"There was no predictor of who would fall into which category before we tested them, we initially thought that everyone would respond similarly," said Eleni Patelaki, a biomedical engineering PhD student at the University of Rochester School of Medicine and Dentistry in the Frederick J and Marion A Schindler Cognitive Neurophysiology Laboratory and first author of the study out now in cerebral cortex.
"It was surprising that for some of the subjects it was easier for them to do dual-tasking - do more than one task - compared to single-tasking - doing each task separately. This was interesting and unexpected because most studies in the field show that the more tasks that we have to do concurrently the lower our performance gets."
Improving means changes in the brain
Using the Mobile Brain/Body Imaging system, or MoBI, researchers monitored the brain activity, kinematics and behavior of 26 healthy 18 to 30-year-olds as they looked at a series of images, either while sitting on a chair or walking on a treadmill. Participants were instructed to click a button each time the image changed. If the same image appeared back-to-back participants were asked to not click.
Performance achieved by each participant in this task while sitting was considered their personal behavioural "baseline". When walking was added to performing the same task, investigators found that different behaviours appeared, with some people performing worse than their sitting baseline - as expected based on previous studies - but also with some others improving compared to their sitting baseline.
The electroencephalogram, or EEG, data showed that the 14 participants who improved at the task while walking had a change in frontal brain function which was absent in the 12 participants who did not improve. This brain activity change exhibited by those who improved at the task suggests increased flexibility or efficiency in the brain.
"To the naked eye, there were no differences in our participants. It wasn't until we started analysing their behaviour and brain activity that we found the surprising difference in the group's neural signature and what makes them handle complex dual-tasking processes differently," Patelaki said.
"These findings have the potential to be expanded and translated to populations where we know that flexibility of neural resources gets compromised."
Edward Freedman, PhD, associate professor of Neuroscience at the Del Monte Institute led this research that continues to expand how the MoBI is helping neuroscientists discover the mechanisms at work when the brain takes on multiple tasks. His previous work has highlighted the flexibility of a healthy brain, showing the more difficult the task the greater the neurophysiological difference between walking and sitting.
"These new findings highlight that the MoBI can show us how the brain responds to walking and how the brain responds to the task," Freedman said. "This gives us a place to start looking in the brains of older adults, especially healthy ones."
Impact on aging
Expanding this research to older adults could guide scientists to identify a possible marker for 'super agers' or people who have a minimal decline in cognitive functions. This marker would be useful in helping better understand what could be going awry in neurodegenerative diseases.