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New MRI maps assess connectivity to establish “brain age” curve for children and adults

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brain connections maturity during developmentAs children grow, brambles of short brain connections are gradually pruned down to longer, stronger neural pathways. Research has shown this trend to follow a fairly standard curve during normal development to adulthood, and scientists are now using this information to create predictive models of brain maturation.

This approach allows for calculations of "brain age" that are based not on structural development, but rather on how well structures are communicating with each other. A new study, published online September 9 in Science, shows the new connection-based model to be at least 92 percent accurate in predicting whether a person was a child or an adult based just on the neural communication patterns in their brain.

The research team scanned the brains—using functional connectivity magnetic resonance imaging (fcMRI)—of 238 normally developing subjects aged 7 to 30, for five minutes. By comparing 200 of 12,720 key functional brain connections and assessing them through multivariate pattern analysis, researchers then predicted volunteer subjects’ developmental status.

Some groundwork for the approach was described in a 2009 study, published in PLoS Computational Biology, in which some of the same researchers described ways in which children’s brains were organized differently from those of adults. Younger brains, they had found, had more close connections among the more physically proximate brain areas, whereas older brains had stronger ties among brain regions that were far apart. This adult organization "lets you connect one node with another in a relatively short number of steps via special nodes," Damien Fair, of Oregon Health and Science University and lead author of that study, noted in a prepared statement last year.

The new analysis demonstrated that rather than resulting from a mix of trimming and building connections, development was most easily predicted (about 68 percent) by just the trimming of the vast number of childhood connections.

brain network longer connections in adultThe scientists behind the study liken this neural connection curve to the standard height and weight measurements kids get each time they go to the doctor for a check-up. "When the patient deviates too strongly from the standardized ranges or veers suddenly from one developmental path to another, the physician knows there’s a need to start asking why," Bradley Schlagger, a pediatric neurologist at Washington University in St. Louis and coauthor of the new study, said in a prepared statement. With enough fcMRI data across individuals at different developmental periods, the standard curve of a brain’s connectivity changes could be used to look for abnormalities, similar to the way in which doctors assess physical measurements—especially if a child is already showing other indications that something is amiss.

Children with cognitive irregularities are often already subjected to a barrage of tests, including MRI scans. But, as Schlagger pointed out, these scans are "typically looking at the data from a structural point of view—what’s different about the shapes of various brain regions." And in many instances, those tests can come back puzzlingly normal. Scientists have known for decades that connections among brain regions are just as important as the health of the regions themselves, and Schlagger’s new research has shown that "MRI also offers ways to analyze how different parts of the brain work together functionally," he noted in the recent prepared statement.

Testing is never cheap, but adding five minutes’ worth of fcMRI to assess brain connections "won’t add that much cost"—especially if a child is already undergoing scans to look for structural abnormalities, Nico Dosenbach, a pediatric neurology resident at St. Louis Children’s Hospital and lead author on the new paper, noted in a prepared statement.

Now that these baseline measurements have been established for a range of normal development, the team members hope to use the curve to study groups of individuals at risk for developmental disorders. "When a fraction of them later develop that disorder, you can go back and construct an analysis like this one that will help predict the characteristics of the next child at highest risk of developing the disorder," Schlagger said. And as a passive measurement it does not rely on a subject’s ability or willingness to perform a task, a common current gauge for different disabilities.

Such an approach might also eventually be able to help parse out a collection of indicators for various developmental disorders. "The beauty of this approach is that it lets you ask what’s different in the way that children with autism, for example, are off the normal development curve versus the way children with attention deficit disorder are off that curve," Schlagger said. "That’s very powerful both clinically and from the perspective of understanding the causes of these disorders."

Images of brain (with areas of connection that grow stronger with development are in orange and those that are weakened during maturation are in green) courtesy of Science/AAAS

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  1. 1. jtdwyer 4:26 pm 09/9/2010

    Great. So a new method of detecting Autism Spectrum Disorders can be developed so that a radiological technician can easily diagnose such developmental disorders my simply subjecting children exhibiting potential developmental disorders to a series of MRI examinations.

    If you’ve ever been subjected to an MRI examination, you’ll likely recall that they (most machines) place the subject in a claustrophobic enclosure for around 30 minutes with the huge machine generates high amplitude audio signals for the pleasure of the subject.

    So the difficult process of diagnosing developmental disorders can be greatly simplified, allowing the quick determination of the medications or other treatments that can be administered to the subject. Great.

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  2. 2. Shulamit 6:06 pm 09/10/2010

    As a person who has had a traumatic brain injury (at age 40, now I’m 46) this research makes me wonder if fcMRI’s could also help diagnose brain damage. I know that in the past six years, I’ve had to "relearn" how to think, how to remember, how to get places, how to organize my life…all the same kinds of things I had to learn as a child, becoming an adult.

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  3. 3. psychteacher 8:19 pm 09/10/2010

    My question is what do the colors really mean because the plus and minus don’t really tell me what they see.

    How exactly is measured? What is the magnetic field changing?

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  4. 4. claire_b 5:43 am 09/11/2010

    @Shulamit, yes there is research starting to look at using resting state fMRI in TBI populations, e.g. (Nakamura et al, 2009). There is also work looking at using fcMRI in diagnosis and monitoring of treatment response in other clinical populations e.g. Alzheimer’s disease, stroke survivors, schizophrenia… the list goes on. I’m using fcMRI to look at stroke recovery for my thesis. There have been a lot of papers coming out in this area in the last few years and the technique is starting to show a lot of potential as a clinical tool. @jtdwyer However as a clinician I still don’t think fcMRI is even remotely close to being an alternative to a comprehensive assessment by a neurologist, psychologist, psychiatrist, paediatrician, etc. I would think that ultimately this technique might become one of the different sources of information a doctor might use in making a diagnosis, along with blood tests, structural brain scans and of course clinical interview and examination.

    @psychteacher the positive and negative colours shows which areas of the brain show either positively or negatively correlated fluctuations of activity. It’s been shown repeatedly that well-known functionally important neural networks (e.g. motor network, language network, attention networks, etc) show synchronised activity even in the absence of overt task performance.

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  5. 5. jtdwyer 1:35 pm 09/11/2010

    claire_b – Thanks for your comment. It seems to me that, in particular, the diagnosis of increasing numbers of children with ASD (now including Asperger’s syndrome and High-functioning autism) is overwhelming the numbers of medically qualified diagnosticians, who are now searching for productivity aids, assistants, etc., to aid them in evaluating potential ‘sufferers’. This looks like just the thing…

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  6. 6. Shulamit 7:54 am 09/13/2010

    @claire_b, I am glad there is some research going into this area. I looked at the example you linked to, and it is interesting. And I understand your concerns about someone trying to use scans instead of comprehensive assessments by competent doctors in the appropriate fields. After my accident, the neurologist in the trauma center, where the ambulance took me, decided that I was *lying* when I said that I couldn’t control my left side, from my shoulder down, because there was no scan to back up my assertions. He actually accused me of lying to bolster a law suit.

    On the other hand, many doctors still believe that recovery from TBI happens mostly in the following 6 months to 2 years after the incident. Just judging from the experiences of the various folks in my TBI group at the hospital, it is clear that some people continue to improve over many years. However, improvement takes work. And if doctors don’t tell patients that they need to keep working, even 5-10 years out, they probably won’t keep working.

    If longitudinal fcMRI research was done on TBI survivors–particularly "mild" brain damaged folks who seem to have considerably more than "mild" negative repercussions to their injuries–perhaps scans could alert doctors to aspects of healing from TBI that they previously did not recognize (or did not believe, so didn’t look for it).

    Just like children growing up takes years, I am convinced (from my own experience, as well as seeing other TBI survivors) that recovery from TBI takes years, and requires direct attention for improvement to happen.

    Mental, social, emotional, physical, and executive functioning, all need to be directly addressed in adults who have suffered deficits in these areas due to TBI (and probably due to strokes, too). I could be wrong, but from the description in this article, it seems to me that fMRI’s and fcMRI’s could help show such longitudinal changes, even when scans taken shortly after the TBI event, do not show obvious insult to the brain tissue.

    Last thought: a young adult (say, age 27) who sustains a TBI, could have a series of fcMRI’s done, and compare them to age-mates, and see if the TBI seems to have caused a loss of "maturity" according to scans of comparable age-mates.

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  7. 7. verdai 6:25 pm 09/17/2010

    it’s nice to know that adults can take shortcuts and delete connections no longer needed.
    keeping it clear.

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