Researchers at the University of Pennsylvania
and Germany’s Central Institute of Mental Health in Mannheim and Charité University Medicine Berlin have used brain scans to shed new light on the question of what makes someone better at switching between different tasks.
In studying networks of activity in the brain's frontal cortex, a region associated with control over thoughts and actions, the researchers have demonstrated that the degree to which these networks reconfigure themselves while switching from task to task predicts people’s cognitive flexibility. Study participants who performed best while alternating between a memory test and a control test demonstrated the most rearrangement of connections within their frontal cortices as well as the most new connections with other areas of their brains. A better understanding of how the brain manages multitasking could lead to better interventions for reduced executive function, such as autism, schizophrenia or dementia.
Danielle Bassett, the Skirkanich Assistant Professor of Innovation in Penn’s School of Engineering and Applied Science, is senior author on the study. Manheim’s Urs Braun and Axel Schäfer were the lead authors. The research also featured work from Andreas Meyer-Lindenberg and Heike Tost of Mannheim, Henrik Walter of Charité, and others. It was published in the Proceedings of the National Academy of Sciences and reported in Bioscience Technology
Rather than looking at the role a single region in the brain plays, Bassett and colleagues study the interconnections between the regions as shown by synchronized activity. Using fMRI, they can measure which parts of the brain are communicating with one another as study participants perform various tasks. By mapping the way this activity network reconfigures itself, researchers gain a more holistic view of how the brain operates.
According to Bassett, “We try to understand how dynamic flexibility of brain networks can predict cognitive flexibility, or the ability to switch from task to task. Rather than being driven by the activity of single brain areas, we believe executive function is a network-level process.”
In a previous study led by Bassett, it was demonstrated that people who could more quickly “disconnect” their frontal cortices did better on a task that involved pressing keys that corresponded to color-coded notes on a screen. The high level decision-making associated with the frontal cortex’s cognitive control was not as critical to playing the short sequences of notes, so those who still engaged this part of the brain were essentially overthinking a simple problem. In the new study, lead by Andreas Meyer-Lindenberg of Mannheim, 344 participants alternated between a working memory task designed to engage the frontal cortex and a control task. The easy task involved pressing the corresponding button as a sequence of numbers appeared on a screen one by one. The hard task also involved a sequence of numbers on a screen, but participants had to press the button that corresponded to the number that appeared two places back in the series each time they saw a new one.