"Here, we evaluate the hypothesis that decreased connectivity in high-functioning adolescents with an autism spectrum disorder relative to typically developing adolescents is concentrated within domain-specific circuits that are specialized for social processing. Using a novel whole-brain connectivity approach in functional magnetic resonance imaging, we found that not only are decreases in connectivity most pronounced between regions of the social brain but also they are selective to connections between limbic-related brain regions involved in affective aspects of social processing from other parts of the social brain that support language and sensorimotor processes."
"BACKGROUND: The autism rate has recently increased to 1 in 100 children. Genetic studies demonstrate poorly understood complexity. Environmental factors apparently also play a role. Magnetic resonance imaging (MRI) studies demonstrate increased brain sizes and altered connectivity. Electroencephalogram (EEG) coherence studies confirm connectivity changes. However, genetic-, MRI- and/or EEG-based diagnostic tests are not yet available. The varied study results likely reflect methodological and population differences, small samples and, for EEG, lack of attention to group-specific artifact.
RESULTS: Total sample PCA [principal components analysis] of coherence data identified 40 factors which explained 50.8% of the total population variance. For the 2- to 12-year-olds, the 40 factors showed highly significant group differences (P < 0.0001). Ten randomly generated split half replications demonstrated high-average classification success (C, 88.5%; ASD, 86.0%). Still higher success was obtained in the more restricted age sub-samples using the jackknifing technique: 2- to 4-year-olds (C, 90.6%; ASD, 98.1%); 4- to 6-year-olds (C, 90.9%; ASD 99.1%); and 6- to 12-year-olds (C, 98.7%; ASD, 93.9%). Coherence loadings demonstrated reduced short-distance and reduced, as well as increased, long-distance coherences for the ASD-groups, when compared to the controls. Average spectral loading per factor was wide (10.1 Hz)."
Dr. Gabriel Dichter presents a new review of fMRI research in ASD, noting common themes of atypical activation and functional connectivity in the brain.
Researchers find increased activation to social stimuli in brain regions involved in social perception in two children with ASD after pivotal response treatment (PRT).
This study uncovers a possible fMRI endophenotype of autism, showing that compared to typically developing controls with no family history of ASD, adolescents with autism and non-autistic siblings had atypical patterns of brain activation during the Embedded Figures Task.
This imaging study led by Carnegie Mellon researchers suggests adults with autism have unreliable neural responses when presented with basic sensory information.
Researchers officially announce the creation of the Autism Brain Imaging Data Exchange, a database of previously collected brain scans from over 15 medical and research institutions worldwide. The founders aim to advance scientific understanding of ASD through this data sharing initiative.
