White Matter Abnormalities in Autism and Unaffected Siblings.

This study was conducted to identify a potential neuroendophenotype for autism using diffusion tensor imaging. Whole-brain, voxel-based analysis of fractional anisotropy was conducted in 50 children: 19 with autism, 20 unaffected siblings, and 11 controls. Relative to controls, participants with autism exhibited bilateral reductions in fractional anisotropy across association, commissure, and projection fibers.

Brain Mechanisms for Processing Affective (and Nonaffective) Touch Are Atypical in Autism.

C-tactile (CT) afferents encode caress-like touch that supports social-emotional development, and stimulation of the CT system engages the insula and cortical circuitry involved in social-emotional processing. Very few neuroimaging studies have investigated the neural mechanisms of touch processing in people with autism spectrum disorder (ASD), who often exhibit atypical responses to touch. Using functional magnetic resonance imaging, we evaluated the hypothesis that children and adolescents with ASD would exhibit atypical brain responses to CT-targeted touch.

Neural mechanisms of improvements in social motivation after pivotal response treatment: two case studies.

Pivotal response treatment (PRT) is an empirically validated behavioral treatment that has widespread positive effects on communication, behavior, and social skills in young children with autism spectrum disorder (ASD). For the first time, functional magnetic resonance imaging was used to identify the neural correlates of successful response to PRT in two young children with ASD. Baseline measures of social communication, adaptive behavior, eye tracking and neural response to social stimuli were taken prior to treatment and after 4 months of PRT.

Autistic traits are associated with diminished neural response to affective touch.

'Social brain' circuitry has recently been implicated in processing slow, gentle touch targeting a class of slow-conducting, unmyelinated nerves, CT afferents, which are present only in the hairy skin of mammals. Given the importance of such 'affective touch' in social relationships, the current functional magnetic resonance imaging (fMRI) study aimed to replicate the finding of 'social brain' involvement in processing CT-targeted touch and to examine the relationship between the neural response and individuals' social abilities. During an fMRI scan, 19 healthy adults received alternating blocks of slow (CT-optimal) and fast (non-optimal) brushing to the forearm.

Brain mechanisms for processing affective touch.

Despite the crucial role of touch in social development, there is very little functional magnetic resonance imaging (fMRI) research on brain mechanisms underlying social touch processing. The "skin as a social organ" hypothesis is supported by the discovery of C-tactile (CT) nerves that are present in hairy skin and project to the insular cortex. CT-fibers respond specifically well to slow, gentle touch such as that which occurs during close social interactions.

Neural signatures of autism.

Functional magnetic resonance imaging of brain responses to biological motion in children with autism spectrum disorder (ASD), unaffected siblings (US) of children with ASD, and typically developing (TD) children has revealed three types of neural signatures: (i) state activity, related to the state of having ASD that characterizes the nature of disruption in brain circuitry; (ii) trait activity, reflecting shared areas of dysfunction in US and children with ASD, thereby providing a promising neuroendophenotype to facilitate efforts to bridge genomic complexity and disorder heterogeneity; and (iii) compensatory activity, unique to US, suggesting a neural system-level mechanism by which US might compensate for an increased genetic risk for developing ASD. The distinct brain responses to biological motion exhibited by TD children and US are striking given the identical behavioral profile of these two groups. These findings offer far-reaching implications for our understanding of the neural systems underlying autism.