24 recherche sur le mot-clé 'Source-localization'

Source localization of brain electric field frequency bands during conscious, spontaneous, visual imagery and abstract thought / D. LEHMANN in Cognitive Brain Research, 1-4 (December 1993)

Public ISBD [article]  inCognitive Brain Research > 1-4 (December 1993) . - p.203-210 Titre : Source localization of brain electric field frequency bands during conscious, spontaneous, visual imagery and abstract thought Type de document : texte imprimé Auteurs : D. LEHMANN, Auteur ; B. HENGGELER, Auteur ; M. KOUKKOU, Auteur ; C.M. MICHEL, Auteur Année de publication : 1993 Article en page(s) : p.203-210 Langues : Anglais (eng) Mots-clés : Source-localization EEG-frequency-band Mentation-class Consciousness Spontaneous-thought Visual-imagery Index. décimale : PER Périodiques Résumé : This paper addresses the issue of mind-brain correspondence, using a novel way to reduce brain electric field data in the frequency domain to estimates of intracerebral model source locations, and applying this method to brain electric data collected during the 2-s epochs immediately before the randomly solicited reports of spontaneous, conscious, covert experiences from 12 normal volunteers. The mentation reports were classified into visual imagery and abstract thought. The mean locations of the EEG model sources associated with abstract thoughts were generally more anterior and deeper than those of visual imagery, particularly significant for the delta/theta band; the finding was common across subjects. Thus, different brain functional states involving different geometries of activated neural populations exist during conscious, spontaneous, task-free mentations of the visual imagery type and of the abstract thought type. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=781 [article] Source localization of brain electric field frequency bands during conscious, spontaneous, visual imagery and abstract thought [texte imprimé] / D. LEHMANN, Auteur ; B. HENGGELER, Auteur ; M. KOUKKOU, Auteur ; C.M. MICHEL, Auteur . - 1993 . - p.203-210. Langues : Anglais (eng) in Cognitive Brain Research > 1-4 (December 1993) . - p.203-210 Mots-clés : Source-localization EEG-frequency-band Mentation-class Consciousness Spontaneous-thought Visual-imagery Index. décimale : PER Périodiques Résumé : This paper addresses the issue of mind-brain correspondence, using a novel way to reduce brain electric field data in the frequency domain to estimates of intracerebral model source locations, and applying this method to brain electric data collected during the 2-s epochs immediately before the randomly solicited reports of spontaneous, conscious, covert experiences from 12 normal volunteers. The mentation reports were classified into visual imagery and abstract thought. The mean locations of the EEG model sources associated with abstract thoughts were generally more anterior and deeper than those of visual imagery, particularly significant for the delta/theta band; the finding was common across subjects. Thus, different brain functional states involving different geometries of activated neural populations exist during conscious, spontaneous, task-free mentations of the visual imagery type and of the abstract thought type. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=781

Divergent aperiodic slope and alpha dynamics expose cortical excitability gradients in fragile X syndrome / Rana ELMAGHRABY in Molecular Autism, 16 (2025)  

Public ISBD [article]  inMolecular Autism > 16 (2025) . - 49 Titre : Divergent aperiodic slope and alpha dynamics expose cortical excitability gradients in fragile X syndrome Type de document : texte imprimé Auteurs : Rana ELMAGHRABY, Auteur ; Yanchen LIU, Auteur ; Priya RAMESH, Auteur ; Grace WESTERKAMP, Auteur ; Meredith A. NELSON, Auteur ; Travis LARSH, Auteur ; Elizabeth SMITH, Auteur ; Donald L. GILBERT, Auteur ; Steve W. WU, Auteur ; Craig ERICKSON, Auteur ; Ernest V. PEDAPATI, Auteur ; Rana ELMAGHRABY, Auteur ; Yanchen LIU, Auteur ; Priya RAMESH, Auteur ; Grace WESTERKAMP, Auteur ; Meredith A. NELSON, Auteur ; Travis LARSH, Auteur ; Elizabeth SMITH, Auteur ; Donald L. GILBERT, Auteur ; Steve W. WU, Auteur ; Craig ERICKSON, Auteur ; Ernest V. PEDAPATI, Auteur Article en page(s) : 49 Langues : Anglais (eng) Mots-clés : Humans  Fragile X Syndrome/physiopathology  Male  Female  Cortical Excitability/physiology  Young Adult  Adult  Electroencephalography  Adolescent  Alpha Rhythm  Case-Control Studies  Aperiodic slope  Cortical excitability  Eeg  Fragile X syndrome  Sex differences  Source localization  SpecParam Index. décimale : PER Périodiques Résumé : BACKGROUND: Fragile X syndrome (FXS) is characterized by cortical hyperexcitability, a core neurophysiological feature that contributes to sensory hypersensitivity, cognitive dysfunction, and other disabling symptoms. This disruption in excitatory-inhibitory balance is a key pharmacological target, yet reliable biomarkers to quantify it noninvasively remain limited. Spectral slope, derived from the aperiodic component of the EEG power spectrum, has emerged as a potential index of cortical excitability. Here, we evaluated spectral slope and theta-alpha peak frequency in individuals with FXS to assess their utility as candidate neurophysiological biomarkers. METHODS: Five minutes of resting state EEG data were collected from 70 subjects with FXS (mean age 20.5 ± 10 years; 32 females) and 71 age-matched controls (mean age 22.2 ± 10.7 years; 30 females). The Spectral Parameterization toolbox (SpecParam) was used to separate periodic and aperiodic components of the source localized power spectra and characterize aperiodic slope and theta-alpha peak frequency. RESULTS: Statistical modeling of aperiodic slope revealed a significant two-way interaction between sex and diagnostic group, but no interaction with brain lobe. Among males, the aperiodic slope was significantly decreased in FXS, indicating greater cortical excitability, compared to typically developing controls (TDC), whereas no difference was observed between FXS and TDC females. For peak alpha frequency, statistical modeling identified significant two-way interactions between sex and diagnostic group, and between brain lobe and diagnostic group, but no significant three-way interaction. LIMITATIONS: This study is limited by the absence of non-invasive measures of cortical fragile X mental retardation protein (FMRP). Additionally, participants were not stratified by mosaic status and FMRP levels were not quantified, which could affect variability and interpretation. CONCLUSION: Compared to traditional band-limited power measures, aperiodic slope provides a more direct and validated index of excitation-inhibition balance. Our findings of reduced aperiodic slope in male subjects with FXS align with preclinical circuit-level evidence of increased excitability in FXS and are consistent with previous findings of reduced individual alpha peak frequency, supporting with thalamocortical dysrhythmia models of FXS. Importantly, aperiodic slope measurements can be applied directly to various modalities of local field potential data, enabling more robust cross-species and translational comparisons. En ligne : https://dx.doi.org/10.1186/s13229-025-00682-0 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=569 [article] Divergent aperiodic slope and alpha dynamics expose cortical excitability gradients in fragile X syndrome [texte imprimé] / Rana ELMAGHRABY, Auteur ; Yanchen LIU, Auteur ; Priya RAMESH, Auteur ; Grace WESTERKAMP, Auteur ; Meredith A. NELSON, Auteur ; Travis LARSH, Auteur ; Elizabeth SMITH, Auteur ; Donald L. GILBERT, Auteur ; Steve W. WU, Auteur ; Craig ERICKSON, Auteur ; Ernest V. PEDAPATI, Auteur ; Rana ELMAGHRABY, Auteur ; Yanchen LIU, Auteur ; Priya RAMESH, Auteur ; Grace WESTERKAMP, Auteur ; Meredith A. NELSON, Auteur ; Travis LARSH, Auteur ; Elizabeth SMITH, Auteur ; Donald L. GILBERT, Auteur ; Steve W. WU, Auteur ; Craig ERICKSON, Auteur ; Ernest V. PEDAPATI, Auteur . - 49. Langues : Anglais (eng) in Molecular Autism > 16 (2025) . - 49 Mots-clés : Humans  Fragile X Syndrome/physiopathology  Male  Female  Cortical Excitability/physiology  Young Adult  Adult  Electroencephalography  Adolescent  Alpha Rhythm  Case-Control Studies  Aperiodic slope  Cortical excitability  Eeg  Fragile X syndrome  Sex differences  Source localization  SpecParam Index. décimale : PER Périodiques Résumé : BACKGROUND: Fragile X syndrome (FXS) is characterized by cortical hyperexcitability, a core neurophysiological feature that contributes to sensory hypersensitivity, cognitive dysfunction, and other disabling symptoms. This disruption in excitatory-inhibitory balance is a key pharmacological target, yet reliable biomarkers to quantify it noninvasively remain limited. Spectral slope, derived from the aperiodic component of the EEG power spectrum, has emerged as a potential index of cortical excitability. Here, we evaluated spectral slope and theta-alpha peak frequency in individuals with FXS to assess their utility as candidate neurophysiological biomarkers. METHODS: Five minutes of resting state EEG data were collected from 70 subjects with FXS (mean age 20.5 ± 10 years; 32 females) and 71 age-matched controls (mean age 22.2 ± 10.7 years; 30 females). The Spectral Parameterization toolbox (SpecParam) was used to separate periodic and aperiodic components of the source localized power spectra and characterize aperiodic slope and theta-alpha peak frequency. RESULTS: Statistical modeling of aperiodic slope revealed a significant two-way interaction between sex and diagnostic group, but no interaction with brain lobe. Among males, the aperiodic slope was significantly decreased in FXS, indicating greater cortical excitability, compared to typically developing controls (TDC), whereas no difference was observed between FXS and TDC females. For peak alpha frequency, statistical modeling identified significant two-way interactions between sex and diagnostic group, and between brain lobe and diagnostic group, but no significant three-way interaction. LIMITATIONS: This study is limited by the absence of non-invasive measures of cortical fragile X mental retardation protein (FMRP). Additionally, participants were not stratified by mosaic status and FMRP levels were not quantified, which could affect variability and interpretation. CONCLUSION: Compared to traditional band-limited power measures, aperiodic slope provides a more direct and validated index of excitation-inhibition balance. Our findings of reduced aperiodic slope in male subjects with FXS align with preclinical circuit-level evidence of increased excitability in FXS and are consistent with previous findings of reduced individual alpha peak frequency, supporting with thalamocortical dysrhythmia models of FXS. Importantly, aperiodic slope measurements can be applied directly to various modalities of local field potential data, enabling more robust cross-species and translational comparisons. En ligne : https://dx.doi.org/10.1186/s13229-025-00682-0 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=569

An Abnormal Cerebellar Network in Children with Autistic Spectrum Disorder: A Morphometric Study / Alessandro GRECUCCI in Autism - Open Access, 6-3 ([01/05/2016])  

Public ISBD [article]  inAutism - Open Access > 6-3 [01/05/2016] . - 6 p. Titre : An Abnormal Cerebellar Network in Children with Autistic Spectrum Disorder: A Morphometric Study Type de document : texte imprimé Auteurs : Alessandro GRECUCCI, Auteur ; Edoardo PAPPAIANNI, Auteur ; Roma SIUGZDAITE, Auteur Article en page(s) : 6 p. Langues : Anglais (eng) Mots-clés : Autism  Structural differences  Source based morphometry  Biological markers Index. décimale : PER Périodiques Résumé : Autism is a neurodevelopmental disorder characterized by poor social abilities, communication deficiency and restricted behavioural patterns. Recently, scholars started to consider the possibility of detecting biological markers for better and faster diagnosing autism. This problem has been approached from different perspectives considering biochemical, neurophysiological, and neuroanatomical markers. Following this perspective, our intent was to investigate whether a structural brain signature of autism can be detected in children by using a whole brain morphological analysis. To this aim, we selected 43 male children with autistic spectrum disorder and 46 male controls, matched for age. Structural brain images (T1 image), intelligence scores (Full IQ, Verbal IQ, Performance IQ), and Autism Diagnostic Observation Schedule (ADOS) scores were considered for analyses. Source-Based Morphometry, a multivariate method based on Independent Component Analysis to detect maximally independent cortical networks of gray matter differences was applied to autistic and control brains. Results showed a statistically different network between ASD children and controls, including several cerebellar regions (Inferior Semi-lunarlobule, Tuble, Uvula, Pyramis, Declive, Cerebellar Tonsil) and the Fusiform Gyrus, confirming, but, also expanding previous results. In addition, separate temporal, frontal, and parietal networks were found to be significantly correlated with the Stereotyped Behaviour ADOS scores. These morphologic differences may be particularly useful in paving the way for future objective methods to diagnose autism. En ligne : https://dx.doi.org/10.4172/2165-7890.1000178 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=410 [article] An Abnormal Cerebellar Network in Children with Autistic Spectrum Disorder: A Morphometric Study [texte imprimé] / Alessandro GRECUCCI, Auteur ; Edoardo PAPPAIANNI, Auteur ; Roma SIUGZDAITE, Auteur . - 6 p. Langues : Anglais (eng) in Autism - Open Access > 6-3 [01/05/2016] . - 6 p. Mots-clés : Autism  Structural differences  Source based morphometry  Biological markers Index. décimale : PER Périodiques Résumé : Autism is a neurodevelopmental disorder characterized by poor social abilities, communication deficiency and restricted behavioural patterns. Recently, scholars started to consider the possibility of detecting biological markers for better and faster diagnosing autism. This problem has been approached from different perspectives considering biochemical, neurophysiological, and neuroanatomical markers. Following this perspective, our intent was to investigate whether a structural brain signature of autism can be detected in children by using a whole brain morphological analysis. To this aim, we selected 43 male children with autistic spectrum disorder and 46 male controls, matched for age. Structural brain images (T1 image), intelligence scores (Full IQ, Verbal IQ, Performance IQ), and Autism Diagnostic Observation Schedule (ADOS) scores were considered for analyses. Source-Based Morphometry, a multivariate method based on Independent Component Analysis to detect maximally independent cortical networks of gray matter differences was applied to autistic and control brains. Results showed a statistically different network between ASD children and controls, including several cerebellar regions (Inferior Semi-lunarlobule, Tuble, Uvula, Pyramis, Declive, Cerebellar Tonsil) and the Fusiform Gyrus, confirming, but, also expanding previous results. In addition, separate temporal, frontal, and parietal networks were found to be significantly correlated with the Stereotyped Behaviour ADOS scores. These morphologic differences may be particularly useful in paving the way for future objective methods to diagnose autism. En ligne : https://dx.doi.org/10.4172/2165-7890.1000178 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=410

Assessing Recollection and Familiarity in Autistic Spectrum Disorders: Methods and Findings / Sally BIGHAM in Journal of Autism and Developmental Disorders, 40-7 (July 2010)  

Public ISBD [article]  inJournal of Autism and Developmental Disorders > 40-7 (July 2010) . - p.878-889 Titre : Assessing Recollection and Familiarity in Autistic Spectrum Disorders: Methods and Findings Type de document : texte imprimé Auteurs : Sally BIGHAM, Auteur ; Jill BOUCHER, Auteur ; Andrew MAYES, Auteur ; Sophie ANNS, Auteur Année de publication : 2010 Article en page(s) : p.878-889 Langues : Anglais (eng) Mots-clés : Declarative-memory Recollection Familiarity Source-memory Recall Recognition Index. décimale : PER Périodiques Résumé : We hypothesise that of the two processes underlying declarative memory, recollection is impaired in high-functioning autism (HFA) whereas recollection and familiarity are impaired in low-functioning autism (LFA). Testing these hypotheses necessitates assessing recollection and familiarity separately. However, this is difficult, because both processes contribute to performance on standard memory tests. Moreover, tests must be suitable for use with young or intellectually disabled participants. This study aimed to develop tests of recollection and familiarity separately, and to make preliminary tests of our hypotheses. We developed a temporal source memory task to assess recollection in LFA, and a shape recognition task to assess familiarity and an action recall task assessing recollection in HFA. The methods and implications of the results are discussed. En ligne : http://dx.doi.org/10.1007/s10803-010-0937-7 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=107 [article] Assessing Recollection and Familiarity in Autistic Spectrum Disorders: Methods and Findings [texte imprimé] / Sally BIGHAM, Auteur ; Jill BOUCHER, Auteur ; Andrew MAYES, Auteur ; Sophie ANNS, Auteur . - 2010 . - p.878-889. Langues : Anglais (eng) in Journal of Autism and Developmental Disorders > 40-7 (July 2010) . - p.878-889 Mots-clés : Declarative-memory Recollection Familiarity Source-memory Recall Recognition Index. décimale : PER Périodiques Résumé : We hypothesise that of the two processes underlying declarative memory, recollection is impaired in high-functioning autism (HFA) whereas recollection and familiarity are impaired in low-functioning autism (LFA). Testing these hypotheses necessitates assessing recollection and familiarity separately. However, this is difficult, because both processes contribute to performance on standard memory tests. Moreover, tests must be suitable for use with young or intellectually disabled participants. This study aimed to develop tests of recollection and familiarity separately, and to make preliminary tests of our hypotheses. We developed a temporal source memory task to assess recollection in LFA, and a shape recognition task to assess familiarity and an action recall task assessing recollection in HFA. The methods and implications of the results are discussed. En ligne : http://dx.doi.org/10.1007/s10803-010-0937-7 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=107

Atypical Neurophysiology Underlying Episodic and Semantic Memory in Adults with Autism Spectrum Disorder / Esha MASSAND 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.298-315 Titre : Atypical Neurophysiology Underlying Episodic and Semantic Memory in Adults with Autism Spectrum Disorder Type de document : texte imprimé Auteurs : Esha MASSAND, Auteur ; Dermot M. BOWLER, Auteur Article en page(s) : p.298-315 Langues : Anglais (eng) Mots-clés : Memory  Episodic  Semantic  Source memory  Autism spectrum disorder  Event-related potential Index. décimale : PER Périodiques Résumé : Individuals with autism spectrum disorder (ASD) show atypicalities in episodic memory (Boucher et al. in Psychological Bulletin, 138 (3), 458–496, 2012). We asked participants to recall the colours of a set of studied line drawings (episodic judgement), or to recognize line drawings alone (semantic judgement). Cycowicz et al. (Journal of Experimental Child Psychology, 65, 171–237, 2001) found early (300 ms onset) posterior old–new event-related potential effects for semantic judgements in typically developing (TD) individuals, and occipitally focused negativity (800 ms onset) for episodic judgements. Our results replicated findings in TD individuals and demonstrate attenuated early old–new effects in ASD. Late posterior negativity was present in the ASD group, but was not specific to this time window. This non-specificity may contribute to the atypical episodic memory judgements characteristic of individuals with ASD. En ligne : http://dx.doi.org/10.1007/s10803-013-1869-9 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=258 [article] Atypical Neurophysiology Underlying Episodic and Semantic Memory in Adults with Autism Spectrum Disorder [texte imprimé] / Esha MASSAND, Auteur ; Dermot M. BOWLER, Auteur . - p.298-315. Langues : Anglais (eng) in Journal of Autism and Developmental Disorders > 45-2 (February 2015) . - p.298-315 Mots-clés : Memory  Episodic  Semantic  Source memory  Autism spectrum disorder  Event-related potential Index. décimale : PER Périodiques Résumé : Individuals with autism spectrum disorder (ASD) show atypicalities in episodic memory (Boucher et al. in Psychological Bulletin, 138 (3), 458–496, 2012). We asked participants to recall the colours of a set of studied line drawings (episodic judgement), or to recognize line drawings alone (semantic judgement). Cycowicz et al. (Journal of Experimental Child Psychology, 65, 171–237, 2001) found early (300 ms onset) posterior old–new event-related potential effects for semantic judgements in typically developing (TD) individuals, and occipitally focused negativity (800 ms onset) for episodic judgements. Our results replicated findings in TD individuals and demonstrate attenuated early old–new effects in ASD. Late posterior negativity was present in the ASD group, but was not specific to this time window. This non-specificity may contribute to the atypical episodic memory judgements characteristic of individuals with ASD. En ligne : http://dx.doi.org/10.1007/s10803-013-1869-9 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=258

Brief Report: Memory for Self-Performed Actions in Adults with Autism Spectrum Disorder: Why Does Memory of Self Decline in ASD? / Kenta YAMAMOTO in Journal of Autism and Developmental Disorders, 48-9 (September 2018)  

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Brief Report: Suboptimal Auditory Localization in Autism Spectrum Disorder: Support for the Bayesian Account of Sensory Symptoms / Joshua C. SKEWES in Journal of Autism and Developmental Disorders, 46-7 (July 2016)  

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Brief Report: The Role of Task Support in the Spatial and Temporal Source Memory of Adults with Autism Spectrum Disorder / Dermot M. BOWLER in Journal of Autism and Developmental Disorders, 45-8 (August 2015)  

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Creating a Unified Representation of Visual and Auditory Space in the Brain / Eric I. KNUDSEN in Annual Review of Neuroscience, 18 (1995)

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Development of Episodic Memory and Foresight in High-Functioning Preschoolers with ASD / Mika NAITO in Journal of Autism and Developmental Disorders, 50-2 (February 2020)  

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