0:00:00 > 0:00:00- Subtitles
0:00:00 > 0:00:02- Subtitles- - Subtitles
0:00:02 > 0:00:05- Every single second of every day...
0:00:05 > 0:00:09- ..our senses gather information - about our environment.
0:00:09 > 0:00:14- The senses connect us - to our surroundings.
0:00:14 > 0:00:17- I'm Dr Anwen Rees, - a Physiology lecturer...
0:00:17 > 0:00:20- ..at Cardiff Metropolitan - University.
0:00:21 > 0:00:27- I'm Dr Katie Hemer, a Bioarchaeology - specialist at Sheffield University.
0:00:27 > 0:00:31- We will look at the way the brain - uses information...
0:00:31 > 0:00:34- ..to create - a unique picture of the world.
0:00:35 > 0:00:39- We will look at familiar - and unfamiliar senses...
0:00:39 > 0:00:41- ..and how they collaborate.
0:00:41 > 0:00:43- And how to trick them.
0:01:00 > 0:01:04- Lying here, I can feel fabric - rubbing against my skin...
0:01:04 > 0:01:07- ..the weight of my body - on the bench...
0:01:08 > 0:01:13- ..the movement of the air - and, of course, Catrin's hands.
0:01:18 > 0:01:21- And if it gets too much for me, - I'll feel pain.
0:01:22 > 0:01:26- Every second, five million - touch receptors on the skin...
0:01:26 > 0:01:31- ..send millions of messages - to the brain about our surroundings.
0:01:31 > 0:01:36- Things like the hat on our head, - the shoes pinching our feet...
0:01:36 > 0:01:38- ..and the things in our hands.
0:01:38 > 0:01:42- They're very sensitive - to pressure, temperature...
0:01:43 > 0:01:45- ..vibration and texture.
0:01:45 > 0:01:49- This lets us know - how tightly to grip an object...
0:01:49 > 0:01:53- ..whether it's hot or cold - and whether it's slippery.
0:01:53 > 0:01:56- The body parts - most sensitive to touch...
0:01:56 > 0:02:00- ..are the fingertips, the lips - and the tip of the tongue.
0:02:01 > 0:02:03- The least sensitive area - is the back.
0:02:04 > 0:02:08- When something touches the skin, - a message is sent to the brain.
0:02:08 > 0:02:12- It decides whether to ignore - that message or react to it.
0:02:12 > 0:02:16- That's vital, as we don't need - to be aware of every tiny touch.
0:02:18 > 0:02:22- The brain receives - millions of messages per second...
0:02:22 > 0:02:25- ..from the touch receptors - on the body.
0:02:26 > 0:02:30- What part of the brain - deals with this information?
0:02:30 > 0:02:36- How does it differentiate between - a touch on the hand and on the foot?
0:02:38 > 0:02:42- At Cardiff University - Brain Research Imaging Centre...
0:02:42 > 0:02:47- ..a machine will let me see the area - of my brain which controls touch.
0:02:51 > 0:02:55- It wouldn't be a scientific test - if I didn't look silly!
0:02:55 > 0:03:00- After some sticking and measuring, - I'm ready to enter the machine.
0:03:02 > 0:03:05- This isn't a futuristic hairdryer!
0:03:05 > 0:03:09- It's a magnetoencephalography, - or MEG, machine.
0:03:09 > 0:03:13- It will measure my brain activity - as I touch this.
0:03:14 > 0:03:19- The device under my hand - sends vibrations to my fingers...
0:03:20 > 0:03:24- ..thus activating the area of - the brain which deals with touch...
0:03:25 > 0:03:27- ..called the somatosensory cortex.
0:03:27 > 0:03:32- The magnetic field around my head - is measured by the MEG machine.
0:03:32 > 0:03:37- All I have to do - is stay as still as possible.
0:03:39 > 0:03:42- I'm not sure how I did - but I hope I stayed still!
0:03:42 > 0:03:45- Fingers crossed for a good result.
0:03:45 > 0:03:48- Data collected by the MEG machine...
0:03:48 > 0:03:51- ..is combined - with an MRI image of my brain.
0:03:52 > 0:03:55- Dr John Evans - will take me through the results.
0:03:56 > 0:04:00- What you see here - is the brain activity detected...
0:04:00 > 0:04:03- ..when you felt vibrations - in different fingers.
0:04:04 > 0:04:08- Active areas change according to - which finger feels something.
0:04:09 > 0:04:10- Who is this little man?
0:04:11 > 0:04:15- He shows you what percentage - of the cortex processes data...
0:04:15 > 0:04:17- ..from different areas of the body.
0:04:18 > 0:04:22- As you can see, his hands are big - and his lips are enormous.
0:04:22 > 0:04:26- That tells you that - a large percentage of the cortex...
0:04:26 > 0:04:29- ..deals with data - from the hands and the lips.
0:04:30 > 0:04:34- These areas are very sensitive - and a lot of data comes in via them.
0:04:34 > 0:04:39- It's important to understand what's - happening on our hands and lips.
0:04:39 > 0:04:43- This diagram - shows which areas of the cortex...
0:04:43 > 0:04:47- ..process data - from specific areas of the body.
0:04:48 > 0:04:50- There's also one-to-one mapping.
0:04:51 > 0:04:55- One area of the cortex deals with - data from one area of the body.
0:04:56 > 0:04:58- But adjacent body parts...
0:04:58 > 0:05:02- ..aren't processed - in adjacent areas of the cortex.
0:05:03 > 0:05:06- The hand is next to the head - in this diagram...
0:05:06 > 0:05:11- ..but, obviously, they're not - next to each other in the body.
0:05:11 > 0:05:15- However, the fingers are - next to each other in the cortex.
0:05:15 > 0:05:17- That was obvious in my brain.
0:05:18 > 0:05:21- Is that what you see in every brain?
0:05:21 > 0:05:24- Is that what you see in every brain?- - Yes, it's the same for most people.
0:05:24 > 0:05:29- That changes for sufferers of - phantom limb pain and chronic pain.
0:05:29 > 0:05:33- This mapping can be distorted - in those cases.
0:05:33 > 0:05:34- It can be destroyed.
0:05:36 > 0:05:40- Understanding why - mapping is affected so badly...
0:05:40 > 0:05:45- ..could lead to more effective - treatments for these patients.
0:05:48 > 0:05:52- How good are we at recognizing - objects through touch alone?
0:05:53 > 0:05:57- I filled a bag with a collection - of different items...
0:05:58 > 0:06:01- ..to put people's sense of touch - to the test.
0:06:01 > 0:06:06- I want you to put your hand in the - bag and tell me what's inside it.
0:06:08 > 0:06:09- It isn't alive, is it?
0:06:09 > 0:06:12- No. It isn't alive - and it won't bite.
0:06:13 > 0:06:14- A banana.
0:06:14 > 0:06:16- A banana.- - A sponge.
0:06:17 > 0:06:19- A toy car.
0:06:19 > 0:06:22- An orange and a hairbrush.
0:06:23 > 0:06:25- No-one could see the objects...
0:06:26 > 0:06:31- ..but the touch system collected - data about the shape, temperature...
0:06:31 > 0:06:34- ..and texture of each object.
0:06:34 > 0:06:39- Everyone did well, but they - struggled to name one object.
0:06:39 > 0:06:41- I don't know what that is.
0:06:41 > 0:06:43- Describe how it feels.
0:06:43 > 0:06:46- It's hard - but my nails can dig into it.
0:06:46 > 0:06:48- I have no idea what that is.
0:06:51 > 0:06:53- Is there anything else in there?
0:06:54 > 0:06:55- Oh! Yes.
0:06:56 > 0:06:57- What's the final one?
0:07:00 > 0:07:01- It feels like ginger.
0:07:02 > 0:07:03- Ginger?
0:07:03 > 0:07:05- Ginger?- - Yes. It's ginger.
0:07:14 > 0:07:16- It's common - for an autistic person...
0:07:17 > 0:07:21- ..to overreact or underreact - to sensory stimuli.
0:07:21 > 0:07:24- Twm and Gruff - are five-year-old twins.
0:07:24 > 0:07:26- Twm is autistic.
0:07:27 > 0:07:29- Ffion, their mother...
0:07:29 > 0:07:35- ..noticed that Twm underreacted to - sensory stimuli compared to Gruff.
0:07:42 > 0:07:43- Twm is very physical.
0:07:46 > 0:07:47- He likes tight hugs.
0:07:47 > 0:07:49- He had a heavy touch.
0:07:52 > 0:07:53- Ready?
0:07:54 > 0:07:57- One, two, three!
0:07:59 > 0:08:02- He won't push slightly. - He'll push hard.
0:08:03 > 0:08:07- His hyposensitivity means he likes - to be rolled on the rug...
0:08:08 > 0:08:09- ..and squeezed.
0:08:09 > 0:08:13- He also enjoys - being pummelled with cushions.
0:08:13 > 0:08:17- You have to reach a high level - for him to actually feel it.
0:08:18 > 0:08:22- It looks terrible but he - laughs his head off and he loves it.
0:08:22 > 0:08:25- He'll make a great rugby player.
0:08:25 > 0:08:28- He doesn't hug you - he tackles you.
0:08:31 > 0:08:35- Being hyposensitive to touch - means you need strong stimulus...
0:08:36 > 0:08:38- ..in order to gain enjoyment.
0:08:38 > 0:08:42- Some people with autism - are hypersensitive to touch.
0:08:43 > 0:08:47- The slightest touch - can make them feel uncomfortable.
0:08:48 > 0:08:52- It's thought this is due to the way - the brain processes data...
0:08:53 > 0:08:54- ..received from the skin.
0:08:55 > 0:08:57- He loves to play in sand.
0:08:57 > 0:09:02- But it gets to the point where he - likes to feel the sand in his mouth.
0:09:04 > 0:09:08- It's not just his hands. - He likes to put it in his mouth.
0:09:09 > 0:09:12- We play with rice, - which may sound strange...
0:09:12 > 0:09:16- ..but he likes to feel it - running through his fingers.
0:09:19 > 0:09:24- People who have hyposensitive touch - tend to seek constant stimulation.
0:09:25 > 0:09:26- Twm follows that pattern.
0:09:27 > 0:09:32- Twm certainly gets pleasure - from working his senses really hard.
0:09:36 > 0:09:38- We find that he gets frustrated.
0:09:38 > 0:09:41- If he doesn't get - that sensory output...
0:09:41 > 0:09:43- ..he becomes very frustrated.
0:09:44 > 0:09:46- I try to find the middle ground.
0:09:52 > 0:09:55- If he has a bit of rough play, - he relaxes...
0:09:55 > 0:09:58- ..because he's got it - out of his system.
0:09:58 > 0:10:01- If he plays with rice, sand - or water...
0:10:01 > 0:10:06- ..it avoids the situation where he - goes upstairs and turns on the taps.
0:10:08 > 0:10:13- He does a few things in an effort - to satisfy his hyposensitivity.
0:10:17 > 0:10:20- We take our senses - totally for granted.
0:10:21 > 0:10:25- We live with them, - so we don't see their importance.
0:10:25 > 0:10:29- That changes when you have a child - who's hyposensitive...
0:10:29 > 0:10:35- ..and you see a tiny glimpse - of the world through their eyes.
0:10:37 > 0:10:38- In addition to touch...
0:10:39 > 0:10:43- ..autism can also affect senses - such as sight or hearing.
0:10:43 > 0:10:47- Our senses mean we all - experience the world differently.
0:10:47 > 0:10:50- Knowing how autism - affects the senses...
0:10:51 > 0:10:55- ..helps us understand how autistic - people experience the world.
0:10:57 > 0:10:57- .
0:11:02 > 0:11:02- Subtitles
0:11:02 > 0:11:04- Subtitles- - Subtitles
0:11:06 > 0:11:11- Pain is essential to warn us - that we're injured and in danger.
0:11:11 > 0:11:15- Like the sense of touch, - pain is sensed on the skin...
0:11:15 > 0:11:17- ..but it uses a different system.
0:11:18 > 0:11:21- Receptors called nociceptors - sense pain.
0:11:21 > 0:11:25- Different nociceptors - are sensitive to different stimuli.
0:11:26 > 0:11:28- Pressure, temperature and chemicals.
0:11:31 > 0:11:36- Chemical receptors are sensitive to - things like capsaicin in chillies.
0:11:37 > 0:11:39- That's why spicy food - can be painful.
0:11:40 > 0:11:43- The pain signal to the brain - is sent via two pathways.
0:11:44 > 0:11:46- A fast pathway and a slow pathway.
0:11:46 > 0:11:49- It can bypass the brain - completely...
0:11:49 > 0:11:54- ..at times when we experience sudden - pain and have to react quickly.
0:11:54 > 0:11:57- The brain - creates the feeling of pain.
0:11:57 > 0:12:02- Once the signal reaches the brain, - it travels to several areas...
0:12:02 > 0:12:05- ..including emotion, pain - and movement...
0:12:06 > 0:12:08- ..so the body can react - to any danger.
0:12:11 > 0:12:15- Anaesthetist, Dr Huw Davies, - is an expert at treating pain.
0:12:20 > 0:12:24- Surgery causes major trauma - to the body.
0:12:25 > 0:12:29- Huw must make sure the patient - feels as little pain as possible.
0:12:32 > 0:12:34- Anaesthetic is a triangle...
0:12:35 > 0:12:38- ..made up of hypnosis - sleep...
0:12:38 > 0:12:42- ..analgesia - dealing with pain - and muscle relaxation.
0:12:43 > 0:12:46- Pain is a little bit - like using a phone.
0:12:47 > 0:12:51- You dial, then the signal - is carried along the nerves...
0:12:52 > 0:12:56- ..and the receptor is the person - at the other end of the phone.
0:12:57 > 0:13:02- If there's a lot of noise around, - it won't hear the message properly.
0:13:03 > 0:13:07- You can change - the way you think about pain...
0:13:07 > 0:13:12- ..if you can find a way to create - a lot of background noise.
0:13:13 > 0:13:17- Or maybe it's a case - of turning down the volume.
0:13:17 > 0:13:20- That's the function - of some of the drugs we use.
0:13:23 > 0:13:28- When painkillers like ibuprofen - or paracetamol won't be effective...
0:13:29 > 0:13:32- ..doctors turn to opiates - like morphine.
0:13:34 > 0:13:39- The body also creates - its own painkillers - endorphins...
0:13:39 > 0:13:44- ..which are released when we're - in pain or after strenuous exercise.
0:13:44 > 0:13:48- Morphine affects the same - pain receptors as endorphins.
0:13:49 > 0:13:52- Local anaesthetic - cuts the pain wires.
0:13:52 > 0:13:54- It doesn't affect the entire body.
0:13:55 > 0:13:59- It concentrates on the area - from which the signal is sent.
0:14:02 > 0:14:06- General anaesthetic itself - doesn't block pain.
0:14:06 > 0:14:09- It puts the brain to sleep.
0:14:10 > 0:14:13- The body - continues to respond to the pain.
0:14:14 > 0:14:19- So I administer an epidural to - deal with the pain during surgery...
0:14:19 > 0:14:24- ..and it will continue to work for a - couple of days after the procedure.
0:14:27 > 0:14:31- Modulation, one of four steps - on the pain pathway...
0:14:31 > 0:14:35- ..is of particular interest - to researchers.
0:14:35 > 0:14:39- It happens when the pain signal - is travelling to the brain...
0:14:39 > 0:14:43- ..and it reaches - the nervous system switchboard.
0:14:43 > 0:14:46- When you hurt yourself, - you rub that area.
0:14:46 > 0:14:48- Why do we all do that?
0:14:48 > 0:14:51- When we rub the area - around an injury...
0:14:52 > 0:14:57- ..the surrounding nerves send - conflicting messages to the brain.
0:14:57 > 0:15:00- It means fewer pain signals - reach the brain...
0:15:01 > 0:15:03- ..and this reduces your pain.
0:15:03 > 0:15:08- It's as though every phone sends a - message to the switchboard at once.
0:15:09 > 0:15:13- The switchboard then struggles - to deal with all of them...
0:15:13 > 0:15:17- ..and so the message is diluted - when it reaches the brain.
0:15:21 > 0:15:24- Analgesics - stop us feeling pain...
0:15:25 > 0:15:28- ..but anaesthetic - sends the brain to sleep.
0:15:29 > 0:15:32- Huw must assess every case - individually...
0:15:32 > 0:15:36- ..to ensure patients feel - as little pain as possible...
0:15:36 > 0:15:39- ..during surgery - and during their recovery.
0:15:45 > 0:15:48- I'm in Carmarthen, - armed with a feather...
0:15:48 > 0:15:52- ..to find out how ticklish - local people are.
0:15:52 > 0:15:55- Nobody knows what makes us ticklish.
0:15:56 > 0:15:57- Are you ticklish?
0:15:57 > 0:15:59- Are you ticklish?- - Maybe.
0:15:59 > 0:16:01- I'm a bit ticklish.
0:16:01 > 0:16:02- I'm a bit ticklish.- - I'm ticklish.
0:16:03 > 0:16:05- What's your most ticklish bit?
0:16:05 > 0:16:07- What's your most ticklish bit?- - I don't want to tell you!
0:16:09 > 0:16:10- The soles of his feet.
0:16:11 > 0:16:12- Behind my ears.
0:16:12 > 0:16:14- Behind my ears.- - My neck.
0:16:14 > 0:16:15- All over!
0:16:16 > 0:16:21- We all tend to be ticklish in the - abdomen, the armpits and the neck.
0:16:21 > 0:16:27- We naturally protect those areas - by hiding them when they're touched.
0:16:28 > 0:16:30- It's a self-protective reflex.
0:16:32 > 0:16:34- How did that feel? - Didn't you like it?
0:16:34 > 0:16:35- No.
0:16:36 > 0:16:37- Were you uncomfortable?
0:16:37 > 0:16:38- Were you uncomfortable?- - Slightly.
0:16:39 > 0:16:40- Nice.
0:16:40 > 0:16:42- Nice? Does it tickle?
0:16:42 > 0:16:43- Nice? Does it tickle?- - Yes, but it's nice.
0:16:44 > 0:16:49- We react strongly and laugh - when a loved one tickles us...
0:16:50 > 0:16:55- ..but we're not keen on it - when it's done by a stranger.
0:16:56 > 0:16:57- Did you like it?
0:16:57 > 0:16:58- Did you like it?- - Not really.
0:16:58 > 0:17:00- How does that feel?
0:17:00 > 0:17:01- How does that feel?- - More ticklish.
0:17:01 > 0:17:03- More ticklish than the neck?
0:17:03 > 0:17:04- More ticklish than the neck?- - Yes.
0:17:04 > 0:17:06- Very nice.
0:17:06 > 0:17:08- Very nice.- - You like that!
0:17:09 > 0:17:11- Who makes you ticklish?
0:17:12 > 0:17:14- My children and my husband.
0:17:14 > 0:17:15- Oh! Lucky you!
0:17:20 > 0:17:23- Pain is vital. - It stops us hurting ourselves.
0:17:23 > 0:17:26- But everyone - reacts differently to pain.
0:17:27 > 0:17:32- We've come to The University Of Bath - to find out how we feel pain...
0:17:32 > 0:17:34- ..and what can affect it.
0:17:37 > 0:17:38- Dr Ed Keogh's team...
0:17:39 > 0:17:43- ..researches the experience of pain - for different people.
0:17:44 > 0:17:49- Today's tests will measure - mine and Katie's pain thresholds.
0:17:50 > 0:17:52- The first test is about to begin.
0:17:53 > 0:17:55- This will measure - our pain thresholds.
0:17:56 > 0:17:59- This gun will be - pressed against our skin.
0:17:59 > 0:18:01- We must say stop when pain kicks in.
0:18:02 > 0:18:03- How will you do?
0:18:03 > 0:18:05- How will you do?- - Terribly! I hate pain.
0:18:09 > 0:18:10- Are you ready?
0:18:11 > 0:18:16- This is a standard test - for measuring pain threshold...
0:18:16 > 0:18:19- ..the point - where we begin to feel pain.
0:18:21 > 0:18:22- Yes.
0:18:23 > 0:18:25- How was it?
0:18:25 > 0:18:27- How was it?- - Fine. It wasn't a sharp pain.
0:18:28 > 0:18:31- It was a pain deep in the arm, - but it was alright.
0:18:32 > 0:18:37- To get an accurate measurement, the - test must be repeated several times.
0:18:38 > 0:18:39- Yes.
0:18:43 > 0:18:46- Don't pull faces, Katie! - You're next.
0:18:46 > 0:18:47- Ready?
0:18:47 > 0:18:49- Ready?- - No!
0:18:49 > 0:18:51- Ouch! Stop!
0:18:53 > 0:18:55- Katie!
0:18:55 > 0:18:56- Katie!- - That was really painful!
0:18:57 > 0:18:58- It was horrendous!
0:19:01 > 0:19:05- The results are in and one of us - outperformed the other!
0:19:05 > 0:19:11- Yes. Your pain threshold is clearly - higher than mine, Anwen.
0:19:12 > 0:19:18- Interestingly, we both became more - tolerant as the test was repeated.
0:19:19 > 0:19:21- Yes. Our first readings were low.
0:19:22 > 0:19:24- Mine was exceptionally low!
0:19:24 > 0:19:27- That may have been - due to the anticipation.
0:19:27 > 0:19:31- We were nervous. We didn't know - how painful it would be.
0:19:35 > 0:19:38- There are many different forms - of pain.
0:19:38 > 0:19:42- My pain threshold is higher than - Katie's in this pressure test...
0:19:43 > 0:19:45- Ouch! Sorry, but that was painful.
0:19:46 > 0:19:50- ..I may have a lower threshold - for a different pain...
0:19:51 > 0:19:53- ..such as this temperature test.
0:19:53 > 0:19:57- We wanted to undergo - another pain threshold test...
0:19:57 > 0:20:01- ..but Katie and I can't do it, - for purely medical reasons.
0:20:02 > 0:20:04- Who can we get to do this test?
0:20:05 > 0:20:10- Who makes us do tests which make us - look silly in the name of science?
0:20:10 > 0:20:12- Aled, the producer.
0:20:13 > 0:20:15- No!
0:20:17 > 0:20:19- Put your arm in the cold water.
0:20:20 > 0:20:24- Tell me the first point at which - you detect a pain sensation.
0:20:24 > 0:20:28- Keep your hand there until you can - no longer stand it, then withdraw.
0:20:29 > 0:20:30- Ready, Aled?
0:20:30 > 0:20:31- Ready, Aled?- - Ready.
0:20:33 > 0:20:37- Aled must signal at what point - he first feels pain in his hand.
0:20:37 > 0:20:39- That's his pain threshold.
0:20:39 > 0:20:41- Yeah!
0:20:41 > 0:20:42- I can feel pain.
0:20:42 > 0:20:44- I can feel pain.- - Pain?
0:20:45 > 0:20:50- He must then keep his hand in the - water to test his pain tolerance.
0:20:53 > 0:20:54- That water is cold!
0:20:55 > 0:20:57- I've got to take it out.
0:20:57 > 0:21:00- Do you want a towel?
0:21:00 > 0:21:01- Do you want a towel?- - Thank you.
0:21:01 > 0:21:03- Look at that!
0:21:04 > 0:21:06- Is it beginning to ease?
0:21:06 > 0:21:08- Is it beginning to ease?- - No. It's still cold.
0:21:10 > 0:21:14- Once Aled's hand is warm again, - he repeats the test.
0:21:15 > 0:21:19- This time, he must focus - on the letters on the screen.
0:21:20 > 0:21:24- He must work out whether or not - the letters follow a sequence.
0:21:25 > 0:21:29- The aim here is to distract Aled - from the pain in his hand.
0:21:34 > 0:21:36- How was it?
0:21:36 > 0:21:39- To be honest, - it was harder than I expected.
0:21:40 > 0:21:44- I thought I could hold my hand there - for longer than I did.
0:21:44 > 0:21:46- I felt pain quite quickly.
0:21:48 > 0:21:53- What about the second time, when - you were distracted by the screen?
0:21:53 > 0:21:55- The second time was much easier.
0:21:57 > 0:21:59- The pain was less noticeable.
0:21:59 > 0:22:03- I think it took longer - for me to feel pain.
0:22:04 > 0:22:06- Yes, and the results back you up.
0:22:06 > 0:22:09- Yes, and the results back you up.- - Look at the test with distractions.
0:22:10 > 0:22:14- Your threshold and your tolerance - were higher than the first time.
0:22:16 > 0:22:16- Much higher.
0:22:16 > 0:22:18- Much higher.- - Yes - much higher!
0:22:19 > 0:22:24- The brain can ignore pain messages - - this is pain tolerance.
0:22:24 > 0:22:28- Pain tolerance varies - from person to person.
0:22:29 > 0:22:33- The test shows that - distraction increases tolerance.
0:22:33 > 0:22:37- Other factors which affect tolerance - are gender, mood, fatigue...
0:22:38 > 0:22:39- ..and even swearing!
0:22:40 > 0:22:44- Touch and pain allow us - to analyse the world around us...
0:22:44 > 0:22:48- ..by recognizing danger - and reacting to it.
0:22:49 > 0:22:52- Touch is important to us - in a social context...
0:22:53 > 0:22:55- ..and to handling everyday life.
0:22:56 > 0:23:00- We all react differently to pain - but without pain, we risk injury.
0:23:01 > 0:23:06- The brain must decipher pain signals - and decide how to react to them.
0:23:07 > 0:23:10- In the next episode, - we test our noses.
0:23:11 > 0:23:13- It reminds me of public toilets.
0:23:14 > 0:23:18- We'll discover how finely-tuned - our sense of smell is.
0:23:18 > 0:23:19- It stinks!
0:23:33 > 0:23:36- S4C subtitles by Eirlys A Jones
0:23:36 > 0:23:36- .