Department of Psychology, University of York, UK.
Department of Psychology, University of York, UK.
Cortex. 2019 Oct;119:165-183. doi: 10.1016/j.cortex.2019.04.014. Epub 2019 May 7.
Patients with multimodal semantic deficits following stroke ('semantic aphasia') have largely intact knowledge, yet difficulty controlling conceptual retrieval to suit the circumstances. Although conceptual representations are thought to be largely distinct from episodic representations of recent events, controlled retrieval processes may overlap across semantic and episodic memory domains. We investigated this possibility by examining item familiarity and source memory for recent events in semantic aphasia following infarcts affecting left inferior frontal gyrus. We tested the hypothesis that the nature of impairment in episodic judgements reflects the need for control over retrieval: item familiarity might be relatively intact, given it is driven by strong cues (re-presentation of the item), while source recollection might be more impaired since this task involves resolving competition between several potential sources. This pattern was observed most strongly when the degree of competition between sources was higher, i.e., when non-meaningful sources had similar perceptual features, and existing knowledge was incongruent with the source. In contrast, when (i) spatial location acted as a strong cue for retrieval; (ii) existing knowledge was congruent with episodic memory and (iii) distinctiveness of sources was increased by means of self-referential processing, source memory reached normal levels. These findings confirm the association between deregulated control of semantic and episodic memory in patients with semantic aphasia and delineate circumstances that ameliorate or aggravate these deficits.
患有多模态语义缺陷的中风患者（“语义性失语症”）在很大程度上保留了知识，但难以控制概念检索以适应情况。尽管概念表示在很大程度上与最近事件的情节记忆表示不同，但控制检索过程可能会在语义和情节记忆领域重叠。我们通过检查影响左侧下额叶梗死的语义性失语症患者的近期事件的项目熟悉度和来源记忆来研究这种可能性。我们假设，情节判断的损伤性质反映了对检索的控制需求：由于项目熟悉度由强烈的线索（项目的再现）驱动，因此可能相对完整，而来源回忆可能受到更大的损害，因为这项任务涉及解决几个潜在来源之间的竞争。当来源之间的竞争程度更高时，即当非有意义的来源具有相似的感知特征且现有知识与来源不一致时，这种模式最为明显。相比之下，当（i）空间位置充当检索的强线索时；（ii）现有知识与情节记忆一致；（iii）通过自我参照处理增加来源的独特性时，来源记忆达到正常水平。这些发现证实了语义性失语症患者的语义和情节记忆的调节控制之间的关联，并描绘了改善或加重这些缺陷的情况。
