Please use this identifier to cite or link to this item: http://hdl.handle.net/10316/80834
Title: Abnormal brain activation in neurofibromatosis type 1: a link between visual processing and the default mode network
Authors: Violante, Inês R 
Ribeiro, Maria J 
Cunha, Gil 
Bernardino, Inês 
Duarte, João V 
Ramos, Fabiana 
Saraiva, Jorge 
Silva, Eduardo 
Castelo-Branco, Miguel 
Issue Date: 2012
Project: University of Coimbra [Grant number III/14/2008] 
PIC/IC/83155/2007 
PTDC_SAU-ORG_118380 
PIC/IC/82986/2007 
SFRH/BD/41348/2007 
SFRH/BPD/34392/2006 
SFRH/BD/41401/ 2007 
Serial title, monograph or event: PLoS One
Volume: 7
Issue: 6
Abstract: Neurofibromatosis type 1 (NF1) is one of the most common single gene disorders affecting the human nervous system with a high incidence of cognitive deficits, particularly visuospatial. Nevertheless, neurophysiological alterations in low-level visual processing that could be relevant to explain the cognitive phenotype are poorly understood. Here we used functional magnetic resonance imaging (fMRI) to study early cortical visual pathways in children and adults with NF1. We employed two distinct stimulus types differing in contrast and spatial and temporal frequencies to evoke relatively different activation of the magnocellular (M) and parvocellular (P) pathways. Hemodynamic responses were investigated in retinotopically-defined regions V1, V2 and V3 and then over the acquired cortical volume. Relative to matched control subjects, patients with NF1 showed deficient activation of the low-level visual cortex to both stimulus types. Importantly, this finding was observed for children and adults with NF1, indicating that low-level visual processing deficits do not ameliorate with age. Moreover, only during M-biased stimulation patients with NF1 failed to deactivate or even activated anterior and posterior midline regions of the default mode network. The observation that the magnocellular visual pathway is impaired in NF1 in early visual processing and is specifically associated with a deficient deactivation of the default mode network may provide a neural explanation for high-order cognitive deficits present in NF1, particularly visuospatial and attentional. A link between magnocellular and default mode network processing may generalize to neuropsychiatric disorders where such deficits have been separately identified.
URI: http://hdl.handle.net/10316/80834
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0038785
Rights: openAccess
Appears in Collections:I&D IBILI - Artigos em Revistas Internacionais

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