Resting State Cortical Connectivity Reflected in EEG Coherence in Individuals With Autism

University of Washington Autism Center, Seattle, Washington 98195, USA.
Biological Psychiatry (Impact Factor: 10.25). 09/2007; 62(3):270-3. DOI: 10.1016/j.biopsych.2006.11.012
Source: PubMed

ABSTRACT Theoretical conceptions of autism spectrum disorder (ASD) and experimental studies of cerebral blood flow suggest abnormalities in connections among distributed neural systems in ASD.
Functional connectivity was assessed with electroencephalographic coherence between pairs of electrodes in a high-density electrode array in narrow frequency bands among 18 adults with ASD and 18 control adults in an eyes closed resting state.
In the theta (3-6 Hz) frequency range, locally elevated coherence was evident for the ASD group, especially within left hemisphere frontal and temporal regions. In the lower alpha range (8-10 Hz), globally reduced coherence was evident for the ASD group within frontal regions and between frontal and all other scalp regions. The ASD group exhibited significantly greater relative power between 3 and 6 Hz and 13-17 Hz and significantly less relative power between 9 and 10 Hz.
Robust patterns of over- and under-connectivity are apparent at distinct spatial and temporal scales in ASD subjects in the eyes closed resting state.

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Available from: Michael Murias, Sep 01, 2015
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    • "In autistic children, perception of emotional faces is impaired, hence, the speed of processing a stimulus is decreased [40]. This may be due to changes in the brain's functional and effective structure which has been shown using EEG studies [45]. Increase in the theta band coherence between the left frontal and temporal regions and decrease in the lower alpha band coherence between frontal region and other parts of the brain have been reported in ASD. "
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    • "Coherence studies in ASD have primarily examined lower frequency bands (i.e. delta, theta, alpha, and beta) and have shown both increased and decreased coherence across unique frequencies [Coben, Clarke, Hudspeth, & Barry, 2008; Murias, Webb, Greenson, & Dawson, 2007]. "
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    • "These findings could explain why cognitive deficits associated with ADHD and ASD often seem to fall within the domain of self-regulation and executive function (Barkley 1997). Furthermore, combined EEG-fMRI studies have indicated a negative relationship between theta power and BOLD signal in the ACC (Meltzer et al. 2007), supporting the view that theta activation in children with ASD is directly associated with under-activation of the ACC (Murias et al. 2007). Hence, our study targeted an electrophysiological component and an associated neural structure which have repeatedly been implicated in ASD. "
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