| Reference code: | PT/FB/BL-2012-132.17 |
| Location: | Arquivo PCA - Pasta 11/2012
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Title:
| Abnormal neuronal oscillations in ASD are specific to stimuli requiring holistic processing
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| Publication year: | 2017
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URL:
| https://ww5.aievolution.com/hbm1701/index.cfm?do=abs.viewAbs&abs=2167
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| Abstract/Results: | ABSTRACT:
INTRODUCTION:
Autism spectrum disorder (ASD) subjects have impaired face recognition and emotional expression identification (Greimel et al. 2014). Some studies have revealed impaired gamma-band responses with reduced coherence for a broad range of perceptual and visuomotor tasks and in particular deficits in simple sensory and complex cognitive tasks requiring holistic processing (Richard 2012; Sun et al. 2012; Buard et al. 2013). Emerging evidence suggests that the deficits in ASD may be related to sensory integration problems and can be explained by abnormal neuronal oscillations (Peiker et al. 2015). We add to previous work by asking whether changes in gamma-band power and synchrony are either specific to stimuli requiring sensory integration or a more general deficit not only related to holistic processes.
METHODS:
We investigated the neural correlates of these phenomena by measuring EEG in high-functioning adults with ASD (n=9; age M=23.1 years; SD=7.04; Full scale IQ>70) and healthy controls (n=16; age M=23.4 years; SD=5.06), during a face decision task. Subjects had a two choice decision (is it a face? Yes or No). The task included a comprehensive set of photographic, schematic and Mooney (which can only be processed holistically) upright and inverted faces, and scrambled images. The 40 channel NuAmps system (Compumedics, Neuroscan) with a 1kHz sampling rate was used. Data were analyzed offline in the time-frequency domain (EEGLAB toolbox v13.6.5b) and a bootstrap approach was applied for statistical comparison of groups. In a subset (n=5) of ASD patients we also acquired Magnetic Resonance Neurospectroscopy (3T Siemens Trio) in a 3x3x3cm voxel located in the bilateral medial prefrontal cortex using MEGA-PRESS for quantification of gamma-aminobutyric acid (GABA) (inhibition) and glutamate (excitation). MRS data was quantified using LCModel software and in-house developed software was used for correction of metabolites concentration for the CSF content of the voxel. The spearman correlation was computed between metabolites concentration and power parameters.
RESULTS:
Behaviorally, ASD and healthy controls were performance matched. Time-frequency data analysis revealed a burst of activity around 200ms replicating previous EEG results with Mooney stimuli (Rodriguez et al. 1999). We found significant differences between groups for three main categories of frequency bands (p<0.001 with bootstrap 1000, 95%). ASD have increased power for the lower band 10-30Hz (Mooney faces upright and inverted faces conditions) but decreased power at 30-45Hz and 55-80Hz (Mooney faces upright and inverted) in comparison to controls. That increase in power was accompanied by a decrease in synchrony for the 10-30Hz band. Interestingly we found a positive correlation (r=0.829, p=0.042) between GABA/Glutamate ratio and power of ambiguous conditions at 30-45Hz in patients.
CONCLUSIONS
We found that abnormal oscillations are specific of conditions requiring holistic integration and thus may be a consequence of cortical E-I (excitation vs inhibition) imbalance and their impact on binding mechanisms and might ultimately constitute a new construct of a biomarker for ASD.
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| Accessibility: | Document does not exist in file
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Language:
| eng
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Author:
| Castelhano, J.
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Secondary author(s):
| Tavares, P., Mouga, S., Pereira, A., Giomar, O., Castelo-Branco, M.
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Document type:
| Online abstract
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Number of reproductions:
| 1
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Reference:
| Castelhano, J., Tavares, P., Mouga, S., Pereira, A., Giomar, O., & Castelo-Branco, M. (2017, June). Abnormal neuronal oscillations in ASD are specific to stimuli requiring holistic processing. Poster presented at the 2017 Annual Meeting of the Human Brain Mapping, Vancouver, Canada. Abstract retrieved at https://ww5.aievolution.com/hbm1701/index.cfm?do=abs.viewAbs&abs=2167
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| Indexed document: | No
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| Keywords: | Autism / Electroencephalogram (EEG) / GABA
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