A degraded, black-and-white image of an object, which appears meaningless on first presentation, is easily identified after a single exposure to the original, intact image. This striking example of perceptual learning reflects a rapid (one-trial) change in performance, but the kind of learning that is involved is not known. We asked whether this learning depends on conscious (hippocampus-dependent) memory for the images that have been presented or on an unconscious (hippocampus-independent) change in the perception of images, independently of the ability to remember them. We tested five memory-impaired patients with hippocampal lesions or larger medial temporal lobe (MTL) lesions. In comparison to volunteers, the patients were fully intact at perceptual learning, and their improvement persisted without decrement from 1 d to more than 5 mo. Yet, the patients were impaired at remembering the test format and, even after 1 d, were impaired at remembering the images themselves. To compare perceptual learning and remembering directly, at 7 d after seeing degraded images and their solutions, patients and volunteers took either a naming test or a recognition memory test with these images. The patients improved as much as the volunteers at identifying the degraded images but were severely impaired at remembering them. Notably, the patient with the most severe memory impairment and the largest MTL lesions performed worse than the other patients on the memory tests but was the best at perceptual learning. The findings show that one-trial, long-lasting perceptual learning relies on hippocampus-independent (nondeclarative) memory, independent of any requirement to consciously remember.

对象的退化的黑白图像在第一次呈现时看起来毫无意义，但在对原始完整图像进行单次曝光后很容易识别。这个感知学习的惊人例子反映了性能的快速（一次试验）变化，但所涉及的学习类型尚不清楚。我们询问这种学习是依赖于对已呈现图像的有意识（依赖海马体）记忆还是依赖于图像感知的无意识（独立于海马体）变化，而与记住它们的能力无关。我们测试了五名患有海马病变或较大内侧颞叶 (MTL) 病变的记忆障碍患者。与志愿者相比，患者在知觉学习方面完全完好，他们的改善持续存在，从 1 天到 5 个月以上没有减少。然而，患者在记忆测试格式方面受到损害，即使在 1 天后，他们对图像本身的记忆也受到损害。为了直接比较感知学习和记忆，在看到退化图像及其解决方案后 7 天，患者和志愿者对这些图像进行命名测试或识别记忆测试。患者在识别退化图像方面的进步与志愿者一样多，但在记住它们方面却严重受损。值得注意的是，记忆障碍最严重和 MTL 损伤最大的患者在记忆测试中的表现比其他患者差，但在知觉学习方面表现最好。研究结果表明，一次试验、持久的感知学习依赖于独立于海马体的（非陈述性）记忆，独立于有意识地记忆的任何要求。