Milner P M
Department of Psychology, McGill University, Montreal, Quebec, Canada.
Neuropsychologia. 1989;27(1):23-30. doi: 10.1016/0028-3932(89)90087-0.
Recent memories are more susceptible to amnesic loss than older memories, the time scale being much longer than can reasonably be explained by a passive chemical or morphological change. A possible explanation is that memories are initially sustained by "soft", easily produced but ephemoral, synaptic changes to which are later added "hard" changes that are more durable but require repeated synaptic activity over a long period to become established. "Soft" synapses are assumed to be concentrated in parts of the limbic system, "hard" synapses in the neocortex. The theory can also explain why objects encountered by patients with anterograde amnesia never become familiar to them.
近期记忆比旧记忆更容易受到失忆症的影响，其时间尺度比被动的化学或形态变化所能合理解释的要长得多。一种可能的解释是，记忆最初由“软”的、易于产生但短暂的突触变化维持，随后会增加“硬”变化，这些变化更持久，但需要长时间反复的突触活动才能确立。“软”突触被认为集中在边缘系统的部分区域，“硬”突触则在新皮层。该理论还可以解释为什么顺行性失忆症患者遇到的物体对他们来说永远不会变得熟悉。
