6 November 2021 | New Scientist | 11Brain implants help
with flexible thinking
NeuroscienceHelen Thomsonin other tasks it didn’t. The task
forces people to use cognitive
control to overcome the difference
between where the number is
on the screen and the keypad.
When their brains were
stimulated, participants were
around 5 per cent faster at
answering correctly. It might not
seem like much, says Widge, but
you don’t need a lot of change in
flexible thinking to help people
make small tweaks in their life
that can then accumulate over
time and help change behaviours.
Although the participants
couldn’t tell when the stimulation
was switched on and off, in trials
where it was on, some people
reported that their thoughts were
more focused and background
anxiety was easier to ignore,
suggesting the stimulation
was having an influence
(Nature Biomedical Engineering,
doi.org/g4gm).
In further experiments, the
team only stimulated the brain
when participants’ accuracy fell
below a specific threshold. This
“closed loop” technique made
participants 10 per cent faster,
says Widge. The researchers later
showed that they could identify
falls in accuracy based on
patterns of brain activity alone.
As a result, it may be possible
to record and stimulate the brain
only when necessary to provide
relief from specific brain activity.
Because the implants are
invasive, this would probably be
only used for treatment-resistant
conditions. Doctors have already
started treating psychiatric
conditions in this way, with varied
results, says Keyoumars Ashkan
at King’s College Hospital in
London. Personalised, closed loop
delivery, may be key to effective
treatment, he says. “Much research
still needs to be done, but at least
we now have a starting point.” ❚ELECTRICAL brain stimulation
in people with pre-existing brain
implants has allowed them to
think more flexibly and clear
anxious thoughts, suggesting
it has the potential to treat
conditions like depression.
Alik Widge at the University
of Minnesota and his colleagues
found that applying an electric
current within the centre of the
brain boosted people’s ability to
rapidly adapt to changing goals,
known as cognitive control,
and in some cases improved
their feelings of well-being too.
The inability to disengage
from habitual ways of thinking
is commonly seen in people
with mood disorders, such
as depression and obsessivecompulsive disorder. In these
conditions, people are often
unable to extricate themselves
from thought processes
triggered by habits or distress.
Widge recruited 21 people who
already had electrodes placed
in their brain as a treatment
for epilepsy. They didn’t have
depression, but some had mood
disorders associated with epilepsy.
He and his team used these
electrodes to provide small
bursts of stimulation to the brain
while participants performed
a cognitive control task, in
which they were shown a trio of
numbers between one and three
on a screen. Two of the numbers
were always the same, and the
participants had to identify the
odd number out and press the
corresponding key on a keypad.
In some tasks, the position of
the unique number matched its
physical position on the keypad,“ It may be possible to
stimulate the brain only
when necessary to relieve
specific brain activity”
OWLS may make maps of their
surroundings in their brains just
like humans do. If this ability is
indeed present in non-mammals
as well as mammals, it means
it may have evolved hundreds
of millions of years ago.
To check for this in barn owls
(Tyto alba), Yoram Gutfreund
at Technion-Israel Institute of
Technology and his colleagues
implanted a wireless neural
recording device into the brains
of six of the birds. The team
used these to analyse brain
activity as the birds flew back
and forth between two perches.
The group was looking for
signs of place cells – neurons
that fire when an animal is in a
specific place. These cells let an
animal make a mental map of
its surroundings and have been
found in people, rodents and
bats, but not in flying birds,
although they have been seen
firing in a tufted titmouse, a
type of songbird, as it walks.
For the owls, the team tracked
each bird for about 20 minutes,
following their flights with eight
high-speed infrared cameras.
By combining data from
the neural recordings with
the infrared footage, the teamfound that certain hippocampus
neurons fired more strongly
at specific points in the flight
path and depending on which
direction a bird was flying
(bioRxiv, doi.org/g4gf).
However, the team notes
that the cells involved might
not be place cells at all. They
could just be time-sensitive,
with their firing dependent
on how long the birds have
been in the air.
Kate Jeffery at University
College London says that she
finds the evidence suggesting
these neurons are in fact place
cells “fairly convincing”. The
cells’ properties are like those
seen in rodents doing a similar
task involving animals moving
in a straight line, she says.
“The findings are consistent
with emerging findings that
many of the phenomena
we have been studying in
mammals have counterparts
in non-mammals, suggesting
an ancient evolutionary origin –
more than 300 million years
[ago],” says Jeffery. ❚Animal behaviourJason Arunn MurugesuBarn owls may
create mental
maps just like us
Neurons known as place cells
may help barn owls keep track
of their location during flightANAN
KAEWKHAMMUL/SHUTT
ER
ST
OCK^