80 fMRI studies of communication functions in ASDs have used tasks requiring listening to speech sounds,54,81,82 sentence comprehension,83-85 verbal fluency,86 pragmatic language comprehension,87 semantic judgments,88 responsenaming,89 and viewing body gestures90-91 (Table IV). Overall, findings indicate differential
lateralization patterns in ASDs (ie, reduced left > right lateralization),82,84,86,87,89 decreased synchrony of brain regions processing language,83,92 decreased automaticity of language processing,93 greater neurofunctional deficits for speech than songs,94 and recruitment of brain regions that do not typically process language.83,95-97 A recent methodological innovation in the domain of language-based Inhibitors,research,lifescience,medical fMRI studies in ASDs has been to present speech stimuli to veryyoung children with ASDs (as young as 12 months old) while asleep.82,98 Although the diagnostic stability of ASDs for children in this age range must be considered, this approach has the potential to leverage task-based fMRI in far younger Inhibitors,research,lifescience,medical children with ASDs to examine altered developmental trajectories associated with impaired receptive language skills. Additionally, sleep fMRI would appear to be well suited to studying early emerging functional
brain activation properties linked to Inhibitors,research,lifescience,medical speech processing in infant high-risk paradigms. Table IV Studies investigating communication in autism spectrum disorders. ASD: Autism Spectrum Disorder; TYP: Neurotypical; Inhibitors,research,lifescience,medical †ASD refers to the entire autism sample in a particular study, including high functioning autism, Asperger’s syndrome, and pervasive … Reward processing The social-communication deficits that characterize ASDs may reflect decreased motivation to engage in social behaviors in early childhood. This decreased motivation may result in fewer experiences with the social environment,99 further compounding social-communicative deficits.100 Reward processing is mediated primarily by dopaminergic projections from the ventral tegmental Inhibitors,research,lifescience,medical area
to the striatum, orbitofrontal cortex, ventromedial prefrontal cortex, and the anterior cingulate cortex, forming Mannose-binding protein-associated serine protease a mesolimbic dopamine reward pathway.101 Emerging evidence suggests that the Sorafenib neural circuits that mediate reward processing may have evolved, at least in part, to facilitate social attachment,102 and reward mechanisms serve to encode and consolidate positive memories of social experiences, facilitating social functioning abilities hypothesized to be impaired in ASDs.103 Reward processing deficits in ASDs have been assessed in six fMRI studies to date (Table V). Schmitz and colleagues104 reported decreased left anterior cingulate gyrus and left midfrontal gyrus activation to rewarded trials during a sustained attention task in ASDs and that anterior cingulate gyrus activation predicted social symptom severity.