title: Disrupted brain connectome in semantic variant of primary progressive aphasia.
abstract: Using resting-state functional magnetic resonance imaging and graph analysis, the topological organization of the functional brain network connectivity was explored in patients with left-sided onset semantic variant (SV) of primary progressive aphasia relative to healthy controls. Functional brain networks in SV patients were characterized by a significantly lower mean network degree, clustering coefficient, and global efficiency, longer characteristic path length and higher assortativity compared with controls. SV patients showed also a strongly left-lateralized loss of hubs, and reduced nodal degree in the inferior and ventral temporal regions and occipital cortices. In SV, the decreased nodal degree extended into the medial and ventral frontal cortex bilaterally, left amygdala and/or hippocampus, and left caudate nucleus. These findings provide evidence that the focal structural degeneration of the inferior temporal, and perysilvian language regions in SV patients ultimately results in a distributed pattern of functional connectivity abnormalities. The local network analysis shows that SV is associated with a functional degradation in the "pan-modal" inferior and/or ventral temporal regions, and the "modality-specific" visual cortical origin of the ventral processing pathway.
authors: Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
authors: Federica
authors: F
authors: Agosta
authors: Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
authors: Sebastiano
authors: S
authors: Galantucci
authors: Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
authors: Paola
authors: P
authors: Valsasina
authors: Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
authors: Elisa
authors: E
authors: Canu
authors: Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
authors: Alessandro
authors: A
authors: Meani
authors: Department of Clinical Neurosciences, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
authors: Alessandra
authors: A
authors: Marcone
authors: Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
authors: Giuseppe
authors: G
authors: Magnani
authors: Department of Neuroradiology and CERMAC, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
authors: Andrea
authors: A
authors: Falini
authors: Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy.
authors: Giancarlo
authors: G
authors: Comi
authors: Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy; Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy. Electronic address: filippi.massimo@hsr.it.
authors: Massimo
authors: M
authors: Filippi
mesh_terms: D000368:Aged; D001037:Aphasia / Q000473:pathology* / Q000503:physiopathology*; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D009778:Occipital Lobe / Q000473:pathology / Q000503:physiopathology; D013702:Temporal Lobe / Q000473:pathology / Q000503:physiopathology
keywords: Functional brain connectivity; Graph theoretical analysis; Resting state functional MRI; Semantic variant of primary progressive aphasia