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Dialogue: 0,0:00:00.00,0:00:03.00,Default,,0000,0000,0000,,I'd like to talk to you today about the human brain,
Dialogue: 0,0:00:03.00,0:00:05.00,Default,,0000,0000,0000,,which is what we do research on at the University of California.
Dialogue: 0,0:00:05.00,0:00:07.00,Default,,0000,0000,0000,,Just think about this problem for a second.
Dialogue: 0,0:00:07.00,0:00:10.00,Default,,0000,0000,0000,,Here is a lump of flesh, about three pounds,
Dialogue: 0,0:00:10.00,0:00:12.00,Default,,0000,0000,0000,,which you can hold in the palm of your hand.
Dialogue: 0,0:00:12.00,0:00:16.00,Default,,0000,0000,0000,,But it can contemplate the vastness of interstellar space.
Dialogue: 0,0:00:16.00,0:00:18.00,Default,,0000,0000,0000,,It can contemplate the meaning of infinity,
Dialogue: 0,0:00:18.00,0:00:21.00,Default,,0000,0000,0000,,ask questions about the meaning of its own existence,
Dialogue: 0,0:00:21.00,0:00:23.00,Default,,0000,0000,0000,,about the nature of God.
Dialogue: 0,0:00:23.00,0:00:25.00,Default,,0000,0000,0000,,And this is truly the most amazing thing in the world.
Dialogue: 0,0:00:25.00,0:00:28.00,Default,,0000,0000,0000,,It's the greatest mystery confronting human beings:
Dialogue: 0,0:00:28.00,0:00:30.00,Default,,0000,0000,0000,,How does this all come about?
Dialogue: 0,0:00:30.00,0:00:32.00,Default,,0000,0000,0000,,Well, the brain, as you know, is made up of neurons.
Dialogue: 0,0:00:32.00,0:00:34.00,Default,,0000,0000,0000,,We're looking at neurons here.
Dialogue: 0,0:00:34.00,0:00:37.00,Default,,0000,0000,0000,,There are 100 billion neurons in the adult human brain.
Dialogue: 0,0:00:37.00,0:00:40.00,Default,,0000,0000,0000,,And each neuron makes something like 1,000 to 10,000 contacts
Dialogue: 0,0:00:40.00,0:00:42.00,Default,,0000,0000,0000,,with other neurons in the brain.
Dialogue: 0,0:00:42.00,0:00:44.00,Default,,0000,0000,0000,,And based on this, people have calculated
Dialogue: 0,0:00:44.00,0:00:47.00,Default,,0000,0000,0000,,that the number of permutations and combinations of brain activity
Dialogue: 0,0:00:47.00,0:00:50.00,Default,,0000,0000,0000,,exceeds the number of elementary particles in the universe.
Dialogue: 0,0:00:50.00,0:00:52.00,Default,,0000,0000,0000,,So, how do you go about studying the brain?
Dialogue: 0,0:00:52.00,0:00:54.00,Default,,0000,0000,0000,,One approach is to look at patients who had lesions
Dialogue: 0,0:00:54.00,0:00:57.00,Default,,0000,0000,0000,,in different part of the brain, and study changes in their behavior.
Dialogue: 0,0:00:57.00,0:00:59.00,Default,,0000,0000,0000,,This is what I spoke about in the last TED.
Dialogue: 0,0:00:59.00,0:01:01.00,Default,,0000,0000,0000,,Today I'll talk about a different approach,
Dialogue: 0,0:01:01.00,0:01:03.00,Default,,0000,0000,0000,,which is to put electrodes in different parts of the brain,
Dialogue: 0,0:01:03.00,0:01:07.00,Default,,0000,0000,0000,,and actually record the activity of individual nerve cells in the brain.
Dialogue: 0,0:01:07.00,0:01:11.00,Default,,0000,0000,0000,,Sort of eavesdrop on the activity of nerve cells in the brain.
Dialogue: 0,0:01:11.00,0:01:14.00,Default,,0000,0000,0000,,Now, one recent discovery that has been made
Dialogue: 0,0:01:14.00,0:01:16.00,Default,,0000,0000,0000,,by researchers in Italy, in Parma,
Dialogue: 0,0:01:16.00,0:01:19.00,Default,,0000,0000,0000,,by Giacomo Rizzolatti and his colleagues,
Dialogue: 0,0:01:19.00,0:01:21.00,Default,,0000,0000,0000,,is a group of neurons called mirror neurons,
Dialogue: 0,0:01:21.00,0:01:24.00,Default,,0000,0000,0000,,which are on the front of the brain in the frontal lobes.
Dialogue: 0,0:01:24.00,0:01:26.00,Default,,0000,0000,0000,,Now, it turns out there are neurons
Dialogue: 0,0:01:26.00,0:01:29.00,Default,,0000,0000,0000,,which are called ordinary motor command neurons in the front of the brain,
Dialogue: 0,0:01:29.00,0:01:31.00,Default,,0000,0000,0000,,which have been known for over 50 years.
Dialogue: 0,0:01:31.00,0:01:34.00,Default,,0000,0000,0000,,These neurons will fire when a person performs a specific action.
Dialogue: 0,0:01:34.00,0:01:37.00,Default,,0000,0000,0000,,For example, if I do that, and reach and grab an apple,
Dialogue: 0,0:01:37.00,0:01:41.00,Default,,0000,0000,0000,,a motor command neuron in the front of my brain will fire.
Dialogue: 0,0:01:41.00,0:01:44.00,Default,,0000,0000,0000,,If I reach out and pull an object, another neuron will fire,
Dialogue: 0,0:01:44.00,0:01:46.00,Default,,0000,0000,0000,,commanding me to pull that object.
Dialogue: 0,0:01:46.00,0:01:48.00,Default,,0000,0000,0000,,These are called motor command neurons that have been known for a long time.
Dialogue: 0,0:01:48.00,0:01:50.00,Default,,0000,0000,0000,,But what Rizzolatti found was
Dialogue: 0,0:01:50.00,0:01:52.00,Default,,0000,0000,0000,,a subset of these neurons,
Dialogue: 0,0:01:52.00,0:01:54.00,Default,,0000,0000,0000,,maybe about 20 percent of them, will also fire
Dialogue: 0,0:01:54.00,0:01:57.00,Default,,0000,0000,0000,,when I'm looking at somebody else performing the same action.
Dialogue: 0,0:01:57.00,0:02:00.00,Default,,0000,0000,0000,,So, here is a neuron that fires when I reach and grab something,
Dialogue: 0,0:02:00.00,0:02:03.00,Default,,0000,0000,0000,,but it also fires when I watch Joe reaching and grabbing something.
Dialogue: 0,0:02:03.00,0:02:05.00,Default,,0000,0000,0000,,And this is truly astonishing.
Dialogue: 0,0:02:05.00,0:02:07.00,Default,,0000,0000,0000,,Because it's as though this neuron is adopting
Dialogue: 0,0:02:07.00,0:02:09.00,Default,,0000,0000,0000,,the other person's point of view.
Dialogue: 0,0:02:09.00,0:02:13.00,Default,,0000,0000,0000,,It's almost as though it's performing a virtual reality simulation
Dialogue: 0,0:02:13.00,0:02:15.00,Default,,0000,0000,0000,,of the other person's action.
Dialogue: 0,0:02:15.00,0:02:18.00,Default,,0000,0000,0000,,Now, what is the significance of these mirror neurons?
Dialogue: 0,0:02:18.00,0:02:21.00,Default,,0000,0000,0000,,For one thing they must be involved in things like imitation and emulation.
Dialogue: 0,0:02:21.00,0:02:24.00,Default,,0000,0000,0000,,Because to imitate a complex act
Dialogue: 0,0:02:24.00,0:02:27.00,Default,,0000,0000,0000,,requires my brain to adopt the other person's point of view.
Dialogue: 0,0:02:27.00,0:02:29.00,Default,,0000,0000,0000,,So, this is important for imitation and emulation.
Dialogue: 0,0:02:29.00,0:02:31.00,Default,,0000,0000,0000,,Well, why is that important?
Dialogue: 0,0:02:31.00,0:02:34.00,Default,,0000,0000,0000,,Well, let's take a look at the next slide.
Dialogue: 0,0:02:34.00,0:02:37.00,Default,,0000,0000,0000,,So, how do you do imitation? Why is imitation important?
Dialogue: 0,0:02:37.00,0:02:39.00,Default,,0000,0000,0000,,Mirror neurons and imitation, emulation.
Dialogue: 0,0:02:39.00,0:02:43.00,Default,,0000,0000,0000,,Now, let's look at culture, the phenomenon of human culture.
Dialogue: 0,0:02:43.00,0:02:47.00,Default,,0000,0000,0000,,If you go back in time about [75,000] to 100,000 years ago,
Dialogue: 0,0:02:47.00,0:02:49.00,Default,,0000,0000,0000,,let's look at human evolution, it turns out
Dialogue: 0,0:02:49.00,0:02:52.00,Default,,0000,0000,0000,,that something very important happened around 75,000 years ago.
Dialogue: 0,0:02:52.00,0:02:54.00,Default,,0000,0000,0000,,And that is, there is a sudden emergence and rapid spread
Dialogue: 0,0:02:54.00,0:02:57.00,Default,,0000,0000,0000,,of a number of skills that are unique to human beings
Dialogue: 0,0:02:57.00,0:02:59.00,Default,,0000,0000,0000,,like tool use,
Dialogue: 0,0:02:59.00,0:03:02.00,Default,,0000,0000,0000,,the use of fire, the use of shelters, and, of course, language,
Dialogue: 0,0:03:02.00,0:03:04.00,Default,,0000,0000,0000,,and the ability to read somebody else's mind
Dialogue: 0,0:03:04.00,0:03:06.00,Default,,0000,0000,0000,,and interpret that person's behavior.
Dialogue: 0,0:03:06.00,0:03:08.00,Default,,0000,0000,0000,,All of that happened relatively quickly.
Dialogue: 0,0:03:08.00,0:03:11.00,Default,,0000,0000,0000,,Even though the human brain had achieved its present size
Dialogue: 0,0:03:11.00,0:03:13.00,Default,,0000,0000,0000,,almost three or four hundred thousand years ago,
Dialogue: 0,0:03:13.00,0:03:15.00,Default,,0000,0000,0000,,100,000 years ago all of this happened very, very quickly.
Dialogue: 0,0:03:15.00,0:03:18.00,Default,,0000,0000,0000,,And I claim that what happened was
Dialogue: 0,0:03:18.00,0:03:21.00,Default,,0000,0000,0000,,the sudden emergence of a sophisticated mirror neuron system,
Dialogue: 0,0:03:21.00,0:03:23.00,Default,,0000,0000,0000,,which allowed you to emulate and imitate other people's actions.
Dialogue: 0,0:03:23.00,0:03:27.00,Default,,0000,0000,0000,,So that when there was a sudden accidental discovery
Dialogue: 0,0:03:27.00,0:03:30.00,Default,,0000,0000,0000,,by one member of the group, say the use of fire,
Dialogue: 0,0:03:30.00,0:03:32.00,Default,,0000,0000,0000,,or a particular type of tool, instead of dying out,
Dialogue: 0,0:03:32.00,0:03:35.00,Default,,0000,0000,0000,,this spread rapidly, horizontally across the population,
Dialogue: 0,0:03:35.00,0:03:38.00,Default,,0000,0000,0000,,or was transmitted vertically, down the generations.
Dialogue: 0,0:03:38.00,0:03:40.00,Default,,0000,0000,0000,,So, this made evolution suddenly Lamarckian,
Dialogue: 0,0:03:40.00,0:03:42.00,Default,,0000,0000,0000,,instead of Darwinian.
Dialogue: 0,0:03:42.00,0:03:45.00,Default,,0000,0000,0000,,Darwinian evolution is slow; it takes hundreds of thousands of years.
Dialogue: 0,0:03:45.00,0:03:47.00,Default,,0000,0000,0000,,A polar bear, to evolve a coat,
Dialogue: 0,0:03:47.00,0:03:50.00,Default,,0000,0000,0000,,will take thousands of generations, maybe 100,000 years.
Dialogue: 0,0:03:50.00,0:03:53.00,Default,,0000,0000,0000,,A human being, a child, can just watch its parent
Dialogue: 0,0:03:53.00,0:03:56.00,Default,,0000,0000,0000,,kill another polar bear,
Dialogue: 0,0:03:56.00,0:03:59.00,Default,,0000,0000,0000,,and skin it and put the skin on its body, fur on the body,
Dialogue: 0,0:03:59.00,0:04:01.00,Default,,0000,0000,0000,,and learn it in one step. What the polar bear
Dialogue: 0,0:04:01.00,0:04:03.00,Default,,0000,0000,0000,,took 100,000 years to learn,
Dialogue: 0,0:04:03.00,0:04:06.00,Default,,0000,0000,0000,,it can learn in five minutes, maybe 10 minutes.
Dialogue: 0,0:04:06.00,0:04:08.00,Default,,0000,0000,0000,,And then once it's learned this it spreads
Dialogue: 0,0:04:08.00,0:04:11.00,Default,,0000,0000,0000,,in geometric proportion across a population.
Dialogue: 0,0:04:11.00,0:04:14.00,Default,,0000,0000,0000,,This is the basis. The imitation of complex skills
Dialogue: 0,0:04:14.00,0:04:17.00,Default,,0000,0000,0000,,is what we call culture and is the basis of civilization.
Dialogue: 0,0:04:17.00,0:04:19.00,Default,,0000,0000,0000,,Now there is another kind of mirror neuron,
Dialogue: 0,0:04:19.00,0:04:21.00,Default,,0000,0000,0000,,which is involved in something quite different.
Dialogue: 0,0:04:21.00,0:04:23.00,Default,,0000,0000,0000,,And that is, there are mirror neurons,
Dialogue: 0,0:04:23.00,0:04:26.00,Default,,0000,0000,0000,,just as there are mirror neurons for action, there are mirror neurons for touch.
Dialogue: 0,0:04:26.00,0:04:28.00,Default,,0000,0000,0000,,In other words, if somebody touches me,
Dialogue: 0,0:04:28.00,0:04:30.00,Default,,0000,0000,0000,,my hand, neuron in the somatosensory cortex
Dialogue: 0,0:04:30.00,0:04:32.00,Default,,0000,0000,0000,,in the sensory region of the brain fires.
Dialogue: 0,0:04:32.00,0:04:35.00,Default,,0000,0000,0000,,But the same neuron, in some cases, will fire
Dialogue: 0,0:04:35.00,0:04:37.00,Default,,0000,0000,0000,,when I simply watch another person being touched.
Dialogue: 0,0:04:37.00,0:04:40.00,Default,,0000,0000,0000,,So, it's empathizing the other person being touched.
Dialogue: 0,0:04:40.00,0:04:42.00,Default,,0000,0000,0000,,So, most of them will fire when I'm touched
Dialogue: 0,0:04:42.00,0:04:45.00,Default,,0000,0000,0000,,in different locations. Different neurons for different locations.
Dialogue: 0,0:04:45.00,0:04:47.00,Default,,0000,0000,0000,,But a subset of them will fire even when I watch somebody else
Dialogue: 0,0:04:47.00,0:04:49.00,Default,,0000,0000,0000,,being touched in the same location.
Dialogue: 0,0:04:49.00,0:04:51.00,Default,,0000,0000,0000,,So, here again you have neurons
Dialogue: 0,0:04:51.00,0:04:53.00,Default,,0000,0000,0000,,which are enrolled in empathy.
Dialogue: 0,0:04:53.00,0:04:56.00,Default,,0000,0000,0000,,Now, the question then arises: If I simply watch another person being touched,
Dialogue: 0,0:04:56.00,0:05:00.00,Default,,0000,0000,0000,,why do I not get confused and literally feel that touch sensation
Dialogue: 0,0:05:00.00,0:05:02.00,Default,,0000,0000,0000,,merely by watching somebody being touched?
Dialogue: 0,0:05:02.00,0:05:06.00,Default,,0000,0000,0000,,I mean, I empathize with that person but I don't literally feel the touch.
Dialogue: 0,0:05:06.00,0:05:08.00,Default,,0000,0000,0000,,Well, that's because you've got receptors in your skin,
Dialogue: 0,0:05:08.00,0:05:10.00,Default,,0000,0000,0000,,touch and pain receptors, going back into your brain
Dialogue: 0,0:05:10.00,0:05:13.00,Default,,0000,0000,0000,,and saying "Don't worry, you're not being touched.
Dialogue: 0,0:05:13.00,0:05:16.00,Default,,0000,0000,0000,,So, empathize, by all means, with the other person,
Dialogue: 0,0:05:16.00,0:05:18.00,Default,,0000,0000,0000,,but do not actually experience the touch,
Dialogue: 0,0:05:18.00,0:05:20.00,Default,,0000,0000,0000,,otherwise you'll get confused and muddled."
Dialogue: 0,0:05:20.00,0:05:22.00,Default,,0000,0000,0000,,Okay, so there is a feedback signal
Dialogue: 0,0:05:22.00,0:05:24.00,Default,,0000,0000,0000,,that vetoes the signal of the mirror neuron
Dialogue: 0,0:05:24.00,0:05:27.00,Default,,0000,0000,0000,,preventing you from consciously experiencing that touch.
Dialogue: 0,0:05:27.00,0:05:30.00,Default,,0000,0000,0000,,But if you remove the arm, you simply anesthetize my arm,
Dialogue: 0,0:05:30.00,0:05:32.00,Default,,0000,0000,0000,,so you put an injection into my arm,
Dialogue: 0,0:05:32.00,0:05:34.00,Default,,0000,0000,0000,,anesthetize the brachial plexus, so the arm is numb,
Dialogue: 0,0:05:34.00,0:05:36.00,Default,,0000,0000,0000,,and there is no sensations coming in,
Dialogue: 0,0:05:36.00,0:05:38.00,Default,,0000,0000,0000,,if I now watch you being touched,
Dialogue: 0,0:05:38.00,0:05:40.00,Default,,0000,0000,0000,,I literally feel it in my hand.
Dialogue: 0,0:05:40.00,0:05:42.00,Default,,0000,0000,0000,,In other words, you have dissolved the barrier
Dialogue: 0,0:05:42.00,0:05:44.00,Default,,0000,0000,0000,,between you and other human beings.
Dialogue: 0,0:05:44.00,0:05:47.00,Default,,0000,0000,0000,,So, I call them Gandhi neurons, or empathy neurons.
Dialogue: 0,0:05:47.00,0:05:48.00,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:05:48.00,0:05:51.00,Default,,0000,0000,0000,,And this is not in some abstract metaphorical sense.
Dialogue: 0,0:05:51.00,0:05:53.00,Default,,0000,0000,0000,,All that's separating you from him,
Dialogue: 0,0:05:53.00,0:05:55.00,Default,,0000,0000,0000,,from the other person, is your skin.
Dialogue: 0,0:05:55.00,0:05:59.00,Default,,0000,0000,0000,,Remove the skin, you experience that person's touch in your mind.
Dialogue: 0,0:05:59.00,0:06:02.00,Default,,0000,0000,0000,,You've dissolved the barrier between you and other human beings.
Dialogue: 0,0:06:02.00,0:06:04.00,Default,,0000,0000,0000,,And this, of course, is the basis of much of Eastern philosophy,
Dialogue: 0,0:06:04.00,0:06:07.00,Default,,0000,0000,0000,,and that is there is no real independent self,
Dialogue: 0,0:06:07.00,0:06:09.00,Default,,0000,0000,0000,,aloof from other human beings, inspecting the world,
Dialogue: 0,0:06:09.00,0:06:11.00,Default,,0000,0000,0000,,inspecting other people.
Dialogue: 0,0:06:11.00,0:06:14.00,Default,,0000,0000,0000,,You are, in fact, connected not just via Facebook and Internet,
Dialogue: 0,0:06:14.00,0:06:17.00,Default,,0000,0000,0000,,you're actually quite literally connected by your neurons.
Dialogue: 0,0:06:17.00,0:06:20.00,Default,,0000,0000,0000,,And there is whole chains of neurons around this room, talking to each other.
Dialogue: 0,0:06:20.00,0:06:22.00,Default,,0000,0000,0000,,And there is no real distinctiveness
Dialogue: 0,0:06:22.00,0:06:24.00,Default,,0000,0000,0000,,of your consciousness from somebody else's consciousness.
Dialogue: 0,0:06:24.00,0:06:26.00,Default,,0000,0000,0000,,And this is not mumbo-jumbo philosophy.
Dialogue: 0,0:06:26.00,0:06:29.00,Default,,0000,0000,0000,,It emerges from our understanding of basic neuroscience.
Dialogue: 0,0:06:29.00,0:06:32.00,Default,,0000,0000,0000,,So, you have a patient with a phantom limb. If the arm has been removed
Dialogue: 0,0:06:32.00,0:06:34.00,Default,,0000,0000,0000,,and you have a phantom, and you watch somebody else
Dialogue: 0,0:06:34.00,0:06:36.00,Default,,0000,0000,0000,,being touched, you feel it in your phantom.
Dialogue: 0,0:06:36.00,0:06:38.00,Default,,0000,0000,0000,,Now the astonishing thing is,
Dialogue: 0,0:06:38.00,0:06:41.00,Default,,0000,0000,0000,,if you have pain in your phantom limb, you squeeze the other person's hand,
Dialogue: 0,0:06:41.00,0:06:43.00,Default,,0000,0000,0000,,massage the other person's hand,
Dialogue: 0,0:06:43.00,0:06:45.00,Default,,0000,0000,0000,,that relieves the pain in your phantom hand,
Dialogue: 0,0:06:45.00,0:06:47.00,Default,,0000,0000,0000,,almost as though the neuron
Dialogue: 0,0:06:47.00,0:06:49.00,Default,,0000,0000,0000,,were obtaining relief from merely
Dialogue: 0,0:06:49.00,0:06:51.00,Default,,0000,0000,0000,,watching somebody else being massaged.
Dialogue: 0,0:06:51.00,0:06:54.00,Default,,0000,0000,0000,,So, here you have my last slide.
Dialogue: 0,0:06:54.00,0:06:56.00,Default,,0000,0000,0000,,For the longest time people have regarded science
Dialogue: 0,0:06:56.00,0:06:58.00,Default,,0000,0000,0000,,and humanities as being distinct.
Dialogue: 0,0:06:58.00,0:07:01.00,Default,,0000,0000,0000,,C.P. Snow spoke of the two cultures:
Dialogue: 0,0:07:01.00,0:07:03.00,Default,,0000,0000,0000,,science on the one hand, humanities on the other;
Dialogue: 0,0:07:03.00,0:07:05.00,Default,,0000,0000,0000,,never the twain shall meet.
Dialogue: 0,0:07:05.00,0:07:07.00,Default,,0000,0000,0000,,So, I'm saying the mirror neuron system underlies the interface
Dialogue: 0,0:07:07.00,0:07:10.00,Default,,0000,0000,0000,,allowing you to rethink about issues like consciousness,
Dialogue: 0,0:07:10.00,0:07:12.00,Default,,0000,0000,0000,,representation of self,
Dialogue: 0,0:07:12.00,0:07:14.00,Default,,0000,0000,0000,,what separates you from other human beings,
Dialogue: 0,0:07:14.00,0:07:16.00,Default,,0000,0000,0000,,what allows you to empathize with other human beings,
Dialogue: 0,0:07:16.00,0:07:19.00,Default,,0000,0000,0000,,and also even things like the emergence of culture and civilization,
Dialogue: 0,0:07:19.00,0:07:21.00,Default,,0000,0000,0000,,which is unique to human beings. Thank you.
Dialogue: 0,0:07:21.00,0:07:23.00,Default,,0000,0000,0000,,(Applause)