A little more progress on this problem. It is a simple problem to define and thus an excellent road toward understanding the workings of the mind. Add in that all face types number around 500 and you have real potential for rational organization.
The truth remains that facial recognition is our most powerful memory system and exploiting this is obvious for ongoing work. it it possible that it links to so called photographic memory
Most interesting is just how little of the brain is engaged suggesting that the whole is linked back to our spirit body..
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Old Friend or Lookalike? How Your Brain Knows
By Jill Rosen, Johns Hopkins University | August 23, 2015
Last Updated: August 21, 2015 6:41 pm
http://www.theepochtimes.com/n3/1727130-old-friend-or-lookalike-how-your-brain-knows/
You see a guy at the grocery store—is he a college classmate or just a lookalike? One tiny spot in the brain holds the answer.
Neuroscientists have identified the part of the hippocampus that
creates and processes this type of memory, furthering our understanding
of how the mind works and what’s going wrong when it doesn’t. The
findings appear in Neuron.
“You see a familiar face and say to yourself, ‘I think I’ve seen that
face.’ But is this someone I met five years ago, maybe with thinner
hair or different glasses—or is it someone else entirely?” asks study
leader James J. Knierim, a professor of neuroscience at the Johns
Hopkins University’s Zanvyl Krieger Mind/Brain Institute.
“That’s one of the biggest problems our memory system has to solve.”
The Hippocampus Hypothesis
Neural activity in the hippocampus allows someone to remember where
they parked their car, find their home even if the paint color changes,
and recognize an old song when it comes on the radio.
Brain researchers theorized 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 dentate
gyrus was thought to automatically encode each stimulus as new, a
process called pattern separation.
In contrast, CA3 was thought to minimize any small changes from one
experience to the next and classify the stimuli as being the same, a
process called pattern completion. So, the dentate gyrus would assume
that the person with thinner hair and unfamiliar glasses was a complete
stranger, while CA3 would ignore the altered details and retrieve the
memory of a college buddy.
Same or Different?
Prior work by Knierim’s group and others provided evidence in favor
of this long-standing theory. The new research shows, however, 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 says.
“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 complete
stranger, you want to create a memory of this new person that is
absolutely distinct from the memory of your familiar friend, so you
don’t make the mistake again.”
Rat ‘Mental Maps’
Knieirm and colleagues monitored rats as they got to know an environment and as that environment changed.
The team implanted electrodes in the hippocampus of the rats. They
trained the rats to run around a track, eating chocolate sprinkles. The
track floor had four different textures: sandpaper, carpet padding, duct
tape, and a rubber mat. The rat could see, feel, and smell the
differences in the textures. Meanwhile, a black curtain surrounding the
track had various objects attached to it. Over 10 days, the rats built
mental maps of that environment.
Then the experimenters changed things up. They rotated the track
counter-clockwise, while rotating the curtain clockwise, creating a
perceptual mismatch in the rats’ minds. The effect was similar, Knierim
says, to opening the door of your home and finding all of your pictures
hanging on different walls and your furniture moved.
“Would you recognize it as your home or think you are lost?” he says.
“It’s a very disorienting experience and a very uncomfortable feeling.”
Even when the perceptual mismatch between the track and curtain was
small, the “pattern separating” part of CA3 almost completely changed
its activity patterns, creating a new memory of the altered environment.
But the “pattern completing” part of CA3 tended to retrieve a similar
activity pattern used to encode the original memory, even when the
perceptual mismatch increased.
The findings, which validate models about how memory works, could
help explain what goes wrong with memory in diseases like Alzheimer’s
and could help to preserve people’s memories as they age.
The National Institute of Health and the Johns Hopkins Brain Sciences Institute supported the work.
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