“There are only a handful of fMRI studies on awake kids aged four to six because it is difficult for them to keep still for so long.”
A fMRI measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled.
Individuals are required to lie still during the actual MR scanning, then when the actual imaging is taking place, loud intermittent banging noises will be heard with headphones or earplugs often provided to minimize the noise during the procedure.
As such, designing a different approach for young children was necessary. Vanderwal says the powerful effect of the visual motion on the children convinced her movies could be used to probe brain connectivity, even in young children.
Drawing on her background in the visual arts, Vanderwal led a team of professional artists to create several movies from scratch.
First they developed a control — abstract visual shapes moving in and out, like a beautiful screen saver that the team called Inscapes. In this, the composer minimized the noxious noises from the MRI by incorporating the pitch and rhythm into the score.
Next they created a highly social story told with simple shapes — a large and a small triangle move through a landscape and interact like a parent and child. Last is a montage of trailers to mimic the “complex soup of stimuli” children live in.
It took over four years to create the movies, not just because the production is detailed and beautiful, but because controversy about the method required extensive proof-of-concept testing.
Critics argue that movies have too many variables to serve as scientific stimuli, and that the complexity in movies makes it difficult to interpret what the brain activity means.
Vanderwal has compared the abstract movie to the current standard used in resting state studies — a blank cross on a screen (called “fixation”) — and found that in many of the brain networks, the slow abstract movie evoked almost the same patterns of activity as the fixation cross.
Moreover, “Inscapes works beautifully for compliance in a testing scenario,” she said, describing how this method allows around 80 percent of data to be used with really young children, instead of 50 percent, which is normal for the fixation cross.
Convinced that abstract movies can serve as a meaningful baseline condition, she is using the examining differences in the brain dynamics between children with ADHD and those without.
One hypothesis about ADHD revolves around a brain network called the default network. Normally the default network is less active during a task, and more active while doing nothing or reflecting about oneself.
In kids with ADHD, some researchers think that the default network may not be suppressed enough. “The hypothesis is that the default network elbows its way into the networks activated by the tasks, and disrupts the way these networks interact and cooperate,” Vanderwal said.
This might explain, for example, why kids with ADHD seem to make errors during certain tasks, and then perform well for awhile, and then make those errors again.
The control video is publicly available for other researchers, and currently at least twelve other research groups in the U.S., Canada and China are using it. Vanderwal shares the videos because they were difficult to produce, and because using the same stimuli allows groups to compare results more readily.
She is also convinced that beautiful, cohesive, artistic stimuli improve the science.
“Most of the time we make really ugly scientific stimuli, and I think the data suffer,” she said, explaining how the brain reacts strongly to odd or unnatural looking stimuli.
“Having artists involved can help decrease neural responses to aesthetic ‘blunders’ and increase the neural responses we are trying to evoke”