Study Finds Neural Phenotype for High-Functioning Autism

Chiu and others researchers at Baylor College of Medicine in Houston carried-out studies with high-functioning males with autism spectrum disorder (ASD) using fMRIs.[1]

Of the many symptoms that characterize those who have been diagnosed with an ASD, probably the most prominent one is the inability to properly respond to social signals emitted by other individuals. The goal of the study was to form a neural standard basis set for the cingulate response and use it to assess the responses of the ASD group.

Using a previously well studied multi-round trust game, the study found that high-functioning ASD males “lack a neural activation pattern in cingulate regions previously shown to encode robust self-specific responses. In stark contrast with the missing self response, the ASD cingulate cortex responded normally when shown a social partner’s decision.”

During the game responses were measured just after the individual takes his turn (self responses) and measured again after the individual learns the action his partner has taken (other responses). In both control groups, the age and IQ adjusted group and the behavior adjusted group, the cingulate cortex produces a response for both the self and other responses. See Figures 1 through 4.

Figure 1. Image shows the response along the medial bank of cingulate cortex after the revelation of a partner’s decision (‘‘other’’ response pattern) for age and IQ matched controls (n = 18).*	Figure 2. Image shows the subsequent response along the medial bank of cingulate cortex following the submission of one’s own decision (‘‘self’’ response pattern) for age and IQ matched controls (n = 18).*
Figure 3. Image shows the response along the medial bank of cingulate cortex after the revelation of a partner’s decision (‘‘other’’ response pattern) for behavior matched controls (n = 15).*	Figure 4. Image shows the subsequent response along the medial bank of cingulate cortex following the submission of one’s own decision (‘‘self’’ response pattern) for behavior matched controls (n = 15).*

In the ASD group, the cingulate cortex produces a response for the other responses, but a severely diminished response for the self responses. See Figure 5 and 6.

Figure 5. Image shows the response along the medial bank of cingulate cortex after the revelation of a partner’s decision (‘‘other’’ response pattern) for ASD adolescents (n = 12).*	Figure 6. Image shows the subsequent response along the medial bank of cingulate cortex following the submission of one’s own decision (‘‘self’’ response pattern) for ASD adolescents (n = 12).*

The study’s authors suggest the reason for the intact other response “may reflect cingulate functions related less to intuiting others’ social intent than observations of others’ acts.”

The inability of individuals with ASD to represent the social intent of their own behaviors by delineating “their own intentions are likely unable to attribute the social goals or intentions of others.”

The diminishment of the self response varies inversely with the assessed symptom severity, suggesting its value as an objective endophenotype.

*Note: Composite Image using data from Figure 6 [1] and brain imaging from Linder [2].

[1] Pearl H. Chiu, M. Amin Kayali, Kenneth T. Kishida, Damon Tomlin, Laura G. Klinger, Mark R. Klinger, and P. Read Montague; Self Responses along Cingulate Cortex Reveal Quantitative Neural Phenotype for High-Functioning Autism; Neuron; Volume 57, Issue 3, Pages 463–473; February 7, 2008.

[2] Christian R. Linder; MRI Saggital transection through the human brain; Wikimedia Commons; 20001013. Accessed 20080208.
http://commons.wikimedia.org/wiki/Image:Brain_chrischan.jpg

~ by Phoenix on February 9, 2008.