ten minutes to solve this puzzle.

How long would it take

if you received constant electric shocks to your hands?

Longer, right?

Because the pain would distract you from the task.

Well, maybe not;

it depends on how you handle pain.

Some people are distracted by pain.

It takes them longer to complete a task,

and they do it less well.

Other people use tasks to distract themselves from pain,

and those people actually do the task

faster and better when they're in pain

than when they're not.

Some people can just send their mind wandering.

to distract themselves from pain.

How can different people

be subjected to the exact same painful stimulus

and yet experience the pain so differently?

And why does this matter?

First of all, what is pain?

Pain is an unpleasant sensory and emotional experience,

associated with actual or potential tissue damage.

Pain is something we experience,

so it's best measured by what you say it is.

Pain has an intensity;

you can describe it on a scale from zero, no pain, to ten, the most pain imaginable.

But pain also has a character,

like sharp, dull, burning, or aching.

What exactly creates these perceptions of pain?

Well, when you get hurt,

special tissue damage-sensing nerve cells,

called nociceptors, fire and send signals

to the spinal cord and then up to the brain.

Processing work gets done

by cells called neurons and glial.

This is your grey matter.

And brain superhighways carry information

as electrical impulses

from one area to another.

This is your white matter.

The superhighway that carries pain information

from the spinal cord to the brain

is our sensing pathway

that ends in the cortex,

a part of the brain that decides what to do

with the pain signal.

Another system of interconnected brain cells

called the salience network

decides what to pay attention to.

Since pain can have serious consequences,

the pain signal immediately activates

the salience network.

Now, you're paying attention.

The brain also responds to the pain

and has to cope with these pain signals.

So, motor pathways are activated

to take your hand off a hot stove, for example.

But modulation networks are also activated

that deliver endorphins and enkephalins,

chemicals released when you're in pain or during extreme exercise,

creating the runner's high .

These chemical systems help regulate and reduce pain.

All these networks and pathways work together

to create your pain experience,

to prevent further tissue damage,

and help you to cope with pain.

This system is similar for everyone,

but the sensitivity and efficacy of these brain circuits

determines how much you feel and cope with pain.

This is why some people have greater pain than others

and why some develop chronic pain

that does not respond to treatment,

while others respond well.

Variability in pain sensitivities

is not so different than all kinds of variability

in responses to other stimuli.

Like how some people love roller coasters,

but other people suffer from terrible motion sickness.

Why does it matter that there is variability

in our pain brain circuits?

Well, there are many treatments for pain,

targeting different systems.

For mild pain, non-prescription medications

can act on cells where the pain signals start.

Other stronger pain medicines and anesthetics

work by reducing the activity in pain-sensing circuits

or boosting our coping system, or endoprhins.

Some people can cope with pain

using methods that involve

distraction, relaxation, meditation, yoga,

or strategies that can be taught,

like cognitive behavioral therapy.

For some people who suffer from severe chronic pain,

that is pain that doesn't go away

months after their injury should've healed,

none of the regular treatments work.

Traditionally, medical science has been about

testing treatments on large groups

to determine what would help a majority of patients.

But this has usually left out

some who didn't benefit from the treatment

or experienced side effects.

Now, new treatments that directly stimulate or block

certain pain-sensing attention or modulation networks

are being developed,

along with ways to tailor them to individual patients,

using tools like Magnetic Resonance Imaging (MRI)

to map brain pathways.

Figuring out how your brain responds to pain

is the key to finding the best treatment for you.

That's true personalized medicine.