Department of Psychology, University of York, UK.
Department of Psychology, University of York, UK; School of Psychology, University of Surrey, UK.
Cortex. 2018 Nov;108:127-143. doi: 10.1016/j.cortex.2018.07.007. Epub 2018 Jul 27.
Semantic cognition is supported by two interactive components: semantic representations and mechanisms that regulate retrieval (cf. 'semantic control'). Neuropsychological studies have revealed a clear dissociation between semantic and episodic memory. This study explores if the same dissociation holds for control processes that act on episodic and semantic memory, or whether both types of long-term memory are supported by the same executive mechanisms. We addressed this question in a case-series of semantic aphasic patients who had difficulty retrieving both verbal and non-verbal conceptual information in an appropriate fashion following infarcts to left inferior frontal gyrus (LIFG). We observed parallel deficits in semantic and episodic memory: (i) the patients' difficulties extended beyond verbal materials to include picture tasks in both domains; (ii) both types of retrieval benefitted from cues designed to reduce the need for internal constraint; (iii) there was little impairment of both semantic and episodic tasks when control demands were minimised; (iv) there were similar effects of distractors across tasks. Episodic retrieval was highly susceptible to false memories elicited by semantically-related distractors, and confidence was inappropriately high in these circumstances. Semantic judgements were also prone to contamination from recent events. These findings demonstrate that patients with deregulated semantic cognition have comparable deficits in episodic retrieval. The results are consistent with a role for LIFG in resolving competition within both episodic and semantic memory, and also in biasing cognition towards task-relevant memory stores when episodic and semantic representations do not promote the same response.
语义表示和调节检索的机制（参见“语义控制”）。神经心理学研究表明，语义记忆和情景记忆之间存在明显的分离。本研究探讨了这种分离是否适用于作用于情景记忆和语义记忆的控制过程，或者两种类型的长期记忆是否都由相同的执行机制支持。我们在一系列语义性失语症患者中进行了研究，这些患者在左额下回（LIFG）梗死后难以以适当的方式检索言语和非言语概念信息。我们观察到语义记忆和情景记忆都存在平行缺陷：（i）患者的困难不仅限于言语材料，还包括两个领域的图片任务；（ii）两种类型的检索都受益于旨在减少内部约束需求的线索；（iii）当控制需求最小化时，两种语义和情景任务的损伤都很小；（iv）任务之间的干扰物有相似的影响。情景检索极易受到语义相关干扰物引发的虚假记忆的影响，并且在这种情况下，置信度过高。语义判断也容易受到最近事件的污染。这些发现表明，调节不良的语义认知患者在情景检索中也存在类似的缺陷。结果与 LIFG 在解决情景和语义记忆内竞争以及在情景和语义表示不促进相同反应时偏向于与任务相关的记忆存储的作用一致。
