New Scientist - 07.09.2019

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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