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TED2011

Antonio Damasio: The quest to understand consciousness

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Every morning we wake up and regain consciousness -- that is a marvelous fact -- but what exactly is it that we regain? Neuroscientist Antonio Damasio uses this simple question to give us a glimpse into how our brains create our sense of self.

- Neuroscientist
Antonio Damasio's research in neuroscience has shown that emotions play a central role in social cognition and decision-making. His work has had a major influence on current understanding of the neural systems, which underlie memory, language, consciousness. Full bio

I'm here to talk about
00:15
the wonder and the mystery
00:17
of conscious minds.
00:20
The wonder is about the fact
00:23
that we all woke up this morning
00:25
and we had with it
00:27
the amazing return of our conscious mind.
00:29
We recovered minds with a complete sense of self
00:32
and a complete sense of our own existence,
00:35
yet we hardly ever pause to consider this wonder.
00:38
We should, in fact,
00:40
because without having this possibility of conscious minds,
00:42
we would have no knowledge whatsoever
00:46
about our humanity;
00:48
we would have no knowledge whatsoever about the world.
00:50
We would have no pains, but also no joys.
00:53
We would have no access to love
00:55
or to the ability to create.
00:58
And of course, Scott Fitzgerald said famously
01:01
that "he who invented consciousness
01:04
would have a lot to be blamed for."
01:07
But he also forgot
01:10
that without consciousness,
01:12
he would have no access to true happiness
01:14
and even the possibility of transcendence.
01:17
So much for the wonder, now for the mystery.
01:19
This is a mystery
01:22
that has really been extremely hard to elucidate.
01:24
All the way back into early philosophy
01:27
and certainly throughout the history of neuroscience,
01:30
this has been one mystery
01:33
that has always resisted elucidation,
01:36
has got major controversies.
01:38
And there are actually many people
01:40
that think we should not even touch it;
01:42
we should just leave it alone, it's not to be solved.
01:44
I don't believe that,
01:46
and I think the situation is changing.
01:48
It would be ridiculous to claim
01:50
that we know how we make consciousness
01:52
in our brains,
01:55
but we certainly can begin
01:57
to approach the question,
01:59
and we can begin to see the shape of a solution.
02:01
And one more wonder to celebrate
02:04
is the fact that we have imaging technologies
02:07
that now allow us to go inside the human brain
02:11
and be able to do, for example,
02:15
what you're seeing right now.
02:17
These are images that come from Hanna Damasio's lab,
02:19
and which show you, in a living brain,
02:22
the reconstruction of that brain.
02:25
And this is a person who is alive.
02:27
This is not a person
02:29
that is being studied at autopsy.
02:31
And even more --
02:34
and this is something that one can be really amazed about --
02:36
is what I'm going to show you next,
02:39
which is going underneath the surface of the brain
02:41
and actually looking in the living brain
02:44
at real connections, real pathways.
02:47
So all of those colored lines
02:50
correspond to bunches of axons,
02:53
the fibers that join cell bodies
02:56
to synapses.
02:58
And I'm sorry to disappoint you, they don't come in color.
03:01
But at any rate, they are there.
03:03
The colors are codes for the direction,
03:06
from whether it is back to front
03:08
or vice versa.
03:10
At any rate, what is consciousness?
03:12
What is a conscious mind?
03:15
And we could take a very simple view
03:17
and say, well, it is that which we lose
03:19
when we fall into deep sleep without dreams,
03:23
or when we go under anesthesia,
03:28
and it is what we regain
03:30
when we recover from sleep
03:32
or from anesthesia.
03:34
But what is exactly that stuff that we lose under anesthesia,
03:36
or when we are in deep, dreamless sleep?
03:40
Well first of all,
03:42
it is a mind,
03:44
which is a flow of mental images.
03:46
And of course consider images
03:48
that can be sensory patterns,
03:50
visual, such as you're having right now
03:52
in relation to the stage and me,
03:54
or auditory images,
03:56
as you are having now in relation to my words.
03:58
That flow of mental images
04:00
is mind.
04:02
But there is something else
04:04
that we are all experiencing in this room.
04:06
We are not passive exhibitors
04:08
of visual or auditory
04:10
or tactile images.
04:13
We have selves.
04:15
We have a Me
04:17
that is automatically present
04:19
in our minds right now.
04:21
We own our minds.
04:23
And we have a sense that it's everyone of us
04:25
that is experiencing this --
04:28
not the person who is sitting next to you.
04:30
So in order to have a conscious mind,
04:33
you have a self within the conscious mind.
04:36
So a conscious mind is a mind with a self in it.
04:40
The self introduces the subjective perspective in the mind,
04:43
and we are only fully conscious
04:46
when self comes to mind.
04:48
So what we need to know to even address this mystery
04:50
is, number one, how are minds are put together in the brain,
04:53
and, number two, how selves are constructed.
04:56
Now the first part, the first problem,
05:00
is relatively easy -- it's not easy at all --
05:03
but it is something that has been approached gradually in neuroscience.
05:06
And it's quite clear that, in order to make minds,
05:10
we need to construct neural maps.
05:13
So imagine a grid, like the one I'm showing you right now,
05:16
and now imagine, within that grid,
05:19
that two-dimensional sheet,
05:21
imagine neurons.
05:23
And picture, if you will,
05:25
a billboard, a digital billboard,
05:27
where you have elements
05:29
that can be either lit or not.
05:31
And depending on how you create the pattern
05:33
of lighting or not lighting,
05:36
the digital elements,
05:39
or, for that matter, the neurons in the sheet,
05:41
you're going to be able to construct a map.
05:43
This, of course, is a visual map that I'm showing you,
05:45
but this applies to any kind of map --
05:48
auditory, for example, in relation to sound frequencies,
05:50
or to the maps that we construct with our skin
05:53
in relation to an object that we palpate.
05:56
Now to bring home the point
05:59
of how close it is --
06:01
the relationship between the grid of neurons
06:03
and the topographical arrangement
06:06
of the activity of the neurons
06:08
and our mental experience --
06:10
I'm going to tell you a personal story.
06:12
So if I cover my left eye --
06:14
I'm talking about me personally, not all of you --
06:17
if I cover my left eye,
06:19
I look at the grid -- pretty much like the one I'm showing you.
06:21
Everything is nice and fine and perpendicular.
06:24
But sometime ago, I discovered
06:27
that if I cover my left eye,
06:29
instead what I get is this.
06:32
I look at the grid and I see a warping
06:34
at the edge of my central-left field.
06:37
Very odd -- I've analyzed this for a while.
06:40
But sometime ago,
06:42
through the help of an opthamologist colleague of mine,
06:45
Carmen Puliafito,
06:48
who developed a laser scanner of the retina,
06:50
I found out the the following.
06:53
If I scan my retina
06:55
through the horizontal plane that you see there in the little corner,
06:57
what I get is the following.
07:00
On the right side, my retina is perfectly symmetrical.
07:02
You see the going down towards the fovea
07:05
where the optic nerve begins.
07:08
But on my left retina there is a bump,
07:10
which is marked there by the red arrow.
07:12
And it corresponds to a little cyst
07:14
that is located below.
07:16
And that is exactly what causes
07:18
the warping of my visual image.
07:21
So just think of this:
07:24
you have a grid of neurons,
07:26
and now you have a plane mechanical change
07:28
in the position of the grid,
07:32
and you get a warping of your mental experience.
07:34
So this is how close
07:36
your mental experience
07:38
and the activity of the neurons in the retina,
07:40
which is a part of the brain located in the eyeball,
07:43
or, for that matter, a sheet of visual cortex.
07:46
So from the retina
07:49
you go onto visual cortex.
07:51
And of course, the brain adds on
07:53
a lot of information
07:55
to what is going on
07:57
in the signals that come from the retina.
07:59
And in that image there,
08:01
you see a variety of islands
08:03
of what I call image-making regions in the brain.
08:05
You have the green for example,
08:08
that corresponds to tactile information,
08:10
or the blue that corresponds to auditory information.
08:12
And something else that happens
08:15
is that those image-making regions
08:17
where you have the plotting
08:20
of all these neural maps,
08:22
can then provide signals
08:24
to this ocean of purple that you see around,
08:26
which is the association cortex,
08:29
where you can make records of what went on
08:31
in those islands of image-making.
08:34
And the great beauty
08:36
is that you can then go from memory,
08:38
out of those association cortices,
08:41
and produce back images
08:43
in the very same regions that have perception.
08:46
So think about how wonderfully convenient and lazy
08:49
the brain is.
08:52
So it provides certain areas
08:54
for perception and image-making.
08:56
And those are exactly the same
08:58
that are going to be used for image-making
09:00
when we recall information.
09:03
So far the mystery of the conscious mind
09:06
is diminishing a little bit
09:09
because we have a general sense
09:11
of how we make these images.
09:13
But what about the self?
09:15
The self is really the elusive problem.
09:17
And for a long time,
09:20
people did not even want to touch it,
09:22
because they'd say,
09:24
"How can you have this reference point, this stability,
09:26
that is required to maintain
09:29
the continuity of selves day after day?"
09:31
And I thought about a solution to this problem.
09:34
It's the following.
09:37
We generate brain maps
09:39
of the body's interior
09:41
and use them as the reference for all other maps.
09:43
So let me tell you just a little bit about how I came to this.
09:46
I came to this because,
09:49
if you're going to have a reference that we know as self --
09:51
the Me, the I
09:55
in our own processing --
09:57
we need to have something that is stable,
10:00
something that does not deviate much
10:02
from day to day.
10:05
Well it so happens that we have a singular body.
10:07
We have one body, not two, not three.
10:09
And so that is a beginning.
10:12
There is just one reference point, which is the body.
10:14
But then, of course, the body has many parts,
10:16
and things grow at different rates,
10:19
and they have different sizes and different people;
10:21
however, not so with the interior.
10:23
The things that have to do
10:26
with what is known as our internal milieu --
10:28
for example, the whole management
10:30
of the chemistries within our body
10:32
are, in fact, extremely maintained
10:34
day after day
10:36
for one very good reason.
10:38
If you deviate too much
10:40
in the parameters
10:42
that are close to the midline
10:44
of that life-permitting survival range,
10:46
you go into disease or death.
10:49
So we have an in-built system
10:51
within our own lives
10:54
that ensures some kind of continuity.
10:56
I like to call it an almost infinite sameness from day to day.
10:59
Because if you don't have that sameness, physiologically,
11:02
you're going to be sick or you're going to die.
11:06
So that's one more element for this continuity.
11:08
And the final thing
11:11
is that there is a very tight coupling
11:13
between the regulation of our body within the brain
11:15
and the body itself,
11:19
unlike any other coupling.
11:21
So for example, I'm making images of you,
11:24
but there's no physiological bond
11:26
between the images I have of you as an audience
11:29
and my brain.
11:32
However, there is a close, permanently maintained bond
11:34
between the body regulating parts of my brain
11:38
and my own body.
11:41
So here's how it looks. Look at the region there.
11:43
There is the brain stem in between the cerebral cortex
11:46
and the spinal cord.
11:49
And it is within that region
11:51
that I'm going to highlight now
11:53
that we have this housing
11:55
of all the life-regulation devices
11:58
of the body.
12:01
This is so specific that, for example,
12:03
if you look at the part that is covered in red
12:06
in the upper part of the brain stem,
12:09
if you damage that as a result of a stroke, for example,
12:11
what you get is coma
12:14
or vegetative state,
12:16
which is a state, of course,
12:18
in which your mind disappears,
12:20
your consciousness disappears.
12:22
What happens then actually
12:25
is that you lose the grounding of the self,
12:27
you have no longer access to any feeling of your own existence,
12:30
and, in fact, there can be images going on,
12:33
being formed in the cerebral cortex,
12:36
except you don't know they're there.
12:38
You have, in effect, lost consciousness
12:40
when you have damage to that red section of the brain stem.
12:43
But if you consider the green part of the brain stem,
12:47
nothing like that happens.
12:50
It is that specific.
12:52
So in that green component of the brain stem,
12:54
if you damage it, and often it happens,
12:57
what you get is complete paralysis,
13:00
but your conscious mind is maintained.
13:02
You feel, you know, you have a fully conscious mind
13:05
that you can report very indirectly.
13:08
This is a horrific condition. You don't want to see it.
13:11
And people are, in fact, imprisoned
13:14
within their own bodies,
13:16
but they do have a mind.
13:18
There was a very interesting film,
13:20
one of the rare good films done
13:22
about a situation like this,
13:24
by Julian Schnabel some years ago
13:26
about a patient that was in that condition.
13:28
So now I'm going to show you a picture.
13:31
I promise not to say anything about this,
13:33
except this is to frighten you.
13:35
It's just to tell you
13:37
that in that red section of the brain stem,
13:39
there are, to make it simple,
13:42
all those little squares that correspond to modules
13:44
that actually make brain maps
13:47
of different aspects of our interior,
13:50
different aspects of our body.
13:53
They are exquisitely topographic
13:55
and they are exquisitely interconnected
13:58
in a recursive pattern.
14:00
And it is out of this and out of this tight coupling
14:02
between the brain stem and the body
14:05
that I believe -- and I could be wrong,
14:07
but I don't think I am --
14:09
that you generate this mapping of the body
14:11
that provides the grounding for the self
14:14
and that comes in the form of feelings --
14:17
primordial feelings, by the way.
14:19
So what is the picture that we get here?
14:21
Look at "cerebral cortex," look at "brain stem,"
14:23
look at "body,"
14:25
and you get the picture of the interconnectivity
14:27
in which you have the brain stem providing the grounding for the self
14:30
in a very tight interconnection with the body.
14:34
And you have the cerebral cortex
14:37
providing the great spectacle of our minds
14:39
with the profusion of images
14:42
that are, in fact, the contents of our minds
14:44
and that we normally pay most attention to,
14:47
as we should, because that's really
14:50
the film that is rolling in our minds.
14:52
But look at the arrows.
14:54
They're not there for looks.
14:56
They're there because there's this very close interaction.
14:58
You cannot have a conscious mind
15:01
if you don't have the interaction
15:03
between cerebral cortex and brain stem.
15:05
You cannot have a conscious mind
15:07
if you don't have the interaction
15:09
between the brain stem and the body.
15:11
Another thing that is interesting
15:13
is that the brain stem that we have
15:15
is shared with a variety of other species.
15:17
So throughout vertebrates,
15:19
the design of the brain stem is very similar to ours,
15:21
which is one of the reasons why I think
15:24
those other species have conscious minds like we do.
15:26
Except that they're not as rich as ours,
15:29
because they don't have a cerebral cortex like we do.
15:32
That's where the difference is.
15:34
And I strongly disagree with the idea
15:36
that consciousness should be considered
15:39
as the great product of the cerebral cortex.
15:42
Only the wealth of our minds is,
15:44
not the very fact that we have a self
15:46
that we can refer
15:49
to our own existence,
15:51
and that we have any sense of person.
15:53
Now there are three levels of self to consider --
15:57
the proto, the core and the autobiographical.
16:00
The first two are shared
16:03
with many, many other species,
16:05
and they are really coming out
16:07
largely of the brain stem
16:09
and whatever there is of cortex in those species.
16:11
It's the autobiographical self
16:14
which some species have, I think.
16:16
Cetaceans and primates have also
16:18
an autobiographical self to a certain degree.
16:21
And everybody's dogs at home
16:23
have an autobiographical self to a certain degree.
16:25
But the novelty is here.
16:28
The autobiographical self is built
16:30
on the basis of past memories
16:32
and memories of the plans that we have made;
16:34
it's the lived past and the anticipated future.
16:37
And the autobiographical self
16:40
has prompted extended memory, reasoning,
16:42
imagination, creativity and language.
16:45
And out of that came the instruments of culture --
16:47
religions, justice,
16:50
trade, the arts, science, technology.
16:52
And it is within that culture
16:54
that we really can get --
16:56
and this is the novelty --
16:58
something that is not entirely set by our biology.
17:00
It is developed in the cultures.
17:04
It developed in collectives of human beings.
17:06
And this is, of course, the culture
17:10
where we have developed something that I like to call
17:12
socio-cultural regulation.
17:15
And finally, you could rightly ask,
17:17
why care about this?
17:19
Why care if it is the brain stem or the cerebral cortex
17:21
and how this is made?
17:24
Three reasons. First, curiosity.
17:26
Primates are extremely curious --
17:28
and humans most of all.
17:30
And if we are interested, for example,
17:32
in the fact that anti-gravity
17:35
is pulling galaxies away from the Earth,
17:37
why should we not be interested in what is going on
17:39
inside of human beings?
17:41
Second, understanding society and culture.
17:44
We should look
17:46
at how society and culture
17:48
in this socio-cultural regulation
17:50
are a work in progress.
17:52
And finally, medicine.
17:54
Let's not forget that some of the worst diseases
17:56
of humankind
17:58
are diseases such as depression,
18:00
Alzheimer's disease, drug addiction.
18:02
Think of strokes that can devastate your mind
18:05
or render you unconscious.
18:08
You have no prayer
18:10
of treating those diseases effectively
18:13
and in a non-serendipitous way
18:16
if you do not know how this works.
18:18
So that's a very good reason
18:20
beyond curiosity
18:22
to justify what we're doing,
18:24
and to justify having some interest in what is going on in our brains.
18:26
Thank you for your attention.
18:29
(Applause)
18:31

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About the Speaker:

Antonio Damasio - Neuroscientist
Antonio Damasio's research in neuroscience has shown that emotions play a central role in social cognition and decision-making. His work has had a major influence on current understanding of the neural systems, which underlie memory, language, consciousness.

Why you should listen

Antonio Damasio is a leader in understanding the biological origin of consciousness. He also argues that emotions, far from being barriers to it, are a crucial component of decision-making. He is founder and director of the USC Brain and Creativity Institute, which draws on partners across academic disciplines to use the explosion of new neuroscience results to tackle issues from mental health to societal and global change.

Damasio is the author of Self Comes to Mind: Constructing the Conscious Brain, which was adapted into a musical composition performed by Yo-Yo Ma at the American Museum of Natural History.

More profile about the speaker
Antonio Damasio | Speaker | TED.com