An ERP assessment of hemispheric projections in foveal and extrafoveal word recognition.

<h4>Background</h4>The existence and function of unilateral hemispheric projections within foveal vision may substantially affect foveal word recognition. The purpose of this research was to reveal these projections and determine their functionality.<h4>Methodology</h4>Single...

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Autores principales:	Timothy R Jordan, Giorgio Fuggetta, Kevin B Paterson, Stoyan Kurtev, Mengyun Xu
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2011
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/322a8e5f314b4c13abbb8fdcc17814fe
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spelling	oai:doaj.org-article:322a8e5f314b4c13abbb8fdcc17814fe2021-11-04T06:08:34ZAn ERP assessment of hemispheric projections in foveal and extrafoveal word recognition.1932-620310.1371/journal.pone.0023957https://doaj.org/article/322a8e5f314b4c13abbb8fdcc17814fe2011-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21935368/?tool=EBIhttps://doaj.org/toc/1932-6203<h4>Background</h4>The existence and function of unilateral hemispheric projections within foveal vision may substantially affect foveal word recognition. The purpose of this research was to reveal these projections and determine their functionality.<h4>Methodology</h4>Single words (and pseudowords) were presented to the left or right of fixation, entirely within either foveal or extrafoveal vision. To maximize the likelihood of unilateral projections for foveal displays, stimuli in foveal vision were presented away from the midline. The processing of stimuli in each location was assessed by combining behavioural measures (reaction times, accuracy) with on-line monitoring of hemispheric activity using event-related potentials recorded over each hemisphere, and carefully-controlled presentation procedures using an eye-tracker linked to a fixation-contingent display.<h4>Principal findings</h4>Event-related potentials 100-150 ms and 150-200 ms after stimulus onset indicated that stimuli in extrafoveal and foveal locations were projected unilaterally to the hemisphere contralateral to the presentation hemifield with no concurrent projection to the ipsilateral hemisphere. These effects were similar for words and pseudowords, suggesting this early division occurred before word recognition. Indeed, event-related potentials revealed differences between words and pseudowords 300-350 ms after stimulus onset, for foveal and extrafoveal locations, indicating that word recognition had now occurred. However, these later event-related potentials also revealed that the hemispheric division observed previously was no longer present for foveal locations but remained for extrafoveal locations. These findings closely matched the behavioural finding that foveal locations produced similar performance each side of fixation but extrafoveal locations produced left-right asymmetries.<h4>Conclusions</h4>These findings indicate that an initial division in unilateral hemispheric projections occurs in foveal vision away from the midline but is not apparent, or functional, when foveal word recognition actually occurs. In contrast, the division in unilateral hemispheric projections that occurs in extrafoveal locations is still apparent, and is functional, when extrafoveal word recognition takes place.Timothy R JordanGiorgio FuggettaKevin B PatersonStoyan KurtevMengyun XuPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 6, Iss 9, p e23957 (2011)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Timothy R Jordan Giorgio Fuggetta Kevin B Paterson Stoyan Kurtev Mengyun Xu An ERP assessment of hemispheric projections in foveal and extrafoveal word recognition.
description	<h4>Background</h4>The existence and function of unilateral hemispheric projections within foveal vision may substantially affect foveal word recognition. The purpose of this research was to reveal these projections and determine their functionality.<h4>Methodology</h4>Single words (and pseudowords) were presented to the left or right of fixation, entirely within either foveal or extrafoveal vision. To maximize the likelihood of unilateral projections for foveal displays, stimuli in foveal vision were presented away from the midline. The processing of stimuli in each location was assessed by combining behavioural measures (reaction times, accuracy) with on-line monitoring of hemispheric activity using event-related potentials recorded over each hemisphere, and carefully-controlled presentation procedures using an eye-tracker linked to a fixation-contingent display.<h4>Principal findings</h4>Event-related potentials 100-150 ms and 150-200 ms after stimulus onset indicated that stimuli in extrafoveal and foveal locations were projected unilaterally to the hemisphere contralateral to the presentation hemifield with no concurrent projection to the ipsilateral hemisphere. These effects were similar for words and pseudowords, suggesting this early division occurred before word recognition. Indeed, event-related potentials revealed differences between words and pseudowords 300-350 ms after stimulus onset, for foveal and extrafoveal locations, indicating that word recognition had now occurred. However, these later event-related potentials also revealed that the hemispheric division observed previously was no longer present for foveal locations but remained for extrafoveal locations. These findings closely matched the behavioural finding that foveal locations produced similar performance each side of fixation but extrafoveal locations produced left-right asymmetries.<h4>Conclusions</h4>These findings indicate that an initial division in unilateral hemispheric projections occurs in foveal vision away from the midline but is not apparent, or functional, when foveal word recognition actually occurs. In contrast, the division in unilateral hemispheric projections that occurs in extrafoveal locations is still apparent, and is functional, when extrafoveal word recognition takes place.
format	article
author	Timothy R Jordan Giorgio Fuggetta Kevin B Paterson Stoyan Kurtev Mengyun Xu
author_facet	Timothy R Jordan Giorgio Fuggetta Kevin B Paterson Stoyan Kurtev Mengyun Xu
author_sort	Timothy R Jordan
title	An ERP assessment of hemispheric projections in foveal and extrafoveal word recognition.
title_short	An ERP assessment of hemispheric projections in foveal and extrafoveal word recognition.
title_full	An ERP assessment of hemispheric projections in foveal and extrafoveal word recognition.
title_fullStr	An ERP assessment of hemispheric projections in foveal and extrafoveal word recognition.
title_full_unstemmed	An ERP assessment of hemispheric projections in foveal and extrafoveal word recognition.
title_sort	erp assessment of hemispheric projections in foveal and extrafoveal word recognition.
publisher	Public Library of Science (PLoS)
publishDate	2011
url	https://doaj.org/article/322a8e5f314b4c13abbb8fdcc17814fe
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An ERP assessment of hemispheric projections in foveal and extrafoveal word recognition.

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