A team of researchers from Drexel University and the University of Pennsylvania recently conducted a cognitive switch test and concluded that some brains are more naturally wired to switch focus quickly.
The study is published in Nature Human Behavior.
Led by John Medaglia, assistant professor of psychology at Drexel’s College of Arts and Sciences, the researchers tested the cognitive flexibility of 30 participants while measuring their brain activity using functional magnetic resonance imaging (fMRI).
Cognitive flexibility is “the mental ability to switch between thinking about two different concepts, and to think about multiple concepts simultaneously.”
It is one of the executive functions and a skill that is involved in “virtually every complex behavior we undertake — from mental arithmetic to driving a car,” according to a press release citing Medaglia.
In the study, during which a different shape flashed in front of the participants every two seconds, they were asked to identify the larger, or global, shape if the image was green and to identify the smaller, or local, shape if the image was white.
“How fast people can make that transition – from the global to the local – is the switch cost, and that’s our index of flexibility,” Medaglia said in a statement. “For some people, that’s a very jarring, effortful task. Even if you’ve learned the rules very well, it’s hard to make the right decision when things are happening fast.”
To reveal the potential basis for cognitive flexibility, the researchers used a combination of human behavior measures, the brain’s structure and function, and the mathematical system of graph signal processing (GSP) to analyze signals on graphs.
“Our behavior is determined both by the way the brain is structured, and, to some extent, the way it is dynamic, or changes over time,” Medaglia said in a statement. “We wanted to find a way to study both of those things at the same time.”
The team took the GSP approach, as GSP is a specialty of Alejandro Ribeiro, associate professor of electrical and systems engineering at the University of Pennsylvania, and Weiyu Huang, doctoral candidate with the Department of Electrical and Systems Engineering at the University of Pennsylvania, according to Medaglia.
“In discussions with Weiyu, we realized that there were many potential opportunities to use GSP to approach the distinct problem of representing brain structure and function in ways that are relevant to cognition,” Medaglia said. “When we realized we could represent measured brain function on top of anatomy, we speculated that the idea of ‘aligning’ signals with anatomy might provide a measure related to cognitive flexibility, and got to work”
He credits Huang with handling “the brunt of the analyses.”
During the study, the researchers realized that “GSP could allow us to see whether the way human network anatomy — the pathways that connect brain regions — organizes functional signals measured with fMRI,” he said.
The researchers “thought that the extent to which these brain signals align might be related to cognitive flexibility,” he continued.
They found that the “switching” speed varies based on the alignment of the brain signals.
“It turns out that if the signals that diverge most from anatomy are more aligned, people are faster at switching,” said Medaglia. “So, GSP gave us a window to examine whether anatomy and function come together to support this mental function, and we found evidence that they do.”
The teams believes that this study is key to future research.
“This study is potentially very important because it shows that we can find measures of cooperation between brain anatomy and function that tell us about cognition,” Medaglia said. “It turns out that it’s really hard to get a measure that is both simple and has a clear interpretation in applied neuroscience. Since we rely on our cognitive flexibility for almost every complex task we do, it’s really crucial that we try to use modern neuroimaging and sophisticated, yet elegant mathematical approaches to get our heads around how the process works in the brain.”
The researchers are hopeful that the new approach could be used as a basis for other studies.
“Weiyu and Alejandro are investigating the use of these approaches in the brain more generally.” Medaglia said. “I’m hopeful that the specific approach we used here might be validated in other studies and tested as a potential target for interventions, such as the brain stimulation techniques we use in our laboratory or pharmacology.”