The neurons that shaped civilization VS Ramachandran
I’d like to talk to you today about the
human brain which is what we do research
on at the University of California just
think about this problem for a second
here’s a lump of flesh about three
pounds but you can hold in the palm of
your hand but it can contemplate the
vastness of interstellar space it can
contemplate the meaning of infinity ask
questions about the meaning of its own
existence about the nature of God and
this is truly the most amazing thing in
the world it’s the greatest mystery
confronting human beings how does this
all come about well the brain as you
know is made up of neurons looking at
neurons here there are 100 billion
neurons in the adult human brain and
each neuron makes something like a
thousand to ten thousand contacts with
other neurons in the brain and based on
this people are calculated that the
number of permutations and combinations
of brain activity exceeds the number of
elementary particles in the universe so
how do you go about studying the brain
one approach is to look at patients who
have had lesions in different part of
the brain and study changes in their
behavior this is what I spoke about in
the last ten today I’ll talk about a
different approach which is to put
electrodes in different parts of the
brain and actually record the activity
of individual nerve cells in the brain
sort of eavesdrop on the activity of
nerve cells in the brain
now one recent discovery that has been
made by researchers in italy in parma by
giacomo rizzolatti and his colleagues is
a group of neurons called mirror neurons
which are in the front of the brain in
the frontal lobes now it turns out there
are neurons which are call ordinary
motor command neurons in the front of
the brain which have been known for over
50 years these neurons will fire when a
person performs a specific action for
example if I do that and reach and grab
an apple am order to command you run in
the front of my brain will fire if I
reach out and pull an object another
neuron will fire commanding me to pull
might pull that object these are called
motor command neurons be known for a
long time but what rijalallah found was
a subset of these neurons maybe about
20% of them will also fire when I’m
looking at somebody else performing the
same action so here’s a neuron that
fires when I reach and grab something
but it also fires when I watch Joe
reaching and grabbing something and this
is truly astonishing because as though
neuron is adopting the other person’s
point of view results almost as though
it’s perfect for mning a virtual reality
simulation of the other person’s action
now what is the significance of these
mirror neurons for one thing there must
be involved in things like imitation and
emulation because to imitate a complex
act it requires my brain to adopt the
other person’s point of view so this is
important for imitation and emulation
but why is that important well let’s
take a look at the next slide so how do
you do imitation why is imitation
important mirror neurons in imitation
emulation now let’s look at culture the
phenomenon of human culture if you go
back in time about seventy five hundred
thousand years ago let’s look at human
evolution it turns out there’s something
very important happened around five
thousand years ago and that is there’s a
sudden emergence and rapid spread of a
number of skills that are unique to
human beings like like tool use the use
of fire use of shelters and of course
language and the ability to read
somebody else’s mind and interpret that
person’s behavior all of that happened
relatively quickly even though the human
brain had achieved its present size
almost three or four hundred thousand
years ago 100 thousand years ago all of
this happened very very quickly and I
claim that what happened was the sudden
emergence of a sophisticated mirror
neuron system which allowed you to
emulate and imitate other people’s
actions so that when there was a sudden
accidental discovery by one member of
the group say use of fire or a
particular type of tool instead of dying
out the spread rapidly horizontally
across the population or was transmitted
vertically down the generations so this
made of illusion suddenly Lamarckian
instead of Darwinian in Darwinian
evolution is slow takes hundreds of
thousands of years a polar bear to
evolve a code will take thousands of
generations maybe a hundred thousand
years of human being a child can just
watch its parent kill another polar bear
and skinned it and put the skin on its
body for on the body and learn it in one
step what the polar bear took a hundred
thousand years to learn it can learn in
five minutes maybe ten minutes right and
then once it’s learned is it spreads by
in geometric proportion across a
population and this is the basis of this
mutation complex skills is what we call
culture in the basis of civilization
there’s another kind of mirror neuron
which is involved in something quite
different and that is that a minute
neuron justice with a million neurons
for action that a mirror neurons with
touch in other words if somebody touches
me my hand neuron in the somatosensory
cortex in the sensory region of the
brain fires but the same neuron in some
cases will fire when I simply watch
another person being touched
so it’s empathizing the other person
being touched so most of them will fire
when I am touched in different locations
different neuron for different occasions
but a subset of them will fire even when
I watch somebody else being touched in
the same location so here again you have
neurons which are enrolled in empathy
now the question then arises if I simply
watch another person being touched why
do I not get confused and literally feel
that touch sensation merely by watching
somebody being touched I empathize with
that person but I don’t literally feel
the touch well that’s because you’ve got
receptors in your skin touching pain
receptors going back into your brain
saying don’t water you’re not being
touched
so empathize by all means with the other
person but do not actually experience
the touch otherwise you’ll get confused
and muddled okay so there’s a feedback
signal that vetoes the signal of the
mirror neuron preventing you from
consciously experiencing that touch but
if you remove the arm
you simply anesthetize my arm so you put
an injection into my arm and it’s two
times the brachial plexus so the arm is
numb as no sensations coming in if I now
watch you being touched I literally feel
it in my hand in other words you’ve
dissolved the barrier between you and
other human beings so I call them
Gandhi neurons or empathy neurons and
this is not in some abstract
metaphorical sense all that’s separating
you from him from the other person is
your skin to remove the skin you
experience that person’s touch in your
mind you’ve dissolved the barrier
between you and other human beings and
this of course is the basis of much of
Eastern philosophy and that is there’s
no real independent self aloof from
other human beings inspecting the world
in inspecting other people you’re in
fact connected not just where Facebook
and the internet you’re actually quite
literally connected by your neurons and
it’s whole chains of neurons around this
room talking to each other and there is
no real distinctiveness of your
consciousness from somebody else’s
consciousness and this is not
mumbo-jumbo philosophy it emerges from
our understanding of basic neuroscience
so you have a patient with the phantom
limb arm has been removed and you’re a
phantom and you watch somebody else
being touched you feel it in your
phantom now the astonishing thing is if
you have pain in your phantom limb you
squeeze the other person’s hand massage
the other person’s hand that relieves
the pain in your phantom hand almost as
though the neuron were obtaining relief
for merely watching somebody else being
massaged so here you have my last slide
for the longest time people have
regarded science and Humanities as being
distinct see peace know spoke of the two
cultures science in the one hand
humanities on the other never the twain
shall meet
so I’m saying the mirror neuron system
lies the interface allowing you to think
think about issues like consciousness
representation of self what separates
you from other human beings what a love
allows you to empathize with other human
beings and also even things like the
emergence of culture and civilization
which is unique to human beings thank
you
you