Neuroimaging Offers Clues to Learning and Recovery From Stroke
Meet the Researchers
Drs. Scott Holland (left) and Vince Schmithorst, shown here in the main lobby of Cincinnati Children's, collaborate on studies using fMRI to look at the size, structure and plasticity of children's brains.
The remarkable plasticity of the brain, its ability to create new neural pathways when existing ones are blocked or injured, means that children who have a perinatal stroke affecting the area of the brain usually responsible for language development can grow up and have normal language skills. Studies at Cincinnati Children's using functional magnetic resonance imaging (fMRI) during verb generation and story listening tasks show how the language development area of the brain reorganizes in children following a perinatal left middle cerebral stroke.
"Perinatal stroke basically deletes the whole left hemisphere language area and, depending on how severe that injury is, the language function completely reemerges on the right hemisphere," explains neurophysicist Scott Holland, PhD.
"What is extraordinary is that when children who have had these horrible brain infarcts at birth are 8 or 9 years old, you can't really tell them from other kids. They seem to walk and talk normally," Dr. Holland says. "When you look at their brain images, you are just blown away that they can be as normal as they are with the kind of brain injury you see. So what is it about the perinatal brain or the neonatal brain that is so capable of reorganizing and recovering? What can we do to stimulate adult brains to do the same type of recovery?"
Stimulating Repair and Recovery
Research addressing these questions is underway at Cincinnati Children's with rodent models. For example, the laboratory of Masato Nakafuku, MD, PhD, is searching for ways to activate endogenous stem cells in the brain to repair injury. Figuring out how to turn these cells on might enable researchers to stimulate repair and recovery. "Through neuroimaging, we hope to be able to visualize how this process works," Dr. Holland says. "Our goal is to use our small animal MRI facility and specialized magnetic labeling methods to eventually work with scientists like Dr. Nakafuku and others to unlock the innate ability of the brain to heal itself, much like a cut on your hand heals itself."
Another study using fMRI and verbal and interactive computer tasks is revealing differences in brain structure and function between boys and girls.
After age 12 or 13, boys tend to grow at a faster rate than girls -- bigger bodies, bigger heads, bigger brains. "The adult male head is about 10 percent bigger than the female head, so it makes sense that the physical brains would be larger too," notes Vince Schmithorst, PhD, research assistant professor, who collaborated with Dr. Holland on these and other studies.
"Architecturally, girls' brains seem to be more connected, whereas with boys, the reverse is true: The brain develops into a more localized architecture, meaning that the areas of the brain are acting more independently in boys than they are in girls," Dr. Schmithorst explains. "In girls, the areas of the brain act more in tandem because they can be more connected due to their smaller size."
How Versus What
These gender differences relate to how the brain functions, not what it can do, and do not mean that one sex is more or less capable of learning than the other. Differences in how boys' and girls' brains process information and learn, however, could have implications for teaching strategies. "Maybe teaching boys and girls together is not optimal," Dr. Holland speculates.
Using functional MRI to better understand brain organization can benefit patients in the long run. Finding that the brains of children with epilepsy are often differently organized than those of other children for language development and processing has helped spare these language areas in children undergoing surgery to excise brain regions responsible for seizures. Recognizing gender differences in brain structure and function is important to understanding conditions with significant gender disparities, such as autism, which predominantly affects males.
Scott Holland, PhD, is professor of radiology, pediatrics, physics and biomedical engineering. Vince Schmithorst, PhD, is a research assistant professor. Their study on language organization in children following perinatal stroke was published in Neuropediatrics (37[1]:46-52, 2006).
