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Auteur M. J. RIBEIRO |
Documents disponibles écrits par cet auteur (2)
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Abnormal late visual responses and alpha oscillations in neurofibromatosis type 1: a link to visual and attention deficits / M. J. RIBEIRO in Journal of Neurodevelopmental Disorders, 6-1 (December 2014)
[article]
Titre : Abnormal late visual responses and alpha oscillations in neurofibromatosis type 1: a link to visual and attention deficits Type de document : Texte imprimé et/ou numérique Auteurs : M. J. RIBEIRO, Auteur ; O. C. D'ALMEIDA, Auteur ; F. RAMOS, Auteur ; J. SARAIVA, Auteur ; E. D. SILVA, Auteur ; Miguel CASTELO-BRANCO, Auteur Article en page(s) : p.4 Langues : Anglais (eng) Index. décimale : PER Périodiques Résumé : BACKGROUND: Neurofibromatosis type 1 (NF1) affects several areas of cognitive function including visual processing and attention. We investigated the neural mechanisms underlying the visual deficits of children and adolescents with NF1 by studying visual evoked potentials (VEPs) and brain oscillations during visual stimulation and rest periods. METHODS: Electroencephalogram/event-related potential (EEG/ERP) responses were measured during visual processing (NF1 n = 17; controls n = 19) and idle periods with eyes closed and eyes open (NF1 n = 12; controls n = 14). Visual stimulation was chosen to bias activation of the three detection mechanisms: achromatic, red-green and blue-yellow. RESULTS: We found significant differences between the groups for late chromatic VEPs and a specific enhancement in the amplitude of the parieto-occipital alpha amplitude both during visual stimulation and idle periods. Alpha modulation and the negative influence of alpha oscillations in visual performance were found in both groups. CONCLUSIONS: Our findings suggest abnormal later stages of visual processing and enhanced amplitude of alpha oscillations supporting the existence of deficits in basic sensory processing in NF1. Given the link between alpha oscillations, visual perception and attention, these results indicate a neural mechanism that might underlie the visual sensitivity deficits and increased lapses of attention observed in individuals with NF1. En ligne : http://dx.doi.org/10.1186/1866-1955-6-4 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=345
in Journal of Neurodevelopmental Disorders > 6-1 (December 2014) . - p.4[article] Abnormal late visual responses and alpha oscillations in neurofibromatosis type 1: a link to visual and attention deficits [Texte imprimé et/ou numérique] / M. J. RIBEIRO, Auteur ; O. C. D'ALMEIDA, Auteur ; F. RAMOS, Auteur ; J. SARAIVA, Auteur ; E. D. SILVA, Auteur ; Miguel CASTELO-BRANCO, Auteur . - p.4.
Langues : Anglais (eng)
in Journal of Neurodevelopmental Disorders > 6-1 (December 2014) . - p.4
Index. décimale : PER Périodiques Résumé : BACKGROUND: Neurofibromatosis type 1 (NF1) affects several areas of cognitive function including visual processing and attention. We investigated the neural mechanisms underlying the visual deficits of children and adolescents with NF1 by studying visual evoked potentials (VEPs) and brain oscillations during visual stimulation and rest periods. METHODS: Electroencephalogram/event-related potential (EEG/ERP) responses were measured during visual processing (NF1 n = 17; controls n = 19) and idle periods with eyes closed and eyes open (NF1 n = 12; controls n = 14). Visual stimulation was chosen to bias activation of the three detection mechanisms: achromatic, red-green and blue-yellow. RESULTS: We found significant differences between the groups for late chromatic VEPs and a specific enhancement in the amplitude of the parieto-occipital alpha amplitude both during visual stimulation and idle periods. Alpha modulation and the negative influence of alpha oscillations in visual performance were found in both groups. CONCLUSIONS: Our findings suggest abnormal later stages of visual processing and enhanced amplitude of alpha oscillations supporting the existence of deficits in basic sensory processing in NF1. Given the link between alpha oscillations, visual perception and attention, these results indicate a neural mechanism that might underlie the visual sensitivity deficits and increased lapses of attention observed in individuals with NF1. En ligne : http://dx.doi.org/10.1186/1866-1955-6-4 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=345 Gyrification, cortical and subcortical morphometry in neurofibromatosis type 1: an uneven profile of developmental abnormalities / I. R. VIOLANTE in Journal of Neurodevelopmental Disorders, 5-1 (December 2013)
[article]
Titre : Gyrification, cortical and subcortical morphometry in neurofibromatosis type 1: an uneven profile of developmental abnormalities Type de document : Texte imprimé et/ou numérique Auteurs : I. R. VIOLANTE, Auteur ; M. J. RIBEIRO, Auteur ; E. D. SILVA, Auteur ; Miguel CASTELO-BRANCO, Auteur Article en page(s) : p.3 Langues : Anglais (eng) Index. décimale : PER Périodiques Résumé : BACKGROUND: Neurofibromatosis type 1 (NF1) is a monogenic disorder associated with cognitive impairments. In order to understand how mutations in the NF1 gene impact brain structure it is essential to characterize in detail the brain structural abnormalities in patients with NF1. Previous studies have reported contradictory findings and have focused only on volumetric measurements. Here, we investigated the volumes of subcortical structures and the composite dimensions of the cortex through analysis of cortical volume, cortical thickness, cortical surface area and gyrification. METHODS: We studied 14 children with NF1 and 14 typically developing children matched for age, gender, IQ and right/left-handedness. Regional subcortical volumes and cortical gyral measurements were obtained using the FreeSurfer software. Between-group differences were evaluated while controlling for the increase in total intracranial volume observed in NF1. RESULTS: Subcortical analysis revealed disproportionately larger thalami, right caudate and middle corpus callosum in patients with NF1. Cortical analyses on volume, thickness and surface area were however not indicative of significant alterations in patients. Interestingly, patients with NF1 had significantly lower gyrification indices than typically developing children primarily in the frontal and temporal lobes, but also affecting the insula, cingulate cortex, parietal and occipital regions. CONCLUSIONS: The neuroanatomic abnormalities observed were localized to specific brain regions, indicating that particular areas might constitute selective targets for NF1 gene mutations. Furthermore, the lower gyrification indices were accompanied by a disproportionate increase in brain size without the corresponding increase in folding in patients with NF1. Taken together these findings suggest that specific neurodevelopmental processes, such as gyrification, are more vulnerable to NF1 dysfunction than others. The identified changes in brain organization are consistent with the patterns of cognitive dysfunction in the NF1 phenotype. En ligne : http://dx.doi.org/10.1186/1866-1955-5-3 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=345
in Journal of Neurodevelopmental Disorders > 5-1 (December 2013) . - p.3[article] Gyrification, cortical and subcortical morphometry in neurofibromatosis type 1: an uneven profile of developmental abnormalities [Texte imprimé et/ou numérique] / I. R. VIOLANTE, Auteur ; M. J. RIBEIRO, Auteur ; E. D. SILVA, Auteur ; Miguel CASTELO-BRANCO, Auteur . - p.3.
Langues : Anglais (eng)
in Journal of Neurodevelopmental Disorders > 5-1 (December 2013) . - p.3
Index. décimale : PER Périodiques Résumé : BACKGROUND: Neurofibromatosis type 1 (NF1) is a monogenic disorder associated with cognitive impairments. In order to understand how mutations in the NF1 gene impact brain structure it is essential to characterize in detail the brain structural abnormalities in patients with NF1. Previous studies have reported contradictory findings and have focused only on volumetric measurements. Here, we investigated the volumes of subcortical structures and the composite dimensions of the cortex through analysis of cortical volume, cortical thickness, cortical surface area and gyrification. METHODS: We studied 14 children with NF1 and 14 typically developing children matched for age, gender, IQ and right/left-handedness. Regional subcortical volumes and cortical gyral measurements were obtained using the FreeSurfer software. Between-group differences were evaluated while controlling for the increase in total intracranial volume observed in NF1. RESULTS: Subcortical analysis revealed disproportionately larger thalami, right caudate and middle corpus callosum in patients with NF1. Cortical analyses on volume, thickness and surface area were however not indicative of significant alterations in patients. Interestingly, patients with NF1 had significantly lower gyrification indices than typically developing children primarily in the frontal and temporal lobes, but also affecting the insula, cingulate cortex, parietal and occipital regions. CONCLUSIONS: The neuroanatomic abnormalities observed were localized to specific brain regions, indicating that particular areas might constitute selective targets for NF1 gene mutations. Furthermore, the lower gyrification indices were accompanied by a disproportionate increase in brain size without the corresponding increase in folding in patients with NF1. Taken together these findings suggest that specific neurodevelopmental processes, such as gyrification, are more vulnerable to NF1 dysfunction than others. The identified changes in brain organization are consistent with the patterns of cognitive dysfunction in the NF1 phenotype. En ligne : http://dx.doi.org/10.1186/1866-1955-5-3 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=345