Alpha Asymmetry in Infants at Risk for Autism Spectrum Disorders / Laurel GABARD-DURNAM in Journal of Autism and Developmental Disorders, 45-2 (February 2015)  

Public ISBD [article]  inJournal of Autism and Developmental Disorders > 45-2 (February 2015) . - p.473-480 Titre : Alpha Asymmetry in Infants at Risk for Autism Spectrum Disorders Type de document : Texte imprimé et/ou numérique Auteurs : Laurel GABARD-DURNAM, Auteur ; Adrienne L. TIERNEY, Auteur ; Vanessa VOGEL-FARLEY, Auteur ; Helen TAGER-FLUSBERG, Auteur ; Charles A. NELSON, Auteur Article en page(s) : p.473-480 Langues : Anglais (eng) Mots-clés : Autism spectrum disorder  Infant siblings  Electroencephalography  Frontal alpha asymmetry  Endophenotype Index. décimale : PER Périodiques Résumé : An emerging focus of research on autism spectrum disorder (ASD) targets the identification of early-developing ASD endophenotypes using infant siblings of affected children. One potential neural endophenotype is resting frontal electroencephalogram (EEG) alpha asymmetry, a metric of hemispheric organization. Here, we examined the development of frontal EEG alpha asymmetry in ASD high-risk and low-risk infant populations. Our findings demonstrate that low and high-risk infants show different patterns of alpha asymmetry at 6 months of age and opposite growth trajectories in asymmetry over the following 12 months. These results support the candidacy of alpha asymmetry as an early neural ASD endophenotype. En ligne : http://dx.doi.org/10.1007/s10803-013-1926-4 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=258 [article] Alpha Asymmetry in Infants at Risk for Autism Spectrum Disorders [Texte imprimé et/ou numérique] / Laurel GABARD-DURNAM, Auteur ; Adrienne L. TIERNEY, Auteur ; Vanessa VOGEL-FARLEY, Auteur ; Helen TAGER-FLUSBERG, Auteur ; Charles A. NELSON, Auteur . - p.473-480. Langues : Anglais (eng) in Journal of Autism and Developmental Disorders > 45-2 (February 2015) . - p.473-480 Mots-clés : Autism spectrum disorder  Infant siblings  Electroencephalography  Frontal alpha asymmetry  Endophenotype Index. décimale : PER Périodiques Résumé : An emerging focus of research on autism spectrum disorder (ASD) targets the identification of early-developing ASD endophenotypes using infant siblings of affected children. One potential neural endophenotype is resting frontal electroencephalogram (EEG) alpha asymmetry, a metric of hemispheric organization. Here, we examined the development of frontal EEG alpha asymmetry in ASD high-risk and low-risk infant populations. Our findings demonstrate that low and high-risk infants show different patterns of alpha asymmetry at 6 months of age and opposite growth trajectories in asymmetry over the following 12 months. These results support the candidacy of alpha asymmetry as an early neural ASD endophenotype. En ligne : http://dx.doi.org/10.1007/s10803-013-1926-4 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=258

Atypical Hemispheric Specialization for Faces in Infants at Risk for Autism Spectrum Disorder / Brandon KEEHN in Autism Research, 8-2 (April 2015)  

Public ISBD [article]  inAutism Research > 8-2 (April 2015) . - p.187-198 Titre : Atypical Hemispheric Specialization for Faces in Infants at Risk for Autism Spectrum Disorder Type de document : Texte imprimé et/ou numérique Auteurs : Brandon KEEHN, Auteur ; Vanessa VOGEL-FARLEY, Auteur ; Helen TAGER-FLUSBERG, Auteur ; Charles A. NELSON, Auteur Article en page(s) : p.187-198 Langues : Anglais (eng) Mots-clés : autism  EEG coherence  face processing  hemispheric specialization  endophenotype  gamma  infancy Index. décimale : PER Périodiques Résumé : Among the many experimental findings that tend to distinguish those with and without autism spectrum disorder (ASD) are face processing deficits, reduced hemispheric specialization, and atypical neurostructural and functional connectivity. To investigate the earliest manifestations of these features, we examined lateralization of event-related gamma-band coherence to faces during the first year of life in infants at high risk for autism (HRA; defined as having an older sibling with ASD) who were compared with low-risk comparison (LRC) infants, defined as having no family history of ASD. Participants included 49 HRA and 46 LRC infants who contributed a total of 127 data sets at 6 and 12 months. Electroencephalography was recorded while infants viewed images of familiar/unfamiliar faces. Event-related gamma-band (30–50?Hz) phase coherence between anterior–posterior electrode pairs for left and right hemispheres was computed. Developmental trajectories for lateralization of intra-hemispheric coherence were significantly different in HRA and LRC infants: by 12 months, HRA infants showed significantly greater leftward lateralization compared with LRC infants who showed rightward lateralization. Preliminary results indicate that infants who later met criteria for ASD were those that showed the greatest leftward lateralization. HRA infants demonstrate an aberrant pattern of leftward lateralization of intra-hemispheric coherence by the end of the first year of life, suggesting that the network specialized for face processing may develop atypically. Further, infants with the greatest leftward asymmetry at 12 months where those that later met criteria for ASD, providing support to the growing body of evidence that atypical hemispheric specialization may be an early neurobiological marker for ASD. En ligne : http://dx.doi.org/10.1002/aur.1438 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=256 [article] Atypical Hemispheric Specialization for Faces in Infants at Risk for Autism Spectrum Disorder [Texte imprimé et/ou numérique] / Brandon KEEHN, Auteur ; Vanessa VOGEL-FARLEY, Auteur ; Helen TAGER-FLUSBERG, Auteur ; Charles A. NELSON, Auteur . - p.187-198. Langues : Anglais (eng) in Autism Research > 8-2 (April 2015) . - p.187-198 Mots-clés : autism  EEG coherence  face processing  hemispheric specialization  endophenotype  gamma  infancy Index. décimale : PER Périodiques Résumé : Among the many experimental findings that tend to distinguish those with and without autism spectrum disorder (ASD) are face processing deficits, reduced hemispheric specialization, and atypical neurostructural and functional connectivity. To investigate the earliest manifestations of these features, we examined lateralization of event-related gamma-band coherence to faces during the first year of life in infants at high risk for autism (HRA; defined as having an older sibling with ASD) who were compared with low-risk comparison (LRC) infants, defined as having no family history of ASD. Participants included 49 HRA and 46 LRC infants who contributed a total of 127 data sets at 6 and 12 months. Electroencephalography was recorded while infants viewed images of familiar/unfamiliar faces. Event-related gamma-band (30–50?Hz) phase coherence between anterior–posterior electrode pairs for left and right hemispheres was computed. Developmental trajectories for lateralization of intra-hemispheric coherence were significantly different in HRA and LRC infants: by 12 months, HRA infants showed significantly greater leftward lateralization compared with LRC infants who showed rightward lateralization. Preliminary results indicate that infants who later met criteria for ASD were those that showed the greatest leftward lateralization. HRA infants demonstrate an aberrant pattern of leftward lateralization of intra-hemispheric coherence by the end of the first year of life, suggesting that the network specialized for face processing may develop atypically. Further, infants with the greatest leftward asymmetry at 12 months where those that later met criteria for ASD, providing support to the growing body of evidence that atypical hemispheric specialization may be an early neurobiological marker for ASD. En ligne : http://dx.doi.org/10.1002/aur.1438 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=256

Resting and Task-Modulated High-Frequency Brain Rhythms Measured by Scalp Encephalography in Infants with Tuberous Sclerosis Complex / Catherine STAMOULIS in Journal of Autism and Developmental Disorders, 45-2 (February 2015)  

Public ISBD [article]  inJournal of Autism and Developmental Disorders > 45-2 (February 2015) . - p.336-353 Titre : Resting and Task-Modulated High-Frequency Brain Rhythms Measured by Scalp Encephalography in Infants with Tuberous Sclerosis Complex Type de document : Texte imprimé et/ou numérique Auteurs : Catherine STAMOULIS, Auteur ; Vanessa VOGEL-FARLEY, Auteur ; Geneva DEGREGORIO, Auteur ; Shafali S. JESTE, Auteur ; Charles A. NELSON, Auteur Article en page(s) : p.336-353 Langues : Anglais (eng) Mots-clés : Tuberous sclerosis complex  Brain dynamics  EEG  Dominant brain rhythms Index. décimale : PER Périodiques Résumé : The electrophysiological correlates of cognitive deficits in tuberous sclerosis complex (TSC) are not well understood, and modulations of neural dynamics by neuroanatomical abnormalities that characterize the disorder remain elusive. Neural oscillations (rhythms) are a fundamental aspect of brain function, and have dominant frequencies in a wide frequency range. The spatio-temporal dynamics of these frequencies in TSC are currently unknown. Using a novel signal decomposition approach this study investigated dominant cortical frequencies in 10 infants with TSC, in the age range 18–30 months, and 12 age-matched healthy controls. Distinct spectral characteristics were estimated in the two groups. High-frequency [in the high-gamma (>50 Hz) and ripple (>80 Hz) ranges], non-random EEG components were identified in both TSC and healthy infants at 18 months. Additional components in the lower gamma (30–50 Hz) ranges were also identified, with higher characteristic frequencies in TSC than in controls. Lower frequencies were statistically identical in both sub-groups. A significant shift in the high-frequency spectral content of the EEG was observed as a function of age, independently of task performance, possibly reflecting an overall maturation of developing neural circuits. This shift occurred earlier in healthy infants than in TSC, i.e., by age 20 months the highest dominant frequencies were in the high gamma range, whereas in TSC dominant frequencies above 100 Hz were still measurable. At age 28–30 months a statistically significant decrease in dominant high frequencies was observed in both TSC and healthy infants, possibly reflecting increased myelination and neuronal connection strengthening with age. Although based on small samples, and thus preliminary, the findings in this study suggest that dominant cortical rhythms, a fundamental aspect of neurodynamics, may be affected in TSC, possibly leading to impaired information processing in the brain. En ligne : http://dx.doi.org/10.1007/s10803-013-1887-7 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=258 [article] Resting and Task-Modulated High-Frequency Brain Rhythms Measured by Scalp Encephalography in Infants with Tuberous Sclerosis Complex [Texte imprimé et/ou numérique] / Catherine STAMOULIS, Auteur ; Vanessa VOGEL-FARLEY, Auteur ; Geneva DEGREGORIO, Auteur ; Shafali S. JESTE, Auteur ; Charles A. NELSON, Auteur . - p.336-353. Langues : Anglais (eng) in Journal of Autism and Developmental Disorders > 45-2 (February 2015) . - p.336-353 Mots-clés : Tuberous sclerosis complex  Brain dynamics  EEG  Dominant brain rhythms Index. décimale : PER Périodiques Résumé : The electrophysiological correlates of cognitive deficits in tuberous sclerosis complex (TSC) are not well understood, and modulations of neural dynamics by neuroanatomical abnormalities that characterize the disorder remain elusive. Neural oscillations (rhythms) are a fundamental aspect of brain function, and have dominant frequencies in a wide frequency range. The spatio-temporal dynamics of these frequencies in TSC are currently unknown. Using a novel signal decomposition approach this study investigated dominant cortical frequencies in 10 infants with TSC, in the age range 18–30 months, and 12 age-matched healthy controls. Distinct spectral characteristics were estimated in the two groups. High-frequency [in the high-gamma (>50 Hz) and ripple (>80 Hz) ranges], non-random EEG components were identified in both TSC and healthy infants at 18 months. Additional components in the lower gamma (30–50 Hz) ranges were also identified, with higher characteristic frequencies in TSC than in controls. Lower frequencies were statistically identical in both sub-groups. A significant shift in the high-frequency spectral content of the EEG was observed as a function of age, independently of task performance, possibly reflecting an overall maturation of developing neural circuits. This shift occurred earlier in healthy infants than in TSC, i.e., by age 20 months the highest dominant frequencies were in the high gamma range, whereas in TSC dominant frequencies above 100 Hz were still measurable. At age 28–30 months a statistically significant decrease in dominant high frequencies was observed in both TSC and healthy infants, possibly reflecting increased myelination and neuronal connection strengthening with age. Although based on small samples, and thus preliminary, the findings in this study suggest that dominant cortical rhythms, a fundamental aspect of neurodynamics, may be affected in TSC, possibly leading to impaired information processing in the brain. En ligne : http://dx.doi.org/10.1007/s10803-013-1887-7 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=258

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