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New report links autism to the ‘extreme male brain'

Dr. Simon Baron-Cohen Research
April 23, 2007

In the November 4th issue of Science, NAAR-funded researcher Dr. Simon Baron-Cohen and his colleagues at Cambridge University presented their theory of autism suggesting that behaviors observed in autism spectrum disorder may be a representation of exaggerated male characteristics. This report summarized the ‘extreme male brain' (EMB) theory, which is based on the idea that males are weaker “empathizers” (feeling of concern for another's emotional state and generation of appropriate response) and stronger “systemizers” (ability to analyze a situation based on a series of rules and predict outcome based on those rules). The EMB theory extends this idea, suggesting that autism may reflect an extreme impairment in empathizing coupled with a superior ability to systemize. Furthermore, his group presented evidence that these differences in psychological functioning have a neurobiological basis, as males and females show differences in brain structure and function. One possible mechanism proposed by the researchers is different prenatal exposure to hormones which contribute to neurobiological development, leading to these differences in behavior. This study points to the relationship between changes in testosterone levels during development with behaviors linked to autism, including eye contact and social functioning. More information on this article can be found


In order to examine this intriguing idea further, NAAR recently awarded Dr. Douglas Portman a pilot grant award to study genes which control sexual differentiation in an animal model. Dr. Portman's group has identified genes in this model which are specific to the male species, and the pilot grant award will allow his research team at the University of Rochester to explore the neurobiological and behavioral consequences of mutations to these genes. By using this innovative approach, the contribution of these genes to brain function and male specific behaviors, as well as what factors may control the expression of these genes can be studied in a more specific way. Because autism is more common in males compared to females, knowledge of genetic contributions to neural development in males is crucial to a better understanding of the disorder.

Established in 1994, the National Alliance for Autism Research (NAAR) is the first non-profit organization in the country dedicated to funding and accelerating biomedical research for autism spectrum disorders. The organization was established by parents of children with autism concerned about the limited amount of funding for autism research. To date, NAAR has committed nearly $30 million in grants for biomedical research projects worldwide that seek to find the causes, prevention, effective treatments and, ultimately, cure for autism spectrum disorders. Walk for Autism Research is the organization's signature fundraising and autism awareness event, which is held annually in numerous communities across the United States. Additionally, NAAR was instrumental in establishing the Autism Tissue Program, a parent-led brain tissue donation program for autism research.