The quest to understand consciousness | Antonio Damasio

I'm here to talk about

the wonder and the mystery

of conscious minds.

The wonder is about the fact

that we all woke up this morning

and we had with it

the amazing return of our conscious mind.

We recovered minds with a complete sense of self

and a complete sense of our own existence,

yet we hardly ever pause to consider this wonder.

We should, in fact,

because without having this possibility of conscious minds,

we would have no knowledge whatsoever

about our humanity;

we would have no knowledge whatsoever about the world.

We would have no pains, but also no joys.

We would have no access to love

or to the ability to create.

And of course, Scott Fitzgerald said famously

that "he who invented consciousness

would have a lot to be blamed for."

But he also forgot

that without consciousness,

he would have no access to true happiness

and even the possibility of transcendence.

So much for the wonder, now for the mystery.

This is a mystery

that has really been extremely hard to elucidate.

All the way back into early philosophy

and certainly throughout the history of neuroscience,

this has been one mystery

that has always resisted elucidation,

has got major controversies.

And there are actually many people

that think we should not even touch it;

we should just leave it alone, it's not to be solved.

I don't believe that,

and I think the situation is changing.

It would be ridiculous to claim

that we know how we make consciousness

in our brains,

but we certainly can begin

to approach the question,

and we can begin to see the shape of a solution.

And one more wonder to celebrate

is the fact that we have imaging technologies

that now allow us to go inside the human brain

and be able to do, for example,

what you're seeing right now.

These are images that come from Hanna Damasio's lab,

and which show you, in a living brain,

the reconstruction of that brain.

And this is a person who is alive.

This is not a person

that is being studied at autopsy.

And even more --

and this is something that one can be really amazed about --

is what I'm going to show you next,

which is going underneath the surface of the brain

and actually looking in the living brain

at real connections, real pathways.

So all of those colored lines

correspond to bunches of axons,

the fibers that join cell bodies

to synapses.

And I'm sorry to disappoint you, they don't come in color.

But at any rate, they are there.

The colors are codes for the direction,

from whether it is back to front

or vice versa.

At any rate, what is consciousness?

What is a conscious mind?

And we could take a very simple view

and say, well, it is that which we lose

when we fall into deep sleep without dreams,

or when we go under anesthesia,

and it is what we regain

when we recover from sleep

or from anesthesia.

But what is exactly that stuff that we lose under anesthesia,

or when we are in deep, dreamless sleep?

Well first of all,

it is a mind,

which is a flow of mental images.

And of course consider images

that can be sensory patterns,

visual, such as you're having right now

in relation to the stage and me,

or auditory images,

as you are having now in relation to my words.

That flow of mental images

is mind.

But there is something else

that we are all experiencing in this room.

We are not passive exhibitors

of visual or auditory

or tactile images.

We have selves.

We have a Me

that is automatically present

in our minds right now.

We own our minds.

And we have a sense that it's everyone of us

that is experiencing this --

not the person who is sitting next to you.

So in order to have a conscious mind,

you have a self within the conscious mind.

So a conscious mind is a mind with a self in it.

The self introduces the subjective perspective in the mind,

and we are only fully conscious

when self comes to mind.

So what we need to know to even address this mystery

is, number one, how are minds are put together in the brain,

and, number two, how selves are constructed.

Now the first part, the first problem,

is relatively easy -- it's not easy at all --

but it is something that has been approached gradually in neuroscience.

And it's quite clear that, in order to make minds,

we need to construct neural maps.

So imagine a grid, like the one I'm showing you right now,

and now imagine, within that grid,

that two-dimensional sheet,

imagine neurons.

And picture, if you will,

a billboard, a digital billboard,

where you have elements

that can be either lit or not.

And depending on how you create the pattern

of lighting or not lighting,

the digital elements,

or, for that matter, the neurons in the sheet,

you're going to be able to construct a map.

This, of course, is a visual map that I'm showing you,

but this applies to any kind of map --

auditory, for example, in relation to sound frequencies,

or to the maps that we construct with our skin

in relation to an object that we palpate.

Now to bring home the point

of how close it is --

the relationship between the grid of neurons

and the topographical arrangement

of the activity of the neurons

and our mental experience --

I'm going to tell you a personal story.

So if I cover my left eye --

I'm talking about me personally, not all of you --

if I cover my left eye,

I look at the grid -- pretty much like the one I'm showing you.

Everything is nice and fine and perpendicular.

But sometime ago, I discovered

that if I cover my left eye,

instead what I get is this.

I look at the grid and I see a warping

at the edge of my central-left field.

Very odd -- I've analyzed this for a while.

But sometime ago,

through the help of an opthamologist colleague of mine,

Carmen Puliafito,

who developed a laser scanner of the retina,

I found out the the following.

If I scan my retina

through the horizontal plane that you see there in the little corner,

what I get is the following.

On the right side, my retina is perfectly symmetrical.

You see the going down towards the fovea

where the optic nerve begins.

But on my left retina there is a bump,

which is marked there by the red arrow.

And it corresponds to a little cyst

that is located below.

And that is exactly what causes

the warping of my visual image.

So just think of this:

you have a grid of neurons,

and now you have a plane mechanical change

in the position of the grid,

and you get a warping of your mental experience.

So this is how close

your mental experience

and the activity of the neurons in the retina,

which is a part of the brain located in the eyeball,

or, for that matter, a sheet of visual cortex.

So from the retina

you go onto visual cortex.

And of course, the brain adds on

a lot of information

to what is going on

in the signals that come from the retina.

And in that image there,

you see a variety of islands

of what I call image-making regions in the brain.

You have the green for example,

that corresponds to tactile information,

or the blue that corresponds to auditory information.

And something else that happens

is that those image-making regions

where you have the plotting

of all these neural maps,

can then provide signals

to this ocean of purple that you see around,

which is the association cortex,

where you can make records of what went on

in those islands of image-making.

And the great beauty

is that you can then go from memory,

out of those association cortices,

and produce back images

in the very same regions that have perception.

So think about how wonderfully convenient and lazy

the brain is.

So it provides certain areas

for perception and image-making.

And those are exactly the same

that are going to be used for image-making

when we recall information.

So far the mystery of the conscious mind

is diminishing a little bit

because we have a general sense

of how we make these images.

But what about the self?

The self is really the elusive problem.

And for a long time,

people did not even want to touch it,

because they'd say,

"How can you have this reference point, this stability,

that is required to maintain

the continuity of selves day after day?"

And I thought about a solution to this problem.

It's the following.

We generate brain maps

of the body's interior

and use them as the reference for all other maps.

So let me tell you just a little bit about how I came to this.

I came to this because,

if you're going to have a reference that we know as self --

the Me, the I

in our own processing --

we need to have something that is stable,

something that does not deviate much

from day to day.

Well it so happens that we have a singular body.

We have one body, not two, not three.

And so that is a beginning.

There is just one reference point, which is the body.

But then, of course, the body has many parts,

and things grow at different rates,

and they have different sizes and different people;

however, not so with the interior.

The things that have to do

with what is known as our internal milieu --

for example, the whole management

of the chemistries within our body

are, in fact, extremely maintained

day after day

for one very good reason.

If you deviate too much

in the parameters

that are close to the midline

of that life-permitting survival range,

you go into disease or death.

So we have an in-built system

within our own lives

that ensures some kind of continuity.

I like to call it an almost infinite sameness from day to day.

Because if you don't have that sameness, physiologically,

you're going to be sick or you're going to die.

So that's one more element for this continuity.

And the final thing

is that there is a very tight coupling

between the regulation of our body within the brain

and the body itself,

unlike any other coupling.

So for example, I'm making images of you,

but there's no physiological bond

between the images I have of you as an audience

and my brain.

However, there is a close, permanently maintained bond

between the body regulating parts of my brain

and my own body.

So here's how it looks. Look at the region there.

There is the brain stem in between the cerebral cortex

and the spinal cord.

And it is within that region

that I'm going to highlight now

that we have this housing

of all the life-regulation devices

of the body.

This is so specific that, for example,

if you look at the part that is covered in red

in the upper part of the brain stem,

if you damage that as a result of a stroke, for example,

what you get is coma

or vegetative state,

which is a state, of course,

in which your mind disappears,

your consciousness disappears.

What happens then actually

is that you lose the grounding of the self,

you have no longer access to any feeling of your own existence,

and, in fact, there can be images going on,

being formed in the cerebral cortex,

except you don't know they're there.

You have, in effect, lost consciousness

when you have damage to that red section of the brain stem.

But if you consider the green part of the brain stem,

nothing like that happens.

It is that specific.

So in that green component of the brain stem,

if you damage it, and often it happens,

what you get is complete paralysis,

but your conscious mind is maintained.

You feel, you know, you have a fully conscious mind

that you can report very indirectly.

This is a horrific condition. You don't want to see it.

And people are, in fact, imprisoned

within their own bodies,

but they do have a mind.

There was a very interesting film,

one of the rare good films done

about a situation like this,

by Julian Schnabel some years ago

about a patient that was in that condition.

So now I'm going to show you a picture.

I promise not to say anything about this,

except this is to frighten you.

It's just to tell you

that in that red section of the brain stem,

there are, to make it simple,

all those little squares that correspond to modules

that actually make brain maps

of different aspects of our interior,

different aspects of our body.

They are exquisitely topographic

and they are exquisitely interconnected

in a recursive pattern.

And it is out of this and out of this tight coupling

between the brain stem and the body

that I believe -- and I could be wrong,

but I don't think I am --

that you generate this mapping of the body

that provides the grounding for the self

and that comes in the form of feelings --

primordial feelings, by the way.

So what is the picture that we get here?

Look at "cerebral cortex," look at "brain stem,"

look at "body,"

and you get the picture of the interconnectivity

in which you have the brain stem providing the grounding for the self

in a very tight interconnection with the body.

And you have the cerebral cortex

providing the great spectacle of our minds

with the profusion of images

that are, in fact, the contents of our minds

and that we normally pay most attention to,

as we should, because that's really

the film that is rolling in our minds.

But look at the arrows.

They're not there for looks.

They're there because there's this very close interaction.

You cannot have a conscious mind

if you don't have the interaction

between cerebral cortex and brain stem.

You cannot have a conscious mind

if you don't have the interaction

between the brain stem and the body.

Another thing that is interesting

is that the brain stem that we have

is shared with a variety of other species.

So throughout vertebrates,

the design of the brain stem is very similar to ours,

which is one of the reasons why I think

those other species have conscious minds like we do.

Except that they're not as rich as ours,

because they don't have a cerebral cortex like we do.

That's where the difference is.

And I strongly disagree with the idea

that consciousness should be considered

as the great product of the cerebral cortex.

Only the wealth of our minds is,

not the very fact that we have a self

that we can refer

to our own existence,

and that we have any sense of person.

Now there are three levels of self to consider --

the proto, the core and the autobiographical.

The first two are shared

with many, many other species,

and they are really coming out

largely of the brain stem

and whatever there is of cortex in those species.

It's the autobiographical self

which some species have, I think.

Cetaceans and primates have also

an autobiographical self to a certain degree.

And everybody's dogs at home

have an autobiographical self to a certain degree.

But the novelty is here.

The autobiographical self is built

on the basis of past memories

and memories of the plans that we have made;

it's the lived past and the anticipated future.

And the autobiographical self

has prompted extended memory, reasoning,

imagination, creativity and language.

And out of that came the instruments of culture --

religions, justice,

trade, the arts, science, technology.

And it is within that culture

that we really can get --

and this is the novelty --

something that is not entirely set by our biology.

It is developed in the cultures.

It developed in collectives of human beings.

And this is, of course, the culture

where we have developed something that I like to call

socio-cultural regulation.

And finally, you could rightly ask,

why care about this?

Why care if it is the brain stem or the cerebral cortex

and how this is made?

Three reasons. First, curiosity.

Primates are extremely curious --

and humans most of all.

And if we are interested, for example,

in the fact that anti-gravity

is pulling galaxies away from the Earth,

why should we not be interested in what is going on

inside of human beings?

Second, understanding society and culture.

We should look

at how society and culture

in this socio-cultural regulation

are a work in progress.

And finally, medicine.

Let's not forget that some of the worst diseases

of humankind

are diseases such as depression,

Alzheimer's disease, drug addiction.

Think of strokes that can devastate your mind

or render you unconscious.

You have no prayer

of treating those diseases effectively

and in a non-serendipitous way

if you do not know how this works.

So that's a very good reason

beyond curiosity

to justify what we're doing,

and to justify having some interest in what is going on in our brains.

Thank you for your attention.

(Applause)