America
Here's why you mistake strangers for familiar faces
New York, Aug 20
Neuroscientists, including an
Indian-origin researcher from Johns Hopkins University, have pinpointed
a part of the brain that helps you decipher memory from new
experiences.
In a supermarket, on board the Metro or at airport,
you suddenly see a familiar face and say to yourself, “I think I have
seen that faceâ€.
“But you ask: is this someone I met five years
ago, maybe with thinner hair or different glasses or is it someone else
entirely,†said neuroscience professor James J Knierim, who led the
research.
“That is one of the biggest problems our memory system has to solve,†he added.
The
newly-identified part of the hippocampus creates and processes memory,
furthering our understanding of how the mind works and what is going
wrong when it does not.
Neural activity in the hippocampus allows
someone to remember where they parked their car, find their home even
if the paint colour changes and recognise an old song when it comes on
the radio.
Along with Sachin S. Deshmukh, former assistant
research scientist in Knierim's lab, the researchers theorised that two
parts of the hippocampus -- the dentate gyrus and CA3 - competed to
decide whether a stimulus was completely new or an altered version of
something familiar.
The new research on rats shows that CA3 is
more complicated than previously thought -- parts of CA3 come to
different decisions and they pass these different decisions to other
brain areas.
“The final job of the CA3 region is to make the decision: Is it the same or is it different?†Knierim noted.
Usually you are correct in remembering that this person is a slightly different version of the person you met years ago.
“But
when you are wrong and it embarrassingly turns out that this is a
stranger, you want to create a memory of this new person that is
absolutely distinct from the memory of your familiar friend, so you do
not make the mistake again,†Knierim explained.
The findings,
published in the journal Neuron, can help explain what goes wrong with
memory in diseases like Alzheimer's and could help to preserve people's
memories as they age.