Neural dynamics of semantic categorization in semantic variant of primary progressive aphasia.
Elife
; 102021 06 22.
Article
em En
| MEDLINE
| ID: mdl-34155973
ABSTRACT
Semantic representations are processed along a posterior-to-anterior gradient reflecting a shift from perceptual (e.g., it has eight legs) to conceptual (e.g., venomous spiders are rare) information. One critical region is the anterior temporal lobe (ATL) patients with semantic variant primary progressive aphasia (svPPA), a clinical syndrome associated with ATL neurodegeneration, manifest a deep loss of semantic knowledge. We test the hypothesis that svPPA patients perform semantic tasks by over-recruiting areas implicated in perceptual processing. We compared MEG recordings of svPPA patients and healthy controls during a categorization task. While behavioral performance did not differ, svPPA patients showed indications of greater activation over bilateral occipital cortices and superior temporal gyrus, and inconsistent engagement of frontal regions. These findings suggest a pervasive reorganization of brain networks in response to ATL neurodegeneration the loss of this critical hub leads to a dysregulated (semantic) control system, and defective semantic representations are seemingly compensated via enhanced perceptual processing.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Semântica
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Lobo Temporal
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Afasia Primária Progressiva
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Degeneração Neural
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Neurônios
Limite:
Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Elife
Ano de publicação:
2021
Tipo de documento:
Article