– SHOW 1101
The Sight of Touch
Grow Your Own Brain
True or False?
What’s in a Dream?
Monastery of the Mind
The Power of Half
ALDA: This mouse is not only building new muscle; it's growing
new brain. And you could too.
ALAN ALDA: (Narration) Find out how running might add new
cells to your brain -- and make you smarter. Join us in an
experiment that rewires a brain.
ALVARO PASCUAL-LEONE: Wow, this is good!
ALDA: (Narration) Meet a young woman whose right brain does
ALAN ALDA: That's amazing.
MACK: That's great. I hope this is on tape!
ALDA: (Narration) Eavesdrop on my dreams -- and peer into
ALDA: I'm Alan Alda, Join me as Scientific American Frontiers
explores novel ways of Changing Your Mind.
SIGHT OF TOUCH
ALDA: "I've changed my mind." We say and do it every day --
about the gift to buy, the candidate to vote for, the route
to take, the dish to order. What we mean of course is that
we've made a different choice -- we haven't actually altered
the structure of our brains. In fact, the conventional wisdom
is that once we are adults, and certainly as we grow older,
our minds -- our brains -- remain pretty much fixed and rigid
-- certainly our opinions do! Well, guess what: you're going
to have to change your mind.
Hi Michelle, I'm Courtney, one of the dieticians.
GERONIMO: Hi Courtney.
How are you?
GERONIMO: How are you?
Good. I just came over to review how the food is going to
be set up for the study. Since you're going to be blindfolded.
ALDA: (Narration) Michelle Geronimo has volunteered to be
the subject of an extraordinary experiment. I'm here to lend
a little moral support. In a few moments, Michelle is going
to lose her sight.
ALDA: Is this real food?
These are food models that we use for teaching purposes.
ALDA: That's a great relief.
GERONIMO: For me too.
ALDA: Because if that was the real food I wouldn't wear that
blindfold if I were you.
ALDA: (Narration) Neuropsychologist Alvaro Pascual-Leone makes
sure Michelle won't peek by tucking a tell-tale snippet of
photographic film into the blindfold.
ALDA: Your last look, huh?
GERONIMO: Yeah, into the darkness.
PASCUAL-LEONE: Here we go.
GERONIMO: Here we go.
ALDA: (Narration) It's now 9 am Monday morning.
PASCUAL-LEONE: We're going to start bandaging, OK?
ALDA: (Narration) Michelle will be totally blind until 3 pm
WARD : There are eye pockets, so you can blink.
ALDA: (Narration) Here's the moral support I mentioned.
ALDA: Michelle, can you hear me?
GERONIMO: Yes I can.
ALDA: Hi! ALAN ALDA: (Narration) To get a sense of Michelle's
next few days, I'm being blindfolded for the morning. CAROL
: Are you both ready to start walking with the cane?
ALDA: Yeah, who's this, here? Who's that, the cameraman?
ALAN ALDA: Well get out of the way!
ALDA: (Narration) We're headed for the hospital's Clinical
Research Center -- and at once my awareness of the surroundings
shifts from sight to my other senses.
: The differences in sound quality.
ALAN ALDA: Sound and temperature.
ALDA: (Narration) In fact the whole point of the experiment
Michelle's about to go through is to see if this shift in
sensory input has an impact on her brain -- in particular,
on her sense of touch while she learns to read Braille.
ALDA: D. It feels a little thicker on the top.
It's like a C with another dot.
ALDA: (Narration) I'm having trouble even feeling the dots,
let alone interpreting them as letters.
ALDA: Eventually you get the shape of it and they just go
automatically into your brain as a letter, I guess.
GIL: "As things turned out, my mother and I were able to leave
Cuba together in 1962"
ALDA: (Narration) But we now need to back up a little in our
story, and meet Gil Busch who's been blind from birth. He
earns his living as a proof-reader for Braille publications.
Information pours into his brain -- principally through the
tip of his right index finger -- at an astonishing rate. For
years, brain scientists have been fascinated by this skill
and have wondered if it involves a change in the way the brain
is organized. This little device presents Braille letters
to a fingertip for just a few milliseconds.
E. I. L.O.
ALDA: (Narration) With Gil's baseline skill established, now
comes the dramatic part of the experiment.
PASCUAL-LEONE: I'm just taking the magnetic stimulation coil.
ALDA: (Narration) This coil will deliver a powerful magnetic
jolt to Gil's brain, temporarily disabling the region immediately
PASCUAL-LEONE: We're targeting the back of your brain and
in fact the back part we call the visual cortex.
ALDA: (Narration) The visual cortex handles information from
the eyes -- at least in those of us with sight.
PASCUAL-LEONE: Does it feel OK?
It feels fine.
ALDA: (Narration) Which makes this experiment seem rather
odd. Why zap the visual cortex, when what's being tested is
a skill involving touch, which is processed in another part
of the brain entirely? In fact, this is a recreation of an
experiment first done by Alvaro and his colleagues several
years ago. Gil's experience today perfectly replicates that
They felt very dim, like the dots weren't coming up as well
ALAN ALDA: (Narration) Gil's accuracy declined too. The extraordinary
implication is that Gil's visual cortex is involved in reading
Braille -- as if his brain has somehow rewired itself to recruit
for touch, brain cells most of us use for seeing. And this
is the reason for Michelle's abrupt encounter with blindness.
The question is: Can her brain also rewire itself to help
read Braille -- in her case after just a few days as compared
with Gil's lifetime without sight?
GERONIMO: Or king, king, G -- six dots.
ALDA: (Narration) But for me, three hours of total blindness
ALDA: That is bright. Michelle, I can't see!
GERONIMO: That's comforting!
ALDA: (Narration) Later on that first day of Michelle's blindness,
she goes to have her head examined -- in an MRI machine that
will take pictures of her brain while different senses are
stimulated. To understand the results we need a brief lesson
in brain anatomy.
ALDA: Can you show me the parts of the brain that I use when
I'm looking at stuff?
PASCUAL-LEONE: Yeah. Let me open up your head.
PASCUAL-LEONE: So basically of course the light would be coming
in through here, and it actually travels all the way to the
very back of the brain, the occipital cortex, that is the
ALDA: Back over here.
PASCUAL-LEONE: Back over there.
ALAN ALDA: So if that's where I see, where do I feel?
PASCUAL-LEONE: Right, so the information from your hand, from
your right hand, will come to the left side of your brain,
specifically here, to the posterior part of the central sulcus.
Information from your left hand will come to the other side,
on the right side of the brain.
ALAN ALDA: (Narration) In this day one testing of Michelle's
brain, the results were no surprise. When the index finger
of her left hand was stimulated, the touch-sensing region
on the right side of her brain lit up, just as it would in
you or me. But now Michelle settles down for her 100 hours
of blindness. A favorite movie doesn't need the picture. There
are walks around the hospital corridors. Activities to exercise
her sense of touch.
GERONIMO: Happy Valentine's Day.
ALDA: (Narration) And practice reading Braille -- hours and
hours of practice reading Braille. Until finally it's Friday.
GERONIMO: 12:39 pm, which means I have 2 hours and 21 minutes
ALDA: (Narration) Michelle's week of total darkness was relieved
by one vivid visual hallucination.
GERONIMO: I had an image on my blindfold, on the left side,
black and white still shot of a face, looking to the left,
really clear, really distinct really odd -- because it was
Elvis Presley. And it was Elvis the later years, Elvis with
a little more hair and the rhinestone outfit with the white
ALDA: (Narration) In these last few hours of blindness, Michelle
returns to the MRI scanner. This time her brain looks very
different. Instead of her touch-sensing region lighting up,
now her visual cortex is activated. It's as if, finding itself
with nothing better to do, the visual cortex has stepped in
to help with a task it's more skilled at than is the touch
region -- making sense of symbols. This possibility is strengthened
when Michelle is tested as Gil was -- to see if disrupting
her visual cortex impairs her ability to read Braille. Her
Braille test is a little easier than Gil's -- to identify
whether pairs of letters are the same or different. Now Michelle's
visual cortex gets 10 minutes under the magnetic coil.
ALVARO PASCUAL-LEONE: OK, we're all done.
ASSISTANT: Michelle, we're going to test your right index
GERONIMO: Yes. Different. Different.
ALDA: (Narration) Sure enough, just like Gil, her accuracy
drops markedly. For Alvaro, already happy as the results emerge,
there's a bonus.
MICHELLE GERONIMO: I found that my fingers have been a little
less sensitive, since the TMS testing, the stimulation, to
the feel of the characters from the Braille task.
PASCUAL-LEONE: That's fabulous. We'll pay you another $500!
GERONIMO: Thank you.
PASCUAL-LEONE: That is exactly what we're looking for. We
were wondering whether there would be some function related
to touch that would be taken over by the visual cortex over
the time that you've been blindfolded. And the fact that your
fingers feel less sensitive now would suggest that that actually
has been the case. Wow! This is good.
ALDA: (Narration) Alvaro has reason to be excited. Michelle's
experience is dramatic confirmation of his hypothesis that
the brain can reorganize itself in just a few days, let alone
PASCUAL-LEONE: I would say that the brain is like, you know,
market economy. There is demand for a certain thing, we activate
what it needs to cover that demand. There is no demand for
it. We use it for something else. It is just like any good
shopkeeper would do: you adjust whatever you offer to people
passing by, by virtue of what they are going to need.
GERONIMO: I feel this blindfold has become part of my face.
PASCUAL-LEONE: You ready? You want to keep your eyes closed
to begin with.
GERONIMO: Oh, geez. Hi. When the blindfold came off I was
a bit disoriented and a bit unbalanced. I'd been dependent
on hearing to orient myself, and then when the vision came
back I found myself off guard and had to take things in a
new way now. But now I'm alright.
PASCUAL-LEONE: So, we'll ask you to put on a blindfold again
-- just for the test -- and do the Braille discrimination.
ALAN ALDA: (Narration) Having her vision restored has in fact
had an even more profound effect than Michelle realizes. When
her visual cortex is zapped the next morning, her ability
to read Braille is unaffected. After just a few hours of working
at its usual job, her vision center has apparently found it's
much too busy to any longer help out with touch. Michelle's
five days of blindness has provided astonishing confirmation
of the malleability of the human brain.
YOUR OWN BRAIN
ALAN ALDA: (Narration) Our next story begins in London, where
of all the brains in the world, few have been changed more
than the one behind the wheel of a London taxicab. No one
can drive a traditional black cab in central London without
first demonstrating "the Knowledge" -- a mental map of London's
Can you take me from Winfield House, the American Ambassador's
residence, to Old Bond Street?
CABBIE: Leave by gate, left down Park Road, bear right Baker
Street, through Portman Square, left into Wigmore Street,
right Welbeck Street.
ALAN ALDA: (Narration) Scientists recently scanned the brains
of 16 volunteer London cabbies, and discovered that they all
possessed a larger than normal hippocampus -- the area of
the brain used for packaging memories before they're stored.
Only months before, an even more astonishing discovery had
been made about this same region of the brain.
GAGE: So this is the imaging room.
ALDA: (Narration) Fred Gage here at the Salk Institute in
California led a team that found brand new neurons in the
hippocampus of Swedish cancer patients. Before they died of
their disease, these patients had volunteered for a study
that labeled any newborn cells in their bodies with a bright
green dye. This is a slice of brain tissue from the hippocampus.
GAGE: The green corresponds to the molecule that was injected
into the blood of the patient 2 years before he died. Which
means that the neuron was born when the patient in this case
was 62 years old. And at some later point, it became a mature
neuron in their brain.
ALAN ALDA: That was clear indication that there were cells
dividing in this mature person?
FRED GAGE: Yes, yes.
ALDA: (Narration) This discovery has set the field of brain
science on its head, overturning the long established dogma
that once we are adults we only lose brain cells, never gain
GAGE: There were not only cells dividing but cells that were
becoming neurons in the adult brain.
ALDA: (Narration) Today research labs all over the world are
scrambling to understand the implications of this discovery.
The starting point for much of this work was a study of rats
done at the University of Illinois. When rats were raised
in an environment that's more interesting and challenging
than the usual lab cage, their brain cells made many more
connections. But there had never been any hint that they also
made new neurons. until Fred Gage and his colleagues set up
a similar study with mice. Not only did they find new neurons
-- once again within the hippocampus -- but mice living a
more interesting and active life had more new neurons than
did mice sitting around being bored. The mice had running
wheels as well as toys in the cage. To find out if simple
exercise had anything to do with growing new brain cells,
the Salk team gave some mice just a running wheel.
VAN PRAAG: To our surprise, we found that mice housed just
with the running wheel had the same number of newborn brain
cells as the enriched environment, suggested that just physical
activity, or exercise alone, can generate new brain cells.
ALDA: (Narration) Having new neurons sounds good. But do they
do any good?
HENRIETTE VAN PRAAG: This is his very first time in the pool,
he's never been in the pool ever before in his life.
ALDA: (Narration) Henriette tested her mice for their ability
to find a platform hidden just beneath the surface of the
ALDA: He doesn't even know there's a platform, huh?
VAN PRAAG: He doesn't know. He knows nothing.
ALDA: Has he found it?
VAN PRAAG: He's found it. But basically he's been lucky. It
usually takes two or three days for the mouse to learn this
task and seven days of training for it to learn it really
well -- for me to put him in the pool and he'll swim to it
in one straight line in two or three seconds.
ALDA: (Narration) Henriette compared the time it took for
both the exercised mice and mice housed in standard cages
to find the platform.
ALDA: Do they tend to go around the outside and then start
to look for other paths? Woom, he found it.
VAN PRAAG: It actually turned out very well for the mice on
the running wheel because they managed to escape from the
water faster, in a shorter amount of time than mice housed
in standard conditions. So this suggests that these mice have
learned better and that they are smarter.
ALDA: (Narration) So running mice not only grow more new neurons.
They also seem to be benefiting from all that extra brain.
ALAN ALDA: Have you started running?
VAN PRAAG: I've started and stopped running.
ALDA: But we all do that! Did you start because of this? And
why did you stop?
HENRIETTE VAN PRAAG: I started because of my experimental
results and because of looking at my slides with this dramatic
increase in new brain cells. But you have to be pretty disciplined
to keep it up and keep running every day.
ALDA: So are you maybe hoping that further experiments will
show that you don't actually have to run? Maybe just rocking
in the chair would be enough to do it, you know.
VAN PRAAG: Well, what worried me was that these mice were
running twelve hours every night. I wondered how we could
even run enough to compare with that. So we did one experiment
where we brought down the time of running to four hours every
night for five days and we already found a 30% increase in
cell division just after the short period of time. So I'm
hoping we can bring it down.
ALDA: To something we can handle. Good. Call me when you find
ALAN ALDA: (Narration) The task now is to find out just how
running or an enriched environment creates new neurons. Growing
cells in a dish outside the brain is one way the Salk researchers
are exploring this question. These are brain cells actually
dividing under the microscope. The hope is to discover the
chemical signals involved, and then find ways to use these
chemicals directly to grow new neurons -- perhaps even in
the brains of people such as Parkinson's or Alzheimer's patients
who have lost neurons to their disease. In the meantime, I'll
never think of my own brain in quite the same way again.
ALDA: There must be in my brain right now a lot of stuff going
on, birth and migration of cells. Am I right about that? Should
I have a new picture of my brain?
GAGE: I think almost more remarkable than just the fact --
which is remarkable enough -- that there's all this movement
and plasticity, that that movement and plasticity and adaptation
that's occurring all the time in the brain is regulated by
the behavior that you emit as an individual. Our brain controls
our behavior, but our behavior can also affect the structure
of our brain, which in turn is going to change how we behave.
ALAN ALDA: (Narration) Which brings us back to those London
cabbies again. Perhaps the reason for their enlarged hippocampus
is that they are adding neurons with all that enrichment they're
getting navigating London streets. Now just imagine how much
extra brain a cabbie might grow if he ran twelve hours a night!
ALDA: (Narration) What I didn't know while I was taking a
walk one morning was that I was being set up -- for a demonstration
that it's not just our brains that are malleable. So too are
a lot of the things we store in them.
SCHACTER: Now we're just going to witness a... simple picnic
scene and we want you to pay attention to how often either
of the folks gets up and down. So whenever someone gets up
and down you just make a mental note of it.
ALDA: (Narration) I knew Dan Schacter to be a noted memory
researcher. But this picnic was a surprise.
ALAN ALDA: Oh good, I love to watch people eat.
ALDA: (Narration) Although Dan had told me to keep track of
how many times the picnickers stood up, I suspected there
was more to this little scene than that. But what? I wasn't
to find out for another two days that the picnic was part
of a carefully choreographed attempt to implant false memories
into my brain - to make me "remember" as real things I'd never
seen. At the time it was like trying to keep track of a very
bad play while sitting uncomfortably close to the author.
After ten bewildering minutes, the picnic - mercifully - came
to an end.
ALDA: Bravo. Very nice, very nice.
SCHACTER: We could have used a little more high drama here
ALDA: Yeah, but it doesn't lack for slowness.
ALDA: (Narration) At this point I was politely asked to leave.
The scene was played over for a stills photographer. But this
time it included things that never happened while I was there.
Which meant I also missed Dan Schacter's basic premise: that
memories are malleable.
SCHACTER: One of the things that we know about memory is that
it's not fixed at the original experience we have. The way
we talk about the event later uh... the way we think about
it uh... can effect, improve or sometimes change our memory.
And photographs are one everyday source of reviewing past
experiences that may have a potent effect on memory and we're
interested in exactly what that effect is.
ALAN ALDA: (Narration) Two days later I was in Dan Schacter's
office at Harvard University, looking at photographs.
SCHACTER: ... is it well cut-out, is it well centered? For
each photo I'm gonna ask you for a one to five rating.
ALAN ALDA: Oh... heh heh, part of me is trying to figure out
what this is really a test of. I'd have to say, you know,
four to four point five. This is a nicely composed picture.
ALDA: (Narration) I didn't believe this rating ploy for a
moment, but graciously played along - even when the photos
where of things I knew I hadn't seen.
ALDA: I take it you don't want me to mention whether or not
this is a picture of something that happened or not, because
this never happened.
SCHACTER: Right, we're not concerned with that right now.
We're just concerned with...
ALAN ALDA:... showing how smart I am.
ALAN ALDA: (Narration) In all I looked at about twenty photographs.
Finally the moment I'd been anticipating... ... the test.
SCHACTER: ... the fishing pole?
ALDA: No. ALAN ALDA: (Narration) The question is: did I see
these things at the picnic or not?
ALDA: No umbrella, no.
SCHACTER: Potato chips?
ALDA: No. The potato chips were in the picture. Well, I remember
them in the picture but I don't remember them on the site.
ALDA: (Narration) I was doing fine until...
SCHACTER: Nail file?
ALDA: Yes I think I remember her filing her nails, although
the picture is also vivid in my mind. But I think I remember
her filing her nails, too.
ALDA: No kite. No, there was no kite. There was a kite in
the picture but that's it.
DAN SCHACTER: OK. A man's cap.
ALDA: (Narration) By now it was obvious that Dan was trying
to confuse my memory of things I'd seen for real...
ALDA: I think he wore a cap.
ALDA: (Narration) ... with things I'd only seen in the photographs.
ALDA: Well, see... I think he was wearing a cap in the photographs
and I think - and I remember when I looked at the photographs
- there's something wrong with this picture. I don't think
he wore a cap.
DAN SCHACTER: A bottle of water?
ALDA: Yes, there was a bottle of water.
ALDA: (Narration) Oh, oh, this would come back to haunt me.
DAN SCHACTER: Folding chairs?
ALDA: No! DAN SCHACTER: No, no way. Pasta?
ALDA: Yes! You think I could forget pasta? Come on!
SCHACTER: It's over.
ALDA: That's it?
SCHACTER: That's it. It's out of your system.
ALDA: So it had nothing to do with how many times they stood
SCHACTER: Well, that was just to get you to pay attention
to what was going on in front of you.
ALDA: Yeah, that's why I paid attention to everything else.
Now what I'm really interested to know is, were you able to
place in my memory things that never occurred in real life?
ALDA: You did? You did?
SCHACTER: We did. Even though um... even though we... you
know, we told you, you knew what the game was. You knew that
some of things that we were showing you in the photographs
had never happened. Despite that...
ALDA: This is horrible.
SCHACTER: One was the nail file.
SCHACTER: That was only in the photo.
ALDA: You know, when I first saw the nail file there was this
little uncertainty - was that real or wasn't it - and then
a second later, I was... I was sure I'd seen it.
ALDA: (Narration) In the final tally, of eight things that
appeared in the pictures only, I wrongly remembered two as
having been at the picnic - the nail file and a bottle of
water. The photographs had somehow lodged in my brain right
along with my memory of the picnic itself and I couldn't tell
which was which. To understand how this can happen means we
have to first understand where in the brain memory is located.
ALDA: Is it possible to point to some place on the brain and
say that's where memory is?
SCHACTER: Well, there's no one place - there's no one place
I can point and say 'there's your memory of high school graduation
and.. and there's your memory for having eaten breakfast yesterday.
Instead of being in one place, many of believe that memory
is kind of scattered in different parts of the brain.
ALDA: (Narration) The idea is that memory consists of all
the bits and pieces of an experience - the sights, the sounds,
the emotions - with each fragment stored in areas of the brain
responsible for handling that particular sensation. So sounds
are stored in the auditory cortex, sights in the visual cortex
and so on. Keeping track of what's where is our old friend
the hippocampus, which functions as a sort of index for our
memories. Recalling an event means re-assembling all those
bits and pieces. It's not like replaying a videotape. It's
more like shaking a kaleidoscope. With every shake - every
recall - the pieces fall together all over again - sometimes,
as in my memory of the picnic, including bits that don't quite
belong. Dan Schacter wondered if he could tell the difference
between real and false memories by peering into the brain
while it was remembering. Twelve people heard word lists like
these, and had to remember as many of the words as they could.
ALDA: Writer... um...
ALDA: (Narration) What's sneaky about the lists is that while
they're each united by a theme, they don't contain the most
SCHACTER: Bed, rest, awake, tired, dream, wake, snooze, blanket,
doze, slumber, snore, nap, peace, yawn, drowsy.
ALDA: Sleep, doze, bed...
ALDA: (Narration) There - right off the bat I said "sleep",
but sleep wasn't on the list. Again, I'd been given a false
ALDA: ... ah, bed...
ALDA: (Narration) The twelve experimental subjects all got
PET scans while doing this test. Recalling both true and false
memories mostly involved the same bits of brain, especially
the hippocampus - the index region. But while the true memory
lit up the auditory cortex, the false memory didn't. So even
though the subjects reported hearing the words that weren't
there, their brains appear to contain no trace of the sounds
of the words.
ALDA: So in a way you really can look inside somebody's brain
and tell whether they're having a true memory or a false memory
under certain conditions.
SCHACTER: Under certain conditions. Within this one experimental
paradigm group of twelve people we were able to see, ah, some
differences between true and false recognition.
ALDA: (Narration) Dan Schacter emphasizes there's a long way
to go before this first faint trace of a false memory could
be turned into a practical test that could be used, for instance,
in a courtroom. Meanwhile, discovering how easily my memory
can be tricked was lesson enough.
ALDA: What I think this really brings home to me is it's very
important to say not 'this is what happened' but 'it seems
to me that I remember this is what happened.'
SCHACTER: I think that's a very important lesson.
IN A DREAM?
ALAN ALDA: (Narration) It's time for me to change my mind
-- from the one I use most of the time during the day.
ALDA: Hello... I sit here?
ALDA: (Narration) To what turns out to be a much more creative
one at night.
HOLMES: OK, he first that we're going to be doing tonight
is putting electrodes on so we can measure your electrical
activity and know your stages of sleep.
ALDA: What's that?
HOLMES: It's called calodian, it's very similar to airplane
glue. And what this...
ALDA: (Narration) Airplane glue in my hair... as it turned
out only the first of several indignities that lay ahead during
my night as a research subject at Harvard University's Sleep
ALDA: I don't want to rush you, but I'm falling asleep.
HOLMES: Are you really? Good.
ALDA: (Narration) The study I'm joining is to find out what
happens to our minds while we're dreaming.
HOLMES: OK, and that's the last electrode.
ALDA: (Narration) Like most people, I've always been fascinated
by dreams - my own especially. How do our brains come up with
that stuff? Even more interesting - why? My night began with
a test of the state of my brain. The task is to spot if the
second of two words flashed on the screen is a real one. Sometimes
the second word seems to be related to the first. When it
is, and my brain makes the association, then I'm usually able
to decide if the second word is real or fake more quickly.
So by measuring my reaction time, the test can tell how good
my brain is at making associations.
ALDA: Bed... bed.
ALDA: (Narration) The only association I was interested in
right then was between bed and sleep - not so easy when you
know a stranger is eavesdropping on your brain.
HOLMES: Alan, I need you to lie quietly with your eyes closed.
OK, if you could blink five times, slowly...
ALDA: (Narration) This is to check the electrodes near my
eye. They'll be looking out for REM - R.E.M. - the rapid eye
movements we all make when we dream.
JEN HOLMES: Great. OK, you're all set. You can go ahead and
get comfortable and have a good night's sleep.
ALDA: (Narration) So if you'll excuse me, I'll leave you in
the care of Jen Holmes while I try to sleep with wires pasted
on my face and glued to my scalp.
HOLMES: Now he's moving, getting comfortable and you'll typically
see some kind of movement when people first start to fall
asleep. He's now officially asleep. Our experiment calls for
him to do the word association test several times during the
night, one of them when he's asleep but not dreaming. That's
what's happening now, so I'll go wake him up.
ALDA: Yep... nope... oh, I'm falling asleep here. I am not
checking into this hotel again.
ALDA: (Narration) Well, after that my night went to pieces.
Every time I drifted off and started to dream I'd think, oh
good, I have to remember this - and promptly wake myself up.
By six in the morning, Jen had been joined by her boss, Bob
Stickgold, and it began to look like we weren't going to find
out what my brain does when it's dreaming.
STICKGOLD: Since about, ah, 2:30 this morning he's been having
a hard time sleeping. Uh, he'll go to sleep - he'll sleep
for ten of fifteen minute series - you can hear the pens slapping
around - he's rolling around in bed now. He's been doing that
for hours now.
ALDA: (Narration) But then, when it was almost too late, I
began drifting into a dream.
ROBERT STICKGOLD: If we wake him up right now we've got an
eighty-five percent chance - a ninety percent chance - of
getting good REM reports. So what we want to do is wait until
it gets another burst - there's some more right there, look
at these, these are really good eyes movements, these are
fast and they're big. So, I think we should go in there now
and see what we can get.
ALDA: I was... uh, being propelled the solar wind but the
wind wasn't behind me, I was going toward the sun. And I was
flying over Berlin and I remember thinking that this was,
uh... called uh... 'Nightgown Over Germany.'
ROBERT STICKGOLD: It's only about six-thirty, it's still early.
ALDA: Oh, it's still early. Well, let's try it.
STICKGOLD: Let's try it. OK. Pleasant dreams.
ALDA: (Narration) With one dream in the bag, I felt better
about trying for another... So that once again I could be
awakened for that exciting word association test.
ROBERT STICKGOLD: So, how does it feel to you that you slept?
ALDA: How did it feel that I slept? I had a worse night of
sleep at a truck route in New Zealand.
ALDA: (Narration) By now all I wanted was a little breakfast
and the airplane glue out of my hair. But I was also curious,
of course, about the tests I'd been taking. What did they
have to do with dreaming? Most dream researchers believe that
during REM sleep the normal signals to the brain from our
bodies are cut off. Instead of receiving inputs from our eyes
and ears, the visual and auditory centers are flooded with
signals surging up from the more primitive regions of the
brain. These signals, the theory goes, are completely random
and meaningless. But dreams, of course, seem to make sense
- at least at the time.
ALDA: ... the wonderful part about it was I went out through
my nose, see? So then I had all these words I was hearing...
ALDA: (Narration) So the key question is, where do the stories
of our dreams come from? According to Bob Stickgold, we simply
make them up as we go along.
ALDA: I'm a little thick this morning because I... I had this
funny night sleep. I still don't quite get how you arrive
at the conclusion that something in the brain is supplying
story and meaning and uh... uh... a coherence to...to these
random images... and not that they're coming up in a more
coherent way already.
STICKGOLD: If you look at your dream, I mean there you have
the start of - gee, it's going to be an out-of-body experience,
and first of all it goes out through your nose. I... I'm sorry,
it's just hard for me to believe that someone scripted that
for you to do. You were just thinking 'out-of-body, how am
I going to get out of body, help me somebody how can I get
out-of-body' and something in your brains says 'oh your nose.'
ALAN ALDA: (Narration) So during dreaming, our brains are
scrambling to make sense of nonsense. Here's where the word
tests are revealing - because subjects woken from REM sleep
are quicker at making associations between words than when
woken from non-REM sleep - or even when they are wide awake
during the day. It's as if during REM sleep our brains are
primed to put together stories from random images and feelings.
ROBERT STICKGOLD: Our guess is - and it's truly just a guess
at this point - is that the brain is just trying to keep up
with these random inputs and trying to use everything it knows
to make some kind of sense out of it.
OF THE MIND
ALDA: (Narration) Cut into the top of a California hill is
the creation of a Nobel prizewinner now well into his third
scientific career. It's a place he likes to compare to older
institutions with a fondness for hilltops.
EDELMAN: Take a look around and look at this surrounding here,
it's like a cloister. So when the architects asked me about
the place, I said I want it to be a scientific monastery.
I don't want it to be like a church. I want it to be a place
where you can contemplate and look ahead 20 years. Now in
science, 10 years is about as much as you can try to look
ahead. Otherwise you're a crackpot. But we try.
ALDA: So you have them looking ahead 20?
EDELMAN: Show a little discretion here!
ALDA: (Narration) Gerry Edelman has looked beyond the horizon
for all his nearly 50 years in science. In 1972 he won the
Nobel Prize for Medicine, having succeeded at a task that
daunted most biologists at the time -- figuring out the structure
of the antibody molecule. He went from that to working on
how living things grow and develop. And then he switched fields
again, to brain science. Five years ago, he conceived of the
Neurosciences Institute, a place that would take on the biggest
scientific mystery of all -- understanding the human mind.
Which meant I was a little unprepared for my first stop at
the Institute -- to visit a modest and very unhuman machine
roving around an indoor pen.
ALDA: What is this little guy doing in here?
EDELMAN: Well, this little guy, whom we call Darwin, after
a very famous biologist and because he's based on a similar
principle to that of natural selection that Darwin invented,
is a creature or a device that's intended to simulate how
the brain and the body work together.
ALDA: How they work together?
TONONI: How they work together. And the idea is something
like this. It looks like a robot but it is not a robot.
ALDA: You mean it hasn't been programmed to do specific actions?
TONONI: That's exactly right. There is no computer program
telling it go three steps, turn to the right, if you see this,
do that. Instead, like an animal, it's born a certain way,
has a brain of a certain kind, and when it make errors it
corrects the errors until it gets something that satisfies
ALDA: (Narration) Darwin's brain is actually much too be big
to be carried around in its body. The brain occupies a supercomputer
in the basement, and keeps in touch with its body by radio.
When Darwin was born it knew next to nothing, not even that
there are two kinds of blocks in its world, one marked with
blobs, the other with stripes. But like a newborn, it does
have sight -- and a liking for things that taste good.
TONONI: There's a gripper in front. The gripper is a little
bit like your tongue -- in a peculiar position -- and it will
sense electricity and conductance. So when it grabs a block
it will get a quote-unquote taste. If the taste is bad it
will drop that block and there will be a change in the strength
of its nervous connections. Therefore it will learn as it
were to stay away from a block with that shape.
ALDA: (Narration) In Darwin's world, it's the blobby blocks
that taste bad, while blocks with stripes taste good. With
just this built-in taste preference, Darwin gradually figures
out what it needs to do to live the good life. The brain itself
is modeled on a mammal's brain, with a visual cortex to receive
the camera image and a second specialized area that interprets
what it sees. In the computer, simulated neurons form a network
with a quarter of a million connections. As Darwin blunders
naively around its pen, these neuronal connections begin to
become organized. Here are groups of neurons firing together
when it sees stripes. Entirely different groups of neurons
light up for a blob. These neurons are in turn connected to
motor nerves that control Darwin's behavior.
EDELMAN: And the rule is very simple. Neurons that fire together,
wire together. So that when the nerve cells or neurons are
strengthened after it gets a reward, that's more likely to
make its behavior similar the next time.
ALDA: (Narration) Darwin's brain is intended as a model for
our own -- except that we have trillions upon trillions of
possible connections between neurons instead of a mere quarter
million. We become who we are through the strengthening of
some of these connections-- between neurons that fire together
-- and the weakening of others. To Edelman, the brain is the
ultimate gooey plastic, capable of near infinite possibilities,
molded by its experience into one of them. Even as we watch,
Darwin's experience is turning it into a creature that craves
stripes and rejects blobs on sight.
ALDA: Do you hit the reset button every few months and let
him be born again to see how he...
EDELMAN: Oh yes. Since it's very expensive to make 20 of them
we generally wipe them clean and start again.
ALDA: And then you see how he learns with this new life that
EDELMAN: And each one does it differently.
ALDA: (Narration) Each one does it differently because its
individual experience in its world is different -- the blocks
are in different places, and it encounters them in a different
order. Each incarnation of Darwin's brain is shaped by its
own particular life -- just as our's is. This makes it very
different from even the most sophisticated conventional computer.
EDELMAN: Gerry Edelman If you are going hunting for birds
in a swamp on a rainy day and I gave you an Air Force computer
that was friendly and spoke English in a teacup, would you
take that or would you take a dog?
EDELMAN: That's what we're trying to understand. How does
the dog recognize novelty? How do some dogs behave better
than others when it comes to certain kinds of stimuli? And
how does that relate to our very being as human beings, which
is the key of course in neurobiology because it's at the center
of human concern. Our brain and body are us.
ALDA: (Narration) Lately, Gerry Edelman has been turning his
thoughts to a mystery so profoundly personal that it has always
seemed beyond the reach of science: the unique world within
our own heads we call consciousness.
EDELMAN: We all know what consciousness is, without having
to ask a philosopher. It's what you lose when you fall into
a deep dreamless sleep, and what you regain when you wake
up. So we have a sense of it, even if we can't put it into
words. And so the problem is this: How do you make it a scientific
subject? How do you actually investigate such a remarkable
thing since it belongs to each individual to some extent privately?
ALDA: So is this an attempt to make it a scientific investigation?
EDELMAN: Exactly. It is indeed. It's to find what they call
in the fancy language, the neural correlates of consciousness.
What happens inside your brain when you actually become conscious
of something. Well, Alan, let me introduce you to Lacey, who's
the lady who really knows how to work this thing. She's going
to take you inside and expose you to this remarkable miracle
of modern science.
ALDA: (Narration) I thought allowing scientists to eavesdrop
on my dreams was pretty brave
ALDA (Narration): But allowing a machine to peer into my consciousness?
The plan here, as I understand it, is to see what happens
in my brain as my consciousness switches from an awareness
of one thing to an awareness of another. What looks like a
giant hair dryer is actually a machine for picking up the
tiny magnetic signals my brain gives off as it busies itself
interpreting the world. In this experiment, my world is limited
to the screen in front of me. To you it looks like a flickering
plaid of blue stripes and red stripes. But the glasses I'm
wearing limit my right eye to seeing only the blue stripes,
and the left eye to seeing only the red stripes. My brain
can't handle these two different signals at the same time,
so it chooses to be aware of -- to be conscious of -- only
one at a time. Every couple of seconds or so it spontaneously
switches -- now I'm aware only of horizontal blue stripes,
now only vertical red ones. As I record which color I'm seeing,
the machine is recording which parts of my brain are responding.
It turns out that neurons fire in response to both red and
blue even when I'm conscious of only one. But there are many
regions of my brain where the response to a color is much
stronger when I am conscious of it. It's as if the blueness,
say, is always there, but springs vividly into my consciousness
only when a vast network of neurons ignites together.
EDELMAN: So think of a kind of flame playing back and forth,
back and forth. The flame is the consciousness if you will,
but there's no one place where the consciousness is.
ALDA: (Narration) The flame flicks between regions of the
brain involved in memory as well as those processing new information
from the senses. Edelman and his colleague Giulio Tononi have
taken snapshots of this metaphorical flame in seven different
subjects like me. At first glance, the flames look similar.
TONONI: But in detail, if you look at it, all people are different.
ALDA: The same thing is happening but it is happening seven
different ways because you have seven different people.
GIULIO TONONI: Seven different faces, seven different brain
activity patterns when you are conscious.
EDELMAN: Seven different signatures when you sign something.
And therefore one of the remarkable conclusions we've come
to is I believe non-trivial to human beings. Individuality
ALDA: (Narration) There's an even more remarkable conclusion
for non-humans. Having an idea of what consciousness is means
you could in principle install one in an artificial brain
EDELMAN: When you synthesize it, it is not going to be like
ALDA:, certainly not. It doesn't have your body, it doesn't
have the same kind of structure. So it will be a consciousness.
Now the question becomes, how do you check it?
ALDA: Yeah, I was going to say, if you can get Darwin to be
conscious, how do you get a report from Darwin?
EDELMAN: You would have to have something like language. Higher
order consciousness. Because otherwise you could only surmise
that it was conscious.
ALDA: (Narration) Knowing what consciousness looks like means
you could also search for it in non-human animals. Edelman
has little doubt that an animal such as a dog would turn out
to possess at least the glimmerings of a consciousness flame.
EDELMAN: The difference between a dog and you however, or
Giulio let's say, is that if you kick a dog the next time
he may bite you or run away, but he doesn't sit around plotting
to remove your professorship!
POWER OF HALF
ALAN ALDA: (Narration) We're ending our show on brain plasticity
with a truly astonishing example. I'm with Jordan Grafman,
looking at the brain scans of a remarkable young woman.
JORDAN GRAFMAN: This is the right side of her brain; this
is the left side of her brain. And what happened was, in utero,
she had a stroke. And the stroke, not entirely, damaged a
large proportion of her left hemisphere.
ALDA: So that never developed?
GRAFMAN: Never developed.
ALDA: What is the left hemisphere usually there for?
GRAFMAN: Verbal processing. Language processing. Not all aspects
of language by the way, but enough that we consider it the
hemisphere that really dominates our language abilities. It
also plays a fairly large role in recognizing objects. Our
ability to look at objects to know what they are and even
how to use them.
ALDA: So if those functions of the brain were only to be found
in that area, then you'd expect that a person without that
part of the brain would have difficulty saying words or recognizing
objects. But this is not the case with Michelle?
GRAFMAN: This is not the case with Michelle.
ALDA: (Narration) Missing almost the entire left side of her
brain, Michelle Mack has an obvious problem controlling the
right side of her body. But at the Catholic Church where her
mother works, it's equally obvious that Michelle has few problems
either with language or recognizing objects. She regularly
helps out with the church records.
MACK: I take them home and I update them on my computer at
home and I bring them back to my mother and I file them.
ALAN ALDA: (Narration) Recently Michelle's mother Carol contacted
Jordan Grafman at the nearby National Institutes of Health
outside Washington DC.
MACK: I wonder what testing Dr. Grafman will be doing.
ALDA: (Narration) Every month or so now, mother and daughter
drive to the NIH to join Grafman and his team in a study of
how Michelle's right brain copes with a workload most brains
share with the left. Today, Carol told the film crew of a
skill even Grafman doesn't know about.
ALAN ALDA: If I say a date, you can come up with what day
of the week it is?
MACK: Yeah, I think so, yes.
ALDA: Well, let me not go too far out. Let's say this year,
the year 2000, October 19th.
MACK: OK. October 19th is going to be on a Thursday.
ALDA: OK, I don't have a calendar so I can't check that. So
far you're doing great. OK. So let me go a year later. The
year 2001, August 12th.
MACK: OK Sunday.
MACK: They're all checking! (Off camera) They're both right.
ALDA: They're both right?
MACK: They're both right.
ALDA: Maybe we should stop at 100% correct, right? That's
MACK: That's great. I hope this is on tape.
ALDA: Did you know she had this ability?
JORDAN GRAFMAN: Not until right now. And that's why it's fun
to work with Michelle because she's always surprising us.
ALAN ALDA: (Narration) Jordan's work with Michelle is only
beginning. But already it's apparent not only that her right
brain has taken on tasks usually done by the left, but that
it's had to make some changes of its own. For instance, Michelle
has problems with tests of her visual-spatial skills, even
though her right brain -- where these are normally tackled
-- is intact.
ALDA: It's almost a question of geography. Like there's a
whole bunch of word people who have no place to live on the
left side, and they're crowding on to the right piece of geography
and there's only a certain amount of land there.
GRAFMAN: They're not asking permission.
ALDA: That's right. They're coming in, they're barging in
and the folks who are living there who handle spatial stuff
are getting crowded out. Not as many of them can do the spatial
stuff. That's what it sounds like is happening.
GRAFMAN: Couldn't have said it better!
ALDA: But that's fascinating isn't it. I mean there's this
old saying that you hear all the time, you know, we only use
10% of our brain. It sounds to me we're all using every bit
GRAFMAN: Every bit we've got, and we'd try to stake out more
if we could.
ALDA: Right. And it's almost as if there are parts of our
ALAN ALDA: for a place to work.
GRAFMAN: Exactly. As you learn new things, there's always
somewhat of a cost. There's a finite amount of space and a
finite amount of tissue, and you can enrich that tissue but
you're also going to compete with adjacent territory as you
learn new skills and have new abilities. And you use the whole
brain, and the whole brain is a competitive organ. Each piece
of the brain is competing with its neighbors to get more territory,
to have more action. And it's happening now in you and it's
happening in Michelle as she takes the tests and develops
throughout her life.
ALDA: (Narration) As we said at the beginning of our show,
we're all having to change our minds about our brains.