Word repetition in amnesia - Electrophysiological measures of impaired and spared memory
Word repetition in amnesia - Electrophysiological measures of impaired and spared memory
复制标题
DOI：
10.1093/brain/123.9.1948
复制
发表时间：
2000-09-01
期刊：
影响因子：
14.5
通讯作者：
Kutas, M
中科院分区：
文献类型：
--
作者：
Olichney, JM;Van Petten, C;Kutas, M
当重复刺激时，痴呆患者通常表现出改善的表现，即使在没有对这些刺激的有意识记忆的情况下，尽管这些表现变化通常归因于知觉或运动系统，但在某些情况下，它们可能与基本的语言处理有关。我们检查了两个神经生理学指标，在12名健忘症患者和12名对照受试者中随单词重复而变化：（i）与有意识记忆相关的事件相关电位（ERP）的晚期阳性成分和（ii）随语言理解而变化的N400成分。在每一次试验中，受试者听到一个类别名称，然后看到一个单词，然后决定这个单词在语义上是一致的还是不一致的（例如，“是”代表“婴儿动物：幼崽”;“否”代表“水上运动：厨房”）。实验结束时的回忆和识别测试显示，对照组受试者对一致性词语的记忆要比不一致性词语的记忆好，健忘症患者也是如此，他们的整体表现不太好。相比之下，健忘症患者在每次试验中所需的类别决策上均未受损，并且与对照组一样，不一致词相对于一致词显示出较大的N400。同样，当在0-13次干预试验后重复不一致试验时，两组的N400均减少。当一致性试验被重复时，观察到了后期的积极重复效应，但仅限于对照组。此外，在患者和对照组中，晚期积极重复效应的幅度与后期单词回忆高度相关。在患者中，也观察到与标准化神经心理学测试的记忆分数的相关性，这些数据与晚期积极重复效应和有意识记忆之间的联系一致。另一方面，N400重复效应与情景记忆能力无关，而是索引了健忘症患者中完整的记忆方面。保留的N400重复效应是健忘症中保留记忆的一个例子，它不容易适合低水平感知处理或运动学习的类别，相反，N400对语义上下文和重复的敏感性可能反映了一个短期记忆过程，该过程实时服务于语言理解。
Amnesic patients often show improved performance when stimuli are repeated, even in the absence of conscious memory for those stimuli, Although these performance changes are typically attributed to perceptual or motor systems, in some cases they may be related to basic language processing. We examined two neurophysiological measures that vary with word repetition in 12 amnesic patients and 12 control subjects: (i) a late positive component of the event-related potential (ERP) linked to conscious memory and (ii) the N400 component that varies with language comprehension. In each trial, the subject heard a category name, then viewed a word, and then decided whether the word was semantically congruous or incongruous (e.g. 'yes' for 'baby animal: cub'; 'no' for 'water sport: kitchen'). Recall and recognition testing at the end of the experiment showed that control subjects had better memory for congruous than for incongruous words, as did the amnesic patients, who performed less well overall. In contrast, amnesic patients were unimpaired on the category decisions required in each trial and, like the control subjects, showed a large N400 for incongruous relative to congruous words, Similarly, when incongruous trials were repeated after 0-13 intervening trials, N400s were reduced in both groups. When congruous trials were repeated, a late positive repetition effect was observed, but only in the control group. Furthermore, the amplitude of the late positive repetition effect was highly correlated with later word recall in both patients and controls. In the patients, the correlation was also observed with memory scores from standardized neuropsychological tests, These data are consistent with a proposed link between the late positive repetition effect and conscious memory On the other hand, the N400 repetition effect was not correlated with episodic memory abilities, but instead indexed an aspect of memory that was intact in the amnesic patients. The preserved N400 repetition effect is an example of preserved memory in amnesia that does not easily fit into the categories of low-level perceptual processing or of motor learning, Instead, the sensitivity of the N400 to both semantic context and repetition may reflect a shortterm memory process that serves language comprehension in realtime.