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)  

Public ISBD [article]  inJournal of Neurodevelopmental Disorders > 6-1 (December 2014) . - p.4 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 [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)  

Public ISBD [article]  inJournal of Neurodevelopmental Disorders > 5-1 (December 2013) . - p.3 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 [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

Medial Frontal Lobe Neurochemistry in Autism Spectrum Disorder is Marked by Reduced N-Acetylaspartate and Unchanged Gamma-Aminobutyric Acid and Glutamate + Glutamine Levels / A. CARVALHO PEREIRA in Journal of Autism and Developmental Disorders, 48-5 (May 2018)  

Public ISBD [article]  inJournal of Autism and Developmental Disorders > 48-5 (May 2018) . - p.1467-1482 Titre : Medial Frontal Lobe Neurochemistry in Autism Spectrum Disorder is Marked by Reduced N-Acetylaspartate and Unchanged Gamma-Aminobutyric Acid and Glutamate + Glutamine Levels Type de document : Texte imprimé et/ou numérique Auteurs : A. CARVALHO PEREIRA, Auteur ; I. R. VIOLANTE, Auteur ; S. MOUGA, Auteur ; G. OLIVEIRA, Auteur ; Miguel CASTELO-BRANCO, Auteur Article en page(s) : p.1467-1482 Langues : Anglais (eng) Mots-clés : Autism diagnostic interview-revised  Autism spectrum disorder  Creatine  Gamma-aminobutyric acid  Glutamate + glutamine  N-acetylaspartate Index. décimale : PER Périodiques Résumé : The nature of neurochemical changes in autism spectrum disorder (ASD) remains controversial. We compared medial prefrontal cortex (mPFC) neurochemistry of twenty high-functioning children and adolescents with ASD without associated comorbidities and fourteen controls. We observed reduced total N-acetylaspartate (tNAA) and total creatine, increased Glx/tNAA but unchanged glutamate + glutamine (Glx) and unchanged absolute or relative gamma-aminobutyric acid (GABA+) in the ASD group. Importantly, both smaller absolute and relative GABA+ levels were associated with worse communication skills and developmental delay scores assessed by the autism diagnostic interview-revised (ADI-R). We conclude that tNAA is reduced in the mPFC in ASD and that glutamatergic metabolism may be altered due to unbalanced Glx/tNAA. Moreover, GABA+ is related to autistic symptoms assessed by the ADI-R. En ligne : http://dx.doi.org/10.1007/s10803-017-3406-8 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=355 [article] Medial Frontal Lobe Neurochemistry in Autism Spectrum Disorder is Marked by Reduced N-Acetylaspartate and Unchanged Gamma-Aminobutyric Acid and Glutamate + Glutamine Levels [Texte imprimé et/ou numérique] / A. CARVALHO PEREIRA, Auteur ; I. R. VIOLANTE, Auteur ; S. MOUGA, Auteur ; G. OLIVEIRA, Auteur ; Miguel CASTELO-BRANCO, Auteur . - p.1467-1482. Langues : Anglais (eng) in Journal of Autism and Developmental Disorders > 48-5 (May 2018) . - p.1467-1482 Mots-clés : Autism diagnostic interview-revised  Autism spectrum disorder  Creatine  Gamma-aminobutyric acid  Glutamate + glutamine  N-acetylaspartate Index. décimale : PER Périodiques Résumé : The nature of neurochemical changes in autism spectrum disorder (ASD) remains controversial. We compared medial prefrontal cortex (mPFC) neurochemistry of twenty high-functioning children and adolescents with ASD without associated comorbidities and fourteen controls. We observed reduced total N-acetylaspartate (tNAA) and total creatine, increased Glx/tNAA but unchanged glutamate + glutamine (Glx) and unchanged absolute or relative gamma-aminobutyric acid (GABA+) in the ASD group. Importantly, both smaller absolute and relative GABA+ levels were associated with worse communication skills and developmental delay scores assessed by the autism diagnostic interview-revised (ADI-R). We conclude that tNAA is reduced in the mPFC in ASD and that glutamatergic metabolism may be altered due to unbalanced Glx/tNAA. Moreover, GABA+ is related to autistic symptoms assessed by the ADI-R. En ligne : http://dx.doi.org/10.1007/s10803-017-3406-8 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=355

Oscillatory motor patterning is impaired in neurofibromatosis type 1: a behavioural, EEG and fMRI study / G. SILVA in Journal of Neurodevelopmental Disorders, 10-1 (December 2018)  

Public ISBD [article]  inJournal of Neurodevelopmental Disorders > 10-1 (December 2018) . - p.11 Titre : Oscillatory motor patterning is impaired in neurofibromatosis type 1: a behavioural, EEG and fMRI study Type de document : Texte imprimé et/ou numérique Auteurs : G. SILVA, Auteur ; I. C. DUARTE, Auteur ; I. BERNARDINO, Auteur ; T. MARQUES, Auteur ; I. R. VIOLANTE, Auteur ; Miguel CASTELO-BRANCO, Auteur Article en page(s) : p.11 Langues : Anglais (eng) Mots-clés : Eeg  Inhibition  Motor coordination  Neurofibromatosis type 1  fMRI Index. décimale : PER Périodiques Résumé : BACKGROUND: Neurofibromatosis type1 (NF1) is associated with a broad range of behavioural deficits, and an imbalance between excitatory and inhibitory neurotransmission has been postulated in this disorder. Inhibition is involved in the control of frequency and stability of motor rhythms. Therefore, we aimed to explore the link between behavioural motor control, brain rhythms and brain activity, as assessed by EEG and fMRI in NF1. METHODS: We studied a cohort of 21 participants with NF1 and 20 age- and gender-matched healthy controls, with a finger-tapping task requiring pacing at distinct frequencies during EEG and fMRI scans. RESULTS: We found that task performance was significantly different between NF1 and controls, the latter showing higher tapping time precision. The time-frequency patterns at the beta sub-band (20-26 Hz) mirrored the behavioural modulations, with similar cyclic synchronization/desynchronization patterns for both groups. fMRI results showed a higher recruitment of the extrapyramidal motor system (putamen, cerebellum and red nucleus) in the control group during the fastest pacing condition. CONCLUSIONS: The present study demonstrated impaired precision in rhythmic pacing behaviour in NF1 as compared with controls. We found a decreased recruitment of the cerebellum, a structure where inhibitory interneurons are essential regulators of rhythmic synchronization, and in deep brain regions pivotally involved in motor pacing. Our findings shed light into the neural underpinnings of motor timing deficits in NF1. En ligne : http://dx.doi.org/10.1186/s11689-018-9230-4 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=351 [article] Oscillatory motor patterning is impaired in neurofibromatosis type 1: a behavioural, EEG and fMRI study [Texte imprimé et/ou numérique] / G. SILVA, Auteur ; I. C. DUARTE, Auteur ; I. BERNARDINO, Auteur ; T. MARQUES, Auteur ; I. R. VIOLANTE, Auteur ; Miguel CASTELO-BRANCO, Auteur . - p.11. Langues : Anglais (eng) in Journal of Neurodevelopmental Disorders > 10-1 (December 2018) . - p.11 Mots-clés : Eeg  Inhibition  Motor coordination  Neurofibromatosis type 1  fMRI Index. décimale : PER Périodiques Résumé : BACKGROUND: Neurofibromatosis type1 (NF1) is associated with a broad range of behavioural deficits, and an imbalance between excitatory and inhibitory neurotransmission has been postulated in this disorder. Inhibition is involved in the control of frequency and stability of motor rhythms. Therefore, we aimed to explore the link between behavioural motor control, brain rhythms and brain activity, as assessed by EEG and fMRI in NF1. METHODS: We studied a cohort of 21 participants with NF1 and 20 age- and gender-matched healthy controls, with a finger-tapping task requiring pacing at distinct frequencies during EEG and fMRI scans. RESULTS: We found that task performance was significantly different between NF1 and controls, the latter showing higher tapping time precision. The time-frequency patterns at the beta sub-band (20-26 Hz) mirrored the behavioural modulations, with similar cyclic synchronization/desynchronization patterns for both groups. fMRI results showed a higher recruitment of the extrapyramidal motor system (putamen, cerebellum and red nucleus) in the control group during the fastest pacing condition. CONCLUSIONS: The present study demonstrated impaired precision in rhythmic pacing behaviour in NF1 as compared with controls. We found a decreased recruitment of the cerebellum, a structure where inhibitory interneurons are essential regulators of rhythmic synchronization, and in deep brain regions pivotally involved in motor pacing. Our findings shed light into the neural underpinnings of motor timing deficits in NF1. En ligne : http://dx.doi.org/10.1186/s11689-018-9230-4 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=351

Testing the excitation/inhibition imbalance hypothesis in a mouse model of the autism spectrum disorder: in vivo neurospectroscopy and molecular evidence for regional phenotypes / J. GONCALVES in Molecular Autism, 8 (2017)  

Public ISBD [article]  inMolecular Autism > 8 (2017) . - 47p. Titre : Testing the excitation/inhibition imbalance hypothesis in a mouse model of the autism spectrum disorder: in vivo neurospectroscopy and molecular evidence for regional phenotypes Type de document : Texte imprimé et/ou numérique Auteurs : J. GONCALVES, Auteur ; I. R. VIOLANTE, Auteur ; J. SERENO, Auteur ; R. A. LEITAO, Auteur ; Y. CAI, Auteur ; A. ABRUNHOSA, Auteur ; A. P. SILVA, Auteur ; A. J. SILVA, Auteur ; Miguel CASTELO-BRANCO, Auteur Article en page(s) : 47p. Langues : Anglais (eng) Mots-clés : Autism spectrum disorders  Excitation/inhibition imbalance  GABA(A) receptor  Magnetic resonance spectroscopy  Neurofibromatosis type 1 Index. décimale : PER Périodiques Résumé : BACKGROUND: Excitation/inhibition (E/I) imbalance remains a widely discussed hypothesis in autism spectrum disorders (ASD). The presence of such an imbalance may potentially define a therapeutic target for the treatment of cognitive disabilities related to this pathology. Consequently, the study of monogenic disorders related to autism, such as neurofibromatosis type 1 (NF1), represents a promising approach to isolate mechanisms underlying ASD-related cognitive disabilities. However, the NF1 mouse model showed increased gamma-aminobutyric acid (GABA) neurotransmission, whereas the human disease showed reduced cortical GABA levels. It is therefore important to clarify whether the E/I imbalance hypothesis holds true. We hypothesize that E/I may depend on distinct pre- and postsynaptic push-pull mechanisms that might be are region-dependent. METHODS: In current study, we assessed two critical components of E/I regulation: the concentration of neurotransmitters and levels of GABA(A) receptors. Measurements were performed across the hippocampi, striatum, and prefrontal cortices by combined in vivo magnetic resonance spectroscopy (MRS) and molecular approaches in this ASD-related animal model, the Nf1(+/-) mouse. RESULTS: Cortical and striatal GABA/glutamate ratios were increased. At the postsynaptic level, very high receptor GABA(A) receptor expression was found in hippocampus, disproportionately to the small reduction in GABA levels. Gabaergic tone (either by receptor levels change or GABA/glutamate ratios) seemed therefore to be enhanced in all regions, although by a different mechanism. CONCLUSIONS: Our data provides support for the hypothesis of E/I imbalance in NF1 while showing that pre- and postsynaptic changes are region-specific. All these findings are consistent with our previous physiological evidence of increased inhibitory tone. Such heterogeneity suggests that therapeutic approaches to address neurochemical imbalance in ASD may need to focus on targets where convergent physiological mechanisms can be found. En ligne : http://dx.doi.org/10.1186/s13229-017-0166-4 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=330 [article] Testing the excitation/inhibition imbalance hypothesis in a mouse model of the autism spectrum disorder: in vivo neurospectroscopy and molecular evidence for regional phenotypes [Texte imprimé et/ou numérique] / J. GONCALVES, Auteur ; I. R. VIOLANTE, Auteur ; J. SERENO, Auteur ; R. A. LEITAO, Auteur ; Y. CAI, Auteur ; A. ABRUNHOSA, Auteur ; A. P. SILVA, Auteur ; A. J. SILVA, Auteur ; Miguel CASTELO-BRANCO, Auteur . - 47p. Langues : Anglais (eng) in Molecular Autism > 8 (2017) . - 47p. Mots-clés : Autism spectrum disorders  Excitation/inhibition imbalance  GABA(A) receptor  Magnetic resonance spectroscopy  Neurofibromatosis type 1 Index. décimale : PER Périodiques Résumé : BACKGROUND: Excitation/inhibition (E/I) imbalance remains a widely discussed hypothesis in autism spectrum disorders (ASD). The presence of such an imbalance may potentially define a therapeutic target for the treatment of cognitive disabilities related to this pathology. Consequently, the study of monogenic disorders related to autism, such as neurofibromatosis type 1 (NF1), represents a promising approach to isolate mechanisms underlying ASD-related cognitive disabilities. However, the NF1 mouse model showed increased gamma-aminobutyric acid (GABA) neurotransmission, whereas the human disease showed reduced cortical GABA levels. It is therefore important to clarify whether the E/I imbalance hypothesis holds true. We hypothesize that E/I may depend on distinct pre- and postsynaptic push-pull mechanisms that might be are region-dependent. METHODS: In current study, we assessed two critical components of E/I regulation: the concentration of neurotransmitters and levels of GABA(A) receptors. Measurements were performed across the hippocampi, striatum, and prefrontal cortices by combined in vivo magnetic resonance spectroscopy (MRS) and molecular approaches in this ASD-related animal model, the Nf1(+/-) mouse. RESULTS: Cortical and striatal GABA/glutamate ratios were increased. At the postsynaptic level, very high receptor GABA(A) receptor expression was found in hippocampus, disproportionately to the small reduction in GABA levels. Gabaergic tone (either by receptor levels change or GABA/glutamate ratios) seemed therefore to be enhanced in all regions, although by a different mechanism. CONCLUSIONS: Our data provides support for the hypothesis of E/I imbalance in NF1 while showing that pre- and postsynaptic changes are region-specific. All these findings are consistent with our previous physiological evidence of increased inhibitory tone. Such heterogeneity suggests that therapeutic approaches to address neurochemical imbalance in ASD may need to focus on targets where convergent physiological mechanisms can be found. En ligne : http://dx.doi.org/10.1186/s13229-017-0166-4 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=330

Training the social brain: Clinical and neural effects of an 8-week real-time functional magnetic resonance imaging neurofeedback Phase IIa Clinical Trial in Autism / B. DIREITO in Autism, 25-6 (August 2021)  

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Virtual Reality Immersion Rescales Regulation of Interpersonal Distance in Controls but not in Autism Spectrum Disorder / Marco SIMÕES in Journal of Autism and Developmental Disorders, 50-12 (December 2020)  

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