Much debate surrounds the role of the left inferior frontal gyrus (LIFG). Evidence from lesion and neuroimagingstudies suggests the LIFG supports a selection mechanism used in single word generation.Single case studies of dynamic aphasic patients with LIFG damage concur with this and extend the findingto selection of sentences at the conceptual preparation stage of language generation. A neuropsychologicalgroup with unselected focal frontal and non-frontal lesions is assessed on a sentence generationtask that varied the number of possible conceptual propositions available for selection. Frontal patientswith LIFG damage when compared to Frontal patients without LIFG damage and Posterior patients wereselectively impaired on sentence generation tests onlywhenstimuli activated multiple conceptual propositionsthat compete with each other for selection. We found that this selective impairment is critical forreduced speech rate, the core deficit of dynamic aphasia, and we would argue it is causative for one formof dynamic aphasia associated with LIFG lesions. These results provide evidence that the LIFG is crucialfor selecting among multiple competing conceptual propositions for language generation. Crown Copyright © 2010 Published by Elsevier Ltd. All rights reserved.
|Numero di pagine||12|
|Stato di pubblicazione||Published - 2010|
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