Everson R M, Prashanth A K, Gabbay M, Knight B W, Sirovich L, Kaplan E
Laboratory for Applied Mathematics, The Mount Sinai School of Medicine, New York, NY 10029, USA.
Proc Natl Acad Sci U S A. 1998 Jul 7;95(14):8334-8. doi: 10.1073/pnas.95.14.8334.
Knowledge of the response of the primary visual cortex to the various spatial frequencies and orientations in the visual scene should help us understand the principles by which the brain recognizes patterns. Current information about the cortical layout of spatial frequency response is still incomplete because of difficulties in recording and interpreting adequate data. Here, we report results from a study of the cat primary visual cortex in which we employed a new image-analysis method that allows improved separation of signal from noise and that we used to examine the neurooptical response of the primary visual cortex to drifting sine gratings over a range of orientations and spatial frequencies. We found that (i) the optical responses to all orientations and spatial frequencies were well approximated by weighted sums of only two pairs of basis pictures, one pair for orientation and a different pair for spatial frequency; (ii) the weightings of the two pictures in each pair were approximately in quadrature (1/4 cycle apart); and (iii) our spatial frequency data revealed a cortical map that continuously assigns different optimal spatial frequency responses to different cortical locations over the entire spatial frequency range.
了解初级视觉皮层对视觉场景中各种空间频率和方向的反应，应有助于我们理解大脑识别模式的原理。由于记录和解释足够数据存在困难，目前关于空间频率反应的皮层布局的信息仍然不完整。在此，我们报告一项对猫初级视觉皮层的研究结果，在该研究中，我们采用了一种新的图像分析方法，该方法能够更好地分离信号与噪声，并且我们用它来研究初级视觉皮层对一系列方向和空间频率的漂移正弦光栅的神经光学反应。我们发现：（i）对所有方向和空间频率的光学反应都可以很好地用仅两对基图像的加权和来近似，一对用于方向，另一对用于空间频率；（ii）每对中两张图像的权重近似成正交关系（相差1/4周期）；（iii）我们的空间频率数据揭示了一种皮层图谱，该图谱在整个空间频率范围内将不同的最佳空间频率反应连续地分配给不同的皮层位置。
