Right Hemisphere Remapping of Naming Functions Depends on Lesion Size and Location in Poststroke Aphasia

The study of language network plasticity following left hemisphere stroke is foundational to the understanding of aphasia recovery and neural plasticity in general. Damage in different language nodes may influence whether local plasticity is possible and whether right hemisphere recruitment is benef...

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Main Authors: Laura M. Skipper-Kallal, Elizabeth H. Lacey, Shihui Xing, Peter E. Turkeltaub
Format: Article
Language:English
Published: Wiley 2017-01-01
Series:Neural Plasticity
Online Access:http://dx.doi.org/10.1155/2017/8740353
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author Laura M. Skipper-Kallal
Elizabeth H. Lacey
Shihui Xing
Peter E. Turkeltaub
author_facet Laura M. Skipper-Kallal
Elizabeth H. Lacey
Shihui Xing
Peter E. Turkeltaub
author_sort Laura M. Skipper-Kallal
collection DOAJ
description The study of language network plasticity following left hemisphere stroke is foundational to the understanding of aphasia recovery and neural plasticity in general. Damage in different language nodes may influence whether local plasticity is possible and whether right hemisphere recruitment is beneficial. However, the relationships of both lesion size and location to patterns of remapping are poorly understood. In the context of a picture naming fMRI task, we tested whether lesion size and location relate to activity in surviving left hemisphere language nodes, as well as homotopic activity in the right hemisphere during covert name retrieval and overt name production. We found that lesion size was positively associated with greater right hemisphere activity during both phases of naming, a pattern that has frequently been suggested but has not previously been clearly demonstrated. During overt naming, lesions in the inferior frontal gyrus led to deactivation of contralateral frontal areas, while lesions in motor cortex led to increased right motor cortex activity. Furthermore, increased right motor activity related to better naming performance only when left motor cortex was lesioned, suggesting compensatory takeover of speech or language function by the homotopic node. These findings demonstrate that reorganization of language function, and the degree to which reorganization facilitates aphasia recovery, is dependent on the size and site of the lesion.
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spelling doaj-art-3387b645142d4fbb8db0966be2a25e922025-08-20T03:55:12ZengWileyNeural Plasticity2090-59041687-54432017-01-01201710.1155/2017/87403538740353Right Hemisphere Remapping of Naming Functions Depends on Lesion Size and Location in Poststroke AphasiaLaura M. Skipper-Kallal0Elizabeth H. Lacey1Shihui Xing2Peter E. Turkeltaub3Department of Neurology, Georgetown University Medical Center, Washington, DC, USADepartment of Neurology, Georgetown University Medical Center, Washington, DC, USADepartment of Neurology, Georgetown University Medical Center, Washington, DC, USADepartment of Neurology, Georgetown University Medical Center, Washington, DC, USAThe study of language network plasticity following left hemisphere stroke is foundational to the understanding of aphasia recovery and neural plasticity in general. Damage in different language nodes may influence whether local plasticity is possible and whether right hemisphere recruitment is beneficial. However, the relationships of both lesion size and location to patterns of remapping are poorly understood. In the context of a picture naming fMRI task, we tested whether lesion size and location relate to activity in surviving left hemisphere language nodes, as well as homotopic activity in the right hemisphere during covert name retrieval and overt name production. We found that lesion size was positively associated with greater right hemisphere activity during both phases of naming, a pattern that has frequently been suggested but has not previously been clearly demonstrated. During overt naming, lesions in the inferior frontal gyrus led to deactivation of contralateral frontal areas, while lesions in motor cortex led to increased right motor cortex activity. Furthermore, increased right motor activity related to better naming performance only when left motor cortex was lesioned, suggesting compensatory takeover of speech or language function by the homotopic node. These findings demonstrate that reorganization of language function, and the degree to which reorganization facilitates aphasia recovery, is dependent on the size and site of the lesion.http://dx.doi.org/10.1155/2017/8740353
spellingShingle Laura M. Skipper-Kallal
Elizabeth H. Lacey
Shihui Xing
Peter E. Turkeltaub
Right Hemisphere Remapping of Naming Functions Depends on Lesion Size and Location in Poststroke Aphasia
Neural Plasticity
title Right Hemisphere Remapping of Naming Functions Depends on Lesion Size and Location in Poststroke Aphasia
title_full Right Hemisphere Remapping of Naming Functions Depends on Lesion Size and Location in Poststroke Aphasia
title_fullStr Right Hemisphere Remapping of Naming Functions Depends on Lesion Size and Location in Poststroke Aphasia
title_full_unstemmed Right Hemisphere Remapping of Naming Functions Depends on Lesion Size and Location in Poststroke Aphasia
title_short Right Hemisphere Remapping of Naming Functions Depends on Lesion Size and Location in Poststroke Aphasia
title_sort right hemisphere remapping of naming functions depends on lesion size and location in poststroke aphasia
url http://dx.doi.org/10.1155/2017/8740353
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