Brain ‘finds it difficult to multitask as we get older’

Washington, April 12: Older adults have a harder time multi-tasking than young adults because they have more difficulty switching their brain network between tasks, according to a new study.

Experts at the University of California, San Francisco (UCSF) showed that the brain's capacity to ignore distractions, or irrelevant information, diminishes with age and that this, too, impacts working memory.

Researchers know that multitasking negatively impacts working memory in both young and older adults.

However, anecdotal accounts of "senior moments" - such as forgetting what one wanted to retrieve from the refrigerator after leaving the couch - combined with scientific studies conducted at UCSF and elsewhere indicate that the impact is greater in older people.

In the current study, researchers compared the working memory of healthy young men and women (mean age 24.5) and older men and women (mean age 69.1) in a visual memory test involving multitasking.

Using functional magnetic resonance imaging, the researchers tracked blood flow in the participants' brains to identify the activity of neural circuits and networks.

Participants were asked to view a natural scene and maintain it in mind for 14.4 seconds.

Then, in the middle of the maintenance period, an interruption occurred: an image of a face popped up and participants were asked to determine its sex and age. They were then asked to recall the original scene.

As expected, older people had more difficulty maintaining the memory of the original image.

When the young and older adults were interrupted, their brains disengaged from a memory maintenance network and reallocated neural resources toward processing the interruption.

However, the younger adults re-established connection with the memory maintenance network following the interruption and disengaged from the interrupting image.

The older adults, on the other hand, failed both to disengage from the interruption and to re-establish the neural network associated with the disrupted memory.

"These results indicate that deficits in switching between functional brain networks underlie the impact of multitasking on working memory in older adults," said lead author Wesley C. Clapp.

The finding is reported in the online early edition of Proceedings of the National Academy of Sciences.

Copyright Asian News International/