New Scientist - 07.09.2019

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7 September 2019 | New Scientist | 19

Neuroscience

Agriculture Physiology

Red wine linked to
diverse microbiome

People who drink red wine
have a more diverse gut
microbiome than people
who drink other kinds of
alcohol, according to a
study of 3000 people
(Gastroenterology, doi.org/
c92f). Having a wide array
of gut bacteria is thought
to be beneficial to health.
The team behind the work
think antioxidants called
polyphenols in red wine
may explain the link.

Worm robot wiggles
through the brain

A worm-like robot can
navigate a tricky network
of blood vessels in a model
brain. The robot is just
0.6 millimetres across
and is steered using
magnets. Such robots
may make brain surgery
less invasive (Science
Robotics, doi.org/c9wd).

Gel helps tooth
enamel to regrow

Tooth enamel is easily
damaged by a lifetime of
chewing, and repairs with
fillings don’t last forever.
Now a gel made with
calcium and phosphate
ions – components
of enamel – seems to
stimulate the material
to regrow itself
(Science Advances,
doi.org/gf7b85).

Illusion makes fabric
seem to move faster

YOUR brain can be tricked to think
rough materials move faster than
smooth ones. The illusion shows
how our brains use skin vibrations
to judge speed and texture – and
sometimes confuse the two.
Sliman Bensmaia at the
University of Chicago and his
team blindfolded volunteers
and strapped their right hands
down facing upwards with their
index fingers extended.
The team dragged materials

CLIMATE change has been good
to banana growers so far, but
temperatures are likely to get so
hot that production gains will drop.
In some places, yields will decline.
Bananas are a staple crop for
an estimated 400 million people.
For the past 60 years, annual
yields have been increasing by
1.37 tonnes a hectare as the
world warms, and now stand at
some 10 to 40 tonnes per hectare.
Dan Bebber at the University
of Exeter, UK, and Varun Varma of
the National Centre for Biological
Sciences in Bangalore, India, have
built a model of optimal conditions
for banana production. It uses data

from 27 countries stretching
back to 1961, and also includes
temperature and rainfall records.
They found that, globally, the
ideal average temperature for
the crop seems to be 26.7°C,
but it varies by country.
The model suggests that as the
world warms, gains in yield will
slow. By 2050, they may be down
to 0.19 to 0.59 tonnes per hectare
(Nature Climate Change, DOI:
10.1038/s41558-019-0559-9).
Big suppliers are under threat,
especially in Latin America, says
Bebber. Colombia will be so badly
affected that yields will begin to
fall, he says. Adam Vaughan

such as corduroy, stretch denim,
microsuede, wool and vinyl over
participants’ fingers at speeds
ranging from 20 to 120 millimetres
per second. Participants were
asked to judge which of a pair of
materials was moving faster.
People tended to say that
rougher textures moved faster
than smooth ones. For instance,
thin corduroy was judged to be
faster than thick corduroy.
The team also measured the
vibrations on the skin, which
increased with rougher textures
and higher speeds (PLoS Biology,
doi.org/c9zt).

Lab brains behave like
those of early babies

MINI brains grown in a lab
show similar activity to that
seen in premature babies’ brains.
This challenges the idea that
brains must develop in a uterus
or be connected to other organs
to function.
Alysson Muotri at the
University of California, San
Diego, and his colleagues added
special growth factors and other
chemicals to make stem cells grow
into various brain cell types that
then spontaneously assembled
into brain-like structures.
Each “artificial brain” grew
to about half a centimetre
in diameter over 10 months.
Measuring their electrical
activity revealed that they began
producing simple brainwaves
after about two months.
Over time, these brainwave
patterns became more complex,
until they were similar to those
of preterm babies born before
28 weeks of gestation (Cell Stem
Cell, doi.org/c9zw).
The mini-brains are the first
models to display human-like
brain activity. However, it is
unlikely they have consciousness,
says Muotri. Such models could
help us understand our brains
and help test treatments for
neurological disorders. RPS

“The stronger the vibrations,
the faster the surface was felt
to move,” says Bensmaia.
Some neurons are sensitive
to both speed and texture, and
others only to texture. Bensmaia
says our perception of speed
depends on both. Those sensitive
to both tell us how fast a
material is moving across the
skin. “The texture-sensitive ones
tell us how much of that signal
can be attributed to the texture,
but we don’t listen to the latter
enough, so our perception of
speed is still biased,” he says.
Ruby Prosser Scully

Bananas’ boost from climate


change will end as it heats up


INSTANTS/GETTY


KAREN ROBINSON/PANOS

Really brief


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