Exposure to new experiences improves memory, according
to research by UCL psychologists and medical doctors that could hold
major implications for the treatment of memory problems. The study,
published in ‘Neuron’ on 3 August, concludes that introducing
completely new facts when learning, significantly improves memory performance.
Researchers have long suspected that the human brain is particularly
attracted to new information and that this might be important for
learning. They are now a step closer to understanding why.
A region in the midbrain (substantia nigra/ventral tegmental), which
is responsible for regulating our motivation and reward-processing,
responds better to novelty than to the familiar. This system also regulates
levels of dopamine, a neurotransmitter in the brain, and could aid
learning. This link between memory, novelty, motivation and reward
could help patients with memory problems.
Dr Emrah Düzel, UCL Institute of Cognitive Neuroscience, said:
“ We
hope that these findings will have an impact on behavioural treatments
for patients with poor memory. Current practice by behavioural psychologists
aims to improve memory through repeatedly exposing a person to information – just
as we do when we revise for an exam. This study shows that revising
is more effective if you mix new facts in with the old. You actually
learn better, even though your brain is also tied up with new information.
_ It is a well-known fact amongst
scientists that the midbrain region regulates our levels of motivation
and our ability to predict
rewards by releasing dopamine in the frontal and temporal regions of
the brain. We have now shown that novelty activates this brain area.
We believe that experiencing novelty might, in itself, have an impact
on our dopamine levels. Our next project will be to test the role of
dopamine in learning. These findings could have implications for drug
development.”
Subjects took part in a series of tests. The first experiment assessed
whether the brain prefers novel stimuli over familiar stimuli even
when the familiar images are made significant because they are either
rare or depict emotionally negative content. Subjects were shown images
of indoor and outdoor scenes and faces, while their brain activity
was analysed using an fMRI scanner. Some images rarely popped up and
some were emotionally negative, such as an angry face or a car accident.
Even the rare and emotional images did not activate the midbrain. It
responded only to new images.
The second experiment, using fMRI, made some of the images more or
less familiar to test how this relativity affected brain activity.
It did not – only completely new images produced activity in
the midbrain area.
Dr Düzel said:
“ We thought that less familiar information
would stand out as being significant when mixed with well-learnt, very
familiar information and so activate the midbrain region just as strongly
as absolutely new information. That was not the case. Only completely
new things cause strong activity in the midbrain area.”
Separate behavioural experiments were also conducted without the use
of a scanner to test the subjects’ memory. Their memory of the
novel, familiar and very familiar images they had studied was tested
after 20 minutes and then a day later. Subjects performed best in these
tests when new information was combined with familiar information during
learning. After a 20 minute delay, subjects’ memory for slightly
familiar information was boosted by 19% if it had been mixed
with new facts during learning sessions.
Dr Düzel said:
“ When we see something new, we see it has
a potential for rewarding us in some way. This potential that lies
in new things motivates us to explore our environment for rewards.
The brain learns that the stimulus, once familiar, has no reward associated
with it and so it loses its potential. For this reason, only completely
new objects activate the midbrain area and increase our levels of dopamine.”
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