So, obviously, the amygdala plays a big role in how we remember but apparently we also have, there’s also a huge role for the hippocampus
which is spatial, with the amygdala being more emotional. Am I right thus far?
Sure.
Okay. That’s all I have! So, if you want to talk about the role of the hippocampus, which is truly fascinating,
you might have heard about this recent bestselling book called "Moonwalking with Einstein"
which talks about people who are specialists in remembering stuff –
memory champs they’re called.
Written by Joshua Foer who couldn’t be here tonight but
he did tape something for us which I want to show you and then we will get into the hippocampus.
Check it out.
The kind folks at the World Science Festival have very generously given me a list
of 150 random words that they want me to memorize.
I’m gonna do that by using an ancient technique
that was invented in the 5th century B.C. called the memory palace.
And the idea is I’m gonna create wild, crazy images of
the words on this list and tie them to a space in my mind.
So the first word on the list is ‘science’. So I’m gonna imagine right here Albert Einstein
sitting on my shoulders and slapping my cheeks. That should be totally memorable.
The second word on the list is ‘heart’ so I’m actually gonna imagine a gigantic, beating bloody heart
and I’m just gonna impale it on this sundial. I don’t think I’m gonna forget that.
Alright so the third word on the list is ‘speech’ so I’m gonna imagine
Colin Firth from The King’s Speech stuttering(stutters actually) right here. That’ll be memorable.
The next word on the list in green peppers. I’m gonna see a rotting, stinking green pepper
right here in this bush.
Error, university, t-shirt, violence, chicken, nation, football, photo...
The final word is tool, and in this bamboo fence I’m just gonna see
a gigantic monkey wrench just embedded in the fence.
Whoo! That's it.
Alright! Now that I remembered all these words, I’m gonna go distract myself for a few minutes
and then come back and see if I can still remember the list.
3.14159
Wilson! Harding!
6535! Alright! That's as far as I can go.
So! It’s recall time! Umm, let’s see. The first word was
science, then heart, speech , error, university, t- shirt, violence,
football, photo, tool.
applause
Lynn, explain that to us.
Ha, ha, ha - sure.
So he made a reference to the fact that this had been invented or discovered in 5th century B.C.
so the actual story goes like this – and I think
we have enough time for me to go a little bit off of the script.
So Simonides was the Greek person to discover this. He was at a party,
in a big buiding
and was called out and when he was called out,
the entire building collapsed and everybody was demolished
And the survivors were interested in who was in the remains, so to speak.
And he reconstructed who was sitting where by remembering where they were sitting.
And it was on the basis of his doing that that he understood that
remembering things on the basis of spatial location works pretty well.
So he then invented this method called the “Method of Loci” as a way, as a memory tool.”
This method was then picked up in the middle ages
by Redereticians and by individuals who had to have good memories
and they created memory palaces of the sort that Joshua just described.
And they used this as a way of remembering sequences of things,
speeches they had to give, oral narratives and all those things
And at that time, nobody really understood, you know, why did this work so well
But what came in this century, we had the work that Dan referred to with his patient
H.M. who had damage to the hippocampus that caused big memory deficits
And then ten or fifteen years later,
a fellow named John who I worked with
discovered that in the right hippocampus, the individual neurons,
some of which Todd was showing you
that those neurons respond to most effectively
to where the animal is located in space.
So that they, in the wrath,it appeared that the hippocampus was interested in space.
And then there was a big problem in the field, how had he put those two together
So why is it the case that a brain system that is so important for memory is also so important for space
And so the answer is, if there is any answer yet,actually this is still somewhat unclear...
The answer is that, we..we probably use this kind of spatial framework as a way of remembering the..
..episodes of our life.
They all happen in a particular location
that is why the spatial context was so important that experiments we did on reconsolidation
that I described before.
So that there is some very deep connection between the way we remember things
..and...
The space in which those things occur
and we use a spatial scaffold as it were
to help us remember the events of our life.
In Josh's book, he sort of says that we evolved this way because we have to
remember the way to the clearing where we killed the Mastadon
No..No...Absolutely..I mean so our ability to..
..to sort of..
I mean there is a lot of interesting connections here.
First of all, being lost in spaces is a profoundly terrifying thing.
We all really want to know where we are.If you come out of the subway..and you.. you know..you suddenly don't
know where you are...It is a very anxiety provoking..so..so knowing where you are in space
..is pretty important.
Precisely because if you don't know where you are you may be in danger.
So knowing how to get to the safest place,knowing how to get to food, knowing how to find water,
..knowing where your mate might be and so all those things are evolutionarily extremely important.
And the circuits that are crucial for this kind of spatial knowledge,that are linked with memory go way back in
..evolution.I mean you can trace them back
..3 or 4 hundred million years.So this kind of ability...
..the need to know how to get around in space and how to find your way in space..
is fundamental to... for any moving organism
So we leave plans out of the equation for the movement.But for the animals, this is absolutely crucial..
..ability and it is somehow got integrated into what became a basis for our ability to remember the episodes
..of our life in a way that turns out to be very effective and so memory tricksters use it but it's not a trick.
It's actually the way the mind and the brain seem to work.