Human memory is unreliable enough as it is, but researchers interested in better understanding
how and where our memories are stored are developing new ways to manipulate them.
The search for memory "engrams," a collection of identifiable neurons that physically represent
a memory, has occupied scientists for over a hundred years.
Turns out, memory is a complex process that involves several brain areas.
We know that when your brain makes a memory, physical changes and a strengthening of connections
between neurons "encode" the information so you can remember it.
The complete network of these neuronal changes is what we now identify as an "engram"
or memory.
Once scientists learned how and where memory was stored they wanted to know if they could
manipulate it.
So, good news for your memory of that painful breakup, teams of researchers have demonstrated
that emotionally important memories can actually be removed in mice.
It's not full "Sunshine of the Spotless Mind" for mice, but we're getting there.
In one study researchers eliminated a set of cells in part of the brain's emotional
processing center, the amygdala, and were able to ERASE a specific fear-associated memory
of receiving an electric shock.
In other studies, scientists were able to use optogenetics to "implant" a memory
of pain and fear into mice.
By activating an engram of one place when the mouse was actually in another.
First, they created a memory of "safety" by placing a genetically modified mouse in
a new cage and letting it enjoy its experience.
Then they placed the mouse in another cage and delivered foot shocks that they did not
enjoy, while stimulating neurons that formed the memory of the 'safe' cage at the same
time.
When the mouse was returned to the "safe" cage, they exhibited a classic freezing response,
which is a mouse's way of showing fear.
This told researchers that as they intended, the painful memory of the shock was now incorrectly
associated with the previously safe place...
Freaky.
New results from experiments with human subjects who already had electrodes implanted in their
brains as a treatment for epilepsy, showed that tracking learning efficiency through
brain wave monitoring by a machine learning algorithm and pairing poor learning predictions
with direct electrical stimulation of the lateral temporal cortex, improved memory and
recall . Meaning, the right kind of stimulation could
help us remember certain things we would otherwise have forgotten.
Which, could come in handy the next time we need to cram for an exam.
Maybe in the future our ability to manipulate memory will help us remember important information
and help us forget painful experiences - like those associated with PTSD.
But the results of these experiments also calls into question how we know what we know.
We use memories all the time to navigate life and make predictions of future outcomes.
The idea that memories are not immutable, shakes our understanding of our subjective
experience.
I mean, who will we trust in the future if not ourselves?
47% of the general population surveyed in a published study believed that "once you
have experienced an event and formed a memory of it, that memory does not change" after
watching this video, do you agree?
Let us know in the comments, and check out Trace's video, here, to find out whether
typing or handwriting is better for your memory!
Don't forget to subscribe, and I'll see you next time on Seeker.
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