Brain mechanisms behind multitasking identified

Researchers have identified the regions and mechanisms in the brain that allow people to multitask, an advance that may lead to better treatments for conditions such as autism, dementia or schizophrenia.
By studying networks of activity in the brain's frontal cortex, a region associated with control over thoughts and actions, the researchers have shown that the degree to which these networks reconfigure themselves while switching from task to task predicts people's cognitive flexibility.
Experiment participants who performed best while alternating between a memory test and a control test showed the most rearrangement of connections within their frontal cortices as well as the most new connections with other areas of their brains.

A more fundamental understanding of how the brain manages multitasking could lead to better interventions for medical conditions associated with reduced executive function, such as autism, schizophrenia or dementia.
Rather than looking at the role a single region in the brain plays, researchers studied the interconnections between the regions as indicated by synchronised activity, using functional magnetic resonance imaging (fMRI).
Mapping the way this activity network reconfigures itself provides a more holistic view of how the brain operates.

"We try to understand how dynamic flexibility of brain networks can predict cognitive flexibility, or the ability to switch from task to task," said senior author Danielle Bassett, assistant professor at the University of Pennsylvania's School of Engineering and Applied Science.

"Rather than being driven by the activity of single brain areas, we believe executive function is a network-level process," Bassett said.
A previous study that Bassett led showed that people who could more quickly "disconnect" their frontal cortices did better on a task that involved pressing keys that corresponded to colour-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 over-thinking a simple problem.
In the new experiment, 344 participants alternated between a working memory task designed to engage the frontal cortex and a control task.

They used novel tools to map how participants' brain activities rearranged during each block of the working memory task, each block of the control task and blocks in between where participants switched gears.
"The nodes in the network that are most involved in reconfigurations are cognitive control areas in the frontal cortex," Bassett said.
"More flexibility within the frontal cortex meant more accuracy on the memory task, and more consistent connectivity between the frontal cortex and other regions was even more predictive," Bassett said.
The study was published in the PNAS.