0:00:02 > 0:00:05We're discovering astonishing things about the human body
0:00:05 > 0:00:08all the time, through people who are different from most.
0:00:11 > 0:00:12I'm Gabriel Weston.
0:00:12 > 0:00:16As a surgeon, I've spent years studying the human body.
0:00:17 > 0:00:21And the secrets of how it works are often revealed by the most
0:00:21 > 0:00:24rare and surprising of cases.
0:00:26 > 0:00:29So I've searched the world to find these extraordinary people
0:00:29 > 0:00:31and bring you their stories.
0:00:32 > 0:00:36This is my heart. I'm the only one that has this.
0:00:37 > 0:00:40I'm Jordy Cernik and I can't feel fear.
0:00:40 > 0:00:43My name is Harnaam Kaur and I'm a fabulous bearded lady.
0:00:43 > 0:00:47With the help of the doctors that treat them and some of the
0:00:47 > 0:00:49world's leading scientists,
0:00:49 > 0:00:54I'll be uncovering exactly what makes their bodies unique.
0:00:55 > 0:00:58I'm going to show you the hidden processes
0:00:58 > 0:01:00that make them exceptional.
0:01:02 > 0:01:03Just look at that!
0:01:05 > 0:01:10I'll discover how they're leading us to the cures of the future.
0:01:10 > 0:01:13When we make a breakthrough like this, it is very exciting.
0:01:15 > 0:01:19And I'll use the latest technology to uncover the secrets of
0:01:19 > 0:01:24their bodies and reveal how all of these cases are giving us a new
0:01:24 > 0:01:30understanding of the most amazing natural machine on the planet -
0:01:30 > 0:01:32the human body.
0:01:53 > 0:01:56The world is full of threats to our survival,
0:01:56 > 0:02:00some we're aware of and some we can't see - and our bodies are
0:02:00 > 0:02:04constantly adapting to these dangers from within and without.
0:02:04 > 0:02:08In this programme, we'll meet some remarkable individuals
0:02:08 > 0:02:11who push this ability to the absolute limit.
0:02:13 > 0:02:17We'll discover how this man can survive for two hours in ice...
0:02:18 > 0:02:23How this woman can live with only half of her brain...
0:02:23 > 0:02:26Why this man can't ever feel fear...
0:02:26 > 0:02:29And why this is the only man on earth to survive
0:02:29 > 0:02:32the world's most notorious virus.
0:02:35 > 0:02:37In our first few cases,
0:02:37 > 0:02:41we'll meet some truly extraordinary people - mavericks who are
0:02:41 > 0:02:46exposing their own bodies to some of the greatest perils in the
0:02:46 > 0:02:52natural world and uncovering hidden survival mechanisms in all of us.
0:02:53 > 0:02:57The first of these pioneers seems to defy the laws of nature.
0:02:59 > 0:03:04I can withstand the venom from the world's deadliest snakes.
0:03:04 > 0:03:08Steve Ludwin has an unusual and highly dangerous habit.
0:03:08 > 0:03:12He regularly injects himself with deadly snake venom,
0:03:12 > 0:03:15yet he is still alive.
0:03:15 > 0:03:18All my life, I've been, you know, reading about snakes,
0:03:18 > 0:03:20seeking them out.
0:03:20 > 0:03:23I started keeping snakes when I was six years old.
0:03:25 > 0:03:28It was as a child that Steve came across the idea
0:03:28 > 0:03:30of injecting their venom.
0:03:32 > 0:03:37My father took me down to the Miami Serpentarium and I got to see
0:03:37 > 0:03:39this guy called Bill Haast.
0:03:41 > 0:03:46He's the first Westerner who started injecting himself with snake venom.
0:03:48 > 0:03:52Snake enthusiast Bill Haast believed that snake venom may have
0:03:52 > 0:03:56healing properties and therefore had been injecting it into his blood.
0:03:58 > 0:04:04It just blew my mind as a kid, I was like, wow! It really stuck with me.
0:04:04 > 0:04:07By the time when I was 17 years old,
0:04:07 > 0:04:10I just had this light bulb moment where it's like,
0:04:10 > 0:04:13"I'm going to do the same thing, I'm going to try and copy him".
0:04:14 > 0:04:20Steve has now been injecting himself with venom for nearly 30 years.
0:04:20 > 0:04:23He's about to take some from a viper from his own collection
0:04:23 > 0:04:25of snakes.
0:04:27 > 0:04:30You get the snake safely behind its head and you have
0:04:30 > 0:04:34a glass with some plastic over the top, a bag, or something like that.
0:04:34 > 0:04:38You hold the snake up and the snake bites into the glass,
0:04:38 > 0:04:41deposits the venom and that's it, it's over.
0:04:41 > 0:04:44It's very quick and painless for the snake.
0:04:47 > 0:04:51This particular venom is what's known as a haemotoxin - one
0:04:51 > 0:04:57that affects the blood and blood vessels and it CAN be fatal.
0:04:57 > 0:05:00Steve places some venom on his arm and then uses
0:05:00 > 0:05:01a needle to break the skin.
0:05:04 > 0:05:06So, yes - here we go.
0:05:17 > 0:05:21And that's just taking the venom down.
0:05:24 > 0:05:28It's not a pleasant feeling, you can feel it burning instantly.
0:05:28 > 0:05:30Steve is lucky to be alive.
0:05:30 > 0:05:35Let me show you what happens when venom enters his blood.
0:05:35 > 0:05:38Here, I've got a dish of my own blood and here,
0:05:38 > 0:05:41in this little vial, I've got some real snake venom.
0:05:41 > 0:05:46Just wait and see what happens when I pour some of the venom into
0:05:46 > 0:05:48the dish of my blood.
0:05:49 > 0:05:53This is a hemotoxic venom, like the one Steve injected.
0:05:55 > 0:05:59So what I can see here as I swirl this round is that the blood
0:05:59 > 0:06:04is becoming dark and sort of solid in areas, it's like
0:06:04 > 0:06:08a jelly and you can imagine if this blood was running through your
0:06:08 > 0:06:12vessels, the blood would basically stop and that's why you'd die.
0:06:13 > 0:06:15Even a small blood clot can be fatal.
0:06:17 > 0:06:19So how has Steve survived?
0:06:23 > 0:06:28My blood is unique, only because I have almost 30 years of doing
0:06:28 > 0:06:32this and it's not magic, it's not voodoo or anything - anybody
0:06:32 > 0:06:34could have done what I've done.
0:06:35 > 0:06:38Steve's gradual exposure to snake venom
0:06:38 > 0:06:41has worked in the same way as vaccinations do in most of us.
0:06:43 > 0:06:47Vaccines give us a low dose of a virus or toxin - not enough
0:06:47 > 0:06:50to harm us, but enough for our body to learn to fight it and
0:06:50 > 0:06:53protect us from it in the future.
0:06:53 > 0:06:57Our immune system does this by producing specialised defence cells
0:06:57 > 0:07:00known as antibodies.
0:07:00 > 0:07:03Each type of antibody is a unique shape to target
0:07:03 > 0:07:05a particular virus or toxin.
0:07:07 > 0:07:10When Steve embarked upon his daredevil experiment,
0:07:10 > 0:07:14he started with extremely low doses.
0:07:14 > 0:07:17His body learned to recognise different venoms and produce
0:07:17 > 0:07:20specific antibodies to fight each one.
0:07:23 > 0:07:27My body reacts differently - my body seems to not swell as much
0:07:27 > 0:07:31and when it does swell, it seems to recover a lot quicker.
0:07:32 > 0:07:36Steve's dangerous habit started as a personal challenge.
0:07:36 > 0:07:41But now, he's caught the attention of scientists working in Denmark.
0:07:43 > 0:07:46At the University of Copenhagen,
0:07:46 > 0:07:50pharmaceutical engineers Andreas Hougaard Laustsen and Brian Lohse
0:07:50 > 0:07:54have been trying to develop an antivenom to treat snakebites.
0:07:58 > 0:08:02A snake bite is a much bigger problem that what most people are aware of.
0:08:02 > 0:08:05It is considered as the most neglected of the neglected
0:08:05 > 0:08:06tropical diseases.
0:08:06 > 0:08:10The estimate is that around one million bites occur in
0:08:10 > 0:08:15sub-Saharan Africa and probably around 50 to 100,000 people
0:08:15 > 0:08:17die each year from snake bite.
0:08:18 > 0:08:20If you're bitten by a venomous snake,
0:08:20 > 0:08:25the only treatment is a dose of antibodies, known as antivenom.
0:08:25 > 0:08:29But there's currently a global shortage and the antivenom
0:08:29 > 0:08:32that does exist is produced in horses and so carries
0:08:32 > 0:08:35a significant risks to humans.
0:08:36 > 0:08:39The human immune system would recognise that this is from
0:08:39 > 0:08:44a horse and it will cause adverse effects and in the worst cases,
0:08:44 > 0:08:48administration of antivenom can even lead to death of the victim.
0:08:48 > 0:08:52Not from the snakebite itself, but from the antivenom.
0:08:52 > 0:08:54To make a safe antivenom, they'd need to find
0:08:54 > 0:08:59a way to produce antibodies from human blood, not horse blood.
0:08:59 > 0:09:03They thought it would take ten years to do this in a laboratory.
0:09:05 > 0:09:09But then they heard of Steve - here was the ready-made
0:09:09 > 0:09:12source of the antibodies they needed.
0:09:12 > 0:09:16Instantly, they knew it was a unique opportunity.
0:09:19 > 0:09:22The scientists are now working with Steve's blood to collect the
0:09:22 > 0:09:26crucial antibodies and replicate them on a mass scale.
0:09:28 > 0:09:32Our goal is to develop the first antivenom based on human
0:09:32 > 0:09:34antibodies that can target all medically relevant snake
0:09:34 > 0:09:36species in sub-Saharan Africa.
0:09:36 > 0:09:40When we've done that, our next goal is to expand the antivenom or
0:09:40 > 0:09:44develop further regional antivenoms based on the same principle
0:09:44 > 0:09:46for other continents of the world.
0:09:47 > 0:09:51Steve's involvement in the project has meant the scientists are much
0:09:51 > 0:09:56closer to producing new antivenoms that could save millions of lives.
0:09:56 > 0:09:59I can dine out with a smile on my face,
0:09:59 > 0:10:03that I've achieved something, I've done something positive.
0:10:03 > 0:10:05And I feel really good about it.
0:10:06 > 0:10:09Steve's dangerous experiments on himself are helping to
0:10:09 > 0:10:12advance medical science.
0:10:14 > 0:10:16And through the history of medicine,
0:10:16 > 0:10:19some of the biggest breakthroughs in understanding how our bodies
0:10:19 > 0:10:21respond to threats and disease,
0:10:21 > 0:10:23have come from extraordinary
0:10:23 > 0:10:27individuals who've put themselves at extreme risk.
0:10:29 > 0:10:34One such pioneer is Australian doctor Barry Marshall.
0:10:34 > 0:10:37In the 1980s, he and his colleague Robin Warren
0:10:37 > 0:10:40became very interested in a bacterium
0:10:40 > 0:10:42called Helicobacter pylori.
0:10:44 > 0:10:47Now, the reason for their interest was that they were sure that
0:10:47 > 0:10:51this was what was causing stomach ulcer disease, which is a
0:10:51 > 0:10:55horrible condition that was thought at the time to be caused by stress.
0:10:56 > 0:11:00The difficulty for them was proving their case
0:11:00 > 0:11:02to the scientific community.
0:11:02 > 0:11:05They needed to clearly show the bacteria led to ulcers,
0:11:05 > 0:11:10but it would have been unethical to test their theory on people.
0:11:10 > 0:11:14And this left Barry Marshall with just one avenue - to
0:11:14 > 0:11:16experiment on himself.
0:11:16 > 0:11:19So what he did was he gathered H pylori
0:11:19 > 0:11:23from the stomach of his patients, mixed it into a broth and drank it.
0:11:25 > 0:11:27It didn't taste very well - it was like swamp water or
0:11:27 > 0:11:30something, it was quite putrid, in fact, so...
0:11:30 > 0:11:33It was a little revolting to do.
0:11:33 > 0:11:34And then on the eighth day,
0:11:34 > 0:11:37I suddenly woke up in the morning, 6am,
0:11:37 > 0:11:42felt very nauseated and ran into the bathroom and vomited in the toilet.
0:11:42 > 0:11:43Sure enough, within a few days,
0:11:43 > 0:11:47he developed symptoms that come before an ulcer.
0:11:47 > 0:11:52He then took a biopsy and this proved the link between H pylori
0:11:52 > 0:11:54and ulcer disease,
0:11:54 > 0:11:58turning a condition that had been chronic and debilitating into
0:11:58 > 0:12:03a simple disease that could be cured with a dose of antibiotics.
0:12:06 > 0:12:09This is Barry Marshall and Robin Warren receiving the
0:12:09 > 0:12:11Nobel Prize for their discovery.
0:12:13 > 0:12:17Even now, advances in modern medicine are being made
0:12:17 > 0:12:21possible by a few pioneering individuals who are prepared
0:12:21 > 0:12:25to put their bodies in the service of science,
0:12:25 > 0:12:28as our next remarkable case shows.
0:12:33 > 0:12:39My name is Wim Hof - they call me the Iceman. I'm 57 years old.
0:12:46 > 0:12:50Wim is a world record-holder in enduring extreme cold.
0:12:53 > 0:12:57On Kilimanjaro, we go up to the summit in shorts.
0:12:57 > 0:12:59Africa's highest point.
0:12:59 > 0:13:02He has set records for swimming beneath ice.
0:13:03 > 0:13:05And being immersed within it.
0:13:10 > 0:13:13In most of us, if we're exposed to extreme cold,
0:13:13 > 0:13:15our core temperature drops.
0:13:15 > 0:13:18If it falls by just 2 degrees, we become hypothermic.
0:13:20 > 0:13:23Our heart and respiratory system will soon fail.
0:13:25 > 0:13:29Most of us would lose consciousness after just 15 minutes and
0:13:29 > 0:13:30would die within an hour.
0:13:32 > 0:13:39But Wim Hof can spend nearly 2 hours in ice and emerge unharmed.
0:13:39 > 0:13:42So how is he able to survive?
0:13:42 > 0:13:46A team of researchers at Radboud University Medical Centre
0:13:46 > 0:13:49in the Netherlands set out to discover the answer.
0:13:49 > 0:13:53They took some key measurements to find out exactly what happens
0:13:53 > 0:13:57in Wim's body when he's encased in ice.
0:13:57 > 0:14:01Matthijs Kox is a researcher at the University.
0:14:01 > 0:14:05All kinds of things are measured, so we measured metabolism, we
0:14:05 > 0:14:07measured of course his skin temperature
0:14:07 > 0:14:09and all kinds of other biometrics
0:14:09 > 0:14:14to learn more about this interesting ability of his to withstand extreme cold.
0:14:17 > 0:14:19The tests revealed that when he's in ice,
0:14:19 > 0:14:23Wim's core temperature doesn't drop as you'd expect.
0:14:23 > 0:14:24It actually goes up slightly.
0:14:26 > 0:14:28It sounds impossible,
0:14:28 > 0:14:31but the scientists have found the answer in his blood.
0:14:33 > 0:14:36So what we actually found is that the adrenaline levels in the
0:14:36 > 0:14:39blood went up to very high levels and they were actually higher
0:14:39 > 0:14:43than in subjects that bungee jumped for the first time.
0:14:44 > 0:14:48Adrenaline is a hormone that our bodies produce automatically
0:14:48 > 0:14:50when we're faced with danger.
0:14:50 > 0:14:51It has many effects on the body,
0:14:51 > 0:14:55one of which is to raise our metabolism, which generates heat.
0:15:00 > 0:15:02But adrenaline is not something
0:15:02 > 0:15:05most of us can consciously choose to produce.
0:15:05 > 0:15:10Wim claims he can do it, thanks to a special breathing technique.
0:15:16 > 0:15:18Anybody can do it. I can prove it.
0:15:18 > 0:15:20Belly first...
0:15:20 > 0:15:22Then chest.
0:15:23 > 0:15:25Then the head.
0:15:27 > 0:15:28Letting go, not fully out.
0:15:30 > 0:15:34But fully in... And then letting go.
0:15:34 > 0:15:37If you do that 30 times, I promise you,
0:15:37 > 0:15:40you are able to do all kinds of things.
0:15:42 > 0:15:43Though it may sound unlikely,
0:15:43 > 0:15:48there is a good scientific reason why this unusual breathing technique
0:15:48 > 0:15:51might cause the body to produce more adrenaline.
0:15:53 > 0:15:57The deep inhalations followed by quick exhalations
0:15:57 > 0:16:01expel more carbon dioxide from the lungs than normal.
0:16:01 > 0:16:04As a result, levels of carbon dioxide in the blood
0:16:04 > 0:16:05drop dramatically.
0:16:06 > 0:16:11This makes it more alkaline, which is measured as a higher pH reading.
0:16:13 > 0:16:15So, with the breathing technique,
0:16:15 > 0:16:19what we see in the blood is that the pH goes up to very high levels
0:16:19 > 0:16:23and this might be involved in triggering of adrenaline release.
0:16:23 > 0:16:28The level of control that Wim over his own body is remarkable.
0:16:28 > 0:16:31By simply breathing in a different way,
0:16:31 > 0:16:34it looks as if he's able to control his own blood chemistry
0:16:34 > 0:16:39in a way that perhaps enables him to produce more adrenaline -
0:16:39 > 0:16:42and it's this that lets him withstand
0:16:42 > 0:16:46extreme temperatures of cold in an almost superhuman way.
0:16:46 > 0:16:51But Wim says it also lets him do something even more impressive.
0:16:51 > 0:16:56I told them I could influence the immune system.
0:16:56 > 0:16:59On the face of it, it sounds like an outlandish claim -
0:16:59 > 0:17:02our immune system responds automatically
0:17:02 > 0:17:06to protect us when our body comes into contact with disease.
0:17:07 > 0:17:10We don't have conscious control of it.
0:17:10 > 0:17:12So Wim actually came to us with his claim
0:17:12 > 0:17:15that he could influence his immune response,
0:17:15 > 0:17:17so that was interesting to us,
0:17:17 > 0:17:21because we actually study the immune response in our department.
0:17:21 > 0:17:25Matthijs's team knew that one of the things that can influence
0:17:25 > 0:17:29the immune system is adrenaline - so could Wim be right?
0:17:32 > 0:17:36The only way to find out was to test Wim's immune response.
0:17:36 > 0:17:39Whilst he breathed using his special technique,
0:17:39 > 0:17:43the scientists injected him with a substance called an endotoxin,
0:17:43 > 0:17:47which tricks the body into thinking it's under bacterial attack.
0:17:50 > 0:17:54The normal immune response would be fever and flu-like symptoms.
0:17:55 > 0:17:59When we injected Wim with this bacterial compound,
0:17:59 > 0:18:01his immune response was much lower
0:18:01 > 0:18:04than what we observed in over 100 volunteers.
0:18:04 > 0:18:08We saw less fever, he had less flu-like symptoms
0:18:08 > 0:18:10and he also had lessened concentrations
0:18:10 > 0:18:13of inflammatory proteins in his blood.
0:18:15 > 0:18:17The tests show that Wim's technique
0:18:17 > 0:18:20might actually suppress his immune response.
0:18:22 > 0:18:25And this is a really exciting discovery,
0:18:25 > 0:18:29because there are a whole set of common diseases
0:18:29 > 0:18:33where the immune system goes into overdrive and even attacks itself.
0:18:35 > 0:18:37So in autoimmune diseases,
0:18:37 > 0:18:41your immune system actually attacks your own body,
0:18:41 > 0:18:43actually - parts of your own body
0:18:43 > 0:18:46and that is actually an inappropriate immune response
0:18:46 > 0:18:47that you don't want.
0:18:47 > 0:18:51The most well-known autoimmune disease is rheumatoid arthritis.
0:18:55 > 0:18:58It may be that Wim's special breathing technique
0:18:58 > 0:19:00could help people with autoimmune diseases
0:19:00 > 0:19:04to suppress the immune response that is causing their illness.
0:19:10 > 0:19:13Now, Matthijs is investigating whether breathing in this way
0:19:13 > 0:19:17affects others the same way as Wim.
0:19:17 > 0:19:20Half of these men are breathing using Wim's technique
0:19:20 > 0:19:22and half are breathing normally.
0:19:22 > 0:19:24Over the coming months,
0:19:24 > 0:19:26Matthijs will be running a number of tests
0:19:26 > 0:19:29to look for any differences in their adrenaline levels
0:19:29 > 0:19:32and immune response.
0:19:32 > 0:19:36The real test is going to be when we test these techniques
0:19:36 > 0:19:38in actual patients with autoimmune diseases
0:19:38 > 0:19:42and when we can show that these are also effective in these patients,
0:19:42 > 0:19:43these techniques,
0:19:43 > 0:19:47then this could mean a new way of treating these patients.
0:19:48 > 0:19:49So, these breathing techniques
0:19:49 > 0:19:53I've been developing by feeling, intuition.
0:19:56 > 0:19:58When I had no scientific validation,
0:19:58 > 0:20:01they called me an idiot, they called me crazy -
0:20:01 > 0:20:05AND yes, it has been shown in scientific experiments
0:20:05 > 0:20:10it all works, so...and greatly - not a little bit, big-time.
0:20:11 > 0:20:14Wim is adding a new chapter to medical science.
0:20:20 > 0:20:23By pushing himself to the absolute limit,
0:20:23 > 0:20:29Wim Hof is changing scientists' understanding of how the body works.
0:20:30 > 0:20:33But in some cases, the body is forced to adapt
0:20:33 > 0:20:35not in response to an external threat,
0:20:35 > 0:20:38but because of a threat from within,
0:20:38 > 0:20:40when a part of the body itself goes wrong.
0:20:43 > 0:20:49Our next case almost defies belief and reveals the human body
0:20:49 > 0:20:54as being capable of adapting in ways that I, even as a doctor,
0:20:54 > 0:20:56would never have imagined possible.
0:20:56 > 0:20:59INDISTINCT SPEECH
0:20:59 > 0:21:03Jodie Graves is living proof of the incredible resilience
0:21:03 > 0:21:05of the human body.
0:21:06 > 0:21:10You wouldn't know now looking at Jodie, in her mid-20s,
0:21:10 > 0:21:12leading a full life,
0:21:12 > 0:21:17what an incredible thing that she went through at the age of three.
0:21:19 > 0:21:20I have half a brain.
0:21:20 > 0:21:23When people meet me, they have no idea.
0:21:25 > 0:21:29Jodie began life as a completely normal baby and toddler.
0:21:29 > 0:21:34And the very first time that they noticed anything that wasn't
0:21:34 > 0:21:37quite right with her was around the age of three,
0:21:37 > 0:21:42when Jodie, very suddenly one day, just collapsed.
0:21:42 > 0:21:46I only remember my very first seizure.
0:21:46 > 0:21:49I was at my day-care playing and the next thing I knew,
0:21:49 > 0:21:51I was in an ambulance.
0:21:51 > 0:21:54We hightailed it to the hospital and just watched her.
0:21:54 > 0:21:56She had another seizure the next morning,
0:21:56 > 0:21:58so I ran her into the hospital again.
0:21:58 > 0:22:02But nothing that they did...worked.
0:22:04 > 0:22:07From that point onwards, things really snowballed for her
0:22:07 > 0:22:11and she began to have fits on a really regular basis.
0:22:11 > 0:22:14If you picture a marionette with the strings,
0:22:14 > 0:22:18it was like someone just dropped one side.
0:22:18 > 0:22:23So she was constantly falling to the left and it got so bad
0:22:23 > 0:22:26that one of us had to be on her left side all the time.
0:22:28 > 0:22:31It was to the point where I was having seizures every three minutes,
0:22:31 > 0:22:34and that wasn't...cool.
0:22:35 > 0:22:38Jodie's parents were so worried that they took her to
0:22:38 > 0:22:41the world-renowned neurology department
0:22:41 > 0:22:43at the Johns Hopkins Hospital.
0:22:45 > 0:22:48Investigations there showed she was suffering from
0:22:48 > 0:22:52a rare condition called Rasmussen's encephalitis.
0:22:54 > 0:22:56This causes chronic inflammation of the brain,
0:22:56 > 0:22:59usually in one hemisphere.
0:22:59 > 0:23:01Without treatment, there was no prospect
0:23:01 > 0:23:04that Jodie's seizures would ever stop.
0:23:04 > 0:23:09There was one possible option, but it was shocking.
0:23:09 > 0:23:14The doctor explained that the only way they
0:23:14 > 0:23:18could treat it was to take out the half of the brain that was affected.
0:23:19 > 0:23:23As a doctor, I have never heard of this kind of surgery.
0:23:23 > 0:23:26If somebody had said to me, "What do you think would happen if you
0:23:26 > 0:23:27"took half of someone's brain out?"
0:23:27 > 0:23:30Um, I would've thought that that would be
0:23:30 > 0:23:32devastating, if not fatal.
0:23:35 > 0:23:38Amy Bastian is Professor of Neuroscience and Neurology
0:23:38 > 0:23:39at Johns Hopkins.
0:23:42 > 0:23:46Having an entire hemisphere of your brain removed
0:23:46 > 0:23:49is a pretty radical thing.
0:23:49 > 0:23:54It's not something that any neurosurgeon would do lightly.
0:23:54 > 0:24:00So how is it possible to have such a drastic operation and still survive?
0:24:00 > 0:24:04Well, Jodie's doctors hope that if they took out the right-hand side
0:24:04 > 0:24:07of her brain, the left hemisphere would compensate
0:24:07 > 0:24:09and take over its functions.
0:24:09 > 0:24:13This is because of something called brain plasticity,
0:24:13 > 0:24:19the remarkable ability of the brain to adapt and reorganise itself.
0:24:21 > 0:24:23In very, very early childhood,
0:24:23 > 0:24:26the brain is thought to be in one of its most plastic states.
0:24:26 > 0:24:29And if you change the brain at that point,
0:24:29 > 0:24:33there may be a better capacity for the brain to reorganise.
0:24:33 > 0:24:37The doctors were optimistic that this would work for Jodie.
0:24:37 > 0:24:40The operation had been performed in over 50 patients
0:24:40 > 0:24:42and had been successful.
0:24:42 > 0:24:45But her parents had mixed feelings about going ahead
0:24:45 > 0:24:48with such a drastic procedure.
0:24:50 > 0:24:51Basically, I said, "No,
0:24:51 > 0:24:54"this sounds like a good deal, I can have my child back,
0:24:54 > 0:24:59"she'll be at least as good as she is now but without the seizures."
0:24:59 > 0:25:01So my reaction was very atypical.
0:25:01 > 0:25:06I was mostly relieved that there was something we could do.
0:25:06 > 0:25:09My husband's reaction was much more typical.
0:25:09 > 0:25:13When we walked out to the garage and got in the car,
0:25:13 > 0:25:16I just totally exploded. I just lost it, right there.
0:25:18 > 0:25:21Well, you know, she was his little girl.
0:25:21 > 0:25:25It took him a couple of weeks to get used to the idea,
0:25:25 > 0:25:30and to agree that it was the best thing that we could do for her.
0:25:30 > 0:25:33I was glad that my parents were right there beside me
0:25:33 > 0:25:35through the whole thing.
0:25:37 > 0:25:41Jodie had her operation when she was just three years old.
0:25:41 > 0:25:45Nobody could know if it had been successful until she woke up.
0:25:47 > 0:25:51She gave Dad the thumbs up - that was their sign,
0:25:51 > 0:25:57so, we knew she was comprehending things, and she was not seizing.
0:25:58 > 0:26:01That was a really big difference.
0:26:02 > 0:26:07Amazingly, then, Jodie just continued to do really, really well.
0:26:07 > 0:26:09As a young child,
0:26:09 > 0:26:12she carried on doing all the things that she wanted to do.
0:26:12 > 0:26:16This may have been because her brain had already started
0:26:16 > 0:26:19to rewire itself, even before the operation.
0:26:21 > 0:26:24You can imagine, if you had a hemisphere of your brain,
0:26:24 > 0:26:26half of your brain, that was sick,
0:26:26 > 0:26:29that was having seizures and was not functioning normally,
0:26:29 > 0:26:32and you're a little kid, and your brain is still developing,
0:26:32 > 0:26:35the other side of the brain is pretty healthy,
0:26:35 > 0:26:38and is able start taking over some of those functions,
0:26:38 > 0:26:42and that's probably why, when you take out the hemisphere,
0:26:42 > 0:26:45that these kids actually do really quite well.
0:26:45 > 0:26:47They've been dealing with the sick hemisphere for so long
0:26:47 > 0:26:49that the function - much of the function -
0:26:49 > 0:26:51has transferred to the other.
0:26:53 > 0:26:55Thanks to its remarkable plasticity,
0:26:55 > 0:27:01the remaining half of Jodie's brain is able to control her entire body.
0:27:01 > 0:27:03I'm a very positive person -
0:27:03 > 0:27:07a lot of times I'll joke that they took out the mean side of my brain,
0:27:07 > 0:27:09and they only left the happy side.
0:27:11 > 0:27:17For me, as a doctor, Jodie's story is a really inspiring example
0:27:17 > 0:27:22of the fact that our bodies may be capable of a whole lot more
0:27:22 > 0:27:25than we think they are, if only we're prepared
0:27:25 > 0:27:27to give them that chance.
0:27:28 > 0:27:35Life now, with half a brain, for me, is no different than anybody else.
0:27:35 > 0:27:39So, I've been married for years, I live on my own with my husband,
0:27:39 > 0:27:44I work - I work with a little boy with ADHD,
0:27:44 > 0:27:47and I do everything that any other person would do.
0:27:47 > 0:27:49I don't get cut any breaks.
0:27:50 > 0:27:52If you had asked me 25 years ago
0:27:52 > 0:27:54if it was possible to take out half the brain
0:27:54 > 0:27:57and still have functioning life,
0:27:57 > 0:27:59I would have said, "You've got to be crazy,"
0:27:59 > 0:28:01but here we are.
0:28:03 > 0:28:06I'm really glad my parents did what they did,
0:28:06 > 0:28:08because I wouldn't be where I am now
0:28:08 > 0:28:13if I had had the surgery any later or had waited any longer.
0:28:17 > 0:28:21Jodie's case shows the power of the human body to adapt physically,
0:28:21 > 0:28:25even after the most extreme trauma - but, to survive,
0:28:25 > 0:28:29we rely on more than the physical structures of our body.
0:28:29 > 0:28:32There's another key part of our make-up
0:28:32 > 0:28:35we depend on far more than we realise.
0:28:35 > 0:28:36Our emotions.
0:28:39 > 0:28:40Emotions are a crucial part
0:28:40 > 0:28:43of how we will respond to the world around us,
0:28:43 > 0:28:48and our next few cases are going to focus on one particular emotion.
0:28:48 > 0:28:50Fear.
0:28:50 > 0:28:53We are hard-wired to respond instantly
0:28:53 > 0:28:56to certain threats or alarm signals.
0:28:56 > 0:29:00It's a process that's vital for our survival,
0:29:00 > 0:29:04and one of the most amazing cases I've seen recently
0:29:04 > 0:29:07is that of a man who's completely lost this ability.
0:29:11 > 0:29:17In 2013, Jordy Cernick did a tandem skydive for charity.
0:29:17 > 0:29:20He'd never jumped from a plane before.
0:29:20 > 0:29:22You get to the point where they get you to dangle your legs
0:29:22 > 0:29:25outside of the plane, of course, you feel the wind
0:29:25 > 0:29:26and you can feel all the noise.
0:29:26 > 0:29:30For most of us, this would be one of the most terrifying moments
0:29:30 > 0:29:33of our life - but not Jordy.
0:29:33 > 0:29:36I didn't feel a thing. There was no reaction.
0:29:38 > 0:29:41I'm Jordy Cernick, and I don't feel fear.
0:29:43 > 0:29:45But Jordy wasn't born this way.
0:29:47 > 0:29:50His journey to fearlessness began in the late 1990s,
0:29:50 > 0:29:52when his body began to change.
0:29:55 > 0:29:58I was quite a slim, physical guy.
0:29:58 > 0:30:01I had done stuff in the Army, and I was quite healthy.
0:30:01 > 0:30:04I started putting on quite a bit of weight -
0:30:04 > 0:30:07and I did lots of diets, I did all the fad diets you can think of.
0:30:07 > 0:30:10I trained up to six, seven times a week,
0:30:10 > 0:30:14and nothing was shifting this fat that I was gaining and gaining.
0:30:16 > 0:30:18Jordy was eventually referred to a specialist
0:30:18 > 0:30:23and diagnosed with a rare condition called Cushing's syndrome.
0:30:23 > 0:30:26It makes you fat, it makes you have high blood pressure,
0:30:26 > 0:30:29it makes you sweat, and it's very dangerous.
0:30:29 > 0:30:31It's the high blood pressure side that's so dangerous,
0:30:31 > 0:30:32and can kill you.
0:30:34 > 0:30:39Cushing's syndrome is caused by abnormally high levels of cortisol,
0:30:39 > 0:30:42a hormone we produce in response to stress.
0:30:42 > 0:30:45It can affect our appetite and our blood sugar,
0:30:45 > 0:30:48and this is what had affected Jordy's weight.
0:30:49 > 0:30:52Cortisol is produced by the combined action
0:30:52 > 0:30:55of the pituitary gland in the base of the brain
0:30:55 > 0:30:58and the adrenal glands just above the kidneys.
0:30:58 > 0:31:01The only possible treatment was an operation.
0:31:03 > 0:31:06They decided to completely remove my adrenals.
0:31:06 > 0:31:09Now, that meant they had to open up the left side of my body
0:31:09 > 0:31:12and just take the adrenals out that way.
0:31:13 > 0:31:17After the procedure, Jordy return to his normal weight -
0:31:17 > 0:31:20but he soon noticed something else was missing.
0:31:24 > 0:31:27We decided to go away for a couple of days on a family holiday,
0:31:27 > 0:31:30and we ended up in a theme park, and I remember going up,
0:31:30 > 0:31:33and it was getting higher and higher and higher,
0:31:33 > 0:31:35I was just thinking, "It's going to kick in.
0:31:35 > 0:31:38"I'll just get ready for it," and it dropped...
0:31:38 > 0:31:41Whee!
0:31:41 > 0:31:44..and I felt nothing. All I felt was the movement.
0:31:46 > 0:31:48And I thought, "You know what?
0:31:48 > 0:31:50"I know there's something not right here."
0:31:50 > 0:31:54Jordy began to realise he could no longer feel fear.
0:32:01 > 0:32:03Normally, the sensation of fear
0:32:03 > 0:32:05is caused by a combination of hormones
0:32:05 > 0:32:08produced in our bodies by particular glands.
0:32:11 > 0:32:15Now, these are the kidneys, here, and sitting on top of them,
0:32:15 > 0:32:20the adrenal glands, and in response to the situation of threat,
0:32:20 > 0:32:24these glands produce hormones like cortisol and adrenaline,
0:32:24 > 0:32:28which quickly enter the bloodstream. This increases the heart rate
0:32:28 > 0:32:32and, at the same time, it floods the blood and the muscles
0:32:32 > 0:32:34with energy and nutrients,
0:32:34 > 0:32:38as well as shutting down the less important processes -
0:32:38 > 0:32:42all of which puts us in the best possible position
0:32:42 > 0:32:47to either escape danger or rise up to meet the threat of it.
0:32:47 > 0:32:51It's one of the oldest emotional responses to the world around us.
0:32:53 > 0:32:55But Jordy had had these glands removed
0:32:55 > 0:32:57to treat his Cushing's syndrome,
0:32:57 > 0:33:00and, as a result, he could no longer produce adrenaline.
0:33:04 > 0:33:08For scientists, Jordy presents a rare opportunity
0:33:08 > 0:33:10to understand how fear works.
0:33:10 > 0:33:13Now, it's long been known that adrenaline
0:33:13 > 0:33:17plays a key part in how our bodies respond to danger,
0:33:17 > 0:33:20but without the glands that produce it,
0:33:20 > 0:33:24is there anything left of our sense of fear at all?
0:33:25 > 0:33:29Dr Sarah Garfinkel is a cognitive neuroscientist
0:33:29 > 0:33:31from the University of Sussex.
0:33:31 > 0:33:35She's going to set up an experiment that's never been tried before
0:33:35 > 0:33:38to test exactly how Jordy's body responds to a situation
0:33:38 > 0:33:41that would ignite fear in most of us.
0:33:43 > 0:33:47This is the National Lift Tower in Northampton.
0:33:47 > 0:33:53It's 127 metres tall, and Jordy is going to abseil down it.
0:33:54 > 0:33:57Now what I want to do is put these bands on you.
0:33:57 > 0:34:00As he descends, Jordy will wear these bands
0:34:00 > 0:34:03to measure what's known as skin conductance.
0:34:04 > 0:34:07These are going to stay on you as you abseil down.
0:34:07 > 0:34:10When we feel fear, moisture levels in our skin
0:34:10 > 0:34:13increase by tiny amounts,
0:34:13 > 0:34:18and this makes it a better conductor of electricity.
0:34:18 > 0:34:22The band will detect any such minute changes in Jordy.
0:34:22 > 0:34:25If his body isn't displaying these typical fear responses,
0:34:25 > 0:34:28then that means that he's not getting
0:34:28 > 0:34:31the body saying, "I'm scared,"
0:34:31 > 0:34:33and if the body is not saying, "I'm scared,"
0:34:33 > 0:34:35then it's not telling the brain, "I'm scared,"
0:34:35 > 0:34:38and then you don't get this sort of feedback loop.
0:34:39 > 0:34:43In most of us, fearful emotions are controlled by a part of the brain
0:34:43 > 0:34:44called the amygdala.
0:34:44 > 0:34:47When we face a threat or danger,
0:34:47 > 0:34:49it signals different parts of the brain and body
0:34:49 > 0:34:50to spring into action,
0:34:50 > 0:34:55triggering a cascade of responses in the hormone and nervous systems.
0:34:55 > 0:34:58Normally, this includes the release of adrenaline.
0:35:00 > 0:35:02- Right then.- OK.- Let's do this. - Good luck.
0:35:02 > 0:35:03- I'll see you at the bottom.- Good.
0:35:05 > 0:35:07- Ready?- Yeah.
0:35:07 > 0:35:09There we ago.
0:35:09 > 0:35:10Going over the edge
0:35:10 > 0:35:13is the moment you'd expect would trigger
0:35:13 > 0:35:15the cascade of fear responses.
0:35:15 > 0:35:18The experiment will show whether, with adrenaline missing,
0:35:18 > 0:35:21any of the system still works in Jordy.
0:35:23 > 0:35:26Dr Garfinkel can now analyse the data
0:35:26 > 0:35:28collected during Jordy's descent.
0:35:28 > 0:35:30That's where you should be seeing this line here,
0:35:30 > 0:35:36so I know, on the graph, where you are just starting your descent.
0:35:37 > 0:35:41This graph plots that any change measured in his skin conductance.
0:35:42 > 0:35:46And what is so interesting about this graph is,
0:35:46 > 0:35:49where we would expect there to be a big peak,
0:35:49 > 0:35:54there is absolutely no rise at all. It's completely flat.
0:35:54 > 0:35:57You've got, like, the tiniest little bump there.
0:35:57 > 0:35:59That's telling me it is working and it is reading -
0:35:59 > 0:36:02you're just not having a response.
0:36:02 > 0:36:05The experiment has shown that, without adrenaline,
0:36:05 > 0:36:08Jordy's entire fear response has broken down.
0:36:18 > 0:36:20But what's most interesting about Jordy
0:36:20 > 0:36:24is that he can still perceive risk and keep himself safe,
0:36:24 > 0:36:27and this is because he still has a vital part
0:36:27 > 0:36:30of the fear of response system in place -
0:36:30 > 0:36:33the amygdala in the brain.
0:36:33 > 0:36:36This tells him when a situation is dangerous.
0:36:36 > 0:36:41He knows he should be scared, he just doesn't feel scared.
0:36:41 > 0:36:43So I'm going to attach this to your finger...
0:36:43 > 0:36:48Sarah, Jordy's rare ability to perceive fear but not feel it
0:36:48 > 0:36:51is an opportunity to understand other medical conditions
0:36:51 > 0:36:56where fear becomes debilitating - like anxiety.
0:36:56 > 0:36:59Jordy doesn't have the subjective feeling of fear,
0:36:59 > 0:37:02and his body is also not showing the fear response,
0:37:02 > 0:37:05and we can take that, based on Jordy,
0:37:05 > 0:37:07and apply it to people with anxiety,
0:37:07 > 0:37:11who have too much fear, to try and understand more
0:37:11 > 0:37:14how novel treatments can potentially be used
0:37:14 > 0:37:16to treat people with anxiety.
0:37:19 > 0:37:22All the stuff that's gone wrong, why not think, "You know what?
0:37:22 > 0:37:23"I've been able to help somebody
0:37:23 > 0:37:27"who has such anxiety that they can't go out the house."
0:37:28 > 0:37:29Wow!
0:37:29 > 0:37:33It would be great to think I've been able to help somebody.
0:37:33 > 0:37:37Jordy's case reveals just how much we depend
0:37:37 > 0:37:40on that fundamental emotion - fear.
0:37:41 > 0:37:46It's an instant and automatic response to our nervous system
0:37:46 > 0:37:48when we encounter danger,
0:37:48 > 0:37:51and is probably our most important survival mechanism,
0:37:51 > 0:37:55and there's one extreme and rather noisy case
0:37:55 > 0:37:59which is casting new light on how it's triggered.
0:38:02 > 0:38:07My name is Jill Drake, and I have the world's loudest scream.
0:38:07 > 0:38:09SHE SCREAMS
0:38:16 > 0:38:19Jill Drake doesn't look like someone
0:38:19 > 0:38:22who is likely to make your blood curdle...
0:38:22 > 0:38:24- Hello.- How are you?- Fine, thank you.
0:38:24 > 0:38:27- What have you got there? - I've got a latte.
0:38:27 > 0:38:31..but, by chance, she discovered she had an unusual talent.
0:38:32 > 0:38:38It was Halloween time and there was a screaming competition going on,
0:38:38 > 0:38:42and I screamed, and I broke the world record.
0:38:42 > 0:38:44And then they said, "Can you do it again?"
0:38:44 > 0:38:47So, I screamed again, and I broke the world record again.
0:38:47 > 0:38:53The volume of the average person screaming is around 100 decibels.
0:38:53 > 0:38:56Jill's was measured at 129.
0:38:56 > 0:38:58SHE SCREAMS
0:39:01 > 0:39:04Before she stumbled across the competition,
0:39:04 > 0:39:07Jill had no idea that she could scream so loudly.
0:39:09 > 0:39:12I'm always getting asked what training do I do,
0:39:12 > 0:39:18and I don't - I just opened my mouth and it comes out, so...
0:39:19 > 0:39:21It's loud!
0:39:22 > 0:39:26When we scream, our lungs push air through our larynx
0:39:26 > 0:39:29and over our vocal cords, which vibrate, making a sound -
0:39:29 > 0:39:34but there aren't many people who can make a sound like Jill.
0:39:34 > 0:39:40So, what enables her to generate this world record-breaking volume?
0:39:42 > 0:39:44At the Royal Holloway University of London,
0:39:44 > 0:39:48Professor David Howard is an expert on the human voice.
0:39:50 > 0:39:52Ahh... Ahhh...!
0:39:52 > 0:39:54This model is a model of the larynx.
0:39:54 > 0:39:57There are two vocal folds, and when we're breathing,
0:39:57 > 0:40:01the vocal folds are apart, so the airway is unobstructed -
0:40:01 > 0:40:03but when we want to speak or sing,
0:40:03 > 0:40:06we move the vocal folds close together
0:40:06 > 0:40:09and air is then passed between them,
0:40:09 > 0:40:12and they start to move towards each other,
0:40:12 > 0:40:14and they crash together.
0:40:14 > 0:40:17How much they crash together, and with what force,
0:40:17 > 0:40:21determines the loudness of the sound.
0:40:22 > 0:40:26To discover why Jill can produce such an ear-splitting volume,
0:40:26 > 0:40:31David is going to measure exactly what's going on in her throat.
0:40:31 > 0:40:33We're going to do that with this little device
0:40:33 > 0:40:35that sits on the neck with two little electrode rings.
0:40:35 > 0:40:37Pop those, one either side,
0:40:37 > 0:40:42- and we're going to take a sound level at the same time.- OK.
0:40:42 > 0:40:46And there's one more vital piece of equipment that David requires -
0:40:46 > 0:40:47earplugs.
0:40:47 > 0:40:49And we're ready to go.
0:40:50 > 0:40:52SHE SCREAMS
0:40:54 > 0:40:56120.1.
0:40:56 > 0:40:58That's very loud -
0:40:58 > 0:41:01not the sort of levels you'd want to listen to for very long.
0:41:01 > 0:41:05- Not bad at 65. - It's very impressive at 65!
0:41:06 > 0:41:07RECORDED SCREAM
0:41:10 > 0:41:13David is now able to analyse the results,
0:41:13 > 0:41:16and uncover why Jill has such a loud scream.
0:41:17 > 0:41:21Your vocal folds are working very fast and rapidly.
0:41:21 > 0:41:24That helps give this bigger acoustic output.
0:41:24 > 0:41:28But, in order to do that, you need two things,
0:41:28 > 0:41:30I believe - I think you have very efficient lungs,
0:41:30 > 0:41:33in terms of how you can get the air out,
0:41:33 > 0:41:36and I suspect your vocal folds are rather bigger
0:41:36 > 0:41:40than for another lady of your age, so that when they do crash together,
0:41:40 > 0:41:44there is more bulk there to give that really strong acoustic output.
0:41:44 > 0:41:46SHE SCREAMS
0:41:49 > 0:41:51But, in fact, it isn't the loudness itself
0:41:51 > 0:41:54that makes a scream strike fear into us.
0:41:54 > 0:41:56Well, we first, I think, have to think about,
0:41:56 > 0:41:58why do humans scream at all?
0:41:58 > 0:42:00To which I think the answer is,
0:42:00 > 0:42:03it's to gain attention when we are in trouble.
0:42:03 > 0:42:07So, during the scream, there are these rapid volume changes.
0:42:07 > 0:42:11This graph shows the volume during Jill's screen.
0:42:11 > 0:42:14In normal speech, the peaks would be all the same size,
0:42:14 > 0:42:16but here there is a lot of variation.
0:42:16 > 0:42:21And the research has shown that for the ear of the listener,
0:42:21 > 0:42:26those rapid volume changes trigger a fear sensation in the brain...
0:42:26 > 0:42:28THEY SCREAM
0:42:28 > 0:42:31..and they tell the listener that something is going on
0:42:31 > 0:42:34that they need to be afraid of, and somebody's in trouble.
0:42:35 > 0:42:39Not only is Jill's scream record-breaking for its volume,
0:42:39 > 0:42:42but it's also scientifically proven to be terrifying.
0:42:44 > 0:42:46SHE SCREAMS
0:42:46 > 0:42:48Jill may be extreme,
0:42:48 > 0:42:52but her case shows how we can all produce particular sounds
0:42:52 > 0:42:55that trigger fear in other people,
0:42:55 > 0:42:58and this spurs us to respond to a threat.
0:43:00 > 0:43:01It's an elegant example
0:43:01 > 0:43:06of how our emotions can become a vital survival mechanism
0:43:06 > 0:43:08that helps keep us safe -
0:43:08 > 0:43:11but I've come across one extraordinary person
0:43:11 > 0:43:14whose emotions are doing quite the opposite.
0:43:18 > 0:43:22Lucy Tonge has a rare condition that can strike at any time,
0:43:22 > 0:43:24putting her in imminent danger.
0:43:24 > 0:43:26When we were on holiday couple of years ago,
0:43:26 > 0:43:29I was with my mum and my sister, and we were in the swimming pool,
0:43:29 > 0:43:31and I can't remember specifically what it was -
0:43:31 > 0:43:33I think my sister said something that made me laugh -
0:43:33 > 0:43:36and I just had my cataplexy.
0:43:36 > 0:43:38Triggered by her laughter,
0:43:38 > 0:43:42Lucy's muscles suddenly became weak and she lost control of her limbs.
0:43:42 > 0:43:46I was in quite deep water - I just started drowning,
0:43:46 > 0:43:49and it took them a while to realise.
0:43:51 > 0:43:56This wasn't a one-off. Lucy has a condition called cataplexy.
0:43:56 > 0:44:00It means that when she experiences a strong emotion,
0:44:00 > 0:44:04it causes a sudden and extreme weakness in her muscles.
0:44:04 > 0:44:07A lot of the time it's just my head and my neck,
0:44:07 > 0:44:10but it can be anything from that to walking along and my knees go
0:44:10 > 0:44:12or, like, full body collapse.
0:44:12 > 0:44:16Things like adverts of dogs for the blind or donkey sanctuaries -
0:44:16 > 0:44:19things that people might think, "Oh, that's sad,"
0:44:19 > 0:44:22but I will just end up having cataplexy at things like that!
0:44:22 > 0:44:24Along with cataplexy,
0:44:24 > 0:44:29Lucy has a second condition whose symptoms are no less extreme.
0:44:29 > 0:44:33On an average day, I'll usually have somewhere in the region
0:44:33 > 0:44:36of 40 or 50 attacks where a fall asleep.
0:44:36 > 0:44:39This is known as narcolepsy.
0:44:40 > 0:44:45We all know what it feels like to be so tired that you just nod off,
0:44:45 > 0:44:49but Lucy doesn't have to feel tired to fall asleep -
0:44:49 > 0:44:52in fact, she loses consciousness without warning
0:44:52 > 0:44:54up to 50 times a day,
0:44:54 > 0:44:58and frequently loses control of her muscles.
0:44:58 > 0:45:00So, what on earth is causing this to happen?
0:45:12 > 0:45:15This is Emmanuel Mignot,
0:45:15 > 0:45:18a professor of psychiatry...
0:45:18 > 0:45:19Up, up, up.
0:45:19 > 0:45:22..and this is a key member of his research team.
0:45:22 > 0:45:25Watson - a narcoleptic Chihuahua.
0:45:27 > 0:45:31Dr Dement, my mentor, was describing a number of sleep disorders
0:45:31 > 0:45:34to the public, and then, one person, who was a veterinarian,
0:45:34 > 0:45:36came to him and said, "It's just amazing, I mean,
0:45:36 > 0:45:40"I have a dog with your problem, narcolepsy."
0:45:40 > 0:45:44When it gets excited, you know, it falls down and it's paralysed,
0:45:44 > 0:45:46and it sleeps all the time.
0:45:46 > 0:45:48So, that gave the idea to Dr Dement
0:45:48 > 0:45:51that maybe one of the ways we could find the cause of narcolepsy
0:45:51 > 0:45:53was to try to study these dogs.
0:45:54 > 0:45:58Dogs are a good model for studying human conditions,
0:45:58 > 0:46:01as they share many of the genes found in the human diseases.
0:46:03 > 0:46:07So, the team embarked on a search for narcoleptic dogs.
0:46:07 > 0:46:11One of their canine recruits is Watson.
0:46:11 > 0:46:14For him, the excitement of some tasty food
0:46:14 > 0:46:17is enough to bring on an attack.
0:46:19 > 0:46:20You see?
0:46:22 > 0:46:26So, he got completely excited by the food,
0:46:26 > 0:46:29and he got completely paralysed.
0:46:29 > 0:46:34He has no more muscle tone - the same way as patients with cataplexy.
0:46:34 > 0:46:37Ah, he's coming back. Oh, we survived! C'est bien!
0:46:37 > 0:46:41C'etait beau, huh? C'est beau. Chicken! Chicken was good.
0:46:42 > 0:46:45To search for a clue to the mysterious condition,
0:46:45 > 0:46:49the researchers began to examine the genes of the narcoleptic dogs.
0:46:51 > 0:46:54They were looking for an abnormality that all the dogs had in common.
0:46:54 > 0:46:58After ten years combing through the dogs' DNA,
0:46:58 > 0:47:01they finally found what they were looking for -
0:47:01 > 0:47:05a fault in one particular gene.
0:47:05 > 0:47:09It was a very new gene that had been described only one year before,
0:47:09 > 0:47:14and it was a receptor for a chemical in the brain called hypocretin.
0:47:15 > 0:47:20Hypocretin is a brain chemical that is known to help us stay awake.
0:47:20 > 0:47:21So, that was very exciting,
0:47:21 > 0:47:24because it suggests that this receptor and chemical
0:47:24 > 0:47:28were maybe very important for narcolepsy and sleep in general.
0:47:28 > 0:47:31Now, Professor Mignot wanted to find out
0:47:31 > 0:47:35if hypocretin was also involved in humans.
0:47:35 > 0:47:39He looked inside the brains of people with and without narcolepsy.
0:47:39 > 0:47:41This is the brain of a normal person,
0:47:41 > 0:47:44and, as you can see here, there is all these black dots,
0:47:44 > 0:47:48and they represent little cells that are producing hypocretin -
0:47:48 > 0:47:52and this is a picture of a patient with narcolepsy.
0:47:52 > 0:47:55As you can see, all of the black dots are gone,
0:47:55 > 0:47:58so there is no cells that is producing hypocretin.
0:48:00 > 0:48:03At last, it seemed they'd found the cause of narcolepsy.
0:48:05 > 0:48:08So, of course, we were very, very happy about that.
0:48:08 > 0:48:12I turned around several times around my house to get calmed down.
0:48:13 > 0:48:17When Professor Mignot investigated why people with narcolepsy
0:48:17 > 0:48:20are lacking these hypocretin cells within the brains,
0:48:20 > 0:48:23he discovered that something was destroying them -
0:48:23 > 0:48:26the patient's own immune system.
0:48:26 > 0:48:30This is what's known as an autoimmune condition.
0:48:30 > 0:48:36The immune system is turning back on itself and attacking its own cells
0:48:36 > 0:48:40in a way that means that cells that are meant to produce hypocretin
0:48:40 > 0:48:44to keep us awake are not producing it in the way they should.
0:48:45 > 0:48:50So, narcolepsy is helping to uncover how autoimmune diseases work
0:48:50 > 0:48:54by turning on our bodies' own cells in particular ways...
0:48:55 > 0:48:58..and now that Professor Mignot understands
0:48:58 > 0:49:00how it affects the cells in our brain,
0:49:00 > 0:49:02he believes he can find a way to treat it.
0:49:05 > 0:49:06In the further future,
0:49:06 > 0:49:09we might be able to replace, really, the hypocretin cells,
0:49:09 > 0:49:12which would be a cure for people who have narcolepsy.
0:49:12 > 0:49:15So, the landscape of narcolepsy has completely changed.
0:49:15 > 0:49:17We have a serious hope for treatments
0:49:17 > 0:49:21that are going to be very different from the ones we are using now.
0:49:22 > 0:49:25At the moment, the treatments for narcolepsy
0:49:25 > 0:49:30are not terribly effective, and what Dr Mignot wants to do
0:49:30 > 0:49:33is find a way of re-establishing those cells
0:49:33 > 0:49:35that are not producing hypocretin
0:49:35 > 0:49:39in order that an actual cure for narcolepsy could be found.
0:49:40 > 0:49:43The future is promising for Lucy and others,
0:49:43 > 0:49:47with her rare combination of cataplexy and narcolepsy -
0:49:47 > 0:49:51but, for now, she's not letting her condition hold her back.
0:49:51 > 0:49:53Hello, you're listening to the politics show
0:49:53 > 0:49:55with me, Lucy, on Smoke Radio.
0:49:55 > 0:49:58We'll be talking about World Mental Health Day and Donald Trump,
0:49:58 > 0:50:00after this from Twenty One Pilots.
0:50:06 > 0:50:10Lucy's condition is caused by her immune system misfiring,
0:50:10 > 0:50:13turning against her own body.
0:50:13 > 0:50:15Seeing what happens when it goes wrong
0:50:15 > 0:50:19gives us an understanding of just how powerful it is.
0:50:19 > 0:50:22It's our bodies emergency response system,
0:50:22 > 0:50:26ensuring we survive the many threats we encounter everyday.
0:50:28 > 0:50:30Some of these defences, we're born with -
0:50:30 > 0:50:33first and foremost, the skin is a protective barrier -
0:50:33 > 0:50:36and others we develop as we go through life.
0:50:36 > 0:50:41Cells which are able to specifically recognise and attack
0:50:41 > 0:50:45foreign invaders - white blood cells, in particular,
0:50:45 > 0:50:47developed in the bone marrow
0:50:47 > 0:50:49and then held within the lymphatic system,
0:50:49 > 0:50:53which is represented here by these green vessels.
0:50:54 > 0:50:57In our final case, we'll witness what happens
0:50:57 > 0:51:01when this crucial system itself comes under attack
0:51:01 > 0:51:05from one of the deadliest diseases of the modern age.
0:51:05 > 0:51:09One that was long thought to be completely incurable -
0:51:09 > 0:51:11but a great leap forward
0:51:11 > 0:51:15has come from one of the most extraordinary cases I've ever seen.
0:51:28 > 0:51:31My name is Timothy Ray Brown and I'm 50 years old.
0:51:32 > 0:51:36Timothy is the only person on earth
0:51:36 > 0:51:41who can claim to have been cured of a devastating disease.
0:51:41 > 0:51:43I used to have HIV.
0:51:48 > 0:51:52In the mid-1990s, Timothy was diagnosed with HIV -
0:51:52 > 0:51:56a deadly virus that attacks certain types of white blood cells,
0:51:56 > 0:51:59a vital part of our immune system.
0:52:02 > 0:52:04At the time, it was a death sentence...
0:52:07 > 0:52:10..but research was moving quickly.
0:52:10 > 0:52:12A year later, new drugs became available
0:52:12 > 0:52:14that allowed him to manage his condition
0:52:14 > 0:52:15and get on with his life...
0:52:19 > 0:52:22I worked in a cafe at that time, in Berlin.
0:52:22 > 0:52:26I was pretty honest about my being diagnosed.
0:52:26 > 0:52:30Everyone knew that I was HIV positive.
0:52:30 > 0:52:35..but ten years later, fortune took another turn for the worse.
0:52:39 > 0:52:41I took a trip to New York,
0:52:41 > 0:52:44and I felt really tired the entire time.
0:52:44 > 0:52:46I thought it was jet-lag.
0:52:47 > 0:52:51It wasn't jet-lag. What he actually had was leukaemia -
0:52:51 > 0:52:54a cancer that affects the bone marrow
0:52:54 > 0:52:56where our white blood cells are produced.
0:53:00 > 0:53:03First HIV, then blood cancer.
0:53:03 > 0:53:08So, how did Tim go from having to deadly diseases
0:53:08 > 0:53:12to being the first person cured of HIV?
0:53:15 > 0:53:18The answer lies with this doctor.
0:53:18 > 0:53:22Gero Hutter treats both blood conditions and cancer.
0:53:22 > 0:53:26Together, he and Tim would make medical history.
0:53:28 > 0:53:32My first thought was that he was a very special patient,
0:53:32 > 0:53:36because the combination of HIV and leukaemia is quite uncommon.
0:53:38 > 0:53:41Dr Hutter came up with a very ambitious idea,
0:53:41 > 0:53:43which he presented to Timothy,
0:53:43 > 0:53:47which was, "I don't just want to cure your cancer,
0:53:47 > 0:53:49"I actually want to cure your HIV."
0:53:49 > 0:53:52Now, you can imagine how this would have sounded to Timothy.
0:53:52 > 0:53:56I was thinking, "Yeah, right. I don't believe it."
0:53:56 > 0:53:57I thought he was crazy!
0:53:59 > 0:54:01But it wasn't as crazy as it sounded.
0:54:03 > 0:54:06Dr Hutter knew that to treat Timothy's cancer
0:54:06 > 0:54:09he would need a transplant of healthy stem cells -
0:54:09 > 0:54:12the type of cells that produce white blood cells.
0:54:13 > 0:54:18He also knew that a small fraction of the population, about 1%,
0:54:18 > 0:54:23are naturally resistant to HIV, meaning they don't become infected.
0:54:23 > 0:54:27And here's where he had a moment of genius.
0:54:27 > 0:54:30If he could give Timothy a stem cell transplant
0:54:30 > 0:54:34from someone who was resistant to HIV,
0:54:34 > 0:54:38maybe he could cure both diseases at once.
0:54:40 > 0:54:43The reason some people are naturally resistant to HIV
0:54:43 > 0:54:46is because of a genetic variation in their white blood cells.
0:54:51 > 0:54:54HIV is a virus that targets a type of white blood cell
0:54:54 > 0:54:55known as a T-cell.
0:54:57 > 0:55:00The HIV virus infects these T-cells
0:55:00 > 0:55:02by attaching itself to their surface...
0:55:06 > 0:55:10..but a small number of people have irregularly shaped T-cells,
0:55:10 > 0:55:14which the HIV virus cannot connect to -
0:55:15 > 0:55:17..so, it stays locked out...
0:55:19 > 0:55:22..and, consequently, this group of people can't get HIV.
0:55:24 > 0:55:28So, Dr Hutter's idea was to give Timothy a stem cell transplant
0:55:28 > 0:55:31from somebody who was immune to HIV.
0:55:32 > 0:55:35Finding a donor with this genetic variation
0:55:35 > 0:55:40who also shared Tim's tissue type wasn't easy,
0:55:40 > 0:55:43but eventually Dr Hutter secured a match.
0:55:45 > 0:55:49Now, he had to carry out an extremely high risk procedure
0:55:49 > 0:55:52to destroy Timothy's diseased bone marrow
0:55:52 > 0:55:55and replace it with healthy bone marrow from the donor.
0:55:58 > 0:56:01I was told about three years later by Gero
0:56:01 > 0:56:05that his team only gave me a 5% chance of surviving that,
0:56:05 > 0:56:09and I'm glad they didn't tell me that then!
0:56:09 > 0:56:11Because I probably would have lost hope.
0:56:14 > 0:56:19Remarkably, within just a few weeks, Timothy began to feel better.
0:56:21 > 0:56:24I felt much better than I had before.
0:56:24 > 0:56:27I realised that something had changed in my body.
0:56:29 > 0:56:33Not only was Timothy cured of his leukaemia,
0:56:33 > 0:56:36he became the first person on earth
0:56:36 > 0:56:39that doctors could claim had been cured of his HIV.
0:56:41 > 0:56:46At that point, I realised that, yes, in fact, I was cured,
0:56:46 > 0:56:49and I was very excited about that,
0:56:49 > 0:56:54and I could finally say I am cured of HIV.
0:56:55 > 0:56:59So far, Timothy's remarkable experience is unique.
0:56:59 > 0:57:03He and his doctors were prepared to accept the high risk
0:57:03 > 0:57:04of the stem cell transplant
0:57:04 > 0:57:07because his life was already in danger from leukaemia.
0:57:09 > 0:57:13For others living with HIV, that risk would be too high -
0:57:13 > 0:57:16but now, scientists are developing ways
0:57:16 > 0:57:18to modify patients own stem cells,
0:57:18 > 0:57:24so they're resistant to HIV without facing the risk of a transplant.
0:57:24 > 0:57:27Their work is bringing new hope of a permanent cure.
0:57:27 > 0:57:31I think what I do is I give people hope.
0:57:31 > 0:57:33That is very important to me.
0:57:35 > 0:57:37As I've explored these cases,
0:57:37 > 0:57:42I've been struck by the vast capacity of the human body to adapt,
0:57:42 > 0:57:48even when faced with the most severe threats, dangers and damage -
0:57:48 > 0:57:52but perhaps the most impressive thing for me as a doctor
0:57:52 > 0:57:57is how we've learned from our own bodies' ability to adapt and survive
0:57:57 > 0:57:59and have used that knowledge
0:57:59 > 0:58:03to develop some of the boldest life-saving treatments
0:58:03 > 0:58:05in modern medicine.
0:58:06 > 0:58:09Next time, we'll meet a man who woke up
0:58:09 > 0:58:12and could suddenly play the piano...
0:58:14 > 0:58:18..a woman who can smell disease before it happens...
0:58:18 > 0:58:20It has a smell.
0:58:20 > 0:58:22It definitely has a smell.
0:58:22 > 0:58:24..and a man who awoke from a vegetative state
0:58:24 > 0:58:27and could remember everything.