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Tag: Semantic Memory

Sympathetic arousal, but not disturbed executive functioning, mediates the impairment of cognitive flexibility under stress

Published in: Cognition, Volume 174, May 2018, 94-102 Abstract “Cognitive flexibility emerges from an interplay of multiple cognitive systems, of which lexical-semantic and executive are thought to be the most important. Yet this has not been addressed by previous studies demonstrating that such forms of flexible thought deteriorate under stress. Motivated by these shortcomings, the present study evaluated several candidate mechanisms implied to mediate the impairing effects of stress on flexible thinking. Fifty-seven healthy adults were randomly assigned to psychosocial stress or control condition while assessed for performance on cognitive flexibility, working memory capacity, semantic fluency, and self-reported cognitive interference. Stress response was indicated… Read More

The ERP correlates of self-knowledge: Are assessments of one’s past, present, and future traits closer to semantic or episodic memory?

Published in: Neuropsychologia, Volume 110, February 2018, 65-83 Abstract “Self-knowledge concerns one’s own preferences and personality. It pertains to the self (similar to episodic memory), yet does not concern events. It is factual (like semantic memory), but also idiosyncratic. For these reasons, it is unclear where self-knowledge might fall on a continuum in relation to semantic and episodic memory. In this study, we aimed to compare the event-related potential(ERP) correlates of self-knowledge to those of semantic and episodic memory, using N400 and Late Positive Component (LPC) as proxies for semantic and episodic processing, respectively. We considered an additional factor: time perspective. Temporally distant… Read More

The cost of switching between taxonomic and thematic semantics

Published in: Memory & Cognition, Volume 46, Issue 2, 191-203 Abstract “Current models and theories of semantic knowledge primarily capture taxonomic relationships (DOG and WOLF) and largely do not address the role of thematic relationships in semantic knowledge (DOG and LEASH). Recent evidence suggests that processing or representation of thematic relationships may be distinct from taxonomic relationships. If taxonomic and thematic relations are distinct, then there should be a cost associated with switching between them even when the task remains constant. This hypothesis was tested using two different semantic-relatedness judgment tasks: Experiment 1 used a triads task and Experiment 2 used an oddball task. In both… Read More

Episodic future thinking and future-based decision-making in a case of retrograde amnesia

Published in: Neuropsychologia, Volume 110, February 2018, 92-103 Abstract “We investigated episodic future thinking (EFT) and future-based cognition and decision-making in patient SG, who developed a dense retrograde amnesiafollowing hypoxia due to a cardiac arrest. Despite intact general cognitive and executive functioning, SG was unable to remember events from his entire lifetime. He had, however, relatively spared anterograde memory and general semantic knowledge. Voxel-based morphometry detected a reduction of gray matter in the thalamus, cerebellum and fusiform gyrus bilaterally, and, at a reduced threshold, in several regions of the autobiographical memory network, including the hippocampi. We show that SG is unable to imagine personal future events, but can imagine fictitious events not self-relevant… Read More

The life stories of adults with amnesia: Insights into the contribution of the medial temporal lobes to the organization of autobiographical memory

Published in: Neuropsychologia, Volume 110, February 2018, 84-91 Abstract “Autobiographical memories are not stored in isolation but rather are organized into life chapters, higher-order knowledge structures that represent major themes conveying the arc of one’s life. Neuropsychological studies have revealed that both episodic memory and some aspects of personal semantic memory are impaired in adults with medial temporal lobe (MTL) damage. However, whether such impairment compromises the retrieval and formation of life chapters is unknown. Therefore, we had 10 adults with MTL amnesia and 20 control participants narrate their life stories, and we extracted life chapters from these narratives using a novel scoring protocol. For the retrograde… Read More

Evolution of autobiographical memory impairments in Alzheimer’s disease and frontotemporal dementia – A longitudinal neuroimaging study

Published in: Neuropsychologia, Volume 110, February 2018, 14-25 Abstract “Compromised autobiographical memory (ABM) retrieval is well established in dementia, attributable to degeneration of a core memory brain network. It remains unclear, however, how the progressive spread of atrophy with advancing disease severity impacts ABM retrieval across life epochs. To this end, we conducted a longitudinal study of recent and remote ABM in Alzheimer’s disease(AD, n =11), and a frontotemporal lobar degeneration group (FTD, n =13) comprising 7 behavioral variant FTD and 6 semantic dementia patients, in comparison with 23 healthy older Controls. Patients were re-assessed approximately one year following their initial visit and underwent repeat testing and brain imaging. Linear mixed… Read More