Cooper Bonnie, Lee Barry B, Cao Dingcai
College of Optometry, State University of New York, New York, New York;
College of Optometry, State University of New York, New York, New York; Max Planck Institute for Biophysical Chemistry, Göttingen, Germany; and
J Neurophysiol. 2016 Jun 1;115(6):2976-88. doi: 10.1152/jn.00411.2015. Epub 2016 Mar 2.
The goal of these experiments was to test how well cell responses to visual patterns can be predicted from the sinewave tuning curve. Magnocellular (MC) and parvocellular (PC) ganglion cell responses to different spatial waveforms (sinewave, squarewave, and ramp waveforms) were measured across a range of spatial frequencies. Sinewave spatial tuning curves were fit with standard Gaussian models. From these fits, waveforms and spatial tuning of a cell's responses to the other waveforms were predicted for different harmonics by scaling in amplitude for the power in the waveform's Fourier expansion series over spatial frequency. Since higher spatial harmonics move at a higher temporal frequency, an additional scaling for each harmonic by the MC (bandpass) or PC (lowpass) temporal response was included, together with response phase. Finally, the model included a rectifying nonlinearity. This provided a largely satisfactory estimation of MC and PC cell responses to complex waveforms. As a consequence of their transient responses, MC responses to complex waveforms were found to have significantly more energy in higher spatial harmonic components than PC responses. Response variance (noise) was also quantified as a function of harmonic component. Noise increased to some degree for the higher harmonics. The data are relevant for psychophysical detection or discrimination of visual patterns, and we discuss the results in this context.
这些实验的目的是测试根据正弦波调谐曲线能在多大程度上预测细胞对视觉模式的反应。在一系列空间频率范围内，测量了大细胞（MC）和小细胞（PC）神经节细胞对不同空间波形（正弦波、方波和斜坡波形）的反应。正弦波空间调谐曲线用标准高斯模型拟合。根据这些拟合结果，通过对波形傅里叶展开级数在空间频率上的功率进行幅度缩放，预测了细胞对其他波形反应的波形和空间调谐，针对不同谐波情况。由于更高的空间谐波以更高的时间频率移动，因此对每个谐波还根据MC（带通）或PC（低通）时间响应进行了额外缩放，并考虑了响应相位。最后，该模型包含一个整流非线性。这对MC和PC细胞对复杂波形的反应提供了基本令人满意的估计。由于它们的瞬态反应，发现MC对复杂波形的反应在更高空间谐波分量中的能量比PC反应显著更多。响应方差（噪声）也作为谐波分量的函数进行了量化。对于更高的谐波，噪声有一定程度的增加。这些数据与视觉模式的心理物理学检测或辨别相关，我们在此背景下讨论结果。
