Pure Pedantry

The title of this pre-publication paper is, “Evidence on the emergence of the brain’s default network from 2-week-old to 2-year-old healthy pediatric subjects.” The authors put kids in functional MRIs to measure resting state activity and detect the emergence of the default network.

While I am certain that it is very interesting research, I have a more technical question: minus sedation, how in Heaven’s name did they get the kids to sit still long enough to collect the data? An fMRI is hardly a crib decorated with puppies and ducklings. You feel like you are about to be shot out of a torpedo tube, and the whole thing is about as loud as being face first in the speakers at a Kiss concert. How did they get the two years-olds to put up with that?

Ideas?

Comments

  1. #1 Lurker
    April 9, 2009

    The pair of headset used in fMRI sound experiment offer some protection against the noise (or more accurately, the rack-a-boom-boom) so if I where to do a similar experiment, I’d use the headset (without music or anything to listen) along with earplugs and hope for the best but please keep in mind that I only participated in such a study (well, mine had sound to listen to…) but never designed one.

    another thing to keep in mind, I enjoyed the whole experiment except the part where a static (structural?) image of my brain was taken; that part made me really anxious…

  2. #2 Kevin H
    April 10, 2009

    the sound isn’t a real problem. It’s loud-ish but good headphones with some earplugs drop everything down to ~70-80dB, certainly manageable.

    The real problem is motion. anything over a few mm seriously starts to impact the quality of the data.

    how did they deal with that? titanium head screws?

    actually looking at the paper they only ran the kids for about 10 minutes each (they don’t actually say how long, but they took 150 epis, which usually take ~2sec each to get a full brain on an adult). so clean data shouldn’t be that hard to come by if they are calm or sleepy when you put them in.

  3. #3 Angela Staples
    April 10, 2009

    I’m not sure about the infants, but Dr. Karin James (http://www.indiana.edu/~canlab/dipmain/What_to_Expect.html) has been successful in running children 4-8 years by treating the fMRI machine as a space ship adventure. The little kids are usually up for this kind of pretend adventure. If I remember correctly there was a movie that played when the children had to be still for the actual scan.

    In an earlier version of Dr. James’ work, children learned to stay still in a practice space ship. She did this by having a movie turn off ever time the child moved. Children quickly learn that they needed to stay still if they wanted the movie to continue. This approach would probably work with most 2 year olds and even younger toddlers (18-24months). Again, I’m not sure about the under-12-month group since I don’t work with that population.

    I would be interested in knowing how many children they were unable to run given the small space, loudness of the machine (even with headphones), and the requirement for being still…

  4. #4 bsci
    April 10, 2009

    The main text says: None of the subjects was sedated for MRI. Before the subjects were imaged, they were fed, swaddled, and fitted with ear protection. All subjects slept during the imaging examination.

    From the supplemental material: In addition, subjects experiencing excessive head motion during scan were also excluded. Kids who didn’t keep their heads still weren’t used. They don’t give their percent exclusion rates, which I think should have been included since it would be vital information in trying to plan a replication of the study.

  5. #5 Will Moore
    April 29, 2009

    In some scanners, there is a head motion detection device that can be linked up with whatever video the subjects are watching. If the head motion passes a certain threshold, the video pauses automatically. Kids learn that to keep the video playing, they have to hold perfectly still.

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