Medical

New study suggests aging has little impact on brain function

New study suggests aging has l...
Age differences in brain activity may have been overestimated in the past because of noise in fMRI signals (Photo: Shutterstock)
Age differences in brain activity may have been overestimated in the past because of noise in fMRI signals (Photo: Shutterstock)
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Age differences in brain activity may have been overestimated in the past because of noise in fMRI signals (Photo: Shutterstock)
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Age differences in brain activity may have been overestimated in the past because of noise in fMRI signals (Photo: Shutterstock)

When we get older, communication between neurons slows down and certain regions of the brain see reduced function. At least, that's the current understanding. But a new study by researchers at the University of Cambridge and Medical Research Council's Cognition and Brain Sciences Unit shows that the difference between older brains and younger ones may not be so great. The researchers demonstrated that functional magnetic resonance imaging (fMRI), which is commonly used to study brain activity, is susceptible to signal noise from changing vascular (blood vessel) activity.

fMRI doesn't directly measure neural activity but rather infers it through changes in regional blood flow (because blood flow increases in a brain region whenever that region is in use). Normally that isn't much of an issue, but blood circulation differs between people of different ages and the emerging method favored in accounting for the resultant signal noise by making additional measurements (such as of people holding their breath) is impractical in larger cohort studies of aging (these are comparative studies conducted over a long period that aim to establish links between risk factors and health outcomes).

Vascular function noise consequently tends to be unaccounted for when exploring the effects of aging on the brain. For this new study, the researchers were able to use resting state fMRI measurements (i.e. the data for when subjects aren't doing anything) to probe and validate CamCAN project data across 335 healthy volunteers over their lifespans.

They found that the age differences in fMRI signals during a task are correlated to vascular, not neuronal, activity. And this extends to sensory tasks. Once corrected for the vascular noise, apparent reductions in brain activity in the visual and auditory areas disappeared. The implication is that prior studies may have overestimated the effect of aging on cognition and other areas of brain activity.

The researchers propose that their method is a suitable alternative to "golden standard" calibration measures in large-scale and ongoing longitudinal studies.

A paper describing the research was published in the journal Human Brain Mapping.

Source: Biotechnology and Biological Sciences Research Council

3 comments
Gadgeteer
Woohoo! So this means I can think as well as ever and I'm not losing my memory in my old... I'm sorry, what were we discussing?
Ryan Gibbons
@Gadgeteer i believe the problems we have with our brain in old age are due to lifestyle more than natural progression of aging. There are many people who are just as sharp and aware in there final years as when they were 30. Actually i'm ready to assume the brain would take a lot longer to die or stop functioning because of age than most of the bodies tissues, if sustained. I would assume neurons experience less genetic defects and telomerase decay, because they divide less than other cells.
Kristianna Thomas
What this study finds is that the changes in the brain is not caused by ageing itself, but is related to how blood feed the brain; feed your brain. The shrinkage of capillaries, veins and arteries cause changes in the brain that would not normally take place in a healthy brain. Added to this the constant dehydration that causes the blood to thicken slowing the blood flow to the brain, and, or blood clots due to HDL in the blood stream resulting in Heart Disease; the brain becomes starved and malnourished deprived of vital nutriments such as B complex vitamins. How long would a well nourished healthy brain last; if properly maintained, and why doesn't one come with an owners manual? Cars and electronics have owners manuals; why is it that brains don't come with an owners manual?