Can we edit memories? | Amy Milton

Transcriber: Joseph Geni Reviewer: Camille Martínez

Translator: Noa Fontan Abeijon Reviewer: Xosé María Moreno

Memory is such an everyday thing that we almost take it for granted.

A memoria é algo tan cotidián que case a damos por feita.

We all remember what we had for breakfast this morning

Todos lembramos o que almorzamos esta mañá

ou o que fixemos a semana pasada.

or what we did last weekend.

It's only when memory starts to fail

É só cando a memoria comeza a fallar

that we appreciate just how amazing it is

cando apreciamos o incrible que é

and how much we allow our past experiences to define us.

e ata que punto deixamos que ás nosas experiencias nos definan

But memory is not always a good thing.

Pero a memoria non sempre é boa

Como dixo o poeta e crego americano John Lancaste Spalding:

As the American poet and clergyman John Lancaster Spalding once said,

"As memory may be a paradise from which we cannot be driven,

"Tanto como a memoria poder ser un paraíso do que non saímos,

tamén poder ser un inferno, do que non podemos escapar."

it may also be a hell from which we cannot escape."

Many of us experience chapters of our lives

Moitos vivimos capítulos da nosa vida

that we would prefer to never have happened.

que nos gustaría que nunca tivesen sucedido

It is estimated that nearly 90 percent of us

Estémase que preto 90% de nós

will experience some sort of traumatic event during our lifetimes.

vivirá experiencias traumáticas durante a súa vida.

Many of us will suffer acutely following these events and then recover,

Moitos de nós sufrirémolas e logo nos recuperaremos,

maybe even become better people because of those experiences.

incluso poderemos ser mellores persoas grazas a elas.

But some events are so extreme that many --

Pero algunhas experiencias son tan extremas que moitos --

up to half of those who survive sexual violence, for example --

ata a metade dos que sobreviven á violencia sexual, por exemplo --

will go on to develop post-traumatic stress disorder,

sufrirán estrés postraumático,

or PTSD.

ou TEPT.

PTSD is a debilitating mental health condition

O TEPT é unha enfermidade mental debilitante

characterized by symptoms such as intense fear and anxiety

con síntomas como medo intenso ou ansiedade

and flashbacks of the traumatic event.

e flashbacks da experiencia traumática.

These symptoms have a huge impact on a person's quality of life

Estes síntomas teñen un impacto enorme na calidade de vida dunha persoa

e soen desecadearse por situacións particulares

and are often triggered by particular situations

or cues in that person's environment.

ou sinais no entorno desa persoa.

The responses to those cues may have been adaptive when they were first learned --

As respostas aos sinais puideron ser adaptativas cando se aprenderon

fear and diving for cover in a war zone, for example --

por exemplo, medo ou buscar refuxio nunha zona de guerra --

but in PTSD,

pero no TEPT,

they continue to control behavior when it's no longer appropriate.

continúan controlando o comportamento cando xa non é apropiado.

If a combat veteran returns home and is diving for cover

Se un veterán de guerra volve guerra e busca refuxio

when he or she hears a car backfiring

cando oe o ruído dun coche petardeando

or can't leave their own home because of intense anxiety,

ou non pode saír da casa por ansiedade,

then the responses to those cues, those memories,

entón as respostas aos sinais, aos recordos,

have become what we would refer to as maladaptive.

convertéronse no que chamamos mal adaptativas.

In this way, we can think of PTSD as being a disorder of maladaptive memory.

Así, podemos ver o TEPT como unha enfermidade mal adaptativa da memoria.

Now, I should stop myself here,

Vou para aquí,

because I'm talking about memory as if it's a single thing.

porque estou falando da memoria como se fose unha única cousa.

It isn't.

Non o é.

There are many different types of memory,

Hai moitos tipos diferentes de memorias,

and these depend upon different circuits and regions within the brain.

e depende dos diferentes circuitos e rexións do cerebro.

As you can see, there are two major distinctions in our types of memory.

Como vedes, hai dúas grandes diferenzas nos nosos tipos de memoria

There are those memories that we're consciously aware of,

Das que somos conscientes

das que sabemos que sabemos

where we know we know

and that we can pass on in words.

e podemos falar delas.

This would include memories for facts and events.

Incluíndo recordos, feitos e experiencias.

Because we can declare these memories,

Como podemos falar destes recordos,

we refer to these as declarative memories.

chamámolos recordos declarativos.

The other type of memory is non-declarative.

O outro tipo de recordo é non declarativo.

These are memories where we often don't have conscious access

Son dos que non temos un acceso consciente

to the content of those memories

ao contido destes recordos.

and that we can't pass on in words.

e non podemos falar deles.

The classic example of a non-declarative memory

O exemplo típico dun recordo non declarativo

is the motor skill for riding a bike.

é como saber montar a bicicleta.

Now, this being Cambridge, the odds are that you can ride a bike.

Aquí, en Cambridge, probablemente non poidas montar en bicicleta.

You know what you're doing on two wheels.

Xa sabedes que se fai a dúas rodas.

But if I asked you to write me a list of instructions

Pero se vos pido que me escribades unhas instrucións

that would teach me how to ride a bike,

para ensinarme a montar en bicicleta

as my four-year-old son did when we bought him a bike

como fixo o meu fillo cando lle mercamos unha

for his last birthday,

polo seu último aniversario,

you would really struggle to do that.

seríavos moi difícil facelo.

How should you sit on the bike so you're balanced?

Como te sentas para manter o equilibrio?

How fast do you need to pedal so you're stable?

Canta velocidade necesitas para manterte estable?

If a gust of wind comes at you,

Se un refacho de vento vén cara ti,

which muscles should you tense and by how much

que músculos tensas e canto

so that you don't get blown off?

para non caer?

Estaría impresionada se me respondesedes ás preguntas.

I'll be staggered if you can give the answers to those questions.

But if you can ride a bike, you do have the answers,

Pero se sabes montar en bici, tes á resposta ás preguntas,

you're just not consciously aware of them.

pero non es consciente delas.

Getting back to PTSD,

Volvendo ao TEPT,

outro tipo de recordo non declarativo

another type of non-declarative memory

is emotional memory.

é a memoria emocional.

Now, this has a specific meaning in psychology

Ten un significado específico en psicoloxía

and refers to our ability to learn about cues in our environment

que se refire á habilidade de recoñecer os sinais do noso entorno

and their emotional and motivational significance.

e o seu significado emocional e motivacional.

What do I mean by that?

Que significa isto?

Well, think of a cue like the smell of baking bread,

Pensa nun sinal como ulir pan no forno

or a more abstract cue like a 20-pound note.

ou máis abstracto como un billete de 20 euros

Because these cues have been pegged with good things in the past,

Estes sinais foron asociadas con cousas boas no pasado,

we like them and we approach them.

gústannos e interésannos.

Other cues, like the buzzing of a wasp, elicit very negative emotions

Outras sinais, o zunido dunha avespa, están asociadas con emocións negativas

and quite dramatic avoidance behavior in some people.

e unha conduta de fuxida dramática nalgúns.

Now, I hate wasps.

Eu detesto as avespas.

I can tell you that fact.

Podo dicirvos que é un feito.

But what I can't give you are the non-declarative emotional memories

Pero no podo falar dos recordos emocionais non declarativos

for how I react when there's a wasp nearby.

que razoan como me comporto se hai unha avespa preto

I can't give you the racing heart,

Non podo explicar o corazón a mil por hora,

the sweaty palms, that sense of rising panic.

as mans suorosas, a sensación de pánico que crece.

I can describe them to you,

Podo describírvolas,

but I can't give them to you.

pero non volas podo explicar.

Now, importantly, from the perspective of PTSD,

Dende a perspectiva do TEPT,

stress has very different effects on declarative and non-declarative memories

o estrés ten moitos efectos nos recordos declarativos e non declarativos

and the brain circuits and regions supporting them.

e non circuítos do cerebro e as rexións que os controlan.

Emotional memory is supported by a small almond-shaped structure

A memoria emocional se controla dende unha estrutura con forma de améndoa

called the amygdala

chamada amígdala

and its connections.

e as súas conexións

Declarative memory, especially the what, where and when of event memory,

A memoria declarativa, o que, o onde e o cando do recordo

is supported by a seahorse-shaped region of the brain

contrólase nunha rexión do cerebro

chamada hipocampo.

called the hippocampus.

The extreme levels of stress experienced during trauma

O nivel de estrés que se produce durante un trauma

have very different effects on these two structures.

teñen moitos efectos nestas dúas estruturas

As you can see, as you increase a person's level of stress

Como vedes, cando crece o nivel de estrés dunha persoa

from not stressful to slightly stressful,

de non estar estresado a un pouco,

the hippocampus,

o hipocampo,

acting to support the event memory,

actúa controlando o recordo,

increases in its activity

aumenta a súa actividade

and works better to support the storage of that declarative memory.

e funciona mellor organizando como almacerar o recordo declarativo

But as you increase to moderately stressful, intensely stressful

Pero se se incrementa de estrés moderado a intenso

and then extremely stressful, as would be found in trauma,

e despois a estrés extremo, como no trauma,

the hippocampus effectively shuts down.

o hipocampo deixa de funcionar.

Isto significa que o os altos niveles de hormonas do estrés

This means that under the high levels of stress hormones

that are experienced during trauma,

que se viven durante un trauma,

we are not storing the details,

non almacenamos os detalles,

the specific details of what, where and when.

os detalles específicos de que, onde e cando

Now, while stress is doing that to the hippocampus,

Mentres o estrés inactiva o hipocampo,

look at what it does to the amygdala,

mirade o que lle fai á amígdala,

that structure important for the emotional, non-declarative memory.

a estrutura dos recordos emocionais non delcarativos

Its activity gets stronger and stronger.

A súa actividade crece e crece

So what this leaves us with in PTSD

Así que o que isto nos deixa no TEPT

is an overly strong emotional -- in this case fear -- memory

é un recordo emocional moi forte, neste caso de medo

that is not tied to a specific time or place,

que non se asocia a un lugar ou tempo,

because the hippocampus is not storing what, where and when.

porque o hipocampo non almacenou qué, onde e cando.

In this way, these cues can control behavior

Deste xeito, estas sinais controlan o comportamento

when it's no longer appropriate,

cando xa non é apropiado,

and that's how they become maladaptive.

e así é como se converten en mal adaptativas.

So if we know that PTSD is due to maladaptive memories,

Se sabemos que os recordos mal adaptativos causan TEPT

can we use that knowledge to improve treatment outcomes

podemos mellorar o resultado do tratamento

for patients with PTSD?

para pacientes con TEPT?

A radical new approach being developed to treat post-traumatic stress disorder

Estáse desenrolando un novo enfoque para tratar TEPT,

aims to destroy those maladaptive emotional memories

que tenta destruír os recordos maladaptativos

that underlie the disorder.

que causan a enfermidade.

This approach has only been considered a possibility

Este enfoque considérase so unha posibilidade

because of the profound changes in our understanding of memory

polos importantes cambios na nosa forma de entender a memoria

in recent years.

nos últimos anos.

Traditionally, it was thought that making a memory

Tradicionalmente, críase que crear recordos

was like writing in a notebook in pen:

era como escribir cun bolígrafo:

once the ink had dried, you couldn't change the information.

unha vez seca a tinta, non podes cambiar a información.

It was thought that all those structural changes

Críase que todos os cambios estrutrais

that happen in the brain to support the storage of memory

que ocorren no cerebro para almacenar o recordo

were finished within about six hours,

acabábanse en máis ou menos 6 horas,

and after that, they were permanent.

e despois diso, eran permanentes.

This is known as the consolidation view.

O que se coñece como consolidación.

However, more recent research suggests that making a memory

Non obstante, investigacións recentes suxiren que crear recordos

is actually more like writing in a word processor.

parécese máis a escribir nun procesador de textos.

We initially make the memory and then we save it or store it.

Creamos o recordo e logo gardámolo ou almacenámolo.

But under the right conditions, we can edit that memory.

Baixo as condicións adecuadas, podemos editar os recordos

This reconsolidation view suggests that those structural changes

Esta hipótese de reconsolidación suxire que os cambios estruturais

that happen in the brain to support memory

que ocorren no cerebro para almacenar os recordos

can be undone,

poden desfacerse

even for old memories.

incluso para recordos vellos.

Now, this editing process isn't happening all the time.

Este proceso de edición non ocorre todo o tempo

It only happens under very specific conditions

só cando se dan unhas condicións específicas

of memory retrieval.

de recuperación da memoria.

So let's consider memory retrieval as being recalling the memory

Consideremos a recuperación da memoria como lembrar

or, like, opening the file.

ou como abrir un documento.

Quite often, we are simply retrieving the memory.

Normalmente, só recuperamos o recordo.

We're opening the file as read-only.

Abrimos o documento só para lectura.

But under the right conditions,

Pero coas condición axeitadas,

we can open that file in edit mode,

podemos abrir o documento en modo edición,

and then we can change the information.

e podemos cambiar a información.

In theory, we could delete the content of that file,

Teoricamente, podemos eliminar o contido do documento

and when we press save,

e cando pulsamos gardar,

that is how the file -- the memory --

é como o documento, o recordo,

persists.

persiste.

Not only does this reconsolidation view

Esta hipótese da reconsolidación non só

allow us to account for some of the quirks of memory,

nos permite explicar algúns dos rasgos da memoria,

like how we all sometimes misremember the past,

como a veces recordamos mal o pasado,

it also gives us a way to destroy those maladaptive fear memories

tamén nos dá a chave para destruír os recordos mal adaptativos de medo

that underlie PTSD.

que causan o TEPT.

All we would need would be two things:

Só necesitamos dúas cousas:

a way of making the memory unstable -- opening that file in edit mode --

unha forma de facer a memoria inestable, abrir o documento para editalo,

and a way to delete the information.

e unha forma de eliminar a información.

We've made the most progress

Progresamos sobre todo

with working out how to delete the information.

en canto á eliminación da información.

It was found fairly early on

Encontrouse rápidamente

that a drug widely prescribed to control blood pressure in humans --

que un fármaco moi utilizado para controlar a presión arterial

a beta-blocker called Propranolol --

un bloqueador beta, chamado Propranolol,

could be used to prevent the reconsolidation

podía previr o reconsolidamento

of fear memories in rats.

de recordos sobre o medo en ratas.

If Propranolol was given while the memory was in edit mode,

Se as ratas consumían Propranolol cando o recordo estaba modificable,

rats behaved as if they were no longer afraid of a frightening trigger cue.

as ratas compootábanse como se xa non tivesen medo da sinal desecandeante.

It was as if they had never learned to be afraid of that cue.

Era como si nunca aprendesen a terlle medo a ese sinal.

And this was with a drug that was safe for use in humans.

E isto ocorría cun fármaco seguro para os humanos.

Now, not long after that,

Ao pouco tempo,

it was shown that Propranolol could destroy fear memories in humans as well,

descubríuse que o fármaco podía destruir estes recordos tamén en humanos

but critically, it only works if the memory is in edit mode.

pero só funciona cando o recordo está modificable

Now, that study was with healthy human volunteers,

Este estudio utilizaba voluntarios saudables,

but it's important because it shows that the rat findings

pero é importante xa que mostran que os descobrementos coas ratas

can be extended to humans and ultimately, to human patients.

poden extenderse ós humanos, e finalmente ós pacientes humanos.

And with humans,

E cos humanos,

you can test whether destroying the non-declarative emotional memory

pódese comprobar se destruír os recordos emocionais non declarativos

does anything to the declarative event memory.

afecta ó recordo declarativo.

And this is really interesting.

E esto é moi interesante.

Even though people who were given Propranolol

Aínda que á xente a que se lle deu Propranolol

while the memory was in edit mode

co recordo modificable

were no longer afraid of that frightening trigger cue,

xa non tiñan medo dese sinal desecadeante,

they could still describe the relationship

aínda podían reescribir a relación

between the cue and the frightening outcome.

entre o sinal e o seu medo.

It was as if they knew they should be afraid,

Como se soubesen que deberían ter medo

and yet they weren't.

pero non o tivesen.

This suggests that Propranolol can selectively target

Esto suxire que o Propranolol pode dirixirse selectivamente

the non-declarative emotional memory

ao recordo emocional non declarativo

but leave the declarative event memory intact.

pero deixando o recordo declarativo intacto.

But critically, Propranolol can only have any effect on the memory

Pero o fármaco só ten efectos no recordo

if it's in edit mode.

cando este está modificable.

So how do we make a memory unstable?

Así que, como facemos un recordo inestable?

How do we get it into edit mode?

Como pode ser modificable?

Well, my own lab has done quite a lot of work on this.

O meu laboratorio traballou moito nisto.

We know that it depends on introducing some but not too much new information

Sabemos que depende de engadir nova información, pero non demasiada

to be incorporated into the memory.

para incorporala ó recordo.

We know about the different chemicals the brain uses

Coñecemos os químicos que usa o cerebro

to signal that a memory should be updated

para sinalar que un recordo debe actualizarse

and the file edited.

e o documento, editarse.

Now, our work is mostly in rats,

O noso traballo foi sobre todo con ratas,

but other labs have found the same factors allow memories to be edited in humans,

pero outros encontraron os mesmos factores que permiten editar os recordos en humanos

even maladaptive memories like those underlying PTSD.

incluso os mal adaptativos como os que pausan o TEPT

In fact, a number of labs in several different countries

Moitos laboratorios en diferentes países

have begun small-scale clinical trials of these memory-destroying treatments

comezaron ensaios clínicos a pequena escala destes tratamentos

for PTSD

para o TEPT

and have found really promising results.

e hai resultados prometedores.

Now, these studies need replication on a larger scale,

Estes estudos necesitan réplicas a gran escala,

but they show the promise of these memory-destroying treatments

pero mostran a promesa destes tratamentos de destrución da memoria

for PTSD.

para o TEPT.

Maybe trauma memories do not need to be the hell from which we cannot escape.

Quizáis os recordos traumáticos non teñen que ser un inferno ineludible.

Now, although this memory-destroying approach holds great promise,

Aínda que este enfoque sexa moi prometedor,

that's not to say that it's straightforward

non se pode dicir que sexa sinxelo

or without controversy.

ou que non cree polémica.

Is it ethical to destroy memories?

É ético destruír recordos?

What about things like eyewitness testimony?

E para cousas como testemuñas presenciais?

What if you can't give someone Propranolol

E se non lles dás Propranolol

because it would interfere with other medicines that they're taking?

porque interferiría coas outras medicinas que toman?

Well, with respect to ethics and eyewitness testimony,

En canto á ética e as testemuñas,

I would say the important point to remember

diría que é importante recordar

is the finding from that human study.

é o resultado do estudio en humanos.

Because Propranolol is only acting on the non-declarative emotional memory,

Xa que o Propranolol só actúa nos recordos emocionais non declarativos,

it seems unlikely that it would affect eyewitness testimony,

parece pouco probable que afectase ás testemuñas presenciais

which is based on declarative memory.

que se basan nos recordos declarativos.

Essentially, what these memory-destroying treatments

O que estes tratamentos

are aiming to do

intentan facer

is to reduce the emotional memory,

é reducir a memoria emocional,

not get rid of the trauma memory altogether.

non eliminar o recordo traumático en si.

This should make the responses of those with PTSD

Esto debería facer que as respostas da xente con TEPT

more like those who have been through trauma

fosen coma os que sofren traumas

and not developed PTSD

e non desenrolan TEPT

than people who have never experienced trauma in the first place.

máis que as resposta da xente que non sufriu trauma nunca

I think that most people would find that more ethically acceptable

Creo que a maioría encontraran isto máis éticamente aceptable

than a treatment that aimed to create some sort of spotless mind.

que un tratamentos enfocado a crear unha mente inmaculada

What about Propranolol?

E o Propanolol?

You can't give Propranolol to everyone,

Non se lle pode dar a todo o mundo,

and not everyone wants to take drugs to treat mental health conditions.

e non todo o mundo quere tomar fármacos para tratar enfermidades mentais.

Well, here Tetris could be useful.

Aquí, o Tetris sería útil.

Yes, Tetris.

Si, o Tetris.

Working with clinical collaborators,

Traballando con colaboradores clínicos

we've been looking at whether behavioral interventions

investigamos se as intervencións do comportamento

can also interfere with the reconsolidation of memories.

tamén interfiren na reconsolidación dos recordos

Now, how would that work?

Como funcionaría?

Well, we know that it's basically impossible

Sabemos que é case imposible

to do two tasks at the same time

facer dúas cousas ao mesmo tempo

if they both depend on the same brain region for processing.

se as dúas dependen do funcionamento do mesmo lado do cerebro.

Think trying to sing along to the radio

Por exemplo, cantar unha canción da radio

while you're trying to compose an email.

á vez que intentas escribir un email.

The processing for one interferes with the other.

O proceso dun interifre co outro.

Well, it's the same when you retrieve a memory,

É o mesmo cando recordamos, sobre todo

especially in edit mode.

cando é modificable.

If we take a highly visual symptom like flashbacks in PTSD

Se collemos un síntoma visual coma os flashbacks no TEPT

and get people to recall the memory in edit mode

e pedimos á xente recordar en modo edición

and then get them to do a highly engaging visual task

e logo lles pedimos facer unha tarefa moi visual

like playing Tetris,

como xogar ó Tetris,

it should be possible to introduce so much interfering information

debería ser posible introducir moita información interferente

into that memory

nese recordo

that it essentially becomes meaningless.

que se volve sen sentido.

That's the theory,

Esa é a teoría.

and it's supported by data from healthy human volunteers.

e baséase en datos de voluntarios saudables.

Now, our volunteers watched highly unpleasant films --

Estes viron películas moi desagradables

so, think eye surgery, road traffic safety adverts,

así que, pensa na cirurxía ocular, anuncios de seguridade vial,

Scorsese's "The Big Shave."

«The Big Shave» de Scorsese.

These trauma films produce something like flashbacks

Estas películas traumáticas producen algo similar ós flashbacks

in healthy volunteers for about a week after viewing them.

nos voluntarios saudables, durante unha semana despois de velas.

We found that getting people to recall those memories,

Descubrimos que facer que a xente recordase esto,

the worst moments of those unpleasant films,

os peores momentos desas películas desagradables,

and playing Tetris at the same time,

e xogar ao Tetris á vez,

massively reduced the frequency of the flashbacks.

reduce moitísimo a frecuencia dos flashbacks.

And again: the memory had to be in edit mode for that to work.

E unha vez máis: a memoria ten que estar modificable para que isto funcione

Now, my collaborators have since taken this to clinical populations.

Os meus colaboradores levaron isto a poblacións clínicas.

They've tested this in survivors of road traffic accidents

Probárono en sobrevivintes de accidentes de tráfico

and mothers who've had emergency Caesarean sections,

e nais que tiveron cesáreas de emerxencia,

both types of trauma that frequently lead to PTSD,

tipos de trauma que poden levar ao TEPT,

and they found really promising reductions in symptoms

e a redución de síntomas é prometedora

in both of those clinical cases.

en ambos casos clínicos.

So although there is still much to learn and procedures to optimize,

Polo que aínda que quede moito que aprender e optimizar

these memory-destroying treatments hold great promise

estes tratamentos de destrución da memoria son prometedores

for the treatment of mental health disorders

para o tratamento de enfermidades mentais

like PTSD.

como o TEPT.

Maybe trauma memories do not need to be a hell from which we cannot escape.

Quizais os recordos traumáticos non teñen que ser un inferno ineludible.

I believe that this approach

Eu creo que este enfoque

should allow those who want to

debería permitir a quen queiran

to turn the page on chapters of their lives

pasar páxina a capítulos da súa vida

that they would prefer to never have experienced,

que preferirían non ter vivido,

and so improve our mental health.

e así mellorar a saúde mental.

Thank you.

Grazas.

(Applause)

(Aplausos)