Can you still feel a limb that's gone? - Joshua W. Pate

Prevodilac: Ivana Krivokuća Lektor: Tijana Mihajlović

The vast majority of people who’ve lost a limb can still feel it—

Velika većina ljudi koja je izgubila ekstremitet i dalje ga mogu osetiti -

not as a memory or vague shape, but in complete lifelike detail.

ne kao sećanje ili nejasan oblik, već u sasvim živim detaljima.

They can flex their phantom fingers

Mogu da savijaju svoje fantomske prste,

and sometimes even feel the chafe of a watchband

a ponekad čak osećaju prianjanje kaiša sata na ruci

or the throb of an ingrown toenail.

ili bol zbog uraslog nokta.

And astonishingly enough,

A što je zapanjujuće,

occasionally even people born without a limb can feel a phantom.

ponekad čak i ljudi rođeni bez nekog uda mogu ga osećati kao fantomski.

So what causes phantom limb sensations?

Pa, šta uzrokuje osećaj fantomskog uda?

The accuracy of these apparitions

Preciznost ovih priviđanja

suggests that we have a map of the body in our brains.

ukazuje da u mozgu imamo mapu tela.

And the fact that it’s possible

A činjenica da je moguće

for someone who’s never had a limb to feel one

da određeni ud oseti neko ko ga nikad nije imao

implies we are born with at least the beginnings of this map.

nagoveštava da se rađamo sa bar nekim začetkom ove mape.

But one thing sets the phantoms that appear after amputation

Ali, jedna stvar se razlikuje kod fantoma koji se javljaju nakon amputacije

apart from their flesh and blood predecessors:

u odnosu na njihove prethodnike od krvi i mesa -

the vast majority of them are painful.

velika većina njih boli.

To fully understand phantom limbs and phantom pain,

Da bismo potpuno razumeli fantomske udove i fantomski bol,

we have to consider the entire pathway from limb to brain.

moramo da razmotrimo čitavu putanju od uda do mozga.

Our limbs are full of sensory neurons responsible for everything

Naši udovi su puni senzornih neurona koji su odgovorni za sve,

from the textures we feel with our fingertips

od tekstura koje osećamo vrhovima prstiju

to our understanding of where our bodies are in space.

do razumevanja gde se naše telo nalazi u prostoru.

Neural pathways carry this sensory input through the spinal cord

Nervni putevi prenose te čulne ulazne informacije

kroz kičmenu moždinu nagore ka mozgu.

and up to the brain.

Pošto se dobar deo ove putanje nalazi van samog ekstremiteta,

Since so much of this path lies outside the limb itself,

most of it remains behind after an amputation.

veći deo ostaje nakon amputacije.

But the loss of a limb

Ali gubitak uda

alters the way signals travel at every step of the pathway.

menja način na koji signali putuju na svakom delu puta.

At the site of an amputation,

Na mestu amputacije,

severed nerve endings can thicken and become more sensitive,

pokidani nervni završeci mogu se zadebljati i postati osetljiviji,

transmitting distress signals even in response to mild pressure.

tako da prenose neprijatne signale čak i kao reakciju na blagi pritisak.

Under normal circumstances,

U normalnim okolnostima,

these signals would be curtailed in the dorsal horn of the spinal cord.

ovi signali bili bi ugašeni u zadnjem rogu kičmene moždine.

For reasons we don’t fully understand, after an amputation,

Iz razloga koje ne razumemo u potpunosti, nakon amputacije,

there is a loss of this inhibitory control in the dorsal horn,

dolazi do gubitka ove inhibitorne kontrole u leđnom rogu, i signali se mogu pojačati.

and signals can intensify.

Once they pass through the spinal cord, sensory signals reach the brain.

Kada prođu kroz kičmenu moždinu, čulni signali stižu do mozga.

There, the somatosensory cortex processes them.

Tu ih obrađuje somatosenzorni korteks.

The entire body is mapped in this cortex.

Celo telo je mapirano u ovom korteksu.

Sensitive body parts with many nerve endings,

Osetljivi delovi tela sa mnogo nervnih završetaka,

like the lips and hands,

kao što su usne i šake,

are represented by the largest areas.

predstavljene su najvećim oblastima.

The cortical homunculus is a model of the human body

Kortikalni homunkulus je model ljudskog tela

with proportions based on the size of each body part’s representation in the cortex,

sa proporcijama zasnovanim na zastupljenosti delova tela u korteksu.

The amount of cortex devoted to a specific body part can grow or shrink

Količina korteksa koja je posvećena određenom delu tela

može se povećavati ili smanjivati

based on how much sensory input the brain receives from that body part.

na osnovu toga koliko čulnih informacija mozak prima od tog dela tela.

For example, representation of the left hand is larger in violinists

Na primer, zastupljenost leve šake je veća kod violinista

than in non-violinists.

nego kod onih koji to nisu.

The brain also increases cortical representation

Mozak takođe povećava kortikalnu zastupljenost

when a body part is injured

kada je deo tela povređen,

in order to heighten sensations that alert us to danger.

da bi se pojačali osećaji koji nas upozoravaju na opasnost.

This increased representation can lead to phantom pain.

Ta povećana zastupljenost može dovesti do fantomskog bola.

The cortical map is also most likely responsible

Kortikalna mapa je takođe najverovatnije odgovorna

for the feeling of body parts that are no longer there,

za osećanje delova tela koji više ne postoje,

because they still have representation in the brain.

zato što su i dalje zastupljeni u mozgu.

Over time, this representation may shrink and the phantom limb may shrink with it.

Vremenom se ta zastupljenost može smanjiti, a sa njom i fantomski ud.

But phantom limb sensations don’t necessarily disappear on their own.

Ali, doživljaj fantomskog uda ne nestaje nužno sam od sebe.

Treatment for phantom pain usually requires

Tretman fantomskog bola obično iziskuje

a combination of physical therapy,

kombinaciju fizikalne terapije,

medications for pain management,

lekova za kontrolu bola,

prosthetics,

prostetiku

and time.

i vreme.

Tehnika zvana terapija kutije sa ogledalom

A technique called mirror box therapy

can be very helpful in developing the range of motion

može znatno pomoći u razvijanju mnogih pokreta

and reducing pain in the phantom limb.

i umanjenju bola u fantomskom udu.

The patient places the phantom limb into a box behind a mirror

Pacijent stavlja fantomski ud u kutiju iza ogledala

and the intact limb in front of the mirror.

i očuvani ud ispred ogledala.

This tricks the brain into seeing the phantom

Ovo prevari mozak tako da vidi fantoma,

rather than just feeling it.

umesto da ga samo oseća.

Scientists are developing virtual reality treatments

Naučnici razvijaju tretmane virtualne realnosti

that make the experience of mirror box therapy even more lifelike.

koji čine prirodnijim doživljaj terapije sa kutijom sa ogledalom.

Prosthetics can also create a similar effect—

Prostetika takođe može stvoriti sličan efekat -

many patients report pain

mnogi pacijenti saopštavaju da se bol najčešće javlja

primarily when they remove their prosthetics at night.

kada noću uklone prostetiku.

And phantom limbs may in turn

Fantomski udovi mogu zauzvrat

help patients conceptualize prosthetics as extensions of their bodies

pomoći da pacijenti konceptualizuju prostetiku kao produžetak svog tela

and manipulate them intuitively.

i da intuitivno manipulišu njome.

There are still many questions about phantom limbs.

Još uvek postoji mnogo pitanja u vezi sa fantomskim udovima.

We don’t know why some amputees escape the pain

Ne znamo zašto neki ljudi sa amputacijom izbegnu bol

typically associated with these apparitions,

koji je obično vezan za ova priviđanja

or why some don’t have phantoms at all.

ili zašto neki uopšte nemaju fantome.

And further research into phantom limbs

Primena budućih istraživanja fantomskih udova

isn’t just applicable to the people who experience them.

nije samo za ljude koji ih doživljavaju.

A deeper understanding of these apparitions

Dublje razumevanje ovih pojava

will give us insight into the work our brains do every day

daće nam uvid u svakodnevni rad našeg mozga

to build the world as we perceive it.

na izgradnji sveta kakvim ga vidimo.

They’re an important reminder

Oni su važan podsetnik

that the realities we experience are, in fact, subjective.

na to da je stvarnost kakvom je doživljavamo

zapravo subjektivna.