508.
Experiments have been performed on unanaesthetized and paralysed cats. The tuning curves for spatial frequency of retinal, lateral geniculate and simple and complex cells of the cortex have been determined in response to sinusoidal gratings of various spatial frequencies at different levels of mean luminance. For all neurones, decreasing the mean luminance leads to a progressive loss of spatial resolution and contrast sensitivity. Retinal ganglion cells of type X show, for scotopic levels of luminance, a flattening of their spatial frequency tuning curves in the low spatial frequency range. For geniculate and cortical neurones, on the contrary, the spatial frequency characteristics at the various levels of luminance remain practically invariant in their bandwidth. On the average, complex cells still respond to mean luminances ten times lower than simple cells. The tuning curves for orientation of cortical cells maintain, to a first approximation, the same shape at the various levels of mean luminance. The results are discussed comparing the electrophysiological with psychophysical data.
实验是在未麻醉且瘫痪的猫身上进行的。已测定视网膜、外侧膝状体以及皮层简单细胞和复杂细胞对不同平均亮度水平下各种空间频率的正弦光栅的空间频率调谐曲线。对于所有神经元，降低平均亮度会导致空间分辨率和对比度敏感度逐渐丧失。X 型视网膜神经节细胞在暗视觉亮度水平下，其低空间频率范围内的空间频率调谐曲线会变平。相反，对于膝状体和皮层神经元，在不同亮度水平下其空间频率特性在带宽上基本保持不变。平均而言，复杂细胞仍能对比简单细胞低十倍的平均亮度做出反应。皮层细胞的方向调谐曲线在不同平均亮度水平下大致保持相同形状。将电生理数据与心理物理学数据进行比较来讨论这些结果。
