NONLINEAR DIRECTIONALLY SELECTIVE SUBUNITS IN COMPLEX CELLS OF CAT STRIATE CORTEX
NONLINEAR DIRECTIONALLY SELECTIVE SUBUNITS IN COMPLEX CELLS OF CAT STRIATE CORTEX
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DOI：
10.1152/jn.1987.58.1.33
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发表时间：
1987-07-01
影响因子：
2.5
通讯作者：
KLEIN, SA
中科院分区：
文献类型：
--
作者：
EMERSON, RC;CITRON, MC;KLEIN, SA
1.我们已经分析了感受野（RF）的定向选择性（DS）复杂的细胞在纹状体皮层的猫。我们确定在何种程度上DS的复杂的细胞取决于空间可识别的亚基内RF通过研究响应的最佳取向，三亮度值，gratinglike刺激，时空随机。2.我们通过非线性空间RF相互作用测试确定了亚基。为此，我们在空间叠加测试中计算了Wiener类内核，该测试每次取决于两个RF位置。在这两个位置处的亮条和暗条的空间和时间分离分别以0.5度和16 ms的增量在8度的空间范围和+/-112 ms的时间范围内变化。3.复杂细胞中的DS反应不能用它们对单个亮条或暗条的反应来解释，因为任何时间过程在空间上均匀的线性叠加反应都没有方向偏好。4.一个闪烁的参考酒吧，是固定的位置和第二个酒吧，是在周围的位置闪烁之间的非线性相互作用，帮助解释DS显示乘法型便利的酒吧对，模仿运动的首选方向和抑制酒吧对，模仿运动的空方向。在优选的方向上的相互作用具有最佳的空间/时间比（速度），表现为在时空坐标系中伸长的、倾斜取向的正域。这种关系在时空上是不可分割的。长轴的斜率指定首选速度，其负值与相反方向上最强烈抑制的速度一致。5.当参考棒的位置在RF上移动时，时空相互作用也随之移动，这表明存在着一个几乎均匀分布在RF上的亚基族。我们称之为子单元的相互作用，平均在整个RF，“运动内核”，因为它的空间和时间变量是那些必要的指定速度，唯一的参数，区分运动图像从时间调制的静止图像。非线性相互作用表现出空间周期性，这表明移动扩展图像的速度选择性机制。（摘要截短至400字）
1. We have analyzed receptive fields (RFs) of directionally selective (DS) complex cells in the striate cortex of the cat. We determined the extent to which the DS of a complex cell depends on spatially identifiable subunits within the RF by studying responses to an optimally oriented, three-luminance-valued, gratinglike stimulus that was spatiotemporally randomized. 2. We identified subunits by testing for nonlinear spatial RF interactions. To do this, we calculated Wiener-like kernels in a spatial superposition test that depended on two RF positions at a time. The spatial and temporal separation of light and dark bars at these two positions varied over a spatial range of 8 degrees and a temporal range of +/- 112 ms in increments of 0.5 degree and 16 ms, respectively. 3. DS responses in complex cells cannot be explained by their responses to single light or dark bars because any linear superposition of responses whose time course is uniform across space shows no directional preference. 4. Nonlinear interactions between a flashed reference bar that is fixed in position and a second bar that is flashed at surrounding positions help explain DS by showing multiplicative-type facilitation for bar pairs that mimic motion in the preferred direction and suppression for bar pairs that mimic motion in the null direction. Interactions in the preferred direction have an optimal space/time ratio (velocity), exhibited by elongated, obliquely oriented positive domains in a space-time coordinate frame. This relationship is inseparable in space-time. The slope of the long axis specifies the preferred speed, and its negative agrees with the most strongly suppressed speed in the opposite direction. 5. When the reference bar position is moved across the RF, the spatiotemporal interaction moves with it. This suggests the existence of a family of nearly uniform subunits distributed across the RF. We call the subunit interaction, as averaged across the RF, the “motion kernel” because its spatial and temporal variables are those necessary to specify the velocity, the only parameter that distinguishes a moving image from a temporally modulated stationary image. The nonlinear interaction shows a spatial periodicity, which suggests a mechanism of velocity selectivity for moving extended images.(ABSTRACT TRUNCATED AT 400 WORDS)