TEDGlobal 2010
Gero Miesenboeck: Re-engineering the brain
Gero Mizenbek preuređuje mozak
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U cilju istraživanja mape mozga, mnogi naučnici su pokušali sa neverovatno teškim zadatkom snimanja aktivnosti svakog neurona. Gero Mizenbek radi unazad -- manipulišući specifičnim neuronima da bi shvatio šta oni tačno rade, kroz seriju zapanjujućih eksperimenata kojim preuređuje način na koji voćne mušice percipiraju svetlost.
Gero Miesenboeck - Optogeneticist
Using light and a little genetic engineering -- optogenetics -- Gero Miesenboeck has developed a way to control how living nerve cells work, and advanced understanding of how the brain controls behavior. Full bio
Using light and a little genetic engineering -- optogenetics -- Gero Miesenboeck has developed a way to control how living nerve cells work, and advanced understanding of how the brain controls behavior. Full bio
Double-click the English transcript below to play the video.
00:15
I have a doppelganger.
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Ja imam zlog dvojnika (Doppelganger).
00:18
(Laughter)
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(Smeh)
00:21
Dr. Gero is a brilliant
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Dr Gero je sjajan
00:24
but slightly mad scientist
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ali pomalo lud naučnik
00:26
in the "Dragonball Z: Android Saga."
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iz Zmajeve kugle Z "Android Sage".
00:29
If you look very carefully,
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Ako pogledate pažljivo,
00:31
you see that his skull has been replaced
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videćete da je njegova lobanja zamenjena
00:34
with a transparent Plexiglas dome
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providnim svodom od pleksiglasa
00:36
so that the workings of his brain can be observed
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kako bi rad njegovog mozga mogao biti posmatran
00:39
and also controlled with light.
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i takođe kontrolisan svetlošću.
00:42
That's exactly what I do --
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To je upravo ono što ja radim --
00:44
optical mind control.
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optička kontrola misli.
00:46
(Laughter)
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(Smeh)
00:48
But in contrast to my evil twin
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Ali za razliku od mog zlog blizanca,
00:50
who lusts after world domination,
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koji žudi za svetskom dominacijom,
00:53
my motives are not sinister.
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moji motivi nisu grešni.
00:56
I control the brain
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Ja kontrolišem mozak
00:58
in order to understand how it works.
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kako bih razumeo način na koji radi.
01:00
Now wait a minute, you may say,
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Čekaj malo, možete reći,
01:02
how can you go straight to controlling the brain
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kako možeš ići pravo na kontrolisanje mozga
01:05
without understanding it first?
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ako ga prvenstveno ne razumeš?
01:07
Isn't that putting the cart before the horse?
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Zar to nije nešto kao uprezanje terentnih kola pre dovođenja konja?
01:11
Many neuroscientists agree with this view
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Mnogi neuronaučnici su saglasni sa ovim gledištem
01:14
and think that understanding will come
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i misle da će razumevanje doći
01:17
from more detailed observation and analysis.
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tek nakon detaljnih opservacija i analiza.
01:20
They say, "If we could record the activity of our neurons,
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Oni kažu, "Kada bismo mogli snimiti aktivnost neurona,
01:24
we would understand the brain."
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razumeli bismo mozak."
01:27
But think for a moment what that means.
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Ali razmislite na trenutak šta to znači.
01:30
Even if we could measure
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Čak i ukoliko bismo mogli da izmerimo
01:32
what every cell is doing at all times,
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šta svaka ćelija radi svo vreme,
01:34
we would still have to make sense
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i dalje bismo morali da pronađemo smisao
01:36
of the recorded activity patterns,
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u modelima snimanih aktivnosti,
01:38
and that's so difficult,
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a to je toliko komplikovano,
01:40
chances are we'll understand these patterns
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šanse da razumemo te modele
01:42
just as little as the brains that produce them.
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su jednako male koliko i razumevanje mozga koji ih produkuje.
01:45
Take a look at what brain activity might look like.
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Pogledajte kako bi moždana aktivnost mogla da izgleda.
01:48
In this simulation, each black dot
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U ovoj simulaciji, svaka crna tačka
01:50
is one nerve cell.
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predstavlja jednu nervnu ćeliju.
01:52
The dot is visible
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Tačka je vidljiva
01:54
whenever a cell fires an electrical impulse.
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kada god ćelija ispali električni impuls.
01:56
There's 10,000 neurons here.
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Ovde je prikazano 10000 neurona.
01:58
So you're looking at roughly one percent
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Tako da vi gledate, u gruboj proceni, jedan procenat
02:00
of the brain of a cockroach.
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mozga bubašvabe.
02:04
Your brains are about 100 million times
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Vaš mozak je oko 100 miliona puta
02:07
more complicated.
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komplikovaniji.
02:09
Somewhere, in a pattern like this,
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Negde se nalazi model sličan ovom,
02:11
is you,
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tu ste vi,
02:13
your perceptions,
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vaša percepcija,
02:15
your emotions, your memories,
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vaše emocije, pamćenje,
02:18
your plans for the future.
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vaši planovi za budućnost.
02:20
But we don't know where,
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Ali ne znamo gde,
02:22
since we don't know how to read the pattern.
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s obzirom da ne umemo da pročitamo te modele.
02:25
We don't understand the code used by the brain.
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Ne razumemo kod koji koristi naš mozak.
02:28
To make progress,
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Da bi napravili pomak,
02:30
we need to break the code.
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potrebno je da otkrijemo šifru.
02:32
But how?
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Ali kako?
02:35
An experienced code-breaker will tell you
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Iskusna osoba u dešifrovanju će vam reći da
02:37
that in order to figure out what the symbols in a code mean,
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kako biste razumeli značenje simbola u šifri,
02:40
it's essential to be able to play with them,
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morate biti u stanju da se igrate njima,
02:43
to rearrange them at will.
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da možete da ih reorganizujete.
02:45
So in this situation too,
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Tako, u ovoj situaciji takođe,
02:47
to decode the information
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da biste dekodirali informaciju
02:49
contained in patterns like this,
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sadržanu u ovakvom modelu,
02:51
watching alone won't do.
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samo posmatranje neće pomoći;
02:53
We need to rearrange the pattern.
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potrebno je da reorganizujemo model.
02:55
In other words,
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Drugim rečima,
02:57
instead of recording the activity of neurons,
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umesto da snimamo aktivnost neurona,
02:59
we need to control it.
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potrebno je da je kontrolišemo.
03:01
It's not essential that we can control
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Nije neophodno da možemo da kontrolišemo
03:03
the activity of all neurons in the brain, just some.
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aktivnost svih neurona u mozgu, samo nekih.
03:06
The more targeted our interventions, the better.
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Mada što je veći deo zahvaćen našim intervencijama, tim bolje.
03:08
And I'll show you in a moment
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I pokazaću vam za momenat
03:10
how we can achieve the necessary precision.
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kako možemo postići neophodnu preciznost.
03:13
And since I'm realistic, rather than grandiose,
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I s obzirom na to da sam realističan, pre nego grandiozan,
03:16
I don't claim that the ability to control the function of the nervous system
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ne tvrdim da će mogućnost kontrole funkcija nervnog sistema
03:19
will at once unravel all its mysteries.
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odmah razotkriti sve misterije.
03:22
But we'll certainly learn a lot.
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Ali sigurno je da će se naučiti dosta.
03:27
Now, I'm by no means
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Ja sam bez sumnje
03:29
the first person to realize
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prva osoba koja shvata
03:31
how powerful a tool intervention is.
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moć ove vrste intervencija.
03:34
The history of attempts
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Istorija pokušaja
03:36
to tinker with the function of the nervous system
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petljanja sa funkcijama nervnog sistema
03:38
is long and illustrious.
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je dugačka i slavna.
03:40
It dates back at least 200 years,
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Datira oko 200 godina unazad,
03:43
to Galvani's famous experiments
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do čuvenih Galvanovih eksperimenata
03:45
in the late 18th century and beyond.
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pri kraju XVIII veka i dalje.
03:49
Galvani showed that a frog's legs twitched
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Galvan je pokazao da se noga žabe zgrči
03:52
when he connected the lumbar nerve
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kada poveže lumbalni nerv
03:54
to a source of electrical current.
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sa izvorom električne struje.
03:57
This experiment revealed the first, and perhaps most fundamental,
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Ovaj eksperiment je otkrio prvu, i možda najbitniju,
04:00
nugget of the neural code:
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stvar o neuralnom kodu:
04:02
that information is written in the form
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da je informacija zapisana u formi
04:04
of electrical impulses.
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električnih impulsa.
04:08
Galvani's approach
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Galvanov pristup
04:10
of probing the nervous system with electrodes
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stimuliranja nervnog sistema elektrodama
04:12
has remained state-of-the-art until today,
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je ostao dominantan pristup sve do danas,
04:15
despite a number of drawbacks.
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uprkos njegovim brojnim manama.
04:18
Sticking wires into the brain is obviously rather crude.
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Zabadanje žica u mozak je bez sumnje prilično surovo.
04:21
It's hard to do in animals that run around,
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Teško je da se to radi sa životinjama koje jure unaokolo,
04:23
and there is a physical limit
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a tu je i fizički limit
04:25
to the number of wires
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koji se odnosi na broj žica
04:27
that can be inserted simultaneously.
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koje je moguće simultano priključiti.
04:30
So around the turn of the last century,
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Tako sam krajem prošlog veka,
04:32
I started to think,
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počeo da razmišljam,
04:34
"Wouldn't it be wonderful if one could take this logic
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kako bi bilo divno kad bi neko mogao da izvrne
04:37
and turn it upside down?"
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ovu logiku.
04:39
So instead of inserting a wire
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Tako da umesto ubacivanja žice
04:41
into one spot of the brain,
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u neku tačku mozga,
04:44
re-engineer the brain itself
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rekonstruišemo sam mozak
04:46
so that some of its neural elements
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tako da neki od neuralnih elemenata
04:49
become responsive to diffusely broadcast signals
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postanu sposobni da odgovaraju na difuznu emisiju signala,
04:52
such as a flash of light.
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kao što su to snopovi svetlosti.
04:55
Such an approach would literally, in a flash of light,
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Takav pristup bi bukvalno, dok trepneš,
04:58
overcome many of the obstacles to discovery.
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prevazišao mnoge prepreke na putu do otkrića.
05:01
First, it's clearly a non-invasive,
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Prvo, očigledno je neinvazivan,
05:04
wireless form of communication.
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bežični oblik komunikacije.
05:07
And second, just as in a radio broadcast,
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I drugo, baš kao i pri radio emitovanju,
05:09
you can communicate with many receivers at once.
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može se komunicirati sa mnogim prijemnicima odjednom.
05:12
You don't need to know where these receivers are,
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Nije potrebno da znate gde se nalaze primaoci.
05:15
and it doesn't matter if these receivers move --
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I nije važno ukoliko su ovi prijemnici u pokretu --
05:17
just think of the stereo in your car.
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samo pomislite na muzički uređaj u svom autu.
05:20
It gets even better,
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I postaje još i bolje,
05:23
for it turns out that we can fabricate the receivers
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jer se ispostavlja da možemo proizvoditi prijemnike
05:26
out of materials that are encoded in DNA.
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od materijala koji je kodiran u DNK.
05:29
So each nerve cell
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Tako će svaka nervna ćelija
05:31
with the right genetic makeup
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sa pravim genetičkim uređenjem
05:33
will spontaneously produce a receiver
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spontano proizvoditi prijemnik
05:36
that allows us to control its function.
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koji će nam omogućiti da kontrolišemo njenu funkciju.
05:39
I hope you'll appreciate
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Nadam se da ćete ceniti
05:41
the beautiful simplicity
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predivnu jednostavnost
05:43
of this concept.
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ovog koncepta.
05:45
There's no high-tech gizmos here,
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Ne postoje komplikovani visoko tehnološki koncepti,
05:47
just biology revealed through biology.
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samo jednostavna biologija otkrivena biologijom.
05:51
Now let's take a look at these miraculous receivers up close.
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Sada pogledajmo ove čudesne prijemnike izbliza.
05:54
As we zoom in on one of these purple neurons,
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Ukoliko zumiramo jedan od ovih purpurnih neurona,
05:57
we see that its outer membrane
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videćemo da njegova spoljašnja membrana
05:59
is studded with microscopic pores.
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okovana mikroskopskim porama.
06:01
Pores like these conduct electrical current
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Pore kao što su ove sakupljaju električnu struju
06:03
and are responsible
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i odgovorne su
06:05
for all the communication in the nervous system.
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za ukupnu komunikaciju na nivou nervnog sistema.
06:07
But these pores here are special.
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Ali ove pore ovde su specifične.
06:09
They are coupled to light receptors
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One su spojene kako bi osvetlile receptore
06:11
similar to the ones in your eyes.
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slično onima u vašim očima.
06:14
Whenever a flash of light hits the receptor,
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Kada snop svetlosti pogodi receptor,
06:16
the pore opens, an electrical current is switched on,
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pora se otvori i električna struja se uključi,
06:19
and the neuron fires electrical impulses.
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i neuron ispaljuje električne impulse.
06:22
Because the light-activated pore is encoded in DNA,
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I jer je svetlosno aktivirana pora kodirana u DNK,
06:25
we can achieve incredible precision.
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možemo postići neverovatnu preciznost.
06:28
This is because,
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To je zbog toga što,
06:30
although each cell in our bodies
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iako svaka ćelija u našim telima
06:32
contains the same set of genes,
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sadrži iste setove gena,
06:34
different mixes of genes get turned on and off
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različiti miksovi gena se pale i gase
06:36
in different cells.
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u različitim ćelijama.
06:38
You can exploit this to make sure
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Možete iskoristiti to kako biste se uverili
06:40
that only some neurons
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da samo neki neuroni
06:42
contain our light-activated pore and others don't.
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sadrže naše svetlosno aktivne pore dok druge ne sadrže.
06:45
So in this cartoon, the bluish white cell
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Tako na ovom crtežu, plavo bela ćelija
06:47
in the upper-left corner
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u gornjem levom uglu
06:49
does not respond to light
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ne reaguje na svetlost
06:51
because it lacks the light-activated pore.
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jer nema svetlosno aktivne pore.
06:54
The approach works so well
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Ovaj pristup funkcioniše toliko dobro
06:56
that we can write purely artificial messages
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da možemo pisati čisto proizvoljne poruke
06:58
directly to the brain.
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direktno u mozak.
07:00
In this example, each electrical impulse,
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U ovom primeru, svaki električni impuls,
07:02
each deflection on the trace,
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svako skretanje sa staze,
07:05
is caused by a brief pulse of light.
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uzrokovano je kratkim blokom svetlosti.
07:08
And the approach, of course, also works
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A ovaj pristup takođe funkcioniše
07:10
in moving, behaving animals.
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kod životinja u pokretu.
07:13
This is the first ever such experiment,
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Ovo je prvi ovakav eksperiment,
07:15
sort of the optical equivalent of Galvani's.
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nešto kao optički ekvivalent Galvanu.
07:18
It was done six or seven years ago
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Urađen je pre šest ili sedam godina
07:20
by my then graduate student, Susana Lima.
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od strane jedne moje svršene studentkinje, Suzane Lime.
07:23
Susana had engineered the fruit fly on the left
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Suzana je preuredila voćnu mušicu sa leve strane
07:26
so that just two out of the 200,000 cells in its brain
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tako da samo dve od 200 000 ćelija u mozgu
07:30
expressed the light-activated pore.
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iskazuju svetlosno aktivne pore.
07:33
You're familiar with these cells
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Poznate su vam ove ćelije
07:35
because they are the ones that frustrate you
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jer su to one koje vas frustriraju
07:37
when you try to swat the fly.
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kada pokušavate da je ubijete.
07:39
They trained the escape reflex that makes the fly jump into the air
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One su uvežbale refleks za bežanje koji omogućava mušici da odleti
07:42
and fly away whenever you move your hand in position.
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kad god pomerite svoju ruku.
07:46
And you can see here that the flash of light has exactly the same effect.
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I možete videti ovde da udar svetlosti ima isti efekat.
07:49
The animal jumps, it spreads its wings, it vibrates them,
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Životinja skoči, raširi krila, vibrira njima,
07:52
but it can't actually take off
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ali ne može zapravo otići,
07:54
because the fly is sandwiched between two glass plates.
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jer je zaglavljena između dve staklene ploče.
07:58
Now to make sure that this was no reaction of the fly
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Kako bi bila sigurna da ovo nije reakcija mušice
08:00
to a flash it could see,
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na svetlost koju može videti,
08:03
Susana did a simple
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Suzana je uradila jednostavan
08:05
but brutally effective experiment.
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ali brutalno efektan eksperiment.
08:07
She cut the heads off of her flies.
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Odsekla je glave mušicama.
08:11
These headless bodies can live for about a day,
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Ova bezglava tela mogu živeti od prilike jedan dan,
08:14
but they don't do much.
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ali ne rade mnogo šta.
08:16
They just stand around
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Ona samo stoje naokolo
08:19
and groom excessively.
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i preterano se doteruju.
08:22
So it seems that the only trait that survives decapitation is vanity.
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Tako izgleda da je jedina osobina koja opstaje i nakon odsecanja glave sujeta.
08:25
(Laughter)
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(Smeh)
08:30
Anyway, as you'll see in a moment,
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U svakom slučaju, kao što ćete videti za trenutak,
08:32
Susana was able to turn on the flight motor
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Suzana je uspela da uključi motor za letenje
08:35
of what's the equivalent of the spinal cord of these flies
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onoga što je ekvivalent kičmenoj moždini kod ovih mušica
08:38
and get some of the headless bodies
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i učini da se neka od ovih obezglavljenih tela
08:40
to actually take off and fly away.
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zaista pokrenu i odlete.
08:47
They didn't get very far, obviously.
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Nisu daleko odmakli, očigledno.
08:50
Since we took these first steps,
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Od kako smo načinili ove prve korake,
08:52
the field of optogenetics has exploded.
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polje optogenetike je "eksplodiralo".
08:55
And there are now hundreds of labs
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I danas postoje stotine laboratorija
08:57
using these approaches.
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koje koriste ove pristupe.
08:59
And we've come a long way
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I prešli smo dugačak put
09:01
since Galvani's and Susana's first successes
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od Galvanovih i Suzaninih prvih uspeha
09:04
in making animals twitch or jump.
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vezanih za trzanje ili skakanje životinja.
09:06
We can now actually interfere with their psychology
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Sada možemo zaći u njihovu psihologiju
09:09
in rather profound ways,
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na dublje načine
09:11
as I'll show you in my last example,
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kao što ću vam pokazati u svom poslednjem primeru
09:13
which is directed at a familiar question.
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koji je povezan sa nekim uobičajenim pitanjima.
09:16
Life is a string of choices
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Život je niz izbora
09:19
creating a constant pressure to decide what to do next.
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i vrši stalni pritisak na vas da odlučite šta da uradite sledeće.
09:23
We cope with this pressure by having brains,
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Borimo se sa ovim pritiskom tako što imamo mozgove,
09:26
and within our brains, decision-making centers
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a unutar naših mozgova, imamo centre za donošenje odluka
09:29
that I've called here the "Actor."
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koje sam ovde nazvao "Operativac".
09:33
The Actor implements a policy that takes into account
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Operativac sprovodi politiku koja uzima u obzir
09:36
the state of the environment
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stanje okruženja
09:38
and the context in which we operate.
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i kontekst u kome deluje.
09:41
Our actions change the environment, or context,
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Naše akcije menjaju sredinu, ili kontekst,
09:44
and these changes are then fed back into the decision loop.
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i ove promene se tada vraćaju u središte odlučivanja.
09:48
Now to put some neurobiological meat
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Sada da stavimo malo neurobiološke mase
09:51
on this abstract model,
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na ovaj apstraktni model,
09:53
we constructed a simple one-dimensional world
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konstruisaćemo jednostavan jednodimenzionalan svet
09:55
for our favorite subject, fruit flies.
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za naše omiljene subjekte, voćne mušice.
09:58
Each chamber in these two vertical stacks
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Svaka komora u ova dva vertikalna skladišta
10:00
contains one fly.
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sadrže po jednu mušicu.
10:02
The left and the right halves of the chamber
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Leva i desna polovina komora
10:05
are filled with two different odors,
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sadrže dve različite vrste mirisa,
10:07
and a security camera watches
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i sigurnosna kamera posmatra
10:09
as the flies pace up and down between them.
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kako se mušice kreću između njih.
10:12
Here's some such CCTV footage.
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Evo nekih snimaka tih kamera.
10:14
Whenever a fly reaches the midpoint of the chamber
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Kad god bi mušica stigla do središta komore
10:17
where the two odor streams meet,
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gde se susreću dve vrste mirisa,
10:19
it has to make a decision.
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morala je da napravi izbor.
10:21
It has to decide whether to turn around
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Morala je da odluči da li da se okrene
10:23
and stay in the same odor,
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i ostane u istom mirisnom polju,
10:25
or whether to cross the midline
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ili da pređe središnju liniju
10:27
and try something new.
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i da proba nešto novo.
10:29
These decisions are clearly a reflection
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Ove odluke su očito refleksija
10:32
of the Actor's policy.
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politike Operativca.
10:36
Now for an intelligent being like our fly,
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E sada, za inteligentno biće kao što je naša mušica,
10:39
this policy is not written in stone
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politika nije nepromenljiva,
10:42
but rather changes as the animal learns from experience.
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već se menja pošto životinje uče iskustvom.
10:45
We can incorporate such an element
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Možemo uključiti taj element
10:47
of adaptive intelligence into our model
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inteligencije prilagođavanja u naš model
10:50
by assuming that the fly's brain
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uz pretpostavku da mozak mušice
10:52
contains not only an Actor,
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sadrži ne samo Operativca,
10:54
but a different group of cells,
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već i različite grupe ćelija,
10:56
a "Critic," that provides a running commentary
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Kritiku, koja omogućava preispitivanje
10:59
on the Actor's choices.
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izbora koje pravi Opertivac.
11:01
You can think of this nagging inner voice
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Možete razmišljati o ovom "džangrizavom" unutrašnjem glasu
11:04
as sort of the brain's equivalent
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kao o vrsti moždanog ekvivalenta
11:06
of the Catholic Church,
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katoličke crkve,
11:08
if you're an Austrian like me,
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ukoliko ste iz Austrije kao ja,
11:11
or the super-ego, if you're Freudian,
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ili superega, ukoliko ste Frojdovac,
11:14
or your mother, if you're Jewish.
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ili vaše majke, ako ste Jevrej.
11:16
(Laughter)
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(Smeh)
11:20
Now obviously,
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Sada ozbiljno,
11:22
the Critic is a key ingredient
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kritika je ključni činilac
11:25
in what makes us intelligent.
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koji nas čini inteligentnima.
11:27
So we set out to identify
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Tako smo krenuli da otkrijemo
11:29
the cells in the fly's brain
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ćelije u mozgu mušice
11:31
that played the role of the Critic.
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koje igraju ulogu Kritike.
11:33
And the logic of our experiment was simple.
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Logika našeg eksperimenta je bila jednostavna.
11:36
We thought if we could use our optical remote control
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Pomislili smo da ako bi bili u stanju da iskoristimo naš optički daljinski upravljač
11:39
to activate the cells of the Critic,
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kako bismo aktivirali ćelije Kritike,
11:42
we should be able, artificially, to nag the Actor
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mogli bismo, veštački, da isprovociramo Operativca
11:45
into changing its policy.
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da promeni politiku.
11:47
In other words,
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Drugim rečima,
11:49
the fly should learn from mistakes
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mušica bi učila na greškama
11:51
that it thought it had made
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pomislila bi da je učinila nešto,
11:53
but, in reality, it had not made.
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što u stvarnosti nije.
11:56
So we bred flies
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Tako smo svrstali mušice
11:58
whose brains were more or less randomly peppered
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čiji su mozgovi bili manje ili više nasumično poprskani
12:01
with cells that were light addressable.
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ćelijama - prijemnicima za svetlo.
12:03
And then we took these flies
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I tada smo uzeli te mušice
12:05
and allowed them to make choices.
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i dozvolili im da naprave izbore.
12:07
And whenever they made one of the two choices,
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I kad god bi napravile jedan od dva izbora,
12:09
chose one odor,
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izabrale jedan miris,
12:11
in this case the blue one over the orange one,
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u ovom slučaju ovaj plavi spram narandžastog,
12:13
we switched on the lights.
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mi bismo promenili svetla.
12:15
If the Critic was among the optically activated cells,
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Da je kritika bila među optički aktiviranim ćelijama,
12:18
the result of this intervention
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rezultat ove intervencije
12:20
should be a change in policy.
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bi trebalo da bude menjanje politike.
12:23
The fly should learn to avoid
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Mušica bi naučila da izbegava
12:25
the optically reinforced odor.
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optički pojačan miris.
12:27
Here's what happened in two instances:
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Evo šta se dešava u dve situacije.
12:30
We're comparing two strains of flies,
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Upoređujemo dve vrste mušica,
12:33
each of them having
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svaka od njih ima
12:35
about 100 light-addressable cells in their brains,
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oko 100 ćelija - prijemnika za svetlo u svojim mozgovima,
12:37
shown here in green on the left and on the right.
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što je prikazano zelenom bojom sa leve i desne strane.
12:40
What's common among these groups of cells
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Ono što je zajedničko u ovim grupama ćelija
12:43
is that they all produce the neurotransmitter dopamine.
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jeste to da one sve produkuju neurotransmiter dopamin.
12:46
But the identities of the individual
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Ali među samim neuronima
12:48
dopamine-producing neurons
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koji proizvode dopamin
12:50
are clearly largely different on the left and on the right.
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postoje velike razlike, između ovih sa leve i ovih sa desne strane.
12:53
Optically activating
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Optički aktivirane
12:55
these hundred or so cells
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ovih stotinu ćelija
12:57
into two strains of flies
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u dve vrste mušica,
12:59
has dramatically different consequences.
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imaju dramatično različite posledice.
13:01
If you look first at the behavior
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Ako pogledate prvo ponašanje
13:03
of the fly on the right,
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mušica na desnoj strani,
13:05
you can see that whenever it reaches the midpoint of the chamber
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možete videti da kad god stignu do središnje tačke komore
13:08
where the two odors meet,
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gde se dva mirisa susreću,
13:10
it marches straight through, as it did before.
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one prolaze pravo napred kao što su to činile i ranije.
13:13
Its behavior is completely unchanged.
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Njihovo ponašanje je u potpunosti nepromenjeno.
13:15
But the behavior of the fly on the left is very different.
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Ali ponašanje mušica sa leve strane je različito.
13:18
Whenever it comes up to the midpoint,
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Kad god dođe do središnje tačke,
13:21
it pauses,
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zastane,
13:23
it carefully scans the odor interface
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pažljivo osmotri unutrašnjost tog dela mirisne komore,
13:25
as if it was sniffing out its environment,
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kao da njuši to okruženje,
13:27
and then it turns around.
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a potom se vraća nazad.
13:29
This means that the policy that the Actor implements
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Ovo znači da politika koju Operativac sada sprovodi
13:32
now includes an instruction to avoid the odor
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uključuje i informaciju da izbegne miris
13:34
that's in the right half of the chamber.
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koji je u desnoj strani komore.
13:37
This means that the Critic
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Ovo znači da je Kritika
13:39
must have spoken in that animal,
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morala progovoriti u toj životinji,
13:41
and that the Critic must be contained
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i da je Kritika sadržana
13:43
among the dopamine-producing neurons on the left,
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unutar neurona koji produkuju dopamin sa leve strane,
13:46
but not among the dopamine producing neurons on the right.
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ali ne i među neuronima sa desne strane.
13:49
Through many such experiments,
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Kroz mnogo ovakvih eksperimenata,
13:52
we were able to narrow down
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uspeli smo da suzimo
13:54
the identity of the Critic
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identitet Kritike
13:56
to just 12 cells.
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na samo 12 ćelija.
13:58
These 12 cells, as shown here in green,
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Ovih 12 ćelija, kao što je pokazano zelenom bojom,
14:01
send the output to a brain structure
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su poslale izveštaj moždanoj strukturi
14:03
called the "mushroom body,"
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koja se zove pečurkasto telo,
14:05
which is shown here in gray.
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i koja je ovde sive boje.
14:07
We know from our formal model
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Znamo iz našeg modela
14:09
that the brain structure
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da je moždana struktura
14:11
at the receiving end of the Critic's commentary is the Actor.
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na kraju prijemnih komentara Kritike zapravo Operativac.
14:14
So this anatomy suggests
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Tako ova anatomija sugeriše
14:16
that the mushroom bodies have something to do
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da pečurkasta tela treba nešto da urade
14:19
with action choice.
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u akciji vršenja izbora.
14:21
Based on everything we know about the mushroom bodies,
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S obzirom na sve što znamo o pečurkastim telima,
14:23
this makes perfect sense.
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ovo savršeno ima smisla.
14:25
In fact, it makes so much sense
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Zapravo, ovo toliko ima smilsla,
14:27
that we can construct an electronic toy circuit
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da možemo konstruisati električnu igračku
14:30
that simulates the behavior of the fly.
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koja simulira ponašanje mušice.
14:33
In this electronic toy circuit,
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U ovoj električnoj igrački
14:36
the mushroom body neurons are symbolized
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neuroni pečurkastog tela su simbolizovani
14:38
by the vertical bank of blue LEDs
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vertikalnim nagibom plave diode,
14:41
in the center of the board.
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na centru table.
14:44
These LED's are wired to sensors
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Ove diode su povezane sa senzorima
14:46
that detect the presence of odorous molecules in the air.
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koji detektuju prisustvo mirisnih molekula u vazduhu.
14:50
Each odor activates a different combination of sensors,
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Svaka vrsta mirisa aktivira različitu kombinaciju senzora,
14:53
which in turn activates
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koji dalje aktiviraju
14:55
a different odor detector in the mushroom body.
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različite detektore mirisa u pečurkastom telu.
14:58
So the pilot in the cockpit of the fly,
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Tako pilot u pilotskoj kabini mušice,
15:00
the Actor,
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Operativac,
15:02
can tell which odor is present
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može reći koji miris je prisutan
15:04
simply by looking at which of the blue LEDs lights up.
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jednostavnim pogledom na to koja je od plavih dioda upaljena.
15:09
What the Actor does with this information
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Šta će Operativac uraditi sa tom informacijom
15:11
depends on its policy,
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zavisi od njegove politike,
15:13
which is stored in the strengths of the connection,
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koja počiva na čvrstini veza,
15:15
between the odor detectors
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između detektora mirisa
15:17
and the motors
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i motora
15:19
that power the fly's evasive actions.
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koji pokreću mušicu na odlučujuću akciju.
15:22
If the connection is weak, the motors will stay off
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Ukoliko je veza slaba, motori će ostati isključeni
15:24
and the fly will continue straight on its course.
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i mušica će nastaviti pravo na svom kursu.
15:27
If the connection is strong, the motors will turn on
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Ako je veza jaka, motori će se uključiti
15:30
and the fly will initiate a turn.
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i mušica će se okrenuti.
15:33
Now consider a situation
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Sada razmotrite situaciju
15:35
in which the motors stay off,
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u kojoj motori ostaju isključeni,
15:37
the fly continues on its path
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i mušica nastavi svojom stazom
15:40
and it suffers some painful consequence
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i doživi neke bolne posledice
15:42
such as getting zapped.
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kao recimo da bude uhvaćena.
15:44
In a situation like this,
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U ovakvoj situaciji,
15:46
we would expect the Critic to speak up
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možemo očekivati da Kritika progovori
15:48
and to tell the Actor
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i kaže Operativcu
15:50
to change its policy.
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da promeni politiku.
15:52
We have created such a situation, artificially,
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Kreirali smo veštačku situaciju
15:55
by turning on the critic with a flash of light.
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pokrenuvši Kritiku snopom svetlosti.
15:58
That caused a strengthening of the connections
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To je dovelo do jačanja veza
16:01
between the currently active odor detector
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između trenutno aktivnog detektora mirisa
16:04
and the motors.
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i motora.
16:06
So the next time
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I tako se sledeći put
16:08
the fly finds itself facing the same odor again,
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mušica našla suočena ponovo sa istim mirisom,
16:11
the connection is strong enough to turn on the motors
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veza je dovoljno jaka da pokrene motore
16:14
and to trigger an evasive maneuver.
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i da pokrene odlučujuću akciju.
16:19
I don't know about you,
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Ne znam za vas,
16:22
but I find it exhilarating to see
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ali ja mislim da je prosvetljujuće
16:25
how vague psychological notions
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kako maglovita psihološka zapažanja
16:28
evaporate and give rise
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nestaju i ostavljaju prostor
16:30
to a physical, mechanistic understanding of the mind,
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za fizička i mehanicistička objašnjenja uma,
16:33
even if it's the mind of the fly.
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pa makar to bio i um mušice.
16:36
This is one piece of good news.
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Ovo je jedan deo dobrih vesti.
16:39
The other piece of good news,
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Drugi deo dobrih vesti,
16:41
for a scientist at least,
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makar i samo za naučnike,
16:43
is that much remains to be discovered.
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jeste to da je ostalo još mnogo toga da bude tek otkriveno.
16:46
In the experiments I told you about,
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U eksperimentima o kojima sam vam govorio,
16:48
we have lifted the identity of the Critic,
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uspeli smo da identifikujemo Kritiku,
16:51
but we still have no idea
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ali i dalje nemamo ideju
16:53
how the Critic does its job.
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kako ona radi svoj posao.
16:55
Come to think of it, knowing when you're wrong
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Kada razmislite o tome, saznanje da ste pogrešili
16:57
without a teacher, or your mother, telling you,
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bez učitelja, ili majke da vam na to ukaže,
17:00
is a very hard problem.
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veoma je velik problem.
17:02
There are some ideas in computer science
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Postoje neke ideje u informatici
17:04
and in artificial intelligence
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i veštačkoj inteligenciji
17:06
as to how this might be done,
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o tome kako je to moguće učiniti,
17:08
but we still haven't solved
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ali još uvek nismo rešili
17:10
a single example
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ni jedan primer
17:12
of how intelligent behavior
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kako inteligentno ponašanje
17:15
springs from the physical interactions
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prelazi iz fizičke interakcije
17:17
in living matter.
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u živu materiju.
17:19
I think we'll get there in the not too distant future.
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Mislim da ćemo dobiti odgovore u bliskoj budućnosti.
17:22
Thank you.
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Hvala vam.
17:24
(Applause)
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(Aplauz)
ABOUT THE SPEAKER
Gero Miesenboeck - OptogeneticistUsing light and a little genetic engineering -- optogenetics -- Gero Miesenboeck has developed a way to control how living nerve cells work, and advanced understanding of how the brain controls behavior.
Why you should listen
Gero Miesenboeck is pioneering the field of optogenetics: genetically modifying nerve cells to respond to light. By flashing light at a modified neuron in a living nervous system, Miesenboeck and his collaborators can mimic a brain impulse -- and then study what happens next. Optogenetics will allow ever more precise experiments on living brains, allowing us to gather better evidence on how electrical impulses on tissue translate into actual behavior and thoughts.
In one experiment, done at Yale, he and his team engineered fruit flies to be light-sensitive in the neural area responsible for escape response. Then the flies were beheaded; fruit flies can live for a day without their heads, but they don't move. When the modified cells were flashed with light, though, the headless flies flew. Miesenboeck had successfully simulated an order from a brain that wasn't even there anymore.
Miesenboeck's current research at Oxford's growing department of neurobiology focuses on the nerve cell networks that underpin what animals perceive, remember and do. In one recent experiment, he used optogenetics to implant an unpleasant memory in a fruit fly, causing it to "remember" to avoid a certain odor as it traveled around. He and his team were able, in fact, to find the fly's specific 12-neuron brain circuit that govern memory formation.
Gero Miesenboeck | Speaker | TED.com