Spatiotemporal Dynamics of Referential and Infere

Authors: Raphaël Fargier Marina Laganaro

Publish Date: 2016/06/22

Volume: 30, Issue: 2, Pages: 182-197

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Abstract

Picture naming tasks are largely used to elicit the production of specific words and sentences in psycholinguistic and neuroimaging research However the generation of lexical concepts from a visual input is clearly not the exclusive way speech production is triggered In inferential speech encoding the concept is not provided from a visual input but is elaborated though semantic and/or episodic associations It is therefore likely that the cognitive operations leading to lexical selection and word encoding are different in inferential and referential expressive language In particular in picture naming lexical selection might ensue from a simple association between a perceptual visual representation and a word with minimal semantic processes whereas richer semantic associations are involved in lexical retrieval in inferential situations Here we address this hypothesis by analyzing ERP correlates during word production in a referential and an inferential task The participants produced the same words elicited from pictures or from short written definitions The two tasks displayed similar electrophysiological patterns only in the timeperiod preceding the verbal response In the stimuluslocked ERPs waveform amplitudes and periods of stable global electrophysiological patterns differed across tasks after the P100 component and until 400–500 ms suggesting the involvement of different taskspecific neural networks Based on the analysis of the timewindows affected by specific semantic and lexical variables in each task we conclude that lexical selection is underpinned by a different set of conceptual and brain processes with semantic processes clearly preceding word retrieval in naming from definition whereas the semantic information is enriched in parallel with word retrieval in picture naming

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