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: 10.26). 09/2007; 62(3):270-3. DOI: 10.1016/j.biopsych.2006.11.012
Source: PubMed


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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    • "Now, more studies pay more attention to Autism Spectrum Disorders (ASD) (Matsuura et al. 2008; Mirman et al. 2012) and Attention Deficit Hyperactivity Disorder (ADHD) (Duch and Dobosz 2011) patients. Previous studies showed that ASD persons had weak functional connections between the frontal lobe and the rest of the cortex (Murias et al. 2007), and a different brain structure in the prefrontal, striatal, cerebellar and thalamic circuits was found in ADHD individuals compared to controls (Krain and Castellanos 2006). Gamma-band oscillatory synchronization plays a key role in brain network integration and attention selection (Engel et al. 2001; Jensen et al. 2007). "

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    • "Ten healthy adults (six males, 21−31 years old) participated in the present study. All participants were right-handed as assessed by the Edinburgh Handedness Inventory (Murias et al., 2007). None had histories of neurological or psychiatric illnesses. "
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    • "This result was replicated by Chan et al. who found that the average quantitative EEG profile from a sample of 66 children with ASD showed significantly less relative alpha activity than the average profile from a sample of 90 children who did not have ASD [24]. In addition, Murias and colleagues [25] found less coherence between the frontal cortex and other brain areas in the alpha bandwidth in a sample of 18 adults with ASD, relative to a sample of 18 adults without ASD. Transcranial direct current stimulation (tDCS) provides a weak current, usually ranging from 1 to 2 mA to the scalp using large electrodes, usually for about 20 minutes at a time [26] [27]. "
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