My brain my pain

[Music]

[Applause]

hi

my name is laura and i hurt people for a

living

wow if that isn’t an icebreaker for the

next dinner party i don’t know what

is but what sounds like a catchy phrase

is actually the truth

i do work in pain research and that

includes applying painful stimuli to

consenting adults

to find out how pain works i’ve been

researching pain now for over 10 years

and i continue to be fascinated by it

every single day

but what makes pain such an interesting

and relevant topic to study

first of all pain is something we all

know

i guess it is safe to assume that each

and every one of you

knows how excruciating a toothache can

feel or

has experienced that dreadful second

when you hit your little toe at the edge

of the shower cabin

and expect that oncoming surge of pain

right

i know however

pain is also something we all need in

its acute form

it notifies us about a potential threat

to our body

and it protects us from more serious

injuries

if it weren’t for pain we would probably

just leave our hand on the hot stove

until it’s too late and the harm is done

do you smell that smells a bit burnt

does it

not a pleasant thought so

as this example tells you a healthy and

long life without pain

is just not possible pain obviously

works as a reliable alarm bell

which goes off whenever our

pain-sensitive skin receptors get

activated

you might assume now that this alarm

bell rings even louder

the more harmful the painful stimulus is

and in principle that’s also true still

the relationship between objective

painful stimulus

and pain experience is not an entirely

linear

or unchanging one in other words

even if the painful stimulus remains

exactly the same

our perception of it may vary from

person to person

from day to day or even from moment to

moment

imagine me having a toothache right now

i’m pretty sure i would still be able to

give this talk

i would be focusing on something else

thanks to adrenaline

but the same tooth egg might keep me

awake at night when there is nothing

else to distract me from it

making me regret that i didn’t make this

dentist appointment

what this example tells you is that pain

experience is not an objective process

instead it is influenced by our previous

experiences

by our expectations or by our current

focus of attention

already 250 years ago the painter gaspar

traversing illustrated this subjective

and

changeable nature in two of his

paintings

on the left you see a doctor performing

a surgical procedure

and this procedure is obviously very

painful because the patient needs to be

constrained and is opening his mouth

widely in agony

on the right side you see the same

surgical procedure being performed

but the presence and the caring

affection of the lady on the right

is obviously a real game changer here

and suddenly

the procedure doesn’t appear all so

painful anymore

i find this direct comparison in

traverses pictures quite amusing

partially because i know it is true it

is indeed incredible to witness

how much our pain experience our

subjective reality of pain can change

from one situation to the other

however that is not always amusing

because it is not always a good thing

there are situations where the gap

between objective painful stimulation

and subjective reality of pain can grow

so large

that it poses a problem and that is the

case in chronic pain

patients with chronic pain experience

continuous pain

sometimes without any physical injury

which could sufficiently explain what

they feel

in their case pain has lost its

protective function

and it continues to exist long after any

potential threat

to the body has ceased so chronic pain

might not be as omnipresent as acute

pain

but it is still surprisingly common 20

of the average adult population in

europe suffer from a chronic pain

condition

be it fibromyalgia arthritis

a migraine or lower back pain if i would

ask you to raise your hand if you are

one of these persons

i guess a lot of hands would raise up in

the air actually including mine

because i happen to suffer from a nasty

migraine several times per month

chronic pain does not only affect the

person who has to live with it

but also their family friends and social

network

chronic pain causes disability

preventing the people to work in their

jobs or

to do what they love and eventually

the consequences of chronic pain also

cause an economic burden to society

so the german healthcare system alone

they cost 38 billions of euros every

year

so what these statistical facts clearly

imply is that currently

we are obviously not able to treat

chronic pain in a satisfying manner

which would mean reducing the individual

suffering to a level

which does not interfere anymore with

daily affairs

now what can we do to change that as a

neuroscientist i say

if we want to be able to treat chronic

pain better

we have to understand chronic pain and

acute pain better

and to do that we have to take a closer

look at the brain

now let me start by telling you about a

study which nicely demonstrates

the importance of the brain in the

development of chronic pain

in this study the researchers observed

40 people

with an acute back injury over the

course of one year

these were generally healthy people who

just have happened to hurt their backs

they suffered from something we would

call a hexanshos in german

or lambago in english

during this one year 50 of the

participants recovered from the episode

of acute pain

while for the other 50 their pain turned

into chronic pain

if you looked at the backs of these

people you would not be able to tell any

difference

for all of them the injury had healed

however what did differ was their brain

activity

on the first visit the brains of all

patients

showed similar brain activity in regions

which are related to acute pain

processing

after one year the brains of the

patients who had recovered didn’t show

any pain related brain activity anymore

however in the brains of the patients

who did develop chronic pain

the activity had gradually shifted from

activity in the acute pain circuit

towards regions which are more related

to the processing of emotions

and effect so in a nutshell what

differentiated those patients who

recovered

from those who developed chronic pain

was not so much determined by their

affected body part

in this case the back but by what

happened in their brains

now how do these and other neuroimaging

studies make pain-related brain activity

visible and measurable one method you

can use whenever you want to know

where something happens in the brain is

functional magnetic resonance imaging

or in short fmri which is also

what the researchers did in the study

which i just told you about

fmri is a non-invasive measure of brain

activity

which indirectly measures neuronal

activity

via the increases and decreases of blood

flow

and these regional changes of blood flow

help us to pinpoint which brain regions

are more or less active

in comparison to a control group or

control condition

another method of neuroimaging which is

commonly used in pain research

also in our lab is the

electroencephalography

or in short eeg and eeg nicely

complements the method of fmri

as it measures neuronal activity

directly and it has a good temporal

resolution

which means it is your method of choice

whenever you want to know

when something happens in the brain

these and other neuroimaging methods

have already taught us some very

important lessons

and one of those lessons i’m going to

share with you today and that is

that there isn’t such a thing as a

single pain center in the brain

and that differentiates pain from our

other senses just like

hearing or seeing which do indeed rely

on some very focal brain areas

instead in pain processing several

regions in the brain are active

and they work together as a network to

create and shape

what we experience as pain some of these

regions are related to bodily awareness

others to emotional processing and even

others to the preparation

and execution of movement

now let us assume for a moment that the

brain is built to be

efficient not redundant if there is so

much going on during pain processing

it is reasonable to assume that the

different brain activity

in different regions of the brain is

also related to different

and complementary tasks in creating our

pain experience

and indeed brain research has begun

to identify brain activity which is more

closely related

to the objective stimulus

characteristics like the intensity or

duration of a stimulus

as opposed to brain activity which is

more related to our subjective pain

experience

what we actually feel and as we already

know

the painful stimulus and how we

experience it can differ widely from one

another

so this blooming knowledge fueled

another research question

and that is can we actually predict

someone’s momentary pain

just by looking at his or her brain

activity or in other words

can we develop an objective measure of

pain a biomarker

and equally important why do we even

want to develop such a biomarker for

pain

now what sounds like the academic idea

of a researcher

is actually highly relevant from a

clinical and practical point of view

until today if we want to quantify

someone’s pain

we have to rely on self-assessment

that means if we want to know whether

someone is in pain

we have to ask him or her about it now

don’t get me wrong

this is not a bad idea as a mentor of

mine always used to say half-jokingly

if everything else fails we can always

resort to talking to our patients

but that might be difficult whenever

communication is impaired

just think of patients who are suffering

from dementia

or who are unconscious on intensive care

units

or even small children in these cases an

objective measure of pain could

reasonably complement

their self-assessment and that is not

all

an objective measure of pain could also

be beneficial in the treatment of

chronic pain

just think back to the study i mentioned

earlier identifying those people at risk

of developing chronic pain

could already be helpful to start pain

therapy

before the pain has become chronic

but although pain research has

progressed a lot in recent years

we are currently not able to reliably

deduce someone’s momentary pain

just from looking at his or her brain

activity alone

developing a biomarker like this is

currently much sought after

and it’s a hot topic in the pain

community and beyond

in fact we ourselves are currently

conducting a large-scale study with

exactly that same goal

in our lab here in munich

so we might not be able to read a

person’s pain

just by looking at his or her brain

activity yet

however we have already learned

something fundamentally new

and important and that is that pain

originates in the brain

what we feel is only partially

determined by

the sensory input to our skin receptors

in large parts it is created

and shaped by processes in our brain

which take into account our previous

experience our current mood

and so much more in the case of chronic

pain

pain may even persist without any

sensory input

back pain does not originate in the back

and leg pain does not necessarily

manifest in the leg

it is widely acknowledged now by experts

in the field that chronic pain is not

only a symptom

but it is a disease in its own right

for many years doctors and patients

alike assume chronic pain to be

something invisible

and brain imaging has changed that

chronic pain is now not anymore

considered something

esoteric potentially imagined anymore

but as a physical condition with a

physiological basis

i hope to spread this message from the

labs of pain research to as many people

as possible

you might not be able to see a person’s

migraine the same way you see a broken

leg

at least not if you don’t happen to have

an mri scan or standing in the living

room

but it is there and it can be just as

debilitating

moreover i believe that understanding

the brain mechanisms underlying pain is

the key

for an optimized treatment of chronic

pain which could alleviate the suffering

of so many people

and we are just beginning to learn where

to look

thank you