Defining the broader phenotype of autism: Genetic, brain, and behavioral perspectives

Abstract

Achieving progress in understanding the cause, nature, and treatment of autism requires an integration of concepts, approaches, and empirical findings from genetic, cognitive neuroscience, animal, and clinical studies. The need for such integration has been a fundamental tenet of the discipline of developmental psychopathology from its inception. It is likely that the discovery of autism susceptibility genes will depend on the development of dimensional measures of broader phenotype autism traits. It is argued that knowledge of the cognitive neuroscience of social and language behavior will provide a useful framework for defining such measures. In this article, the current state of knowledge of the cognitive neuroscience of social and language impairments in autism is reviewed. Following from this, six candidate broader phenotype autism traits are proposed: (a) face processing, including structural encoding of facial features and face movements, such as eye gaze; (b) social affiliation or sensitivity to social reward, pertaining to the social motivational impairments found in autism; (c) motor imitation ability, particularly imitation of body actions; (d) memory, specifically those aspects of memory mediated by the medial temporal lobe–prefrontal circuits; (e) executive function, especially planning and flexibility; and (f) Language ability, particularly those aspects of language that overlap with specific language impairment, namely, phonological processing.

ERP Evidence of Atypical Face Processing in Young Children with Autism

“…These two reports utilize the same population of children, but employed different stimuli sets. For the autism group, the faster neural response to objects relative to faces could be interpreted as preferential or altered processing abilities for nonsocial as compared to social stimuli (Dawson, Meltzoff, Osterling, & Rinaldi, 1998;Dawson et al, 2003). Further replication of these paradigms with another sample of children will be needed.…”

Strategies for Conducting Research on Language in Autism

“…Within the field of autism there is growing appreciation of the importance of studying the heterogeneity that is found across the spectrum of this disorder in all aspects of cognition as well as language (Dawson et al, 2002;Happé, 2003;Tager-Flusberg & Joseph, 2003). As illustrated here, by directly investigating heterogeneity we can identify more homogenous subtypes within the population.…”

Brief Report: Perceptual Load and the Autism Spectrum in Typically Developed Individuals

“…There is evidence that the spectrum may also extend into the nonclinical population (Dawson et al 2002). The Autism Spectrum Quotient (AQ; Baron-Cohen et al 2001) can detect diagnosed individuals but is also sensitive to variation of non-clinical autistic traits and does not correlate with overall IQ (Baron-Cohen et al 2001).…”