Middle longitudinal fascicle is associated with semantic processing deficits in primary progressive aphasia
The middle longitudinal fascicle (MdLF) is a recently delineated association cortico-cortical fiber pathway in humans, connecting superior temporal gyrus and temporal pole principally with the angular gyrus, and is likely to be involved in language processing. However, the MdLF has not been studied...
Main Authors: | , , , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Elsevier
2020-01-01
|
Series: | NeuroImage: Clinical |
Online Access: | http://www.sciencedirect.com/science/article/pii/S2213158219304620 |
id |
doaj-a8ed8dc6ca6346c6a1dc557b73ae53ab |
---|---|
record_format |
Article |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Chunyan Luo Sara Makaretz Michael Stepanovic George Papadimitriou Megan Quimby Senthil Palanivelu Bradford C. Dickerson Nikos Makris |
spellingShingle |
Chunyan Luo Sara Makaretz Michael Stepanovic George Papadimitriou Megan Quimby Senthil Palanivelu Bradford C. Dickerson Nikos Makris Middle longitudinal fascicle is associated with semantic processing deficits in primary progressive aphasia NeuroImage: Clinical |
author_facet |
Chunyan Luo Sara Makaretz Michael Stepanovic George Papadimitriou Megan Quimby Senthil Palanivelu Bradford C. Dickerson Nikos Makris |
author_sort |
Chunyan Luo |
title |
Middle longitudinal fascicle is associated with semantic processing deficits in primary progressive aphasia |
title_short |
Middle longitudinal fascicle is associated with semantic processing deficits in primary progressive aphasia |
title_full |
Middle longitudinal fascicle is associated with semantic processing deficits in primary progressive aphasia |
title_fullStr |
Middle longitudinal fascicle is associated with semantic processing deficits in primary progressive aphasia |
title_full_unstemmed |
Middle longitudinal fascicle is associated with semantic processing deficits in primary progressive aphasia |
title_sort |
middle longitudinal fascicle is associated with semantic processing deficits in primary progressive aphasia |
publisher |
Elsevier |
series |
NeuroImage: Clinical |
issn |
2213-1582 |
publishDate |
2020-01-01 |
description |
The middle longitudinal fascicle (MdLF) is a recently delineated association cortico-cortical fiber pathway in humans, connecting superior temporal gyrus and temporal pole principally with the angular gyrus, and is likely to be involved in language processing. However, the MdLF has not been studied in language disorders as primary progressive aphasia (PPA). We hypothesized that the MdLF will exhibit evidence of neurodegeneration in PPA patients. In this study, 20 PPA patients and 25 healthy controls were recruited in the Primary Progressive Aphasia program in the Massachusetts General Hospital Frontotemporal Disorders Unit. We used diffusion tensor imaging (DTI) tractography to reconstruct the MdLF and extract tract-specific DTI metrics (fractional anisotropy (FA), radial diffusivity (RD), mean diffusivity (MD) and axial diffusivity (AD)) to assess white matter changes in PPA and their relationship with language impairments. We found severe WM damage in the MdLF in PPA patients, which was principally pronounced in the left hemisphere. Moreover, the WM alterations in the MdLF in the dominant hemisphere were significantly correlated with impairments in word comprehension and naming, but not with articulation and fluency. In addition, asymmetry analysis revealed that the DTI metrics of controls were similar for each hemisphere, whereas PPA patients had clear laterality differences in MD, AD and RD. These findings add new insight into the localization and severity of white matter fiber bundle neurodegeneration in PPA, and provide evidence that degeneration of the MdLF contribute to impairment in semantic processing and lexical retrieval in PPA. Keywords: Diffusion tensor imaging, Middle longitudinal fascicle, Middle longitudinal fasciculus, Primary progressive aphasia, Semantic processing |
url |
http://www.sciencedirect.com/science/article/pii/S2213158219304620 |
work_keys_str_mv |
AT chunyanluo middlelongitudinalfascicleisassociatedwithsemanticprocessingdeficitsinprimaryprogressiveaphasia AT saramakaretz middlelongitudinalfascicleisassociatedwithsemanticprocessingdeficitsinprimaryprogressiveaphasia AT michaelstepanovic middlelongitudinalfascicleisassociatedwithsemanticprocessingdeficitsinprimaryprogressiveaphasia AT georgepapadimitriou middlelongitudinalfascicleisassociatedwithsemanticprocessingdeficitsinprimaryprogressiveaphasia AT meganquimby middlelongitudinalfascicleisassociatedwithsemanticprocessingdeficitsinprimaryprogressiveaphasia AT senthilpalanivelu middlelongitudinalfascicleisassociatedwithsemanticprocessingdeficitsinprimaryprogressiveaphasia AT bradfordcdickerson middlelongitudinalfascicleisassociatedwithsemanticprocessingdeficitsinprimaryprogressiveaphasia AT nikosmakris middlelongitudinalfascicleisassociatedwithsemanticprocessingdeficitsinprimaryprogressiveaphasia |
_version_ |
1724499355046510592 |
spelling |
doaj-a8ed8dc6ca6346c6a1dc557b73ae53ab2020-11-25T03:48:15ZengElsevierNeuroImage: Clinical2213-15822020-01-0125Middle longitudinal fascicle is associated with semantic processing deficits in primary progressive aphasiaChunyan Luo0Sara Makaretz1Michael Stepanovic2George Papadimitriou3Megan Quimby4Senthil Palanivelu5Bradford C. Dickerson6Nikos Makris7Frontotemporal Disorders Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, ChinaFrontotemporal Disorders Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USAFrontotemporal Disorders Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USACenter for Morphometric Analysis, Massachusetts General Hospital, 149 13th Street, Office 10.006, Charlestown, MA 02129, USA; Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USAFrontotemporal Disorders Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USACenter for Morphometric Analysis, Massachusetts General Hospital, 149 13th Street, Office 10.006, Charlestown, MA 02129, USA; Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USAFrontotemporal Disorders Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Alzheimer's Disease Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USACenter for Morphometric Analysis, Massachusetts General Hospital, 149 13th Street, Office 10.006, Charlestown, MA 02129, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Correspondence author at: Center for Morphometric Analysis, Massachusetts General Hospital, 149 13th Street, Office 10.006, Charlestown, MA 02129, USA.The middle longitudinal fascicle (MdLF) is a recently delineated association cortico-cortical fiber pathway in humans, connecting superior temporal gyrus and temporal pole principally with the angular gyrus, and is likely to be involved in language processing. However, the MdLF has not been studied in language disorders as primary progressive aphasia (PPA). We hypothesized that the MdLF will exhibit evidence of neurodegeneration in PPA patients. In this study, 20 PPA patients and 25 healthy controls were recruited in the Primary Progressive Aphasia program in the Massachusetts General Hospital Frontotemporal Disorders Unit. We used diffusion tensor imaging (DTI) tractography to reconstruct the MdLF and extract tract-specific DTI metrics (fractional anisotropy (FA), radial diffusivity (RD), mean diffusivity (MD) and axial diffusivity (AD)) to assess white matter changes in PPA and their relationship with language impairments. We found severe WM damage in the MdLF in PPA patients, which was principally pronounced in the left hemisphere. Moreover, the WM alterations in the MdLF in the dominant hemisphere were significantly correlated with impairments in word comprehension and naming, but not with articulation and fluency. In addition, asymmetry analysis revealed that the DTI metrics of controls were similar for each hemisphere, whereas PPA patients had clear laterality differences in MD, AD and RD. These findings add new insight into the localization and severity of white matter fiber bundle neurodegeneration in PPA, and provide evidence that degeneration of the MdLF contribute to impairment in semantic processing and lexical retrieval in PPA. Keywords: Diffusion tensor imaging, Middle longitudinal fascicle, Middle longitudinal fasciculus, Primary progressive aphasia, Semantic processinghttp://www.sciencedirect.com/science/article/pii/S2213158219304620 |