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Multi-model mapping of phonemic fluency
The voluntary generation of non-overlearned responses is usually assessed with phonemic fluency. Like most frontal tasks, it draws upon different complex processes and systems whose precise nature is still incompletely understood. Many claimed aspects regarding the pattern of phonemic fluency perfor...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8530259/ https://www.ncbi.nlm.nih.gov/pubmed/34693285 http://dx.doi.org/10.1093/braincomms/fcab232 |
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author | Cipolotti, Lisa Xu, Tianbo Harry, Bronson Mole, Joe Lakey, Grace Shallice, Tim Chan, Edgar Nachev, Parashkev |
author_facet | Cipolotti, Lisa Xu, Tianbo Harry, Bronson Mole, Joe Lakey, Grace Shallice, Tim Chan, Edgar Nachev, Parashkev |
author_sort | Cipolotti, Lisa |
collection | PubMed |
description | The voluntary generation of non-overlearned responses is usually assessed with phonemic fluency. Like most frontal tasks, it draws upon different complex processes and systems whose precise nature is still incompletely understood. Many claimed aspects regarding the pattern of phonemic fluency performance and its underlying anatomy remain controversial. Major limitations of past investigations include small sample size, scant analysis of phonemic output and methodologically insufficient lesion analysis approaches. We investigated a large number of patients with focal unilateral right or left frontal (n = 110) or posterior (n = 100) or subcortical (n = 65) lesions imaged with magnetic resonance or computed tomography and compared their performance on the number of overall responses, words produced over time, extremely infrequent/unknown words and inappropriate words generated. We also employed, for the first time parcel‐based lesion-symptom mapping, tract-wise statistical analysis as well as Bayesian multi-variate analysis based on meta-analytically defined functional region of interest, including their interactions. We found that left frontal damage was associated with greater impairment than right frontal or posterior damage on overall fluency performance, suggesting that phonemic fluency shows specificity to frontal lesions. We also found that subcorticals, similar to frontals, performed significantly worse than posteriors on overall performance suggesting that subcortical regions are also involved. However, only frontal effects were found for words produced over time, extremely infrequent/unknown and inappropriate words. Parcel‐based lesion-symptom mapping analysis found that worse fluency performance was associated with damage to the posterior segment of the left frontal middle and superior gyrus, the left dorsal anterior cingulate gyrus and caudate nucleus. Tract-wise statistical analysis revealed that disconnections of left frontal tracts are critical. Bayesian multi-variate models of lesions and disconnectome maps implicated left middle and inferior frontal and left dorsomedial frontal regions. Our study suggests that a set of well localized left frontal areas together with subcortical regions and several left frontal tracts are critical for word generation. We speculate that a left lateralized network exists. It involves medial, frontal regions supporting the process of ‘energization’, which sustains activation for the duration of the task and middle and inferior frontal regions concerned with ‘selection’, required due to the competition produced by associated stored words, respectively. The methodology adopted represents a promising and empirically robust approach in furthering our understanding of the neurocognitive architecture underpinning executive processes. |
format | Online Article Text |
id | pubmed-8530259 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-85302592021-10-22 Multi-model mapping of phonemic fluency Cipolotti, Lisa Xu, Tianbo Harry, Bronson Mole, Joe Lakey, Grace Shallice, Tim Chan, Edgar Nachev, Parashkev Brain Commun Original Article The voluntary generation of non-overlearned responses is usually assessed with phonemic fluency. Like most frontal tasks, it draws upon different complex processes and systems whose precise nature is still incompletely understood. Many claimed aspects regarding the pattern of phonemic fluency performance and its underlying anatomy remain controversial. Major limitations of past investigations include small sample size, scant analysis of phonemic output and methodologically insufficient lesion analysis approaches. We investigated a large number of patients with focal unilateral right or left frontal (n = 110) or posterior (n = 100) or subcortical (n = 65) lesions imaged with magnetic resonance or computed tomography and compared their performance on the number of overall responses, words produced over time, extremely infrequent/unknown words and inappropriate words generated. We also employed, for the first time parcel‐based lesion-symptom mapping, tract-wise statistical analysis as well as Bayesian multi-variate analysis based on meta-analytically defined functional region of interest, including their interactions. We found that left frontal damage was associated with greater impairment than right frontal or posterior damage on overall fluency performance, suggesting that phonemic fluency shows specificity to frontal lesions. We also found that subcorticals, similar to frontals, performed significantly worse than posteriors on overall performance suggesting that subcortical regions are also involved. However, only frontal effects were found for words produced over time, extremely infrequent/unknown and inappropriate words. Parcel‐based lesion-symptom mapping analysis found that worse fluency performance was associated with damage to the posterior segment of the left frontal middle and superior gyrus, the left dorsal anterior cingulate gyrus and caudate nucleus. Tract-wise statistical analysis revealed that disconnections of left frontal tracts are critical. Bayesian multi-variate models of lesions and disconnectome maps implicated left middle and inferior frontal and left dorsomedial frontal regions. Our study suggests that a set of well localized left frontal areas together with subcortical regions and several left frontal tracts are critical for word generation. We speculate that a left lateralized network exists. It involves medial, frontal regions supporting the process of ‘energization’, which sustains activation for the duration of the task and middle and inferior frontal regions concerned with ‘selection’, required due to the competition produced by associated stored words, respectively. The methodology adopted represents a promising and empirically robust approach in furthering our understanding of the neurocognitive architecture underpinning executive processes. Oxford University Press 2021-10-07 /pmc/articles/PMC8530259/ /pubmed/34693285 http://dx.doi.org/10.1093/braincomms/fcab232 Text en © The Author(s) (2021). Published by Oxford University Press on behalf of the Guarantors of Brain. https://creativecommons.org/licenses/by-nc/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com |
spellingShingle | Original Article Cipolotti, Lisa Xu, Tianbo Harry, Bronson Mole, Joe Lakey, Grace Shallice, Tim Chan, Edgar Nachev, Parashkev Multi-model mapping of phonemic fluency |
title | Multi-model mapping of phonemic fluency |
title_full | Multi-model mapping of phonemic fluency |
title_fullStr | Multi-model mapping of phonemic fluency |
title_full_unstemmed | Multi-model mapping of phonemic fluency |
title_short | Multi-model mapping of phonemic fluency |
title_sort | multi-model mapping of phonemic fluency |
topic | Original Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8530259/ https://www.ncbi.nlm.nih.gov/pubmed/34693285 http://dx.doi.org/10.1093/braincomms/fcab232 |
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