New Scientist - USA (2019-10-12)

12 October 2019 | New Scientist | 17

Cancer screening

Neuroscience Space

App spots signs of

disease in photos

An app can detect “white

eye” in photos of children,

a possible sign of health

problems, over a year

before it would normally

be picked up. White eye

occurs when a camera

flash makes a pupil appear

white. Normally this is

nothing to worry about, but

it can be a sign of disease,

including cancer (Science

Advances, doi.org/db97).

Wildlife trade is far

bigger than thought

More than 500O species

of wild animal are being

traded, according to the

most comprehensive global

estimate yet (Science

Advances, doi.org/dcdb).

That is 40 to 60 per cent

higher than previously

thought. Large or

distinctive species are

most likely to be traded.

Artificial limb

attaches to nerves

A new prosthetic leg

tested by three people felt

like an extension of their

own bodies and helped

them avoid tripping over.

Sensors in the foot and

knee of the prosthesis were

directly connected to the

participants by implanting

electrodes into their nerves

(Science Translational

Medicine, doi.org/dcdj).

Yet more doubts

over cancer checks

BOWEL cancer screening should

be recommended only for people

at high risk due to their age, family

history or other factors, according

to new guidelines.

Checks for this cancer have been

introduced in many countries,

usually from around the age of 50.

Doctors can look at the bowel with

a camera on a flexible tube or

people can send in a stool sample.

But a review of the evidence

suggests that, in most cases, the

YOUNG zebra finches have had

memories implanted in their

brains that change the length

of the notes they sing.

The birds usually learn a series of

notes by memorising their father’s

song. Now Todd Roberts at the

University of Texas Southwestern

Medical Center and his team have

manipulated the brains of young

finches, making it seem like they

had a memory of a song despite

never hearing an adult sing it.

Previous work had shown that

a region of the brain in birds called

HVC is important for learning songs.

This gets input from another brain

area called NIf, and neurons in this

structure fire at the beginning

and end of notes. That suggested

these neurons have a role in coding

the length of notes, or syllables.

Roberts and his colleagues

used optogenetics – a genetic

technique that enables neurons

to be activated by light - to

manipulate this pathway and

make the birds learn to sing longer

notes (Science, doi.org/gf9f4f).

“We identified a pathway in

the brain that, if we activate it,

can implant false memories for

the duration of the syllables,

without the bird having experience

with another bird,” says Roberts.

Sam Wong

benefits are small and uncertain

and outweighed by potential

harms from false positives, anxiety

and bowel perforation. Screening

is worth it only in those whose risk

of bowel cancer in the next 15 years

is 3 per cent or more, say Lise

Helsingen of Oslo University

Hospital in Norway and her team.

They don’t suggest a firm age

cut-off. Instead, doctors should

calculate people’s risk with

software that uses their age and

other factors such as sex, family

history and whether they smoke

or drink – but age is the most

important (BMJ, doi.org/dcbj).

Andromeda had a

two-course meal

OUR nearest major galactic

neighbour has feasted on several

galaxies in its lifetime. Now it

seems it had two distinct courses.

We know Andromeda ate other

galaxies because it has a large halo

of stars on the periphery, caught

in its orbit during collisions with

smaller, dwarf galaxies.

To see when this happened, a

team led by Geraint Lewis at the

University of Sydney, Australia,

studied data on the halo. They

focused on groups of millions of

stars packed in spheres known as

globular clusters. These clusters

would have retained a degree of

structure from their parent dwarf

galaxy for a while after they were

captured by Andromeda. Lewis

and his colleagues traced what

remains of these structures.

They found that half of the

clusters were orbiting one way

around Andromeda’s core and

the other half in a perpendicular

orientation. The former still have

some substructure intact, so the

collision that created them was

relatively recent, probably a few

billion years ago. The second

group of clusters retain less of

their original structure, suggesting

they were swallowed 7 to 10 billion

years ago (Nature, doi.org/db95).

Ruby Prosser Scully

“The 3 per cent threshold

represents the cumulative risk

above which the balance of

benefits and harms tilts in favour

of screening,” said Philippe Autier

at the International Prevention

Research Institute in Lyon, France,

in an accompanying editorial.

Concerns have also been raised

about screening for other cancers,

such as PSA blood tests for prostate

tumours and mammograms for

breast cancer. The fear is that

these programmes may do more

harm than good by finding tiny

tumours that are unlikely to carry

on growing. Clare Wilson

Bird brains retuned with

the help of fake memories

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Really brief

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