Memory Repression: Brain Mechanisms underlying Dissociative Amnesia
Memory Repression: Brain Mechanisms underlying Dissociative Amnesia
复制标题
DOI：
10.1162/jocn.2009.21212
复制
发表时间：
2010-03-01
影响因子：
3.2
通讯作者：
Mori, Etsuro
中科院分区：
文献类型：
--
作者：
Kikuchi, Hirokazu;Fujii, Toshikatsu;Mori, Etsuro
解离性遗忘症通常发生在压力事件之后，并且不能归因于明显的脑损伤。它被认为反映了可能由于记忆抑制而导致的记忆检索的可逆性缺陷。然而，这种情况背后的神经机制尚不清楚。我们使用功能磁共振成像来研究两名分离性遗忘症患者与记忆检索相关的神经活动。为每位患者准备了三类面部照片和三类与照片相对应的人名：“可认出”的高中朋友，即与患者相识且可认出的人名；“不可认出”的同事，即实际上很熟悉但由于患者记忆障碍而无法认出的同事；以及“控制”分心者，即与患者不熟悉的人名。在功能磁共振成像期间，患者会在视觉上看到这些刺激，并被要求表明他们个人是否熟悉这些刺激。在将无法识别的情况与可识别的情况进行比较时，我们发现两名患者的 pFC 活动增加，而海马活动减少。逆行性遗忘症治疗后，一名逆行性记忆恢复的患者大脑激活模式的改变消失了，而另一名逆行性记忆未恢复的患者则保持不变。我们的研究结果提供了直接证据，表明解离性遗忘症中的记忆抑制与神经活动模式的改变有关，并且它们表明前额叶皮层可能在抑制海马体在记忆抑制中的活动中发挥重要作用。
Dissociative amnesia usually follows a stressful event and cannot be attributable to explicit brain damage. It is thought to reflect a reversible deficit in memory retrieval probably due to memory repression. However, the neural mechanisms underlying this condition are not clear. We used fMRI to investigate neural activity associated with memory retrieval in two patients with dissociative amnesia. For each patient, three categories of face photographs and three categories of people's names corresponding to the photographs were prepared: those of "recognizable" high school friends who were acquainted with and recognizable to the patients, those of "unrecognizable" colleagues who were actually acquainted with but unrecognizable to the patients due to their memory impairments, and "control" distracters who were unacquainted with the patients. During fMRI, the patients were visually presented with these stimuli and asked to indicate whether they were personally acquainted with them. In the comparison of the unrecognizable condition with the recognizable condition, we found increased activity in the pFC and decreased activity in the hippocampus in both patients. After treatment for retrograde amnesia, the altered pattern of brain activation disappeared in one patient whose retrograde memories were recovered, whereas it remained unchanged in the other patient whose retrograde memories were not recovered. Our findings provide direct evidence that memory repression in dissociative amnesia is associated with an altered pattern of neural activity, and they suggest the possibility that the pFC has an important role in inhibiting the activity of the hippocampus in memory repression.