Spitzer H, Hochstein S
J Neurophysiol. 1985 May;53(5):1266-86. doi: 10.1152/jn.1985.53.5.1266.
The time course of the response of a single cortical neuron to counterphase-grating stimulation may vary as a function of stimulation parameters, as shown in the preceding paper (19). The poststimulus-time histograms of the response amplitudes against time are single or double peaked, and where double peaked, the two peaks are of equal or unequal amplitudes. Furthermore, the spatial-phase dependence of cortical complex-cell responses may be a function of spatial frequency, so that the receptive field appears to have linear spatial summation at some spatial frequencies and nonlinear spatial summation at others (19). In the first part of this paper, we analyze a model receptive field that displays this behavior, and in the second part experimental data are presented and analyzed with regard to the model. The model cortical receptive field in its simplest form contains (two rows) of geniculate X-cell-like, DOG (difference-of-Gaussians)-shaped, center-surround antagonistic, circular-input subunits. We propose nonlinear summation between these two subunits, by introducing a half-wave rectification stage before pooling. The model is tested for the responses it predicts for the application of counterphase-grating stimulation. This simple model predicts the appearance of three response forms as a function of counterphase-stimulation parameters. At periodic spatial frequencies the expected-response histogram has a single peak, whose amplitude has a sinusoidal dependence on spatial phase. At spatial frequencies halfway between these, the expected-response histogram has two equal peaks whose amplitudes have a full-wave rectified sinusoidal dependence on spatial phase. At all intermediate spatial frequencies the expected-response histogram has a "mixed" form; the histogram appears sometimes with one peak, sometimes with two equal peaks, and generally with two peaks of unequal amplitude, as a function of spatial phase. Null responses are expected to appear at specific spatial phases only for the periodic spatial frequencies that give "pure" response time courses as in paragraph 5 above, and not in the more common mixed response case of paragraph 6. The analysis procedure described in the preceding paper (19) is used, separating the odd and even Fourier components of the response histograms reflecting the receptive-field intrasubunit linear summation and intersubunit nonlinear summation, respectively. We propose that this model may be used as a working hypothesis for the analysis of these aspects of the various cortical receptive-field types. Experimental data are described and discussed in terms of the model.(ABSTRACT TRUNCATED AT 400 WORDS)
单个皮层神经元对反相光栅刺激的反应时间进程可能会随刺激参数而变化，如前文（19）所示。反应幅度随时间的刺激后时间直方图为单峰或双峰，若为双峰，两个峰的幅度相等或不等。此外，皮层复杂细胞反应的空间相位依赖性可能是空间频率的函数，因此感受野在某些空间频率下表现出线性空间总和，而在其他频率下表现出非线性空间总和（19）。在本文的第一部分，我们分析了一个表现出这种行为的模型感受野，在第二部分中，我们给出了实验数据并根据该模型进行了分析。最简单形式的模型皮层感受野包含（两行）膝状X细胞样、高斯差分（DOG）形状、中心-外周拮抗的圆形输入亚单位。我们通过在合并之前引入一个半波整流阶段，提出了这两个亚单位之间的非线性总和。对该模型预测的反相光栅刺激应用的反应进行了测试。这个简单的模型预测了三种反应形式的出现，这是反相刺激参数的函数。在周期性空间频率下，预期反应直方图有一个单峰，其幅度对空间相位呈正弦依赖性。在这些频率的中间频率处，预期反应直方图有两个相等的峰，其幅度对空间相位呈全波整流正弦依赖性。在所有中间空间频率下，预期反应直方图具有“混合”形式；直方图有时出现一个峰，有时出现两个相等的峰，通常出现两个幅度不等的峰，这是空间相位的函数。仅对于给出如上文第5段所述“纯”反应时间进程的周期性空间频率，预期在特定空间相位会出现零反应，而在第6段更常见的混合反应情况下则不会。使用前文（19）中描述的分析程序，分别分离反映感受野亚单位内线性总和和亚单位间非线性总和的反应直方图的奇次和偶次傅里叶分量。我们提出，这个模型可以用作分析各种皮层感受野类型这些方面的一个工作假设。根据该模型对实验数据进行了描述和讨论。（摘要截断于400字）
