Bird Chris M, Burgess Neil
Institute of Cognitive Neuroscience, University College London, London, UK.
Curr Biol. 2008 Dec 23;18(24):1932-6. doi: 10.1016/j.cub.2008.10.046. Epub 2008 Dec 11.
Bilateral damage to the human hippocampus profoundly impairs the ability to form long-term, consciously accessible memories, producing a classic amnesic syndrome. However, the effect of hippocampal damage on our ability to recognize items via a feeling of familiarity is hotly disputed. Dual-process theory predicts no effect, whereas declarative memory theory predicts impairment of all types of recognition memory. Here, we demonstrate a striking material specificity in the effect of focal hippocampal damage: Recognition memory is impaired for words but intact for faces. The latter finding is incompatible with declarative memory theory, whereas the former constrains dual-process theory by revealing the limitations of postulated extrahippocampal familiarity-based processes. We suggest that the hippocampus boosts recognition of well-known stimuli (high-frequency words) by activating pre-experimental associations that enrich the context of their presentation. By contrast, recognition memory for some kinds of previously unfamiliar stimuli (unfamiliar faces) may be supported by extrahippocampal familiarity-based processes, at least over short intervals.
人类海马体的双侧损伤会严重损害形成长期的、有意识可及记忆的能力，从而产生典型的失忆综合征。然而，海马体损伤对我们通过熟悉感识别物品能力的影响存在激烈争议。双加工理论预测没有影响，而陈述性记忆理论预测所有类型的识别记忆都会受损。在这里，我们证明了局灶性海马体损伤效应中一种显著的材料特异性：对单词的识别记忆受损，但对面孔的识别记忆完好。后一发现与陈述性记忆理论不相符，而前一发现通过揭示假定的基于海马体外熟悉度的过程的局限性，对双加工理论进行了限制。我们认为，海马体通过激活实验前的关联来增强对知名刺激（高频单词）的识别，这些关联丰富了它们呈现的背景。相比之下，对某些以前不熟悉的刺激（不熟悉的面孔）的识别记忆可能至少在短时间内由基于海马体外熟悉度的过程支持。
