BBC Science Focus - 10.2019

DISCOVERIES

e secrets

of strong

memories

decoded

Why is it that you can remember the

names of childhood friends that you

haven’t seen in years, yet easily forget

the name of someone you just met a

moment ago? Researchers at Caltech

may have found the answer: strong,

persistent memories are encoded by

‘teams’ of neurons all firing together

to ensure that certain memories stay

remembered.

The researchers developed a test to

examine the neural activity of mice

as they learnt and remembered a new

place. First, they placed mice one at a

time in a long, white enclosure with

signs marked at various locations along

the walls, like a plus at one end, and

a slash in the centre. Treat dispensers

containing sugar water were positioned

at either end. As the mice explored, the

team measured the activity of specific

neurons in the hippocampus – the

region of the brain where new memories

are formed – that are known to encode

memories of places.

At first, they found that single

neurons were activated when the mice

spotted one of the symbols. As the mice

became familiar with the track, and

remembered the locations of the sugar,

more and more neurons were activated

whenever they spotted a symbol.

Essentially, the mice were recognising

where they were within the track.

BRAIN

After a 20-day break, the researchers

returned the mice to the track. Those

that had formed memories encoded by a

higher number of neurons remembered

the task more quickly.

“For years, people have known that

the more you practice an action, the

better chance that you will remember it

later,” said Prof Carlos Lois, who led the

research. “The conventional theories

about memory storage postulate that

making a memory more stable

requires the strengthening of the

connections to an individual neuron.

Our results suggest that increasing the

number of neurons that encode the

same memory enables the memory to

persist for longer.”

A greater number of neurons,

like the one visualised here,

will activate when a task is

repeated, therefore forming

stronger memories

People who get less than six hours

of sleep per night, or more than

nine, could be at higher risk of heart

disease, according to a study at the

University of Colorado Boulder.

Even taking into account lifestyle

factors such as diet, exercise and

smoking, those who got sleep

within this ‘Goldilocks range’ were

the least likely to have a heart

aack over a seven-year period.

Good news if heart disease runs in

the family: just like having a good

diet, geing your sleep habits

‘just right’ can also reduce your risk

of a heart aack.

SLEEPING TOO MUCH OR TOO LITTLE CAN INCREASE

YOUR RISK OF HEART ATTACK

DISCOVERIES

e secrets

of strong

memories

decoded

Why is it that you can remember the
names of childhood friends that you
haven’t seen in years, yet easily forget
the name of someone you just met a
moment ago? Researchers at Caltech
may have found the answer: strong,
persistent memories are encoded by
‘teams’ of neurons all firing together
to ensure that certain memories stay
remembered.
The researchers developed a test to
examine the neural activity of mice
as they learnt and remembered a new
place. First, they placed mice one at a
time in a long, white enclosure with
signs marked at various locations along
the walls, like a plus at one end, and
a slash in the centre. Treat dispensers
containing sugar water were positioned
at either end. As the mice explored, the
team measured the activity of specific
neurons in the hippocampus – the
region of the brain where new memories
are formed – that are known to encode
memories of places.
At first, they found that single
neurons were activated when the mice
spotted one of the symbols. As the mice
became familiar with the track, and
remembered the locations of the sugar,
more and more neurons were activated
whenever they spotted a symbol.
Essentially, the mice were recognising
where they were within the track.

BRAIN

After a 20-day break, the researchers

returned the mice to the track. Those

that had formed memories encoded by a

higher number of neurons remembered

the task more quickly.

“For years, people have known that

the more you practice an action, the

better chance that you will remember it

later,” said Prof Carlos Lois, who led the

research. “The conventional theories

about memory storage postulate that

making a memory more stable

requires the strengthening of the

connections to an individual neuron.

Our results suggest that increasing the

number of neurons that encode the

same memory enables the memory to

persist for longer.”

A greater number of neurons,

like the one visualised here,

will activate when a task is

repeated, therefore forming

stronger memories

People who get less than six hours

of sleep per night, or more than

nine, could be at higher risk of heart

disease, according to a study at the

University of Colorado Boulder.

Even taking into account lifestyle

factors such as diet, exercise and

smoking, those who got sleep

within this ‘Goldilocks range’ were

the least likely to have a heart

aack over a seven-year period.

Good news if heart disease runs in

the family: just like having a good

diet, geing your sleep habits

‘just right’ can also reduce your risk

of a heart aack.

SLEEPING TOO MUCH OR TOO LITTLE CAN INCREASE

YOUR RISK OF HEART ATTACK