Diagnosis via Brain Scans?

In order to identify the key systems that fail in autism, an understanding of the neural bases for typical language acquisition is needed. A study focused on this was conducted via sleep fMRI study of typical toddlers. In response to speech, typical toddlers in the study displayed extended networks of activation to complex speech information. Specifically, functional activity was prominent in a number of different frontal and cerebellar regions that are involved in social, emotional, attention, novelty detection or sequence tracking functions in adults, whereas activity in 3 year old typical children was prominent primarily in classic adult receptive language cortices. Reference: fMRI Studies, Autism Center of Excellence in a Redclay 2007 Study Autistic spectrum disorder is a lifelong condition caused by abnormalities in the development of the brain. The vast majority of these are male, and diagnosis usually involves a lengthy process of interviews and personal accounts from family and friends close to the patient.

Medical researchers compared the brain scans of 20 adults with autism against those of 20 adults without. They found significant differences in the thickness of tissue in parts of the grey matter in areas of the frontal and parietal lobes which are responsible for functions including behaviour and language.

In the experiment, Ecker showed that her imaging technique was able to detect which people in her group had autism, with 90% accuracy. "If we get a new case, we will also hopefully be 90% accurate," she said.

Reference:

Autism can be diagnosed with brain scan – study; Alok Jha,guardian.co.uk, Tuesday 10 August 2010

Another study focused on the cingulate gyrus in high-functioning autistic subjects. These subjects were studied under fMRI in simple social interactions. The task at hand was an iterated trust game in which two subjects take turns as investor or trustee. The investor chooses how much to money to invest. This chosen amount is tripled on its way to the trustee, and the trustee then chooses how much to repay to the investor.

Read Montague and his colleagues have studied this game extensively in large groups of volunteers and have observed a characteristic pattern of brain activity in the anterior cingulate cortex. When making an investment (self phase), transient increases in activity are seen in an area of mid cingulate cortex, the results suggest that the abnormality associated with autism is restricted to only one phase of the interactive game: the point where the autistic volunteer makes an investment, not the point where the autistic volunteer is told about the repayment made by their partner.

Additional results from Read Montague's group give further clues as to the implications of this result. First, the same pattern of activity in cingulate cortex is observed when volunteers are shown pictures of people engaged in athletic activities and asked to imagine themselves taking part. This is further evidence as to the nature of the cognitive process associated with this pattern of activity: it involves thinking about the self acting in a social context. Second, the characteristic patterns of activity in the cingulate cortex are only observed when the trust game is played with a human partner. No such distinct patterns emerge when the game is played in the absence of a responsive social partner...At least part of the imagining must involve thinking about how one would fit in with the group, and how other group members would evaluate one's performance. Actually, this is a question about the kind of reputation one might gain in the eyes of the others. Likewise, in the self phase of the trust game, the amount one invests can be seen as a measure of how much one trusts one's partner. It is not just giving an amount of money; it is giving a signal to the other person: “trust me” and “I trust you.

Reference:

Chiu P.H., Kayali M.A., Kishida K.T., Tomlin D., Klinger L.G., Klinger M.R., Montague P. .

Self Responses along Cingulate Cortex Reveal Quantitative Neural Phenotype for High-Functioning Autism

(2008) Neuron, 57 (3), pp. 463-473.