New Delhi: Among older adults, activity in the brain region responsible for language may be identical to that seen in brains of younger adults, even as activity in the brain system involved in decision-making might differ between the two age groups, a new study has found.
Findings published in the journal Nature Communications suggest that specialised brain regions, including those involved in processing language, might be more resilient to ageing, compared to other brain regions, researchers said.
The researchers from the Massachusetts Institute of Technology (MIT) and Boston University said that cognitive functions tend to decline with age — brain scans from previous studies have shown changes in function of a brain network involved in working memory and problem-solving.
“It’s well known that executive functions, such as attention, working memory, and cognitive control, tend to decline with age. And it’s also known that in opposition to that, language skills typically tend to remain quite stable or even improve with age,” said lead author Anne Billot, who carried out the work while doing her PhD at Boston University.
“These two types of functions really go in opposite directions in healthy ageing. In terms of behaviour, that’s quite well-established, and we wanted to see if that was also the case in the brain,” she said.
The study revealed that in older adults, activity of the language processing network is nearly identical to that seen in the brains of younger adults during language tasks.
However, the researchers found that activation patterns in the ‘multiple demand network’, a brain system involved in executive control tasks such as decision-making, were very different in older and younger adults.
The findings suggested that parts of the brain specialised for specific functions, such as language processing, may be more resilient to ageing than the multiple demand network, a more general-purpose network that has a greater flexibility in its function, the team said.
Two groups of people aged 17-39 and 41-80 were studied.
The researchers designed tasks that would elicit responses primarily in either the language network or the multiple demand network, allowing them to identify, for each participant, the brain areas that belong to each network.
While performing a spatial memory task — remembering the location of squares in a grid — the researchers confirmed that the multiple demand network showed an altered activity in older adults. Compared to the younger subjects, their networks were found to be smaller and less well-synchronised, with a weaker overall activation.
For identifying the language network, the participants were asked to listen to stories and read sentences. In both groups, brain activity in response to language showed similar levels and spatial distribution across the network.
The team also found that younger and older subjects showed similar brain responses when they encountered an unfamiliar word or an unusual grammatical construction.
The researchers also showed that in older people, the language network did not show any signs of becoming less synchronised.
