The beautiful, mysterious science of how you hear | Jim Hudspeth

Transcriber: Joseph Geni Reviewer: Camille Martínez

Prevoditelj: Leona Grujić Recezent: Sanda Liker

Can you hear me OK?

Čujete li me dobro?

Audience: Yes.

Publika: Da.

Jim Hudspeth: OK. Well, if you can, it's really amazing,

Hudspeth: Okej. Ako čujete, to je uistinu nevjerojatno,

because my voice is changing the air pressure where you sit

jer moj glas mijenja tlak zraka na mjestu na kojem sjedite

by just a few billionths of the atmospheric level,

tek za milijarditi dio atmosferske razine,

yet we take it for granted

a ipak uzimamo zdravo za gotovo

that your ears can capture that infinitesimal signal

da naše uši mogu uloviti taj neznatni signal

and use it to signal to the brain the full range of auditory experiences:

i iskoristiti ga da mozgu prenesu čitavu lepezu zvučnih iskustava:

the human voice, music, the natural world.

ljudski glas, glazbu, zvukove prirode.

How does your ear do that?

Kako naše uši to rade?

And the answer to that is:

Odgovor je -

through the cells that are the real hero of this presentation --

pomoću stanica koje su pravi junaci ovog izlaganja,

the ear's sensory receptors,

ušni osjetilni receptori

which are called "hair cells."

zvani "dlačne stanice."

Now, these hair cells are unfortunately named,

To je zapravo nezgodan naziv,

because they have nothing at all to do with the kind of hair

jer nemaju nikakve veze s onom vrstom dlaka

of which I have less and less.

kojih ja imam sve manje.

These cells were originally named that by early microscopists,

Te su stanice tako nazvali ljudi koji su ih gledali kroz mikroskop

who noticed that emanating from one end of the cell

i primijetili da se iz jednog kraja stanice

was a little cluster of bristles.

širi sitan busen čekinja.

With modern electron microscopy, we can see much better

Modernim elektronskim mikroskopima možemo mnogo bolje utvrditi

the nature of the special feature that gives the hair cell its name.

prirodu tog posebnog obilježja po kojem su dlačne stanice nazvane.

That's the hair bundle.

Ovo je snop dlačica.

It's this cluster of 20 to several hundred fine cylindrical rods

U ovom snopu ima između 20 i nekoliko stotina finih cilindričnih šipki

that stand upright at the top end of the cell.

koje uspravno stoje na vrhu stanice.

And this apparatus is what is responsible for your hearing me right this instant.

Taj aparat je ono što vam omogućuje da me sada čujete.

Now, I must say that I am somewhat in love with these cells.

Moram priznati da sam donekle zaljubljen u ove stanice.

I've spent 45 years in their company --

Proveo sam 45 godina s njima...

(Laughter)

(Smijeh)

and part of the reason is that they're really beautiful.

a jedan od razloga je što su uistinu lijepe.

Postoji estetska komponenta u ovome.

There's an aesthetic component to it.

Here, for example, are the cells

Ovdje, recimo, imamo stanice

with which an ordinary chicken conducts its hearing.

pomoću kojih obična kokoš čuje.

These are the cells that a bat uses for its sonar.

Ovo su stanice koje šišmiš koristi za svoj sonar.

We use these large hair cells from a frog for many of our experiments.

Koristimo žablje velike dlačne stanice u mnogim pokusima.

Hair cells are found all the way down to the most primitive of fishes,

Dlačne stanice nalazimo i kod najprimitivnijih riba,

and those of reptiles often have this really beautiful,

a kod gmazova one imaju uistinu predivan,

almost crystalline, order.

gotovo kristalni poredak.

But above and beyond its beauty,

Ali one nisu samo lijepe,

the hair bundle is an antenna.

snopovi dlačica su i antena.

It's a machine for converting sound vibrations into electrical responses

To su strojevi za pretvaranje zvučnih vibracija u električne signale

that the brain can then interpret.

koje mozak može protumačiti.

At the top of each hair bundle, as you can see in this image,

Na vrhu svake dlačne stanice, kao što vidite,

there's a fine filament connecting each of the little hairs,

nalaze se fina vlakna koja spajaju sve dlačice,

the stereocilia.

stereocilije.

It's here marked with a little red triangle.

Ovdje su označene crvenim trokutićem.

And this filament has at its base a couple of ion channels,

Ta vlakna u korijenu imaju nekoliko ionskih kanala,

which are proteins that span the membrane.

koji su proteini koji se protežu membranom.

And here's how it works.

Evo kako funkcioniraju.

This rat trap represents an ion channel.

Ova mišolovka predstavlja ionski kanal.

It has a pore that passes potassium ions and calcium ions.

Ima otvor koji propušta kalijeve i kalcijeve ione.

It has a little molecular gate that can be open, or it can be closed.

Ima mala molekulska vrata koja se mogu otvoriti i zatvoriti.

And its status is set by this elastic band which represents that protein filament.

O tome odlučuje ova elastična vrpca koja predstavlja proteinsko vlakno.

Now, imagine that this arm represents one stereocilium

Zamislite da je ova ruka jedna stereocilija,

and this arm represents the adjacent, shorter one

a ova ruka je susjedna, kraća stereocilija

with the elastic band between them.

s elastičnom vrpcom između njih.

When sound energy impinges upon the hair bundle,

Kad energija zvuka dosegne dlačnu stanicu,

it pushes it in the direction towards its taller edge.

gurne je u smjeru višeg ruba.

The sliding of the stereocilia puts tension in the link

Klizanje stereocilija optereti vezu

until the channels open and ions rush into the cell.

sve dok se kanal ne otvori i ioni pojure u stanicu.

When the hair bundle is pushed in the opposite direction,

Kad se dlačnu stanicu gurne u suprotnom smjeru,

the channels close.

kanali se zatvore.

And, most importantly,

Najvažnije,

a back-and-forth motion of the hair bundle,

ovo pomicanje stanice naprijed i natrag,

as ensues during the application of acoustic waves,

uzrokovano djelovanjem akustičnih valova,

alternately opens and closes the channel,

naizmjenično otvara i zatvara kanal,

and each opening admits millions and millions of ions into the cell.

a svako otvaranje propušta milijune iona u stanicu.

Those ions constitute an electrical current

Ti ioni tvore električnu struju

that excites the cell.

koja uzbuđuje stanicu.

The excitation is passed to a nerve fiber,

Ta uzbuđenost dolazi do živčanog vlakna

and then propagates into the brain.

i zatim odlazi u mozak.

Notice that the intensity of the sound

Primijetite da je intenzitet zvuka

is represented by the magnitude of this response.

predstavljen magnitudom ovog odziva.

A louder sound pushes the hair bundle farther,

Glasniji zvuk gura dlačnu stanicu dalje,

opens the channel longer,

drži kanal otvorenim dulje,

lets more ions in

propušta više iona

and gives rise to a bigger response.

i uzrokuje veći odziv.

Now, this mode of operation has the advantage of great speed.

Ovom načinu rada prednost daje velika brzina.

Some of our senses, such as vision,

Neka od naših osjetila, poput vida,

use chemical reactions that take time.

koriste kemijske reakcije kojima treba vremena.

And as a consequence of that,

Kao posljedica toga,

if I show you a series of pictures at intervals of 20 or 30 per second,

ako vam pokažem niz slika u intervalima od 20 ili 30 u sekundi,

you get the sense of a continuous image.

vi ćete ih vidjeti kao jednu kontinuiranu sliku.

Because it doesn't use reactions,

Budući da ne koristi te reakcije,

the hair cell is fully 1,000 times faster than our other senses.

dlačna stanica je 1000 puta brža od naših ostalih osjetila.

We can hear sounds at frequencies as great as 20,000 cycles per second,

Možemo čuti zvuk na frekvencijama do 20 000 ciklusa po sekundi,

and some animals have ever faster ears.

a neke životinje imaju i brže uši.

The ears of bats and whales, for example, can respond to their sonar pulses

Uši šišmiša i kitova, primjerice, reagiraju na sonarne pulsove

at 150,000 cycles a second.

od 150 000 ciklusa po sekundi.

But this speed doesn't entirely explain why the ear performs so well.

Ali brzina ne objašnjava u potpunosti zašto naše uši rade tako dobro.

And it turns out that our hearing benefits from an amplifier,

Našem sluhu pomaže pojačivač,

something called the "active process."

nešto što se zove "aktivni proces".

The active process enhances our hearing

Aktivni proces pojačava naš sluh

and makes possible all the remarkable features that I've already mentioned.

i omogućava sva ona nevjerojatna svojstva koja sam spomenuo.

Let me tell you how it works.

Evo kako to funkcionira.

First of all, the active process amplifies sound,

Najprije, aktivni proces pojačava zvuk

so you can hear, at threshold, sounds that move the hair bundle

pa možete čuti u najmanju ruku zvukove koji pomiču snop dlačica

by a distance of only about three-tenths of a nanometer.

za otprilike tri desetinke nanometra.

That's the diameter of one water molecule.

To je dijametar jedne molekule vode.

It's really astonishing.

To je uistinu nevjerojatno.

The system can also operate

Sustav također zahvaća

over an enormously wide dynamic range.

nevjerojatno široki dinamički domet.

Why do we need this amplification?

Zašto trebamo ovo pojačavanje?

The amplification, in ancient times, was useful

U drevnim vremenima, pojačavanje je bilo korisno,

because it was valuable for us to hear the tiger before the tiger could hear us.

jer se isplatilo čuti tigra prije nego bi on čuo vas.

And these days, it's essential as a distant early warning system.

Čak i danas, ono je nužno kao rani sustav upozorenja na daljinu.

It's valuable to be able to hear fire alarms

Isplati se moći čuti alarme za požar,

or contemporary dangerous such as speeding fire engines or police cars or the like.

ili suvremene opasnosti poput jurećih vatrogasnih kola ili policije i slično.

When the amplification fails, our hearing's sensitivity plummets,

Kad pojačavanje nije uspješno, osjetljivost našeg sluha naglo pada

and an individual may then need an electronic hearing aid

pa pojedinci trebaju elektronička slušna pomagala

to supplant the damaged biological one.

kako bi nadomjestili biološko oštećenje.

This active process also enhances our frequency selectivity.

Ovaj aktivni proces također pojačava našu frekvencijsku selektivnost.

Even an untrained individual can distinguish two tones

Čak i neuvježbani pojedinac može razlučiti dva tona

that differ by only two-tenths of a percent,

koji se razlikuju za samo dvije desetinke postotka,

which is one-thirtieth of the difference between two piano notes,

što je jedna tridesetina razlike između dvije klavirske note,

and a trained musician can do even better.

a uvježbani glazbenik može i bolje.

This fine discrimination is useful

Ovakvo istančano razlučivanje pridonosi

in our ability to distinguish different voices

našoj sposobnosti razlikovanja različitih glasova

and to understand the nuances of speech.

i razumijevanju nijansi govora.

And, again, if the active process deteriorates,

Opet, ako se aktivni proces pogorša,

it becomes harder to carry out verbal communication.

verbalna komunikacija je otežana.

Finally, the active process is valuable in setting the very broad range

Konačno, aktivni proces doprinosi uspostavljanju vrlo širokog raspona

of sound intensities that our ears can tolerate,

zvučnog intenziteta koji naše uši mogu podnijeti,

from the very faintest sound that you can hear, such as a dropped pen,

od jedva čujnog zvuka, poput pada kemijske olovke,

to the loudest sound that you can stand --

do najglasnijeg zvuka koji možete podnijeti,

say, a jackhammer or a jet plane.

recimo, bušilice ili mlažnjaka.

The amplitude of sounds spans a range of one millionfold,

Zvučna amplituda obuhvaća raspon od milijun puta,

which is more than is encompassed by any other sense

više nego što obuhvaća ijedno drugo osjetilo,

or by any man-made device of which I'm aware.

ili ijedna druga ljudska naprava za koju znam.

And again, if this system deteriorates,

Ponovno, ako sustav oslabi,

an affected individual may have a hard time

pojedincu će biti teško čuti

hearing the very faintest sounds

najslabije zvukove,

or tolerating the very loudest ones.

ili podnijeti najglasnije zvukove.

Now, to understand how the hair cell does its thing,

Kako bismo razumjeli kako dlačna stanica radi,

one has to situate it within its environment within the ear.

moramo je promatrati u njezinom okruženju, u uhu.

We learn in school that the organ of hearing

U školi nas uče da je slušni organ

is the coiled, snail-shaped cochlea.

ova zavojita pužnica.

It's an organ about the size of a chickpea.

To je organ veličine zrna slanutka.

It's embedded in the bone on either side of the skull.

Ugrađen je u kosti na obje strane lubanje.

We also learn that an optical prism

Također nas uče da prizma

can separate white light into its constituent frequencies,

može rastaviti svjetlost na njezine konstitutivne frekvencije

which we see as distinct colors.

koje mi vidimo kao različite boje.

In an analogous way,

Analogno tome,

the cochlea acts as sort of an acoustic prism

pužnica je neka vrsta akustičke prizme

that splits apart complex sounds into their component frequencies.

koja rastavlja složene zvukove na njihove frekvencijske komponente.

So when a piano is sounded,

Kad čujete klavir,

different notes blend together into a chord.

različite note se stapaju u akord.

The cochlea undoes that process.

Vaša pužnica obrće taj proces.

It separates them and represents each at a different position.

Ona ih rastavlja i stavlja svaku na drukčiji položaj.

In this picture, you can see where three notes --

Na ovoj slici vidite gdje su tri note -

middle C and the two extreme notes on a piano --

srednje C i dvije ekstremne note na klaviru -

are represented in the cochlea.

predstavljene u pužnici.

The lowest frequencies go all the way up to the top of the cochlea.

Najniže frekvencije idu na vrh pužnice.

The highest frequencies, down to 20,000 Hz,

Najviše frekvencije, do 20 000 Hz,

go all the way to the bottom of the cochlea,

spuštaju se na dno pužnice,

and every other frequency is represented somewhere in between.

a sve ostale frekvencije su smještene negdje u sredini.

And, as this diagram shows,

Kako vidite na ovom dijagramu,

successive musical tones are represented a few tens of hair cells apart

sukcesivni glazbeni tonovi su udaljeni nekoliko desetaka stanica jedan od drugog

along the cochlear surface.

duž površine pužnice.

Now, this separation of frequencies

Ovo rastavljanje frekvencija

is really key in our ability to identify different sounds,

je zapravo ključ naše sposobnosti da identificiramo različite zvukove,

because very musical instrument,

jer svaki muzički instrument,

every voice,

svaki glas,

emits a distinct constellation of tones.

ima različitu konstelaciju tonova.

The cochlea separates those frequencies,

Pužnica razdvaja te frekvencije,

and the 16,000 hair cells then report to the brain

a 16 000 dlačnih stanica onda javlja mozgu

how much of each frequency is present.

koliko je svaka od frekvencija zastupljena.

The brain can then compare all the nerve signals

Mozak tako može usporediti sve živčane signale

and decide what particular tone is being heard.

i odlučiti koji se točno ton čuje.

But this doesn't explain everything that I want to explain.

Ali to ne objašnjava sve što želim objasniti.

Where's the magic?

Gdje je tu magija?

I told you already about the great things that the hair cell can do.

Već sam vam rekao o super stvarima koje dlačna stanica može.

How does it carry out the active process

Kako ona provodi aktivni proces

and do all the remarkable features that I mentioned at the outset?

i radi sve one nevjerojatne stvari koje sam spomenuo na početku?

The answer is instability.

Odgovor je nestabilnost.

We used to think that the hair bundle was a passive object,

Mislili smo da je snop dlačica pasivni objekt

it just sat there, except when it was stimulated.

koji naprosto miruje osim kad ga se stimulira.

But in fact, it's an active machine.

Ali to je zapravo aktivni stroj.

It's constantly using internal energy to do mechanical work

Neprestano koristi unutarnju energiju za obavljanje mehaničkih poslova

and enhance our hearing.

i pojačavanje našeg sluha.

So even at rest, in the absence of any input,

Čak i kad odmara, kad nema nikakvog inputa,

an active hair bundle is constantly trembling.

aktivni snop dlačica neprestano titra.

It's constantly twitching back and forth.

Neprestano se trza naprijed-natrag.

But when even a weak sound is applied to it,

Ali kada čak i do njega dođe slabi zvuk,

it latches on to that sound and begins to move very neatly

priključi se na taj zvuk i počne se uredno kretati

in a one-to-one way with it,

zajedno s njim,

and by so doing, it amplifies the signal about a thousand times.

i time pojačava signal otprilike tisuću puta.

This same instability also enhances our frequency selectivity,

Ta nestabilnost također pojačava frekvencijsku selektivnost,

for a given hair cell tends to oscillate best

jer dlačna stanica najbolje oscilira

at the frequency at which it normally trembles

na frekvenciji na kojoj obično titra

when it's not being stimulated.

kad nije stimulirana.

So, this apparatus not only gives us our remarkably acute hearing,

Dakle, taj aparat ne samo da nam daje naš nevjerojatno izoštren sluh,

but also gives us the very sharp tuning.

već ga neprestano ugađa.

I want to offer you a short demonstration

Želim vam ponuditi kratku demonstraciju

of something related to this.

nečeg vezanog uz ovo.

I'll ask the people who are running the sound system

Zamolit ću ljude zadužene za ozvučenje

to turn up its sensitivity at one specific frequency.

da pojačaju osjetljivost na jednu specifičnu frekvenciju.

So just as a hair cell is tuned to one frequency,

Kao što je dlačna stanica uštimana za jednu frekvenciju,

the amplifier will now enhance a particular frequency in my voice.

pojačivač će sada pojačati jednu frekvenciju u mom glasu.

Notice how specific tones emerge more clearly from the background.

Slušajte kako specifični tonovi postaju jasniji u pozadini.

This is exactly what hair cells do.

Upravo to rade dlačne stanice.

Each hair cell amplifies and reports one specific frequency

Svaka stanica pojačava i javlja jednu specifičnu frekvenciju

and ignores all the others.

i zanemaruje sve ostale.

And the whole set of hair cells, as a group, can then report to the brain

A cijeli skup dlačnih stanica onda mogu javiti mozgu

exactly what frequencies are present in a given sound,

točno koje su frekvencije prisutne u nekom zvuku

and the brain can determine what melody is being heard

i mozak može odrediti koju melodiju čuje

or what speech is being intended.

ili što se govori.

Now, an amplifier such as the public address system

Kao sustav javnog obraćanja, pojačivač može

can also cause problems.

također uzrokovati probleme.

If the amplification is turned up too far,

Ako je pojačavanje prejako,

it goes unstable and begins to howl

postane nestabilno i počne zavijati,

or emit sounds.

ili ispuštati zvuk.

And one wonders why the active process doesn't do the same thing.

Pitamo se zašto aktivni proces ne radi isto.

Why don't our ears beam out sounds?

Zašto naše uši ne ispuštaju zvuk?

And the answer is that they do.

Odgovor je da ispuštaju zvuk.

In a suitably quiet environment, 70 percent of normal people

U vrlo tihom okruženju, 70 % normalnih ljudi

will have one or more sounds coming out of their ears.

čuje zvukove u ušima.

(Laughter)

(Smijeh)

I'll give you an example of this.

Dat ću vam primjer.

You will hear two emissions at high frequencies

Čut ćete dvije emisije visokih frekvencija

coming from a normal human ear.

koje ispušta normalno ljudsko uho.

You may also be able to discern background noise,

Također ćete razaznati buku u pozadini,

like the microphone's hiss,

poput šištanja mikrofona,

the gurgling of a stomach, the heartbeat, the rustling of clothes.

kruljenja u želucu, kucanja srca, šuštanja odjeće.

(Hums, microphone hiss, dampened taps, clothes rustling)

(Šumovi, šištanje mikrofona, potmulo tapkanje, šuštanje odjeće)

This is typical.

Ovo je tipično.

Most ears emit just a handful of tones,

Većina ušiju ispušta tek nekoliko tonova,

but some can emit as many as 30.

ali neka ispuštaju do čak 30 različitih tonova.

Every ear is unique, so my right ear is different from my left,

Svako je uho jedinstveno, moje desno uho je drukčije od lijevog,

my ear is different from your ear,

moje su uši drukčije od vaših ušiju,

but unless an ear is damaged,

ali osim ako nije oštećeno,

it continues to emit the same spectrum of frequencies

uho nastavlja emitirati isti spektar frekvencija

over a period of years or even decades.

tijekom godina, ili čak desetljeća.

So what's going on?

Dakle, što se događa?

It turns out that the ear can control its own sensitivity,

Ispada da uho može kontrolirati svoju osjetljivost,

its own amplification.

upravljati pojačavanjem.

So if you're in a very loud environment, like a sporting event

Ako ste u vrlo glasnom okruženju, na sportskoj manifestaciji,

or a musical concert,

ili muzičkom koncertu,

you don't need any amplification,

ne treba vam pojačavanje,

and the system is turned down all the way.

i sustav je potpuno stišan.

If you are in a room like this auditorium,

Ako ste u prostoriji poput ove,

you might have a little bit of amplification,

možda ćete malo pojačati,

but of course the public address system does most of the work for you.

ali zvučni sustav uglavnom radi umjesto vas.

And finally, if you go into a really quiet room

Konačno, ako odete u jako tihu sobu,

where you can hear a pin drop,

u kojoj možete čuti pad igle,

the system is turned up almost all the way.

sustav se pojača skoro do kraja.

But if you go into an ultraquiet room such as a sound chamber,

Ali ako odete u ultra tihu sobu, poput zvučne komore,

the system turns itself up to 11,

sustav se pojača do maksimuma,

it goes unstable

postane nestabilan

and it begins to emit sound.

i počne ispuštati zvuk.

And these emissions constitute a really strong demonstration

Te emisije snažno demonstriraju

of just how active the hair cell can be.

koliko aktivna dlačna stanica može biti.

So in the last minute, I want to turn to another question that might come up,

U preostaloj minuti želim se pozabaviti pitanjem koje bi moglo iskrsnuti,

which is: Where do we go from here?

a to je: Kamo dalje?

And I would say that there are three issues

Mislim da postoje tri stvari

that I would really like to address in the future.

kojima bih se volio baviti u budućnosti.

The first is: What is the molecular motor

Prva je: što je molekularni motor

that's responsible for the hair cell's amplification?

koji pokreće pojačavanje dlačne stanice?

Somehow, nature has stumbled across a system

Priroda je nekako nabasala na sustav

that can oscillate or amplify at 20,000 cycles per second,

koji može oscilirati ili pojačavati 20 000 ciklusa po sekundi,

or even more.

ili čak više.

That's much faster than any other biological oscillation,

To je mnogo brže od bilo koje druge biološke oscilacije,

and we would like to understand where it comes from.

i voljeli bismo shvatiti otkuda to dolazi.

The second issue is how the hair cell's amplification is adjusted

Drugo je pitanje kako se pojačavanje prilagođava

to deal with the acoustic circumstances.

akustičkim okolnostima.

Who turns the knob to increase or decrease the amplification

Što okreće gumbe koji povećavaju ili smanjuju pojačavanje

in a quiet or in a loud environment?

u tihom ili glasnom okruženju?

And the third issue is one that concerns all of us,

I treće je pitanje koje se tiče svih nas,

which is what we can do about the deterioration of our hearing.

a to je što možemo poduzeti u vezi s pogoršanjem sluha.

Thirty million Americans,

30 milijuna Amerikanaca

and more than 400 million people worldwide,

i više od 400 milijuna ljudi širom svijeta

have significant problems on a daily basis

svaki dan imaju velike probleme

with understanding speech in a noisy environment

s razumijevanjem govora u glasnom okruženju

or over the telephone.

ili preko telefona.

Many have even worse deficits.

Mnogi imaju i gore probleme.

Moreover, these deficits tend to get worse with time,

Usto, ti se problemi pogoršavaju s vremenom,

because when human hair cells die,

jer kad ljudske dlačne stanice umru,

they're not replaced by cell division.

ne zamjenjuju se putem stanične diobe.

But we know that nonmammalian animals can replace their cells,

Ali znamo da životinje koje nisu sisavci mogu zamijeniti svoje stanice

and those creatures' cells are dying and being replaced throughout life,

i u tih stvorenja umrle stanice bivaju zamijenjene tijekom života

so the animals maintain normal hearing.

pa one zadržavaju normalni sluh.

Here's an example from a little zebra fish.

Evo primjera male ribe, zebrice.

The cell at the top will undergo a division

Stanice na vrhu će proći diobu

to produce two new hair cells.

i stvoriti dvije nove dlačne stanice.

They dance for a little bit,

Malo će plesati,

and then settle down and go to work.

a onda će se smiriti i prionuti na posao.

So we believe that if we can decode the molecular signals that are used

Vjerujemo da, ako uspijemo dekodirati molekularne signale

by these other animals to regenerate their hair cells,

koje te životinje koriste za regeneraciju stanica,

we'll be able to do the same thing for humans.

možemo isto napraviti i za ljude.

And our group and many other groups are now engaged in research

Naša grupa, kao i mnoge druge, sada istražuju

trying to resurrect these amazing hair cells.

kako uskrsnuti te izvanredne dlačne stanice.

Thank you for your attention.

Hvala na pažnji.

(Applause)

(Pljesak)