A neurophysiologically plausible population code model for human contrast discrimination
A neurophysiologically plausible population code model for human contrast discrimination
复制标题
DOI：
10.1167/9.7.15
复制
发表时间：
2009-01-01
影响因子：
1.8
通讯作者：
Henning, G. Bruce
中科院分区：
文献类型：
--
作者：
Goris, Robbe L. T.;Wichmann, Felix A.;Henning, G. Bruce
基座效应是指在存在相同方向、空间频率和相位的另一个光栅（通常称为基座）的情况下，正弦光栅的可检测性得到改善。最近的证据表明，基座效应会受到频谱平坦和陷波滤波噪声的不同影响：基座效应在平坦噪声中减弱，但在存在陷波噪声时几乎消失（G. B. Henning & F. A. Wichmann，2007）。在这里，我们考虑一个由单元组成的网络，其对比度响应函数类似于被认为是人类模式视觉基础的皮层细胞的单元，并证明，当多个单元的输出通过简单的加权求和（类似于最佳信息组合并产生对比度相关的权重分布的启发式决策规则）组合时，网络产生与心理物理学观察一致的对比度辨别数据：基座效应在没有噪声的情况下存在，在宽带噪声中减少，但在陷波噪声中几乎消失。这些发现自然地遵循初级视觉皮层中简单细胞的归一化模型，然后是基于响应的池化，并且表明在处理低对比度正弦光栅时，视觉系统可以组合跨神经元调整到不同空间频率和方向的信息。
The pedestal effect is the improvement in the detectability of a sinusoidal grating in the presence of another grating of the same orientation, spatial frequency, and phase-usually called the pedestal. Recent evidence has demonstrated that the pedestal effect is differently modified by spectrally flat and notch-filtered noise: The pedestal effect is reduced in flat noise but virtually disappears in the presence of notched noise (G. B. Henning & F. A. Wichmann, 2007). Here we consider a network consisting of units whose contrast response functions resemble those of the cortical cells believed to underlie human pattern vision and demonstrate that, when the outputs of multiple units are combined by simple weighted summation-a heuristic decision rule that resembles optimal information combination and produces a contrast-dependent weighting profile-the network produces contrast-discrimination data consistent with psychophysical observations: The pedestal effect is present without noise, reduced in broadband noise, but almost disappears in notched noise. These findings follow naturally from the normalization model of simple cells in primary visual cortex, followed by response-based pooling, and suggest that in processing even low-contrast sinusoidal gratings, the visual system may combine information across neurons tuned to different spatial frequencies and orientations.