Richness of information about novel words influences how episodic and semantic memory networks interact during lexicalization
Publication year
2014Number of pages
14 p.
Source
NeuroImage, 84, (2014), pp. 265-278ISSN
Publication type
Article / Letter to editor

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Organization
SW OZ BSI OLO
Former Organization
F.C. Donders Centre for Cognitive Neuroimaging
Journal title
NeuroImage
Volume
vol. 84
Languages used
English (eng)
Page start
p. 265
Page end
p. 278
Subject
DI-BCB_DCC_Theme 1: Language and Communication; Learning and Plasticity; PsycholinguisticsAbstract
The complementary learning systems account of declarative memory suggests two distinct memory networks, a fast-mapping, episodic system involving the hippocampus, and a slower semantic memory system distributed across the neocortex in which new information is gradually integrated with existing representations. In this study, we investigated the extent to which these two networks are involved in the integration of novel words into the lexicon after extensive learning, and how the involvement of these networks changes after 24 h. In particular, we explored whether having richer information at encoding influences the lexicalization trajectory. We trained participants with two sets of novel words, one where exposure was only to the words' phonological forms (the form-only condition), and one where pictures of unfamiliar objects were associated with the words' phonological forms (the picture-associated condition). A behavioral measure of lexical competition (indexing lexicalization) indicated stronger competition effects for the form-only words. Imaging (fMRI) results revealed greater involvement of phonological lexical processing areas immediately after training in the form-only condition, suggesting that tight connections were formed between novel words and existing lexical entries already at encoding. Retrieval of picture-associated novel words involved the episodic/hippocampal memory system more extensively. Although lexicalization was weaker in the picture-associated condition, overall memory strength was greater when tested after a 24 hour delay, probably due to the availability of both episodic and lexical memory networks to aid retrieval. It appears that, during lexicalization of a novel word, the relative involvement of different memory networks differs according to the richness of the information about that word available at encoding.
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- Faculty of Social Sciences [28418]
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