Atherton Kathryn E, Nobre Anna C, Zeman Adam Z, Butler Christopher R
Department of Experimental Psychology, University of Oxford, Oxford, UK; Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
Department of Experimental Psychology, University of Oxford, Oxford, UK; Oxford Centre for Human Brain Activity, University of Oxford, Oxford, UK.
Cortex. 2014 May;54(100):92-105. doi: 10.1016/j.cortex.2014.02.009. Epub 2014 Feb 21.
Accelerated long-term forgetting (ALF) is a form of memory impairment in which learning and initial retention of information appear normal but subsequent forgetting is excessively rapid. ALF is most commonly associated with epilepsy and, in particular, a form of late-onset epilepsy called transient epileptic amnesia (TEA). ALF provides a novel opportunity to investigate post-encoding memory processes, such as consolidation. Sleep is implicated in the consolidation of memory in healthy people and a deficit in sleep-dependent memory consolidation has been proposed as an explanation for ALF. If this proposal were correct, then sleep would not benefit memory retention in people with ALF as much as in healthy people, and ALF might only be apparent when the retention interval contains sleep. To test this theory, we compared performance on a sleep-sensitive memory task over a night of sleep and a day of wakefulness. We found, contrary to the hypothesis, that sleep benefits memory retention in TEA patients with ALF and that this benefit is no smaller in magnitude than that seen in healthy controls. Indeed, the patients performed significantly more poorly than the controls only in the wake condition and not the sleep condition. Patients were matched to controls on learning rate, initial retention, and the effect of time of day on cognitive performance. These results indicate that ALF is not caused by a disruption of sleep-dependent memory consolidation. Instead, ALF may be due to an encoding abnormality that goes undetected on behavioural assessments of learning, or by a deficit in memory consolidation processes that are not sleep-dependent.
加速性长期遗忘（ALF）是一种记忆障碍形式，其中信息的学习和初始保持看似正常，但随后的遗忘速度过快。ALF最常与癫痫相关，特别是与一种称为短暂性癫痫性失忆症（TEA）的迟发性癫痫形式有关。ALF为研究编码后记忆过程（如巩固）提供了一个新的机会。睡眠与健康人的记忆巩固有关，有人提出睡眠依赖性记忆巩固缺陷是ALF的一种解释。如果这一观点正确，那么睡眠对ALF患者记忆保持的益处将不如对健康人那么大，并且ALF可能仅在保持间隔包含睡眠时才明显。为了验证这一理论，我们比较了在一夜睡眠和一天清醒状态下一项对睡眠敏感的记忆任务的表现。我们发现，与假设相反，睡眠对患有ALF的TEA患者的记忆保持有益，并且这种益处的程度并不小于在健康对照组中观察到的。事实上，患者仅在清醒状态下的表现明显比对照组差，而在睡眠状态下并非如此。患者在学习率、初始保持以及一天中的时间对认知表现的影响方面与对照组相匹配。这些结果表明，ALF不是由睡眠依赖性记忆巩固的破坏引起的。相反，ALF可能是由于在学习的行为评估中未被检测到的编码异常，或者是由于非睡眠依赖性记忆巩固过程的缺陷所致。
