Ito M, Fujita I, Tamura H, Tanaka K
Institute of Physical and Chemical Research (RIKEN), Saitama, Japan.
Cereb Cortex. 1994 Sep-Oct;4(5):499-508. doi: 10.1093/cercor/4.5.499.
Cells in the anterior part of the inferotemporal cortex (anterior IT) respond to moderately complex stimulus features of object images. To study dependency of their responses on contrast polarity of stimulus images, we selected cells with optimal stimuli that were defined only by shape and not related to texture or color, and examined effects of reversing the contrast of the image or removing it except for edges between dark and bright parts of the image ("outlining"). The contrast reversal produced a reduction of the response to the optimal stimulus by > 50% in 60% of tested cells; the outlining, in 70%. When the two transformations were considered together, 94% of the cells showed a reduction by > 50%. Effects of the transformations on shape selectivity were also studied by comparing responses to several different shapes each of whose contours were expressed in different ways. Statistically significant changes in relative effectiveness of the different shapes as a function of contour expression were observed in more than half of the cells. These results suggest that responses of individual cells in anterior IT carry information about contrast polarity as well as about shape.
颞下皮质前部（前颞下皮质，anterior IT）的细胞对物体图像的中等复杂刺激特征做出反应。为了研究它们的反应对刺激图像对比度极性的依赖性，我们选择了仅由形状定义且与纹理或颜色无关的最佳刺激细胞，并研究了反转图像对比度或除图像明暗部分之间的边缘外去除对比度（“勾勒轮廓”）的效果。在60%的测试细胞中，对比度反转使对最佳刺激的反应降低了50%以上；在70%的细胞中，勾勒轮廓产生了同样的效果。当将这两种变换一起考虑时，94%的细胞显示出降低了50%以上。还通过比较对几种不同形状的反应来研究变换对形状选择性的影响，每种形状的轮廓都以不同方式表示。在超过一半的细胞中观察到不同形状作为轮廓表示函数的相对有效性的统计学显著变化。这些结果表明，前颞下皮质中单个细胞的反应携带有关对比度极性以及形状的信息。
