[Applause]
imagine you are walking in the
countryside by a beautiful winter evening
all your senses are sharpened by the
cold
and you marvel at small
perception the flicker of the ice
in the trees the snow creak
under your feet and you wonder is
what it’s really possible that
each of these perceptions is the
result of the calculations of the neurons of
my brain is what I can believe in
this theory
this is the extraordinary hypothesis
which is proposed to us today by
neuroscience
each of our perceptions each of our
conscious states is a state
of activities of our brain and we
can begin to decode them by
neuroscience methods it’s
this exploration of the brain which is a
extraordinary adventure of the end of
twentieth century of those of our century
of the twentieth century that I would like you
tell today an adventure that
is made possible by advances
amazing brain imaging
the very old idea that the soul
the mind is different from the body we
we may find it already in
this engraving that you will find at
end of the cave of lascaux it is
the idea that in the dream
we mentally escape our
mind can fly away while the body
is inert
we fly to landscapes
far to people that
maybe we did not meet
for a very long time that they are
maybe dead but that we can
find in dream and it may be
this idea which is already illustrated here
in this scene since lascaux
see a person who is lying well
it’s clearly a man I believe that
it’s clear and you see is in
erection
he is lying down it is typical of sleep
paradoxical and maybe this man is he
dreaming maybe the
first representation of a state of
dream
he dreams that he is hunting
and that he managed to hurt a buffalo
we see the bison guts that are in
train to escape here and next to
him you see there is a bird this man
has a bird’s head in all
cultures
the bird represents the spirit the soul the
dream the capacity of the soul of
fly away from the body
so we all have this idea so
dualistic that mind and body that
is not at all the same thing these are
radically different things and
this dualistic idea and well she has
been formalized by a philosopher who
is called rené descartes you see
here we often attribute to rené
errors and this is
become current to make cards
bashing if we can say to say that
philosopher was wrong there is a book
of a euro scientist is called damasio
who wrote the error of descartes and I
would like to first restore a tiny
little reputation of our philosopher
French because I think that
he was an extraordinary pioneer of
materialism and attempt
explanation of psychological states
of the brain ages rené descartes
had tried with the means of
the time was limited to understand
how the vision the action the memory
wakefulness and sleep result from
heap of our brain back then
thought it was the pineal gland
who lean to one side they excel
idea is to find all kinds of
mechanisms to explain its functions
and he writes so
extraordinarily modern the
breathing
the night before sleep the reception of the
light the sounds the smells the
retention of these ideas in the
memory and finally the movements
outside of all members follow
quite naturally this machine of the
simple provision of its organs nor
no more and no less than do the movements
of a clock or other automatons of
that of his counterweights or serou
you see it’s a materialism
absolutely extraordinary why
did any cards remain
associated with the idea of dualism the idea
that the thinking thing is to say this
he called rèze cogitant
beetles years old is different from the thing
material art is external that and
well because he did not see he’s
very honest and he did not see
how could one explain by a
machine the human behaviors the
human behaviors are of a
extraordinary diversity can not
act very flexibly and it’s
sees especially in our words we
are not at all similar to
automata of the time we press a
button and we get maybe a sound
but here in humans there is a
diversity of behaviors that was
difficult explained at the time of
decks and actually maps was
a great precursor and it took
wait for the twentieth century middle of the
twentieth century with
turing with john von neumann the arrival
of contemporary computing that you
know who made it possible to understand
that yes in fact a machine can
produce speech yes a machine
can act and flexibility
we all have in the pockets of
smartphones that are machines
extraordinary that that should have
dreamed of cards but that allows to
see that intelligence is no longer
inaccessible to machines you know
a machine beat the best
go global player we are
now dominated on the plane of
intelligence by these machines
but then what about states
subjective is what a machine for
to be conscious and have a conscience
subjective and what is after all
subjective states of consciousness
does not completely escape the study
scientist because science is trying
to be objective whereas there he
is subjective states and well that’s
that I would like to show you today
is that it is not at all
difficult actually to analyze the
subjective states of the brain and I
would like to make you show a whole
little experience
here you are watching this carefully
scene here I ask you to set the
white point
try not to move your eyes from
white dot that is in the center and at the end
of a while you will do
the experience of this phenomenon
perfectly subjective yellow dots
go away does it work
sometimes they all disappear at the same time
time
sometimes one of them flashes
it lights up it comes back so it’s
interesting you all have this
subjective phenomenon each of
you there at a different time but
we have all this phenomenon it is
reproducible we can analyze it in
laboratory
what’s going on well he’s getting
happens that your brain takes a
decision he says if there are any points
fixed on my retina on my sensors
it’s probably sensor faults
and I ‘ll do better to eliminate for better
see the image behind it is this
what would any machine do
would have a stain on his camera by
example that’s what our brain does
it’s a decision
the subjective consciousness is the
result of unconscious calculations and the
more objective possible then I you
give another example another
illusion that show you that
virtually any scene that
you see that you analyze and the
result of a non-conscious processing
and gives rise to subjective states
what is special here seems to be
a perfectly normal scene and a
chessboard had black squares and
white boxes
there is nothing particular until
that I draw your attention to the fact
that on the plane
objective these two cases are
strictly identical they have
exactly the same level of gray and
on your retina it’s the same thing
but I come back to the subjective aspect and
in half a second your brain calculating
that one is black and the other and
identical subjective objectives
different then what’s going on
right here
and in fact see a cylinder on
the chessboard then to an area that
corresponds to its shadow in fact it’s
not a shadow
it’s a stain on your retina but
your brain interprets that as
being a shadow and suddenly gives you
to see the color of the chessboard without
this shadow because that’s what is
interesting to perceive and no matter
which machine should analyze these
images and who would try to
determine the color of the chessboard
would make the same mistake a state
subjective can be the result of a
objective calculation then 3rd illusion that
was easier for us analyzed in
laboratory this is called the
subliminal images
you have here I remind you a
episode that was a little bit
outrageous we can say it was the
presentation of the face of françois
mitterrand for a period
extraordinarily brief in the
generic name of what was called
the time antenna 2 during the campaign
presidential
one wonders if that led to
bias the decision of a particular vote
in May this or that voter but we know
now that its effects are duration
very brief but still he
works one can in the laboratory
present a word for a period
extraordinarily brief and if he is
sandwiched by other forms on
do not see it we can make it
strictly invisible and then
lengthening a little bit the word in
spreading the masks we can make it
visible again so we can in
lab manipulate at will
your subjective consciousness do
appear or disappear from your
consciousness
a word that is yet present on
your retina then the last
ingredient of this science of
consciousness of course it is that equipped with
all these ways there are still good
others to manipulate your consciousness
we can then go to see in
your brain and especially at
neurospin center that I lead in the
south of paris
we have a whole series of
machines that allow like you the
certainly know to go see
states of brain activity in large
anatomical details with the irm
functional and then
time with evoked potentials
magnetoencephalography and even
sometimes with electrodes that are
placed directly in the brain
so I reassure you right now I
do not ask for a volunteer today
for this intervention
but it turns out that there are patients
epileptics that are explored with
electrodes in the brain and one
can rely on this situation
clinic to do research
so what did we learn and well
first thing we learned
it is the extraordinary extent of
non- conscious treatment in the brain
we are constantly dealing with
information virtually every single
regions of our cortex is in the process of
process information in a non
conscious
you recognize a way face
unconscious even without awareness
to have perceived it if a word and
present you are reading it unconsciously
you go to his senses
unconsciously if its meaning is a sense
emotional for example the word rape you
go activated the cerebral tonsil which
is a region specializing in
negative emotions and especially the
scared you went is activated a
evaluation of its positive meaning or
negative if it’s a number you have
performed calculations unconsciously
you will unconsciously detect if
these calculations are wrong or not and you
you will be able to activate until your
motor cortex without consciousness and this does not
are just examples
there are dozens experience
today who show that the brain
works primarily on a
non conscious mode but then you me
say what happens when
word crossed the threshold of consciousness
well here is one of the first
images that we got and which
you still shows that a
huge difference
an unconscious word remain confined
in specialized circuits
he’s sort of dealing with
automatic way by circuits
specialized whereas the word conscious
saw him training a whole
increased activity
what’s called the conflagration
Confident to a kind of conflagration
neuronal in a brain space
much larger the information that
is conscious becomes diffused to
the scale of the whole brain and that’s
for that we can act when
we are conscious of how
flexible what was hitting cards we
can name for example what we
are aware
because our brain circuits are going
bring the information to the circuit of
language that allow to name it and
in general when we
are aware of the information we
can use it in a way
extraordinarily flexible then this
neural conflagration we saw it
with other methods says
friends only by presenting a word that can
to be either visible or invisible as
I explained it to you above
you have brain activity for
the least visible down activity
cerebral for the word visible if I
start this movie you’ll see that at
departure things are rigorously
identical for about 200 300
milliseconds our brain does
exactly the same way so
conscious or not conscious see it
activates the occipital pole the
visual recognition of words
produced identically but that’s
only in the later stages
that you will see a conflagration
specific to the conscious condition
when you become aware
of information the frontal cortex is going to
turn on the information will expand to
these anterior regions of the brain the
frontal cortex
it’s here about 33% of the brain
human being a region that has
particularly developed in our
species we can go further and
watch consciousness at a
unique neuron and that’s absolutely
extraordinary we have today
very special cases of patients
with epilepsy in which one can
insert electrodes sufficiently
fine to record a single neuron
in the human brain and have made
remarkable discoveries for example
that there are neurons that code for
a particular concept see here a
neuron that codes for the concept of the wall
trade center before the attempt
and you have those neurons that do not
unload cowell trade center and not
to dozens of other concepts of
people from places that are different
and by the way these neurons only dump
that if we become aware of
information etc if the information is
presented extremely briefly
a subliminal image
no discharge of this neurons
and even to last constant if the
patient said ah well I did not succeed
to see the picture
the neuro is not going to unload it does not
discharge only for a conscious concept
so see that you have to imagine that
each of our thoughts and the result
of such a neuronal code we have some
neuron populations probably
several thousand or millions at each
once they code each of our thoughts
of course consciousness is not
only perceive an object in the
outside world when one is conscious
we continue to be conscious when
is for example in the dark that has more
particular stimulation but our
thoughts continues to unfold on a
conscious mode and here again the imagery
brain showed it very
clear
the brain actually roles
when he is aware of a whole series
of activity states that continues to
change constantly and who
correspond to a large extent to
content of our conscious thoughts
we can analyze these activity states
but that change in
permanence and one can on the one hand the
decode with machine methods
learning machine learning and
see which can decode states
conscious and unconscious and we can
even go further and we can
start decoding the content
particular of consciousness if one
wake up a person for example then
she was in REM sleep
wake up and ask him what
in your dream
there was a face or not and of which one
can predict whether there was a face or
not in the dream
by decoding brain activity
in the regions that deal with
faces in the brain so you see
we start to see a
remarkable correspondence that one can
reverse by decoding between state
of brain activities and states
mental problems reported by the subject where
this science is one of his
most important areas of application
these are the clinical applications
you know that unfortunately we can
all lose consciousness or because
we fall asleep at night and we lose our
consciousness either because we are
anesthetized and understanding of
Anesthetized is an important goal
but also because we have an accident of
car a vascular accident
our brain is aggrieved and you know
that some people will find
in a coma will fall into what we
calls a vegetative state that is
maybe even worse ie the
brain continues to fall asleep and
to wake up but during the day
the person does not answer anymore we do not arrive
more to communicate with her she does not
move more voluntarily and sometimes at
after a few weeks what was
rim have come to realize that in fact
she’s always conscious she’s bad the
eyelid and if we analyze this beat
of the eyelid
we can see that there is someone at
inside someone who can be
sometimes perfectly conscious as
was jean dominique bauby when he
wrote this novel absolutely
extraordinary this story of his life
this biography the scuba and the
butterfly that you may have him
which is entirely dictated by beating
of the eyelid
so how do you differentiate between
an unconscious patient and a patient
aware that sometimes there are
patients who do not even have the
eyelids are they still
conscious and well
the domain has been revolutionized
when we saw that actually
could use brain imaging
to make a difference
here it is one of the first
studies in a patient who was in
apparent vegetative state except that
when asked to imagine that she
play tennis or imagine that she is
walk in his apartment
and she has a status of activities that
are identical to those of a subject
normal conscious she is definitely
conscious in the same way one can
watch a hitchcock movie and see
that the moments of suspense are
moments where the brain this space of
global work that allows awareness
are activated when we are riveted
by the action in the film is well
can measure so a state of activities
conscious and in some patients one
see him also
we still have many more
possibilities we can stimulate the
brain and look up to what
depth will spread
activity if it spreads far it
means that a reverberant state of
awareness on the part of the subject and in
my laboratory we look at the exchanges
information between regions
distant brain and we see that these
exchange of information on many
richer
when the person is aware that
when it is not and it’s a
another way to diagnose the
consciousness and you may have seen
in the media recently it becomes
possible not only to measure
diagnosed but also to stimulate the
consciousness with electrodes
deep as we do in the
Parkinson
we will be able to do it in patients
with disturbances of consciousness and
restore or in any case facilitate the
restoration of consciousness at
some of them when the cortex
is not too damaged
so that’s this story so of
science of consciousness I believe that
we must accept that each of our
even the most intimate mental states
loved me more moving are the
result of calculations of our brain and
without is not less interesting
am my brain must accept this
idea there but there is a second idea
also behind this presentation is that the
cranial box opens it becomes
visible brain imaging makes
visible mental states that up
present were hidden is that he
must be concerned
maybe but I think it’s also
an absolutely
extraordinary to understand each other
to analyze the origins of our
behaviors and progress
collectively in this area knew
that one of the
idea of Greek philosophy the most
important maybe it was known
you yourself and I think that if socrates
and platon was coming back today
well he would rush to the
neuroscience and live know yourself
even that means learns to
know your own brain thank you
a lot
[Applause]
ap
”
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