Concentrations of Cortical GABA and Glutamate in Young Adults With Autism Spectrum Disorder / Tamar KOLODNY in Autism Research, 13-7 (July 2020)  

Public ISBD [article]  inAutism Research > 13-7 (July 2020) . - p.1111-1129 Titre : Concentrations of Cortical GABA and Glutamate in Young Adults With Autism Spectrum Disorder Type de document : Texte imprimé et/ou numérique Auteurs : Tamar KOLODNY, Auteur ; Michael-Paul SCHALLMO, Auteur ; Jennifer GERDTS, Auteur ; Richard A. E. EDDEN, Auteur ; Raphael BERNIER, Auteur ; Scott O. MURRAY, Auteur Article en page(s) : p.1111-1129 Langues : Anglais (eng) Mots-clés : auditory cortex  autism spectrum disorders  glutamate  magnetic resonance spectroscopy  sensorimotor cortex  visual cortex  ?-aminobutyric acid Index. décimale : PER Périodiques Résumé : The balance of excitation and inhibition in neural circuits is hypothesized to be increased in autism spectrum disorder, possibly mediated by altered signaling of the inhibitory neurotransmitter ?-aminobutyric acid (GABA), yet empirical evidence in humans is inconsistent. We used edited magnetic resonance spectroscopy (MRS) to quantify signals associated with both GABA and the excitatory neurotransmitter glutamate in multiple regions of the sensory and sensorimotor cortex, including primary visual, auditory, and motor areas in adult individuals with autism and in neurotypical controls. Despite the strong a priori hypothesis of reduced GABA in autism spectrum disorder, we found no group differences in neurometabolite concentrations in any of the examined regions and no correlations of MRS measure with psychophysical visual sensitivity or autism symptomatology. We demonstrate high data quality that is comparable across groups, with a relatively large sample of well-characterized participants, and use Bayesian statistics to corroborate the lack of any group differences. We conclude that levels of GABA and Glx (glutamate, glutamine, and glutathione) in the sensory and sensorimotor cortex, as measured with MRS at 3T, are comparable in adults with autism and neurotypical individuals. Autism Res 2020, 13: 1111-1129. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: ?-Aminobutyric acid (GABA) and glutamate are the main inhibitory and excitatory neurotransmitters in the human brain, respectively, and their balanced interaction is necessary for neural function. Previous research suggests that the GABA and glutamate systems might be altered in autism. In this study, we used magnetic resonance spectroscopy to measure concentrations of these neurotransmitters in the sensory areas in the brains of young adults with autism. In contradiction to the common hypothesis of reduced GABA in autism, we demonstrate that concentrations of both GABA and glutamate, in all the brain regions examined, are comparable in individuals with autism and in neurotypical adults. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. En ligne : http://dx.doi.org/10.1002/aur.2300 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=429 [article] Concentrations of Cortical GABA and Glutamate in Young Adults With Autism Spectrum Disorder [Texte imprimé et/ou numérique] / Tamar KOLODNY, Auteur ; Michael-Paul SCHALLMO, Auteur ; Jennifer GERDTS, Auteur ; Richard A. E. EDDEN, Auteur ; Raphael BERNIER, Auteur ; Scott O. MURRAY, Auteur . - p.1111-1129. Langues : Anglais (eng) in Autism Research > 13-7 (July 2020) . - p.1111-1129 Mots-clés : auditory cortex  autism spectrum disorders  glutamate  magnetic resonance spectroscopy  sensorimotor cortex  visual cortex  ?-aminobutyric acid Index. décimale : PER Périodiques Résumé : The balance of excitation and inhibition in neural circuits is hypothesized to be increased in autism spectrum disorder, possibly mediated by altered signaling of the inhibitory neurotransmitter ?-aminobutyric acid (GABA), yet empirical evidence in humans is inconsistent. We used edited magnetic resonance spectroscopy (MRS) to quantify signals associated with both GABA and the excitatory neurotransmitter glutamate in multiple regions of the sensory and sensorimotor cortex, including primary visual, auditory, and motor areas in adult individuals with autism and in neurotypical controls. Despite the strong a priori hypothesis of reduced GABA in autism spectrum disorder, we found no group differences in neurometabolite concentrations in any of the examined regions and no correlations of MRS measure with psychophysical visual sensitivity or autism symptomatology. We demonstrate high data quality that is comparable across groups, with a relatively large sample of well-characterized participants, and use Bayesian statistics to corroborate the lack of any group differences. We conclude that levels of GABA and Glx (glutamate, glutamine, and glutathione) in the sensory and sensorimotor cortex, as measured with MRS at 3T, are comparable in adults with autism and neurotypical individuals. Autism Res 2020, 13: 1111-1129. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: ?-Aminobutyric acid (GABA) and glutamate are the main inhibitory and excitatory neurotransmitters in the human brain, respectively, and their balanced interaction is necessary for neural function. Previous research suggests that the GABA and glutamate systems might be altered in autism. In this study, we used magnetic resonance spectroscopy to measure concentrations of these neurotransmitters in the sensory areas in the brains of young adults with autism. In contradiction to the common hypothesis of reduced GABA in autism, we demonstrate that concentrations of both GABA and glutamate, in all the brain regions examined, are comparable in individuals with autism and in neurotypical adults. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. En ligne : http://dx.doi.org/10.1002/aur.2300 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=429

Increased alpha power in autistic adults: Relation to sensory behaviors and cortical volume / Scott O. MURRAY ; Daniela L. Seczon ; Mark Pettet ; Hannah M. REA ; Kristin M. WOODARD ; Tamar KOLODNY ; Sara Jane WEBB in Autism Research, 18-1 (January 2025)  

Public ISBD [article]  inAutism Research > 18-1 (January 2025) . - p.56-69 Titre : Increased alpha power in autistic adults: Relation to sensory behaviors and cortical volume : Autism Research Type de document : Texte imprimé et/ou numérique Auteurs : Scott O. MURRAY, Auteur ; Daniela L. Seczon, Auteur ; Mark Pettet, Auteur ; Hannah M. REA, Auteur ; Kristin M. WOODARD, Auteur ; Tamar KOLODNY, Auteur ; Sara Jane WEBB, Auteur Article en page(s) : p.56-69 Langues : Anglais (eng) Mots-clés : alpha  autism spectrum disorder  EEG  sensory processing  vision Index. décimale : PER Périodiques Résumé : Abstract Alpha-band (~10?Hz) neural oscillations, crucial for gating sensory information, may offer insights into the atypical sensory experiences characteristic of autism spectrum disorder (ASD). We investigated alpha-band EEG activity in autistic adults (n?=?29) compared with a nonautistic group (n?=?23) under various stimulus-driven and resting-state conditions. The autistic group showed consistently higher alpha amplitude across all time points. In addition, there was proportionally more suppression of alpha at stimulus onset in the autistic group, and alpha amplitude in this stimulus-onset period correlated with sensory behaviors. Recent research suggests a link between subcortical structures' volume and cortical alpha magnitude. Prompted by this, we explored the association between alpha power and the volume of subcortical structures and total cortical volume in ASD. Our findings indicate a significant correlation with total cortical volume and a group by hippocampal volume interaction, pointing to the potential role of anatomical structural characteristics as potential modulators of cortical alpha oscillations in ASD. Overall, the results highlight altered alpha in autistic individuals as potentially contributing to the heightened sensory symptoms in autistic compared with nonautistic adults. En ligne : https://doi.org/10.1002/aur.3266 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=546 [article] Increased alpha power in autistic adults: Relation to sensory behaviors and cortical volume : Autism Research [Texte imprimé et/ou numérique] / Scott O. MURRAY, Auteur ; Daniela L. Seczon, Auteur ; Mark Pettet, Auteur ; Hannah M. REA, Auteur ; Kristin M. WOODARD, Auteur ; Tamar KOLODNY, Auteur ; Sara Jane WEBB, Auteur . - p.56-69. Langues : Anglais (eng) in Autism Research > 18-1 (January 2025) . - p.56-69 Mots-clés : alpha  autism spectrum disorder  EEG  sensory processing  vision Index. décimale : PER Périodiques Résumé : Abstract Alpha-band (~10?Hz) neural oscillations, crucial for gating sensory information, may offer insights into the atypical sensory experiences characteristic of autism spectrum disorder (ASD). We investigated alpha-band EEG activity in autistic adults (n?=?29) compared with a nonautistic group (n?=?23) under various stimulus-driven and resting-state conditions. The autistic group showed consistently higher alpha amplitude across all time points. In addition, there was proportionally more suppression of alpha at stimulus onset in the autistic group, and alpha amplitude in this stimulus-onset period correlated with sensory behaviors. Recent research suggests a link between subcortical structures' volume and cortical alpha magnitude. Prompted by this, we explored the association between alpha power and the volume of subcortical structures and total cortical volume in ASD. Our findings indicate a significant correlation with total cortical volume and a group by hippocampal volume interaction, pointing to the potential role of anatomical structural characteristics as potential modulators of cortical alpha oscillations in ASD. Overall, the results highlight altered alpha in autistic individuals as potentially contributing to the heightened sensory symptoms in autistic compared with nonautistic adults. En ligne : https://doi.org/10.1002/aur.3266 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=546

Rhythmic attentional sampling in autism / Tamar KOLODNY ; Kristin M. WOODARD ; Aydin TASEVAC ; Wesley R. GANZ ; Hannah M. REA ; Evangeline C. KURTZ-NELSON ; Sara Jane WEBB ; Scott O. MURRAY in Autism Research, 16-11 (November 2023)  

Public ISBD [article]  inAutism Research > 16-11 (November 2023) . - p.2090-2099 Titre : Rhythmic attentional sampling in autism Type de document : Texte imprimé et/ou numérique Auteurs : Tamar KOLODNY, Auteur ; Kristin M. WOODARD, Auteur ; Aydin TASEVAC, Auteur ; Wesley R. GANZ, Auteur ; Hannah M. REA, Auteur ; Evangeline C. KURTZ-NELSON, Auteur ; Sara Jane WEBB, Auteur ; Scott O. MURRAY, Auteur Article en page(s) : p.2090-2099 Langues : Anglais (eng) Index. décimale : PER Périodiques Résumé : Abstract Individuals diagnosed with autism often display alterations in visual spatial attention toward visual stimuli, but the underlying cause of these differences remains unclear. Recent evidence has demonstrated that covert spatial attention, rather than remaining constant at a cued location, samples stimuli rhythmically at a frequency of 4-8?Hz (theta). Here we tested whether rhythmic sampling of attention is altered in autism. Participants were asked to monitor three locations to detect a brief target presented 300-1200?ms after a spatial cue. Visual attention was oriented to the cue and modified visual processing at the cued location, consistent with previous studies. We measured detection performance at different cue-target intervals when the target occurred at the cued location. Significant oscillations in detection performance were identified using both a traditional time-shuffled approach and a new autoregressive surrogate method developed by Brookshire in 2022. We found that attention enhances behavioral performance rhythmically at the same frequency in both autism and control group at the cued location. However, rhythmic temporal structure was not observed in a subgroup of autistic individuals with co-occurring attention-deficit/hyperactivity disorder (ADHD). Our results imply that intrinsic brain rhythms which organize neural activity into alternating attentional states is functional in autistic individuals, but may be altered in autistic participants who have a concurrent ADHD diagnosis. En ligne : https://doi.org/10.1002/aur.3021 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=517 [article] Rhythmic attentional sampling in autism [Texte imprimé et/ou numérique] / Tamar KOLODNY, Auteur ; Kristin M. WOODARD, Auteur ; Aydin TASEVAC, Auteur ; Wesley R. GANZ, Auteur ; Hannah M. REA, Auteur ; Evangeline C. KURTZ-NELSON, Auteur ; Sara Jane WEBB, Auteur ; Scott O. MURRAY, Auteur . - p.2090-2099. Langues : Anglais (eng) in Autism Research > 16-11 (November 2023) . - p.2090-2099 Index. décimale : PER Périodiques Résumé : Abstract Individuals diagnosed with autism often display alterations in visual spatial attention toward visual stimuli, but the underlying cause of these differences remains unclear. Recent evidence has demonstrated that covert spatial attention, rather than remaining constant at a cued location, samples stimuli rhythmically at a frequency of 4-8?Hz (theta). Here we tested whether rhythmic sampling of attention is altered in autism. Participants were asked to monitor three locations to detect a brief target presented 300-1200?ms after a spatial cue. Visual attention was oriented to the cue and modified visual processing at the cued location, consistent with previous studies. We measured detection performance at different cue-target intervals when the target occurred at the cued location. Significant oscillations in detection performance were identified using both a traditional time-shuffled approach and a new autoregressive surrogate method developed by Brookshire in 2022. We found that attention enhances behavioral performance rhythmically at the same frequency in both autism and control group at the cued location. However, rhythmic temporal structure was not observed in a subgroup of autistic individuals with co-occurring attention-deficit/hyperactivity disorder (ADHD). Our results imply that intrinsic brain rhythms which organize neural activity into alternating attentional states is functional in autistic individuals, but may be altered in autistic participants who have a concurrent ADHD diagnosis. En ligne : https://doi.org/10.1002/aur.3021 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=517

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