UC Davis
neuroscientists were able to able to identify a signal
associated with a
rewarding memory, in this case related to a photo of
a basketball
court. Credit: Charan Ranganath
(February 12, 2016) Why
do we remember some events, places and things, but not others? Our brains
prioritize rewarding memories over others, and reinforce them by replaying them
when we are at rest, according to new research from the University of
California, Davis, Center for Neuroscience, published Feb. 11 in the journal
Neuron.
“Rewards help you remember things, because you want future
rewards,” said Professor Charan Ranganath, a UC Davis neuroscientist and senior
author on the paper. “The brain prioritizes memories that are going to be
useful for future decisions.”
It’s estimated that we only retain detailed memories for a
small proportion of the events of each day, Ranganath said. People with very
detailed memories become overwhelmed with information. So if the brain is going
to filter information and decide what to remember, it makes sense to save those
memories that might be most important for obtaining rewards in the future.
Ranganath and postdoctoral researcher Matthias Gruber put
this to the test by scanning the brains of volunteers by functional magnetic
resonance imaging as they answered simple yes-no questions on short series of
objects — for example, “do these objects weigh more than a basketball?” Each
series of objects was shown on a background image for context, and depending on
the context, the volunteers were told they would either get a large (dollars)
or small (cents) reward for giving correct answers. At the end of a series,
participants were told how much money they just won.