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  • 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 is a lump of flesh about £3 which 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 that are 100 billion neurons in the adult human brain.

  • And each neuron makes something like 1000 to 10,000 contacts with other neurons in the brain.

  • And based on this, people have 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 had lesions in different part of the brain and study changes in their behavior.

  • This is what I spoke about in the last 10.

  • 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 Gelati 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 called 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, a motor command your own in the front of my brain will fire.

  • If I reach out and pull an object, another neuron will fire, commanding me to pull my pull.

  • That object.

  • These are called motor command neurons be known for a long time, but what vigilante farm 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.

  • This is truly astonishing because it as though this neuron is adopting the other person's point of view, exalts almost perfect, performing a virtual reality simulation of the other person's action.

  • Now, what is the significance of these mirror neurons?

  • For one thing, they must be involved in things like imitation and emulation, because to imitate a complex act 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?

  • But let's take a look at the next slide.

  • So how do you do imitation?

  • Why is imitation important mirror neurons and imitation emulation?

  • Now let's look at culture, the phenomenon of human culture.

  • If you go back in time about 8500 years ago, let's look at human evolution.

  • It turns out there's something very important happened around 25,000 years ago, and that is a sudden emergence and rapid spread a number of skills that are unique to human beings 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 400,000 years ago, 100,000 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 a fire or a particular type of tool instead of dying out to spread rapidly, horizontally across the population or was transmitted vertically down the generations.

  • So this made of illusion suddenly Lamarque instead of Darwinian in Darwinian evolution is slow, takes hundreds of thousands of years of polar bear to evolve.

  • A coat will take thousands of generations.

  • Maybe 100,000 years of human being.

  • A child could just watch its parent kill another polar bath and skin.

  • It and put the skin on its body fur on the body and learn it in one step.

  • What the polar bear took 100,000 years to learn.

  • It can learn in five minutes, maybe 10 minutes and then, once it's learned, is it spreads in geometric proportion across the population.

  • This is the basis of the imitation of complex skills is what we call culture and the basis of civilization.

  • Now there's another kind of mirror neuron, which is involved in something quite different, and that is that a minute neurons it is.

  • There are mirror neurons for action that amid a neurons for touch.

  • In other words, if somebody touches me my hand neuron in the semana sensory cortex and sensitive 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'm touched in different locations.

  • Different neuron for different locations.

  • 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 had 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?

  • And I empathize with that person, but I don't literally feel the touch.

  • Well, that's because you've got receptors in your skin touch and 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 anesthetized my arm.

  • So you put in the injection into my arm anesthetized, breaking plexus.

  • So the arm is numbers, no sensations coming in.

  • If I now want you being touched, I literally feel it in my hand.

  • In other words, you have dissolved the barrier between you and other human beings.

  • 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, 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 riel independent, self aloof from other human beings inspecting the world, inspecting other people.

  • You are, in fact, connected, not just via Facebook and Internet.

  • You're actually quite literally connected by your neurons and his 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.

  • Do you have a patient with a phantom limb arm has been removed and you have a phantom and you watch somebody else being touched.

  • You feel it in your phantom.

  • 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 obtaining relief from 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.

  • C.

  • P.

  • Snow spoke of the two cultures.

  • Science on 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 loves 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.

I'd like to talk to you today about the human brain, which is what we do research on at the University of California.

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B2 TED-Ed neuron brain human touched imitation

The neurons that shaped civilization - VS Ramachandran

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    林宜悉 posted on 2020/07/03
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