One more reason to get a good night’s sleep | Jeff Iliff

Prevoditelj: Anja Kolobarić Recezent: Ivan Stamenković

Sleep.

Spavanje.

It's something we spend about a third of our lives doing,

Trećinu svog života provedemo spavajući,

but do any of us really understand what it's all about?

ali razumije li itko od nas o čemu se tu zapravo radi?

Two thousand years ago, Galen,

Prije dvije tisuće godina Galen,

one of the most prominent medical researchers

jedan od najistaknutijih istraživača medicine

of the ancient world,

starog svijeta,

proposed that while we're awake,

tvrdio je da dok smo budni,

our brain's motive force, its juice,

pokretačka sila našeg mozga, njegov sok,

would flow out to all the other parts of the body,

prelijeva se u druge dijelove tijela,

animating them but leaving the brain all dried up,

oživljavajući ih, ali ujedno ostavljajući mozak potpuno osušenim,

and he thought that when we sleep,

i smatrao je da se, kada spavamo,

all this moisture that filled the rest of the body

sva ta vlaga koja je prethodno ispunjavala naše tijelo,

would come rushing back,

vraća natrag,

rehydrating the brain

ponovo hidratizirajući mozak

and refreshing the mind.

i osvježavajući um.

Now, that sounds completely ridiculous to us now,

Danas nam to zvuči potpuno suludo,

but Galen was simply trying to explain

ali Galen je jednostavno pokušao objasniti

something about sleep

spavanje kao

that we all deal with every day.

nešto što radimo svaki dan.

See, we all know based on our own experience

Svi mi iz vlastitog iskustva znamo

that when you sleep, it clears your mind,

da kada spavamo, mozak postaje bistriji,

and when you don't sleep,

a kada ne spavamo

it leaves your mind murky.

mozak postaje mutniji.

But while we know a great deal more about sleep now

Ali unatoč tome što danas znamo mnogo više o spavanju

than when Galen was around,

negoli u Galenovo vrijeme,

we still haven't understood why it is that sleep,

još uvijek nismo otkrili zašto baš spavanje,

of all of our activities, has this incredible

od svih naših aktivnosti, ima ovakvu nevjerojatnu

restorative function for the mind.

funkciju obnavljanja uma.

So today I want to tell you about

Danas bih vam želio reći nešto više

some recent research

o nedavnom istraživanju

that may shed new light on this question.

koje bi moglo razjasniti ovo pitanje.

We've found that sleep may actually be

Otkrili smo da bi spavanje zapravo moglo biti

a kind of elegant design solution

vrlo elegantno osmišljeno rješenje

to some of the brain's most basic needs,

za neke od najosnovnijih potreba mozga,

a unique way that the brain

jedinstven način na koji mozak

meets the high demands and the narrow margins

udovoljava visokim zahtjevima i finesama

that set it apart from all the other organs of the body.

koji ga razlikuju od ostalih organa.

So almost all the biology that we observe

Skoro sva biologija koju promatramo

can be thought of as a series of problems

može se promišljati kao niz problema

and their corresponding solutions,

i niz odgovarajućih rješenja,

and the first problem that every organ must solve

a glavni problem koji svaki organ mora riješiti jest

is a continuous supply of nutrients to fuel

konstantna opskrba svih tih stanica

all those cells of the body.

hranjivim materijalima.

In the brain, that is especially critical;

To je posebno važno za mozak;

its intense electrical activity uses up

njegova intenzivna električna aktivnost crpi

a quarter of the body's entire energy supply,

četvrtinu sveukupne energetske zalihe tijela

even though the brain accounts

iako on čini

for only about two percent of the body's mass.

tek dva posto tjelesne mase.

So the circulatory system

Krvotok

solves the nutrient delivery problem

rješava problem dostave hranjivih tvari

by sending blood vessels to supply nutrients

kroz krvne žile koje opskrbljuju hranjivim tvarima

and oxygen to every corner of our body.

i kisikom svaki djeličak našeg tijela.

You can actually see it in this video here.

Možete to vidjeti u ovom videu.

Here, we're imaging blood vessels

Ovdje smo snimili krvne žile

in the brain of a living mouse.

u mozgu živog miša.

The blood vessels form a complex network

Krvne žile čine složenu mrežu

that fills the entire brain volume.

koja pokriva cijeli mozak.

They start at the surface of the brain,

Počinju na površini mozga

and then they dive down into the tissue itself,

i zaranjaju u samo tkivo,

and as they spread out, they supply nutrients

i kako se šire, opskrbljuju hranjivim tvarima

and oxygen to each and every cell in the brain.

i kisikom svaku stanicu u mozgu zasebno.

Now, just as every cell requires

Kao što svakoj stanici trebaju

nutrients to fuel it,

hranjive tvari za njen pogon,

every cell also produces waste as a byproduct,

tako svaka stanica proizvodi otpad kao nusproizvod,

and the clearance of that waste

i rješavanje tog otpada

is the second basic problem

drugi je glavni problem

that each organ has to solve.

koji svaki organ mora riješiti.

This diagram shows the body's lymphatic system,

Ovaj dijagram pokazuje limfni sustav u tijelu

which has evolved to meet this need.

koji se razvio kako bi ispunio ovu potrebu.

It's a second parallel network of vessels

To je druga paralelna mreža žila

that extends throughout the body.

koja se širi tijelom.

It takes up proteins and other waste

Uzima proteine i drugi otpad iz

from the spaces between the cells,

međustaničnog prostora,

it collects them, and then dumps them into the blood

skuplja ih i ubacuje u krv

so they can be disposed of.

kako bi se oni uklonili.

But if you look really closely at this diagram,

Ako pažljivije promotrite

you'll see something

ovaj dijagram, vidjet ćete nešto

that doesn't make a lot of sense.

što nema puno smisla.

So if we were to zoom into this guy's head,

Ukoliko bismo zumirali glavu ovog čovjeka,

one of the things that you would see there

primijetili biste da

is that there are no lymphatic vessels in the brain.

u mozgu nema limfnih žila.

But that doesn't make a lot of sense, does it?

Ali to baš i nema previše smisla, zar ne?

I mean, the brain is this intensely active organ

Mozak je iznimno aktivan organ

that produces a correspondingly large amount of waste

koji proizvodi velike količine otpada

that must be efficiently cleared.

kojega se mora učinkovito riješiti.

And yet, it lacks lymphatic vessels, which means that

A opet, tu nema limfnih žila, što znači da

the approach that the rest of the body takes

pristup koji ostatak tijela koristi

to clearing away its waste

pri rješavanju otpada,

won't work in the brain.

neće funkcionirati u mozgu.

So how, then, does the brain solve

Pa kako mozak rješava

its waste clearance problem?

svoj problem rješavanja otpada?

Well, that seemingly mundane question

Upravo je ovo naizgled obično pitanje

is where our group first jumped into this story,

navelo našu grupu da se uključi u priču

and what we found

i otkrili smo,

as we dove down into the brain,

kad smo zaronili duboko u mozak,

down among the neurons and the blood vessels,

duboko među neurone i krvne žile,

was that the brain's solution

rješenje mozga

to the problem of waste clearance,

za problem rješavanja otpada,

it was really unexpected.

bilo je uistino neočekivano.

It was ingenious,

Bilo je genijalno,

but it was also beautiful.

ali je i lijepo.

Let me tell you about what we found.

Ispričat ću vam što smo pronašli.

So the brain has this large pool

Mozak ima veliki bazen

of clean, clear fluid called cerebrospinal fluid.

bistre tekućine nazvane "cerebrospinalna tekućina".

We call it the CSF.

Mi je zovemo CST.

The CSF fills the space that surrounds the brain,

CST ispunjava prostor koji okružuje mozak,

and wastes from inside the brain

i otpad iz mozga

make their way out to the CSF,

izlazi u CST,

which gets dumped, along with the waste, into the blood.

koja se s otpadom izbacuje u krv.

So in that way, it sounds a lot like

Podsjeća na

the lymphatic system, doesn't it?

limfni sustav, zar ne?

But what's interesting is that the fluid and the waste

Ali zanimjivo je da se tekućina i otpad

from inside the brain,

iz mozga

they don't just percolate their way randomly

ne filtriraju nasumično

out to these pools of CSF.

u bazene CST, već

Instead, there is a specialized network of plumbing

postoji vodoinstalacijski sustav

that organizes and facilitates this process.

koji organizira i olakšava ovaj proces.

You can see that in these videos.

Možete to vidjeti u ovim videima.

Here, we're again imaging into the brain

Ovdje ponovno skeniramo mozak

of living mice.

živog miša.

The frame on your left shows

Isječak s vaše lijeve strane pokazuje

what's happening at the brain's surface,

što se događa na površini mozga,

and the frame on your right shows

a ovaj s desne pokazuje

what's happening down below the surface of the brain

što se događa ispod površine mozga

within the tissue itself.

unutar samog tkiva.

We've labeled the blood vessels in red,

Označili smo krvne žile crvenom bojom,

and the CSF that's surrounding the brain

a CST koja okružuje mozak

will be in green.

jest zelene boje.

Now, what was surprising to us

I ono što je nas iznenadilo

was that the fluid on the outside of the brain,

jest da tekućina koja se nalazi izvan mozga,

it didn't stay on the outside.

nije ostala vani,

Instead, the CSF was pumped back into

već je CST ispumpana natrag u

and through the brain

i kroz mozak

along the outsides of the blood vessels,

uz rub krvnih žila.

and as it flushed down into the brain

I dok se tekućina spuštala kroz mozak

along the outsides of these vessels,

uz rubove žila,

it was actually helping to clear away,

pomagala je u čišćenju

to clean the waste from the spaces

otpada iz međustaničnog

between the brain's cells.

prostora mozga.

If you think about it,

Ako malo razmislite o tome,

using the outsides of these blood vessels like this

koristeći vanjski rub krvnih žila na ovaj način

is a really clever design solution,

zaista je pametno osmišljeno rješenje

because the brain is enclosed

jer je mozak zatvoren

in a rigid skull

unutar tvrde lubanje,

and it's packed full of cells,

a prepun je stanica,

so there is no extra space inside it

tako da tu nema viška prostora

for a whole second set of vessels like the lymphatic system.

za cijeli paralelni sustav žila kao što je limfni sustav.

Yet the blood vessels,

No krvne žile se ipak

they extend from the surface of the brain

šire od površine mozga

down to reach every single cell in the brain,

i dopiru do svake stanice u mozgu,

which means that fluid

što znači da tekućina

that's traveling along the outsides of these vessels

koja putuje uz rub žila

can gain easy access to the entire brain's volume,

ima lak pristup cijelom mozgu,

so it's actually this really clever way

pa je to vrlo pametan način

to repurpose one set of vessels, the blood vessels,

prenamjene jednog sustava žila, krvnih žila,

to take over and replace the function

kako bi preuzeo i zamijenio funkciju

of a second set of vessels, the lymphatic vessels,

drugog sustava žila, limfnih žila,

to make it so you don't need them.

kako ih ne bismo uopće trebali.

And what's amazing is that no other organ

Čudesno je to što nijedan drugi organ

takes quite this approach

nema ovakav pristup

to clearing away the waste from between its cells.

čišćenju međustaničnog otpada.

This is a solution that is entirely unique to the brain.

To je rješenje karakteristično za mozak,

But our most surprising finding

ali naše otkriće koje nas je najviše iznenadilo

was that all of this,

bilo je da sve ovo,

everything I just told you about,

sve ovo što sam vam ispričao

with all this fluid rushing through the brain,

o tekućini koja ispire mozak,

it's only happening in the sleeping brain.

to se događa samo dok mozak spava.

Here, the video on the left

Ovdje, video s lijeve strane

shows how much of the CSF is moving

pokazuje kretanje CST-a

through the brain of a living mouse while it's awake.

kroz mozak budnog živog miša.

It's almost nothing.

Skoro ništa.

Yet in the same animal,

A ipak kod iste životinje,

if we wait just a little while until it's gone to sleep,

ako pričekamo samo malo dok ne ode spavati,

what we see is that the CSF

vidimo da CST

is rushing through the brain,

juri kroz mozak,

and we discovered that at the same time

a otkrili smo da

when the brain goes to sleep,

kad mozak ide spavati

the brain cells themselves seem to shrink,

ujedno se smanjuju moždane stanice

opening up spaces in between them,

povećavajući prostore između njih

allowing fluid to rush through

dozvoljavajući tekućini da protekne njima

and allowing waste to be cleared out.

i tako očisti otpad.

So it seems that Galen may actually have been

Stoga se čini da je Galen možda čak

sort of on the right track when he wrote about

bio na pravom tragu pišući o

fluid rushing through the brain

tekućini koja juri mozgom

when sleep came on.

kada zaspemo.

Our own research, now it's 2,000 years later,

Naše istraživanje, 2000 godina kasnije,

suggests that what's happening is that

pretpostavlja da

when the brain is awake

mozak u budnom i

and is at its most busy,

najaktivnijem stanju

it puts off clearing away the waste

odgađaa čišćenje otpada

from the spaces between its cells until later,

iz međustaničnih prostora za kasnije,

and then, when it goes to sleep

a kada ode spavati

and doesn't have to be as busy,

i nije toliko zauzet,

it shifts into a kind of cleaning mode

prebacuje se u stanje čišćenja

to clear away the waste

kako bi očistio otpad

from the spaces between its cells,

iz međustaničnih prostora,

the waste that's accumulated throughout the day.

otpad koji se nakupio tijekom dana.

So it's actually a little bit like how you or I,

Na neki je način nalik tome kako vi ili ja

we put off our household chores during the work week

odgađamo kućanske poslove tijekom radnih dana kada se

when we don't have time to get to it,

ne stignemo njima baviti

and then we play catch up on all the cleaning that we have to do

i onda sve to čišćenje pokušavamo nadoknaditi

when the weekend rolls around.

preko vikenda.

Now, I've just talked a lot about waste clearance,

Puno sam pričao o čišćenju otpada,

but I haven't been very specific

ali nisam baš precizno rekao

about the kinds of waste

kakav to otpad

that the brain needs to be clearing

mozak treba očistiti

during sleep in order to stay healthy.

za vrijeme spavanja kako bi ostao zdrav.

The waste product that these recent studies

Nusproizvod na koji se nova

focused most on is amyloid-beta,

istraživanja najviše usredotočuju je amyloid-beta,

which is a protein that's made in the brain all the time.

protein koji se u mozgu neprestano stvara.

My brain's making amyloid-beta right now,

Moj ga mozak proizvodi upravo sada,

and so is yours.

baš kao i vaš.

But in patients with Alzheimer's disease,

Ali kod oboljelih od Alzheimera,

amyloid-beta builds up and aggregates

amyloid-beta nakuplja se

in the spaces between the brain's cells,

u prostorima između stanica mozga,

instead of being cleared away like it's supposed to be,

umjesto da se čisti na način na koji bi trebao,

and it's this buildup of amyloid-beta

a baš je to nakupljanje amyloid-bete

that's thought to be one of the key steps

navodno jedan od ključnih koraka

in the development of that terrible disease.

u razvijanju ove strašne bolesti.

So we measured how fast amyloid-beta is cleared

Stoga smo izmjerili koliko se brzo amyloid-beta čisti

from the brain when it's awake

iz mozga u stanju budnosti

versus when it's asleep,

i u stanju spavanja

and we found that indeed,

i otkrili smo da je

the clearance of amyloid-beta

čišćenje amyloid-bete

is much more rapid from the sleeping brain.

ustinu brže za vrijeme spavanja.

So if sleep, then,

Stoga, ako je spavanje

is part of the brain's solution

jedna metoda mozga za

to the problem of waste clearance,

čišćenje otpada,

then this may dramatically change how we think

to može dramatično promijeniti naš način

about the relationship between sleep,

razmišljanja o odnosu između sna,

amyloid-beta, and Alzheimer's disease.

amyloid-bete i Alzheimera.

A series of recent clinical studies

Niz novih kliničkih studija

suggest that among patients

navodi da kod pacijenata

who haven't yet developed Alzheimer's disease,

koji još nisu razvili Alzheimerovu bolest,

worsening sleep quality and sleep duration

pogoršanje u kvaliteti sna i njegovoj dužini

are associated with a greater amount

povezani su s većom količinom

of amyloid-beta building up in the brain,

nakupina amyloid-bete u mozgu,

and while it's important to point out

i iako je važno napomenuti

that these studies don't prove

da ove studije ne dokazuju

that lack of sleep or poor sleep

da manjak sna ili loš san

cause Alzheimer's disease,

uzrokuju Alzheimerovu bolest,

they do suggest that the failure of the brain

one sugeriraju da nemogućnost mozga

to keep its house clean

da održi svoj životni prostor čistim,

by clearing away waste like amyloid-beta

čisteći ga od otpada poput amyloid-bete,

may contribute to the development

može doprinijeti razvitku

of conditions like Alzheimer's.

poremećaja poput Alzheimera.

So what this new research tells us, then,

Ovo novo israživanje govori nam

is that the one thing that all of you

da bi sve ono što smo svi mi

already knew about sleep,

već znali o spavanju,

that even Galen understood about sleep,

ono što je čak i Galen shvaćao,

that it refreshes and clears the mind,

da ono osvježava i pročišćava um,

may actually be a big part

mogao biti glavni

of what sleep is all about.

razlog postojanja sna.

See, you and I, we go to sleep

Vi i ja idemo spavati

every single night,

svake noći,

but our brains, they never rest.

ali naši mozgovi nikad ne odmaraju.

While our body is still

Dok je naše tijelo u mirovanju,

and our mind is off walking in dreams somewhere,

a naš um šeće po snovima,

the elegant machinery of the brain

mozak kao uglađen stroj

is quietly hard at work

tiho, ali naporno

cleaning and maintaining

čisti i održava

this unimaginably complex machine.

taj nezamislivo kompleksni stroj.

Like our housework,

Poput kućanskih poslova,

it's a dirty and a thankless job,

to je prljav i nezahvalan posao,

but it's also important.

ali je i važan posao.

In your house, if you stop cleaning your kitchen

Ako prestanemo čistiti

for a month,

kuhinju na mjesec dana,

your home will become completely unlivable

naš će cijeli dom vrlo brzo postati

very quickly.

neprikladan za život.

But in the brain, the consequences

U mozgu posljedice

of falling behind may be much greater

odgađanja čišćenja mogu biti mnogo veće

than the embarrassment of dirty countertops,

od neugode koju će kod nas izazvati prljavi šankovi

because when it comes to cleaning the brain,

jer kad se radi o čišćenju mozga,

it is the very health and function

tada je na kocki zdravlje i funkcija

of the mind and the body that's at stake,

uma i tijela

which is why understanding these

i zato je ključno danas razumjeti

very basic housekeeping functions of the brain today

ove osnovne održavajuće funkcije mozga

may be critical for preventing and treating

koje bi mogle biti ključne u prevenciji i liječenju

diseases of the mind tomorrow.

bolesti uma sutra.

Thank you.

Hvala vam!

(Applause)

(Pljesak. )