Laboratory of Imaging and Cognitive Neurosciences, UMR 7237, IFR 37, Strasbourg University, Strasbourg, France.
Cortex. 2013 Sep;49(8):2007-20. doi: 10.1016/j.cortex.2012.11.007. Epub 2012 Nov 28.
Refined investigation of infrequent dissociations within remote memory, such as preservation of autobiographical episodic memory and selective impairment of public semantic memory could provide some insight on the interactions of long-term memory systems and their underlying brain correlates. Combining clinical neuropsychological and neuroimaging methods in the present study, we examined a patient surgically treated for temporal lobe epilepsy showing this rare pattern of dissociation. Specifically, we investigated along the two temporal directions, past and future, his autobiographical episodic memory, semantic memory for public events and famous people and their interaction through the concept of autobiographical significance (AS). The results showed impaired ability not only to recall past but also to imagine future public events in a context of preserved past and future personal episodic memory. Remarkably, impersonal future thinking was impaired regardless of AS, while the autobiographical-significant public past knowledge relied exclusively on the patient's spared autobiographical episodic memory. These results were corroborated by neuroimaging data showing the absence of brain activation for public knowledge devoid of personal significance and activation of the autobiographical memory cerebral network for personally significant public knowledge. Our findings suggest that AS did not 'restore' the code to access public semantic memory, but bypassed it by using personal memory sources successful only for past public recollections. Therefore, remembering impersonal and imagining public events seems to require the contribution of public semantic knowledge per se. The patient's cognitive profile suggested a reorganization of memory systems.
对远程记忆中不常见的分离现象进行精细化研究，例如保留自传体情节记忆和选择性损害公共语义记忆，可以深入了解长期记忆系统及其潜在的大脑关联。本研究结合临床神经心理学和神经影像学方法，对一名接受颞叶癫痫手术治疗的患者进行了研究，该患者表现出这种罕见的分离模式。具体来说，我们沿着过去和未来两个时间方向，研究了他的自传体情节记忆、公共事件和名人的语义记忆及其通过自传体意义（AS）的概念的相互作用。结果表明，该患者不仅回忆过去的能力受损，而且在保留过去和未来个人情节记忆的情况下，想象未来的公共事件的能力也受损。值得注意的是，非个人的未来思维受损，而与 AS 无关，而自传体意义重大的公共过去知识仅依赖于患者保留的自传体情节记忆。神经影像学数据证实了这些结果，这些数据显示，缺乏个人意义的公共知识没有大脑激活，而具有个人意义的公共知识的自传体记忆网络则被激活。我们的研究结果表明，AS 并没有“恢复”访问公共语义记忆的代码，而是通过仅对过去的公共回忆有用的个人记忆来源绕过了它。因此，记忆非个人和想象公共事件似乎需要公共语义知识本身的贡献。患者的认知特征表明记忆系统发生了重组。
