abnormal brain activation in neurofibromatosis type 1 a link between visual processing and the default mode network不正常的大脑活动在神经纤维瘤病1型视觉处理和默认模式网络之间的联系.pdfVIP

Abnormal Brain Activation in Neurofibromatosis Type 1: A Link between Visual Processing and the Default Mode Network ˆ 1 1 1 ˆ 1 ˜ 1 2 Ines R. Violante , Maria J. Ribeiro , Gil Cunha , Ines Bernardino , Joao V. Duarte , Fabiana Ramos , 2 3 1 Jorge Saraiva , Eduardo Silva , Miguel Castelo-Branco * 1Visual Neuroscience Laboratory, Institute of Biomedical Research in Light and Image, Faculty of Medicine, University of Coimbra, Coimbra, Portugal, 2 Medical Genetic Department, Pediatric Hospital of Coimbra, Coimbra, Portugal, 3 Centre for Hereditary Eye Diseases, Department of Ophthalmology, University Hospital of Coimbra, Coimbra, Portugal 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 adult