Negative, or complementary afterimages are experienced following brief adaptation to chromatic or achromatic stimuli, and are believed to be formed in the post-receptoral layers of the retinae. Afterimages can be cancelled by the addition of real images, suggesting that afterimages and real images are processed by similar mechanisms. However given their retinal origin, afterimage signals represented at the cortical level might have different spatio-temporal properties from their real images counterparts. To test this we determined whether afterimages reduce the contrast threshold of added real images, i.e. produce the classic "dipper" function characteristic of contrast discrimination, a behavior believed to be cortically mediated. Stimuli were chromatic and achromatic disks on a grey background. Observers adapted for 1.0 s to two side-by-side disks of a particular color. Following stimulus offset, a test disk added to one side was ramped downwards for 1.5 s to approximately match the temporal characteristic of the afterimage, and the observer was required to indicate the side containing the test disk. The test hue/brightness was either the same as that of the afterimage or a different hue/brightness. The independent variable was the contrast of the adaptor. A dipper followed by masking was observed in most conditions in which the afterimage and test colors had the same hue or brightness. We conclude that afterimages are represented similarly to their real image counterparts at the cortical level.

中文翻译：

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负残像有助于检测真实图像。

在短暂适应彩色或消色差刺激后，会出现负残影或互补残像，并被认为在视网膜的受体后层形成。可以通过添加真实图像来消除残像，这表明残像和真实图像可以通过类似的机制进行处理。然而，考虑到它们的视网膜起源，在皮层水平上表示的余像信号可能具有与真实图像对应物不同的时空特性。为了测试这一点，我们确定了残像是否降低了添加的真实图像的对比度阈值，即产生了对比度判别的经典“ dipper”功能特性，这种行为被认为是皮质介导的。刺激是在灰色背景上的彩色和无彩色光盘。观察者适用于1。0秒到两个特定颜色的并排磁盘。刺激偏移后，将添加到一侧的测试盘向下倾斜1.5 s，以大致匹配余像的时间特性，并且要求观察者指出包含测试盘的一侧。测试色相/亮度与残像相同或不同。自变量是适配器的对比度。在余像和测试色具有相同色相或亮度的大多数情况下，会观察到浸涂器和掩膜。我们得出的结论是，残像在皮质层级上的表示与真实图像类似。5 s的时间与残像的时间特性大致匹配，观察者需要指示包含测试盘的一面。测试色相/亮度与残像相同或不同。自变量是适配器的对比度。在余像和测试色具有相同色相或亮度的大多数情况下，会观察到浸涂器和掩膜。我们得出的结论是，残像在皮质层级上的表示与真实图像类似。5 s的时间与残像的时间特性大致匹配，观察者需要指示包含测试盘的一面。测试色相/亮度与残像相同或不同。自变量是适配器的对比度。在余像和测试色具有相同色相或亮度的大多数情况下，会观察到浸涂器和掩膜。我们得出的结论是，残像在皮质层级上的表示与真实图像类似。在余像和测试色具有相同色相或亮度的大多数情况下，会观察到浸涂器和掩膜。我们得出的结论是，残像在皮质层级上的表示与真实图像类似。在余像和测试色具有相同色相或亮度的大多数情况下，会观察到浸涂器和掩膜。我们得出的结论是，残像在皮质层级上的表示与真实图像类似。