title: Ventral and dorsal visual streams in posterior cortical atrophy: a DT MRI study.
abstract: Using diffusion tensor magnetic resonance imaging tractography, ventral (inferior longitudinal fasciculus) and fronto-occipital (inferior fronto-occipital fasciculus) and dorsal (fronto-parietal superior longitudinal fasciculus) visual pathways were assessed in 7 patients with posterior cortical atrophy (PCA), showing either predominantly ventral or additional dorsal cognitive deficits. Corpus callosum and corticospinal tracts were also studied. Gray and white matter atrophy was assessed using voxel-based morphometry. In all PCA patients, abnormal diffusivity indexes were found in bilateral inferior longitudinal fasciculus and inferior fronto-occipital fasciculus, with a left-side predominance. Patients also had mild microstructural damage to the corpus callosum. The 2 patients with more dorsal symptoms also showed right fronto-parietal superior longitudinal fasciculus abnormalities. Corticospinal tracts were normal, bilaterally. When studied separately, patients with ventral clinical impairment showed a pattern of atrophy mainly located in the ventral occipitotemporal regions, bilaterally; patients with both ventral and dorsal clinical deficits showed additional atrophy of the bilateral inferior parietal lobe. Magnetic resonance imaging patterns of abnormalities mirror closely the clinical phenotypes and could provide reliable ante mortem markers of tissue damage in PCA.
authors.affiliation: Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Migliaccio
authors.forename: Federica
authors.initials: F
authors.lastname: Agosta
authors.forename: Elisa
authors.initials: E
authors.lastname: Scola
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Magnani
authors.forename: Stefano F
authors.initials: SF
authors.lastname: Cappa
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Pagani
authors.forename: Elisa
authors.initials: E
authors.lastname: Canu
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Comi
authors.forename: Andrea
authors.initials: A
authors.lastname: Falini
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Gorno-Tempini
authors.forename: Paolo
authors.initials: P
authors.lastname: Bartolomeo
authors.forename: Massimo
authors.initials: M
authors.lastname: Filippi
mesh_terms: D000368:Aged; D001284:Atrophy; D001921:Brain / Q000473:pathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D009415:Nerve Net / Q000473:pathology*; D019636:Neurodegenerative Diseases / Q000473:pathology*