31 August 2019 | New Scientist | 13YOUR brain isn’t necessarily the
same age as the rest of you. Now,
it may be possible to predict how
quickly a person’s brain will age
throughout life based on tests
taken when they are 3 years old.
A person’s biological age may
be a better indicator of their health
than their chronological age. Brain
age can be measured using brain
scans and machine learning to
determine if a person’s brain looks
older or younger than the average
healthy brain for people of the
same age.
To find out if brain age might
reveal anything about a person’s
health in midlife, Max Elliott at
Duke University in North Carolina
and his colleagues assessed the
brains of 869 adults in New
Zealand who have undergone
regular medical and cognitive
testing since they were 3 years old.
When the volunteers, all aged
between 43 and 46, underwent
MRI brain scans, the team found
that their brain ages ranged from
23 to 71. Those with older brain
ages performed worse on tests
of cognition, memory and IQ.
The researchers also measured
things like cholesterol and blood
sugar levels to estimate the
biological age of the volunteers’
bodies. They found that this was
loosely linked to brain age, but not
totally. “There are some people
who have a very advanced brain
age whose bodies seem to be
ageing slowly, and vice versa,” says
Elliott. However, the team found
that those who had the highest
scores on cognitive tests whenthey were 3 years old went on to
have the youngest-looking brains
(bioRxiv, doi.org/c9ng).
This suggests we might be able
to tell who is at risk of accelerated
brain ageing early in life, says
Elliott. He hopes that predicting
brain ageing earlier in life could
allow treatments for conditions
like dementia to be started sooner.
This means they might have a
better chance of working.
James Cole at King’s College
London cautions that it will be
difficult to make predictions
based on a 3-year-old’s test results.“Acceleration or delay could be
positive or negative,” says Cole.
“If a 60-year-old has a brain that
looks 70, that’s bad, but if a 3-year-
old has a brain that looks 5, that
might be a good thing.”
The team also asked other
researchers to guess how old the
volunteers were based on photos
of their faces. Again, the responses
varied hugely, with estimates
coming in 20 years above and
below their actual age. Those who
looked older also had older brain
ages. “It suggests that the outward
signs of ageing are reflected by the
internal signs of ageing,” says Cole.
That doesn’t mean that all older-
looking individuals will be on
their way to dementia, says Elliott.
We don’t yet have a way to treat
brain ageing, but given the known
benefits to the brain of healthy
eating and exercise, these aren’t
a bad place to start. “Ageing is a
complex interaction of genes
and environment,” says Cole.
“The environmental factors are
likely to be things like stress levels,
diet, how much physical exercise
people get and how much they
use their brains,” he says. ❚Neuroscience
Jessica Hamzelou
SALLYANSC
OMBE/GETT
YSpace
A black hole has
been seen eating
a neutron star
ALMOST 900 million years ago,
two objects – one a black hole, the
other almost certainly a neutron
star – slammed together with
incredible force, sending shock
waves through space-time.
These gravitational waves
have now washed over Earth.
Last week, scientists from the Laser
Interferometer Gravitational-Wave
Observatory said the waves were
picked up by LIGO’s detectors in the
US and by Italy’s Virgo detector.
“We’re very confident that
we’ve just detected a black hole
gobbling up a neutron star,” says
Susan Scott, a theoretical physicist
at the Australian National University
in Canberra and part of the LIGO
collaboration.
If confirmed, the observation
would complete the trifecta of
cataclysmic events researchers had
hoped to detect when LIGO was first
proposed: the collision of two black
holes; the collision of neutron stars
in a binary system; and the merger
of a black hole and a neutron star.
In April, LIGO researchers thoughtthey had seen their first black hole
and neutron star merger, only for the
observation to be chalked off due to
the high possibility the signal was
background noise from Earth. This
time, researchers are almost certain
the signal came from beyond Earth.
Researchers around the globe
are now running the numbers to
confirm the identity of the two
objects involved. Given its size,
researchers agree the largeris a black hole. Based on initial
estimates of its mass, the smaller is
probably a neutron star. “But there
is the remote possibility it could
actually be a very light black hole,”
says Scott. If that proves to be the
case, it would be by far the lightest
black hole ever observed. “We have
to look at the signal to see if we can
confirm it is behaving like a neutron
star in the in-spiral,” says Scott.
Ticking off the final of the three
types of event doesn’t mean LIGO
will be powered down, however.
“That’s just the end of the
beginning,” says Scott. ❚
James Mitchell CrowTests at 3 years old could predict
brain ageing in later life
Lower stress levels and
exercise may help your
brain stay young900 m
Approximate number of years
since the collision spotted by LIGO