Syntactic processing depends on dorsal language tracts.
Frontal and temporal language areas involved in syntactic processing are connected by several dorsal and ventral tracts, but the functional roles of the different tracts are not well understood. To identify which white matter tract(s) are important for syntactic processing, we examined the relationship between white matter damage and syntactic deficits in patients with primary progressive aphasia, using multimodal neuroimaging and neurolinguistic assessment. Diffusion tensor imaging showed that microstructural damage to left hemisphere dorsal tracts--the superior longitudinal fasciculus including its arcuate component--was strongly associated with deficits in comprehension and production of syntax. Damage to these dorsal tracts predicted syntactic deficits after gray matter atrophy was taken into account, and fMRI confirmed that these tracts connect regions modulated by syntactic processing. In contrast, damage to ventral tracts--the extreme capsule fiber system or the uncinate fasciculus--was not associated with syntactic deficits. Our findings show that syntactic processing depends primarily on dorsal language tracts.
Department of Speech, Language and Hearing Sciences, University of Arizona, 1131 E. 2nd Street, Tucson, AZ 85721, USA. smwilson@u.arizona.edu
Stephen M
SM
Wilson
Sebastiano
S
Galantucci
Maria Carmela
MC
Tartaglia
Kindle
K
Rising
Dianne K
DK
Patterson
Maya L
ML
Henry
Jennifer M
JM
Ogar
Jessica
J
DeLeon
Bruce L
BL
Miller
Maria Luisa
ML
Gorno-Tempini
D000368:Aged; D000369:Aged, 80 and over; D018888:Aphasia, Primary Progressive / Q000473:pathology* / Q000503:physiopathology; D001284:Atrophy / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007802:Language; D007807:Language Tests; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology* / Q000502:physiology; D059906:Neuroimaging; D012660:Semantics