The scientific data building around autism has been growing fast and furious. Most studies done, in terms of methodology, have, in some fashion, compared and contrasted populations of autistic and non-autistic individuals. Researchers in a new study, whose peer-reviewed results have been published in the latest issue of The American Journal of Psychiatry have tried a different approach. The results of their study, and the methodology used are special enough to have been highlighted in an editorial in the Journal.
More below the fold:
(First, for those who would prefer to examine the study and editorial directly, links are provided here and here, respectively. I will be briefly paraphrasing the study; I encourage anyone with a serious interest to click on the links.)
The researchers, in a novel twist, elected to examine brain activity in a population consisting solely of non-autistic individuals. Even NTs may have autistic traits. The study focussed on how the degree of autistic traits in these non-autistic individuals related to the functional relationship between two specific areas of the brain. (For those who, unlike me, might understand the significance of the two areas chosen to study, they are the pregenual anterior cingulate and the anterior mid-insula.)
In order to identify autistic traits in non-autistic individuals, the researchers used the Social Responsiveness Scale, which is a questionnaire with 65 questions. This questionnaire is designed to measure the severity and type of social impairments which are characteristic of autistic spectrum conditions. Even individuals who are not autistic may exhibit autistic social impairment on some level.
What did the researchers find? Quoting from the editorial:
To briefly summarize their main result, Di Martino and colleagues found that functional connectivity between the pregenual anterior cingulate cortex and anterior mid-insula was sensitive to the level of autistic traits across a sample of nonautistic individuals. Those with higher levels of autistic traits had lower functional connectivity, while those with lower levels of autistic traits had greater functional connectivity. Based on previous research and the pattern of anterior cingulate-insula connectivity they identified in their present study, the authors speculate that the anterior mid-insular region might serve as a transition zone between the anterior insula and posterior insula, regions thought to be involved in social and emotional cognition and somatic representation, respectively.
Now, an important part of the study's structure is that it focusses on the brain at rest. This may prove to be an important feature, as further studies examine autistic populations in light of the connectivities found. Current studies, in demanding complex tasks, may skew toward selecting higher functioning autistics, who are better able to comply, as part of a study population. If the only requirement is for a study subject to simply remain still, it may allow for a more diverse sample of subjects to be chosen.
As the authors point out, the significance of their findings for understanding autism is unknown at present and will only be borne out by additional studies that include an autism sample. However, being able to quantify the degree of autistic traits in the general population along side those with autism might yield important insight into the nature of autism. For instance, it is presently unclear whether autism represents an extreme end of a continuum within the general population or whether the diagnosis represents both a qualitative and quantitative rift from typical development. If the former were true, one might expect to see a continuation of the brain-behavior relationship identified in the Di Martino study that spans across diagnostic category. If the latter were true, however, one might expect to find a distinct brain-behavior relationship within each group (autism versus comparison).
The implications of this study, and the methodology used, open up new and exciting vistas to be explored, as we nail down what autism is, and how it manifests. And it poses the revolutionary idea that the autistic continuum is simply a subset of the overall continuum, rather than separate from it. Perhaps that will enable us to move to a day when autistics are treated more like "who", and less like "what".