Proton magnetic resonance spectroscopic imaging of the brain in childhood autism.
ABSTRACT Autism is a developmental disorder of unknown neurologic basis. Based on prior work, we used proton magnetic resonance spectroscopic imaging ((1)H- MRSI) to investigate brain structures, including cingulate and caudate, that we hypothesized would reveal metabolic abnormalities in subjects with autism.
In 22 children with autism, 5 to 16 years old, and 20 age-matched healthy control subjects, (1)H-MRSI assessed levels of N-acetyl compounds (NAA), choline compounds (Cho), and creatine plus phosphocreatine (Cr) at 272 msec echo-time and 1.5 T.
In subjects with autism compared with control subjects, Cho was 27.2% lower in left inferior anterior cingulate and 19.1% higher in the head of the right caudate nucleus; Cr was 21.1% higher in the head of the right caudate nucleus, but lower in the body of the left caudate nucleus (17.9%) and right occipital cortex (16.6%).
Results are consistent with altered membrane metabolism, altered energetic metabolism, or both in the left anterior cingulate gyrus, both caudate nuclei, and right occipital cortex in subjects with autism compared with control subjects.
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ABSTRACT: Research indicates that individuals with autism spectrum disorders (ASD) may have a reduced ability to utilize performance feedback to regulate their behavior; however, it is unclear to what degree alterations in the environmental context affect feedback processing and contribute to the symptoms of ASD. We utilized the observational FRN (oFRN), an event-related potential (ERP) component that putatively indexes feedback processing while observing feedback directed toward another person, to examine the influence of motivational and social demands on feedback processing in ASD. High-density electroencephalogram recordings were collected from 38 youth with ASD and 31 control participants similar on age and IQ while they observed a confederate performing a modified Eriksen Flanker task. Participants were instructed to count the confederate’s errors and were told they would be awarded based on performance: the confederate would either earn points for the participant or herself. Both groups showed robust oFRN activity on traditional scalp-electrode waveforms and waveforms identified using temporospatial principal components analysis. Amplitude of oFRN did not differentiate groups. Results remained non-significant when comparing medicated to non-medicated participants. There were no significant correlations between oFRN amplitudes, autism symptom severity, and anxiety symptoms. Findings suggest that the social context of the task and motivational significance of the confederate’s performance did not limit feedback processing in ASD. Future research in which the context is manipulated further is warranted to determine whether increased environmental complexity influences feedback processing in ASD.International journal of psychophysiology: official journal of the International Organization of Psychophysiology 04/2014; DOI:10.1016/j.ijpsycho.2014.01.009 · 2.65 Impact Factor
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ABSTRACT: A new virtual reality task was employed which uses preference for interpersonal distance to social stimuli to examine social motivation and emotion perception in children with Autism Spectrum Disorders. Nineteen high function children with higher functioning Autism Spectrum Disorder (HFASD) and 23 age, gender, and IQ matched children with typical development (TD) used a joy stick to position themselves closer or further from virtual avatars while attempting to identify six emotions expressed by the avatars, happiness, fear, anger, disgust, sadness, and surprise that were expressed at different levels of intensity. The results indicated that children with HFASD displayed significantly less approach behavior to the positive happy expression than did children with TD, who displayed increases in approach behavior to higher intensities of happy expressions. Alternatively, all groups tended to withdraw from negative emotions to the same extent and there were no diagnostic group differences in accuracy of recognition of any of the six emotions. This pattern of results is consistent with theory that suggests that some children with HFASD display atypical social-approach motivation, or sensitivity to the positive reward value of positive social-emotional events. Conversely, there was little evidence that a tendency to withdraw from social-emotional stimuli, or a failure to process social emotional stimuli, was a component of social behavior task performance in this sample of children with HFASD.Journal of Autism and Developmental Disorders 01/2014; DOI:10.1007/s10803-014-2036-7 · 3.06 Impact Factor
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ABSTRACT: ObjectiveThalamic abnormalities have been reported in people with pervasive developmental disorders (PDD) including Asperger's Disorder (ASP). The aim of the present study was to compare the volume and volume fraction of the thalamus and the metabolite concentrations in children and adolescents with ASP using the magnetic resonance imaging and proton magnetic resonance spectroscopy. Additionally, the relationships between thalamic abnormalities and clinical features were examined.MethodsVolume and volume fractional and metabolic measurements of bilateral thalamus were collected from 15 boys with ASP with a total IQ over 70 (age range 7-18 years, mean age 11.6±3.79 years), and 15 healthy controls matching age, sex and IQ. The thalamic volumes, hemisphere volumes and total brain volumes (TBV) were estimated using the stereological methods on magnetic resonance images. Chemical metabolites of thalamus were evaluated by 1H spectroscopy.ResultsNo differences in thalamic volumes, volume fractions and metabolites were observed between the groups. There were significant correlation between thalamic volume and total brain volume in both groups. The ASP group showed a significant left-minus-right thalamus difference as well as a significantly greater laterality index. In addition, a significant correlation between the laterality index and Autism Behavior Checklist language scores was observed.ConclusionFindings from this investigation point to a significant increase in laterality of the thalamus and a relationship with language problems in individuals with ASP. Our findings suggest that thalamic abnormalities may be related to mild language problems observed in ASP.Psychiatry investigation 07/2014; 11(3):237-42. DOI:10.4306/pi.2014.11.3.237 · 1.15 Impact Factor