In recent years, scientists have used magnetic-resonance imaging to map out the brain and identify the physical processes behind emotions, memories, trauma and more. Now a scientist at Brown University wants to use MRI to demystify early-childhood brain development.
Sean Deoni, assistant professor of engineering, has won a $2.5 million, five-year grant from the National Institute of Mental Health to do MRI scans of children ages 2 months to 5 years, focusing on myelination – the formation of a fatty layer around brain neurons and fibers that is crucial in developing effective communication pathways in the brain.
Deoni will collaborate with another NIMH award recipient, Dr. Daniel Dickstein, an assistant professor of psychiatry and human behavior and head of the Pediatric Mood, Imaging and Neurodevelopment (Pedi-MIND) program at Bradley Hospital.
Deoni recently spoke with Providence Business News about his project and the science and technology behind it.
PBN: You have developed a specialized MRI technique you’ll be using in your study. How does it work?
DEONI: MRI is based on imaging water – the [hydrogen] protons attached to the water molecules are what gives us our signal. … Via imaging, we acquire signals from a number of different points, and we normally think of that signal to be a single water pool. But if you look down a microscope, you know that’s not true – water is compartmentalized into all sorts of little structures. Within the brain, we have water within the cells, inside and outside the axon, and, more importantly, trapped within this lipid myelin bilayer that surrounds the axon. The more tightly water protons are bound, the more rapidly the signal they give off decays over time … and within the myelin sheath, the water is very tightly bound, whereas inside the axon or outside the axon, the protons are relatively free. … So what we’ve come up with is a way to preferentially image the signal associated with the myelin water, and thereby quantify the amount of myelin.
DEONI: Myelin is really essential for rapid communication between brain regions. It’s like the electrical insulator on electric wire. When you take it off, the electrical impulses travel much more slowly, and as a result, any sort of coordinated movement or function that requires different brain areas becomes impaired.
When we’re born, we come out of the womb with virtually no myelin … [and] over time, in about the first year or two, there’s a rapid process where most of the white matter axons get myelinated. … There’s a hypothesis that if this process is disrupted, it’s going to lead to functional impairment [and] … disorders such as autism. There’s an idea that autism is either an overconnectivity of shortly distanced areas in the brain or an underconnectivity of longer distances.
Rhode Island's Market Has Changed. Developers, Builders, Investors and Sellers Must Change With It.
By Emilio DiSpirito IV License Partner | Engel & Völkers Oceanside Leader | The DiSpirito…
Learn More
PBN: You’re recruiting 256 children for your study. How will that work?
DEONI: It’s basically from the Providence and Rhode Island area. There are two groups: One group [of 64 boys and 64 girls] will be recruited at age 2 to 3 months and followed up to 2 years of age. Another group [also half boys, half girls] will be recruited at 2 1/2 to 3 years of age and will be followed until 5. … The older kids will be imaged once per year, and the younger cohort will be imaged once per six months.
PBN: Will you be recruiting children you expect might have abnormal development?
DEONI: In the first instance, it will be mainly healthy kids … because although we know a lot about brains and brain development, the process of myelination is unknown. There’s only one study that has been done, about 40 years ago [looking at the brains of dead infants] … so we don’t know how myelination proceeds in normal children, or how it relates to normal development. … In addition to scanning, we’ll also do neuropsychology evaluations – in this case, very playful activities to get some sort of quantitative measure of their primary cognitive functions.
DEONI: Yes. It just happens that we come at the same problem from opposite ends. I come at it with an imaging knowledge, and he comes in with the medical questions, and the ability to take what I say, “This has changed,” into a medically meaningful statement.
PBN: You will be imaging the children at the Brown MRI facility. What kind of technological challenges are involved in doing such detailed scans of babies and toddlers?
DEONI: The technology aspects were quite difficult, actually, because normally, MRI is quite loud. So we’ve had quite a bit of work to make it silent, because all of our kids will be imaged while they’re sleeping. Obviously we’re imaging healthy kids, so we’re not allowed to do any sedation. … We’ll be making the MRI facility pretty dark, and as child-friendly as we can.
PBN: How do you make an MRI quiet?
DEONI: The sound is related to the change in the magnetic field. In order to image, we bury the magnetic field in every point in space, and we do that very quickly. Sound is related to how quickly you change that magnetic field. … So to make it silent, we have to slow things down … which carries a penalty, that the scan will take longer. So we need to find the optimal balance between how quiet we need to be so they stay asleep, but how fast we can go so they don’t wake up during the scan. We’ve managed to get the scan down to about 10 minutes. •
