Semantic memory in developmental amnesia

Elward, Rachael L.; Vargha‐Khadem, Faraneh

doi:10.1016/j.neulet.2018.04.040

Cited by 48 publications

(44 citation statements)

References 37 publications

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“…Thus, our evidence for non-hippocampal learning suggests that other brain regions may support early developmental language milestones. This is consistent with findings from developmentally amnesic individuals with perinatal hippocampal pathology (Vargha-Khadem et al, 1997;Elward and Vargha-Khadem, 2018), as those individuals showed relatively preserved vocabulary acquisition (low-normal) despite severe deficits in declarative memory. New studies in developmental populations could test the implications of a greater childhood reliance on non-hippocampal learning by comparing the efficiency and quality of CSSL in children and adults.…”

Section: Cssl Hippocampus and Language Developmentsupporting

confidence: 88%

Cross-Situational Statistical Learning of New Words Despite Bilateral Hippocampal Damage and Severe Amnesia

Warren

Roembke

Covington

et al. 2020

Front. Hum. Neurosci.

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Word learning requires learners to bind together arbitrarily-related phonological, visual, and conceptual information. Prior work suggests that this binding can be robustly achieved via incidental cross-situational statistical exposure to words and referents. When cross-situational statistical learning (CSSL) is tested in the laboratory, there is no information on any given trial to identify the referent of a novel word. However, by tracking which objects co-occur with each word across trials, learners may acquire mappings through statistical association. While CSSL behavior is well-characterized, its brain correlates are not. The arbitrary nature of CSSL mappings suggests hippocampal involvement, but the incremental, statistical nature of the learning raises the possibility of neocortical or procedural learning systems. Prior studies have shown that neurological patients with hippocampal pathology have word-learning impairments, but this has not been tested in a statistical learning paradigm. Here, we used a neuropsychological approach to test whether patients with bilateral hippocampal pathology (N = 3) could learn new words in a CSSL paradigm. In the task, patients and healthy comparison participants completed a CSSL word-learning task in which they acquired eight word/object mappings. During each trial of the CSSL task, participants saw two objects on a computer display, heard one novel word, and selected the most likely referent. Across trials, words were 100% likely to co-occur with their referent, but only 14.3% likely with non-referents. Two of three amnesic patients learned the associations between objects and word forms, although performance was impaired relative to healthy comparison participants. Our findings show that the hippocampus is not strictly necessary for CSSL for words, although it may facilitate such learning. This is consistent with a hybrid account of CSSL supported by implicit and explicit memory systems, and may have translational applications for remediation of (word-) learning deficits in neurological populations with hippocampal pathology.

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Section: Cssl Hippocampus and Language Developmentsupporting

confidence: 88%

Cross-Situational Statistical Learning of New Words Despite Bilateral Hippocampal Damage and Severe Amnesia

Warren

Roembke

Covington

et al. 2020

Front. Hum. Neurosci.

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“…It is well known that the hippocampal formation (HF) is crucial for memory binding processes, as confirmed by several studies of patients with hippocampal damage (Elward et al, 2018;Gold et al, 2006;Baddeley, VarghaKhadem, & Mishkin, 2001;Brizzolara et al, 2003;Hurley, Maguire, & Vargha-Khadem, 2011;Rosenbaum et al, 2011).…”

Section: Significance Statementmentioning

confidence: 89%

The development of spatiotemporal organization of episodic memory in children and its disruption in Williams Syndrome

Mastrogiuseppe

Bertelsen

M³

et al. 2019

Preprint

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Theories of hippocampal function have proposed that spatiotemporal representations provide a scaffold upon which episodic memories are built. If this is true, does the developmental emergence of adult-like episodic memory in children depend on the successful binding of space with time? To address this question, we report results from two studies aimed at revealing the developmental changes in episodic memory and the specific role of spatiotemporal binding in that process. Study 1 investigated the cognitive mechanisms underlying normal developmental changes in episodic memory across 2-to-8 years of age using an object-hiding game dissociating the content ("what") of memories from their spatial ("where") and temporal ("when") contexts. Study 2 investigated the same episodic memory binding processes in Williams Syndrome patients, who exhibit spatial impairments attributed to their abnormal hippocampal development. Our results indicate that, indeed, the successful binding spatial and temporal memory components emerges first in typical development and is impaired in Williams Syndrome. Furthermore, we found that space-time memory binding not only precedes but also predicts the emergence of episodic memory ability. Finally, an analysis of the separate components of episodic memory suggests that the association of objects to spatial location may play a mediating role in the development of successful episodic memory. Importantly, these effects are not explained by improvements in object or location memory. We interpret these findings to indicate that the ontogenetic origins of episodic memories depend on spatiotemporally organization of memories and that such representations rely, at least in part, on normal hippocampal development and function.

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“…(1) We have already noted (Elward and Vargha-Khadem 2018) that scene understanding can proceed in the absence of hippocampus. In other words, the fact that these areas may be engaged in diverse tasks related to scene construction does not rule out the engagement of areas outside their "construction network" also being engaged in scene construction.…”

Section: Neuroscience Linking Episodic Memory and Imaginationmentioning

confidence: 99%

From spatial navigation via visual construction to episodic memory and imagination

Arbib

2020

Biol Cybern

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This hybrid of review and personal essay argues that models of visual construction are essential to extend spatial navigation models to models that link episodic memory and imagination. The starting point is the TAM-WG model, combining the Taxon Affordance Model and the World Graph model of spatial navigation. The key here is to reject approaches in which memory is restricted to unanalyzed views from familiar places, and their later recall. Instead, we will seek mechanisms for imagining truly novel scenes and episodes. We thus introduce a specific variant of schema theory and VISIONS, a cooperative computation model of visual scene understanding in which a scene is represented by an assemblage of schema instances with links to lower-level "patches" of relevant visual data. We sketch a new conceptual framework for future modeling, Visual Integration of Diverse Multi-Modal Aspects, by extending VISIONS from static scenes to episodes combining agents, actions and objects and assess its relevance to both navigation and episodic memory. We can then analyze imagination as a constructive process that combines aspects of memories of prior episodes along with other schemas and adjusts them into a coherent whole which, through expectations associated with diverse episodes and schemas, may yield the linkage of episodes that constitutes a dream or a narrative. The result is IBSEN, a conceptual model of Imagination in Brain Systems for Episodes and Navigation. The essay closes by analyzing other papers in this Special Issue to assess to what extent their results relate to the research proposed here.

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Semantic memory in developmental amnesia

Abstract: HighlightsProfile of patients with developmental amnesia and dissociations in cognitive memory.Variables affecting semantic learning in developmental amnesia.Differences between adult-onset versus early-onset amnesia.

Cited by 48 publications

References 37 publications

Cross-Situational Statistical Learning of New Words Despite Bilateral Hippocampal Damage and Severe Amnesia

Cross-Situational Statistical Learning of New Words Despite Bilateral Hippocampal Damage and Severe Amnesia

The development of spatiotemporal organization of episodic memory in children and its disruption in Williams Syndrome

From spatial navigation via visual construction to episodic memory and imagination

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