Functional Contributions of the Arcuate Fasciculus to Language Processing
Current evidence strongly suggests that the arcuate fasciculus (AF) is critical for language, from spontaneous speech and word retrieval to repetition and comprehension abilities. However, to further pinpoint its unique and differential role in language, its anatomy needs to be explored in greater d...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2021-06-01
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| Series: | Frontiers in Human Neuroscience |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fnhum.2021.672665/full |
| _version_ | 1818849388972212224 |
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| author | Maria V. Ivanova Maria V. Ivanova Allison Zhong Allison Zhong And Turken Juliana V. Baldo Nina F. Dronkers Nina F. Dronkers Nina F. Dronkers |
| author_facet | Maria V. Ivanova Maria V. Ivanova Allison Zhong Allison Zhong And Turken Juliana V. Baldo Nina F. Dronkers Nina F. Dronkers Nina F. Dronkers |
| author_sort | Maria V. Ivanova |
| collection | DOAJ |
| description | Current evidence strongly suggests that the arcuate fasciculus (AF) is critical for language, from spontaneous speech and word retrieval to repetition and comprehension abilities. However, to further pinpoint its unique and differential role in language, its anatomy needs to be explored in greater detail and its contribution to language processing beyond that of known cortical language areas must be established. We address this in a comprehensive evaluation of the specific functional role of the AF in a well-characterized cohort of individuals with chronic aphasia (n = 33) following left hemisphere stroke. To evaluate macro- and microstructural integrity of the AF, tractography based on the constrained spherical deconvolution model was performed. The AF in the left and right hemispheres were then manually reconstructed using a modified 3-segment model (Catani et al., 2005), and a modified 2-segment model (Glasser and Rilling, 2008). The normalized volume and a measure of microstructural integrity of the long and the posterior segments of the AF were significantly correlated with language indices while controlling for gender and lesion volume. Specific contributions of AF segments to language while accounting for the role of specific cortical language areas – inferior frontal, inferior parietal, and posterior temporal – were tested using multiple regression analyses. Involvement of the following tract segments in the left hemisphere in language processing beyond the contribution of cortical areas was demonstrated: the long segment of the AF contributed to naming abilities; anterior segment – to fluency and naming; the posterior segment – to comprehension. The results highlight the important contributions of the AF fiber pathways to language impairments beyond that of known cortical language areas. At the same time, no clear role of the right hemisphere AF tracts in language processing could be ascertained. In sum, our findings lend support to the broader role of the left AF in language processing, with particular emphasis on comprehension and naming, and point to the posterior segment of this tract as being most crucial for supporting residual language abilities. |
| first_indexed | 2024-12-19T06:32:27Z |
| format | Article |
| id | doaj.art-e52b2f02e619450e925b683eef25c318 |
| institution | Directory Open Access Journal |
| issn | 1662-5161 |
| language | English |
| last_indexed | 2024-12-19T06:32:27Z |
| publishDate | 2021-06-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Human Neuroscience |
| spelling | doaj.art-e52b2f02e619450e925b683eef25c3182022-12-21T20:32:21ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612021-06-011510.3389/fnhum.2021.672665672665Functional Contributions of the Arcuate Fasciculus to Language ProcessingMaria V. Ivanova0Maria V. Ivanova1Allison Zhong2Allison Zhong3And Turken4Juliana V. Baldo5Nina F. Dronkers6Nina F. Dronkers7Nina F. Dronkers8Aphasia Recovery Lab, Department of Psychology, University of California, Berkeley, Berkeley, CA, United StatesCenter for Language, Imaging, Mind & Brain, VA Northern California Health Care System, Martinez, CA, United StatesCenter for Language, Imaging, Mind & Brain, VA Northern California Health Care System, Martinez, CA, United StatesSchool of Medicine, New York Medical College, Valhalla, NY, United StatesCenter for Language, Imaging, Mind & Brain, VA Northern California Health Care System, Martinez, CA, United StatesCenter for Language, Imaging, Mind & Brain, VA Northern California Health Care System, Martinez, CA, United StatesAphasia Recovery Lab, Department of Psychology, University of California, Berkeley, Berkeley, CA, United StatesCenter for Language, Imaging, Mind & Brain, VA Northern California Health Care System, Martinez, CA, United StatesDepartment of Neurology, University of California, Davis, Davis, CA, United StatesCurrent evidence strongly suggests that the arcuate fasciculus (AF) is critical for language, from spontaneous speech and word retrieval to repetition and comprehension abilities. However, to further pinpoint its unique and differential role in language, its anatomy needs to be explored in greater detail and its contribution to language processing beyond that of known cortical language areas must be established. We address this in a comprehensive evaluation of the specific functional role of the AF in a well-characterized cohort of individuals with chronic aphasia (n = 33) following left hemisphere stroke. To evaluate macro- and microstructural integrity of the AF, tractography based on the constrained spherical deconvolution model was performed. The AF in the left and right hemispheres were then manually reconstructed using a modified 3-segment model (Catani et al., 2005), and a modified 2-segment model (Glasser and Rilling, 2008). The normalized volume and a measure of microstructural integrity of the long and the posterior segments of the AF were significantly correlated with language indices while controlling for gender and lesion volume. Specific contributions of AF segments to language while accounting for the role of specific cortical language areas – inferior frontal, inferior parietal, and posterior temporal – were tested using multiple regression analyses. Involvement of the following tract segments in the left hemisphere in language processing beyond the contribution of cortical areas was demonstrated: the long segment of the AF contributed to naming abilities; anterior segment – to fluency and naming; the posterior segment – to comprehension. The results highlight the important contributions of the AF fiber pathways to language impairments beyond that of known cortical language areas. At the same time, no clear role of the right hemisphere AF tracts in language processing could be ascertained. In sum, our findings lend support to the broader role of the left AF in language processing, with particular emphasis on comprehension and naming, and point to the posterior segment of this tract as being most crucial for supporting residual language abilities.https://www.frontiersin.org/articles/10.3389/fnhum.2021.672665/fullaphasiastrokelanguagediffusion MRItractographyarcuate fasciculus |
| spellingShingle | Maria V. Ivanova Maria V. Ivanova Allison Zhong Allison Zhong And Turken Juliana V. Baldo Nina F. Dronkers Nina F. Dronkers Nina F. Dronkers Functional Contributions of the Arcuate Fasciculus to Language Processing Frontiers in Human Neuroscience aphasia stroke language diffusion MRI tractography arcuate fasciculus |
| title | Functional Contributions of the Arcuate Fasciculus to Language Processing |
| title_full | Functional Contributions of the Arcuate Fasciculus to Language Processing |
| title_fullStr | Functional Contributions of the Arcuate Fasciculus to Language Processing |
| title_full_unstemmed | Functional Contributions of the Arcuate Fasciculus to Language Processing |
| title_short | Functional Contributions of the Arcuate Fasciculus to Language Processing |
| title_sort | functional contributions of the arcuate fasciculus to language processing |
| topic | aphasia stroke language diffusion MRI tractography arcuate fasciculus |
| url | https://www.frontiersin.org/articles/10.3389/fnhum.2021.672665/full |
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