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.
0:00:49 > 0:00:53- THE OTHERS
0:01:12 > 0:01:17- During the series, we've looked at - all our familiar senses.
0:01:17 > 0:01:19- We have some unfamiliar ones too.
0:01:19 > 0:01:24- Without these, simple things - like sitting up, standing up...
0:01:24 > 0:01:27- ..and riding a bike - would be hard work.
0:01:27 > 0:01:29- It's already hard! Come on, Anwen!
0:01:29 > 0:01:30- It's already hard! Come on, Anwen!- - I'm pedalling!
0:01:31 > 0:01:33- What is proprioception?
0:01:33 > 0:01:38- Proprioception is the brain's - ability to sense stimuli...
0:01:38 > 0:01:41- ..regarding the position - of arms and legs...
0:01:41 > 0:01:44- ..without using - any of the other senses.
0:01:44 > 0:01:47- Close your eyes - and touch your nose.
0:01:47 > 0:01:49- You're using proprioception.
0:01:50 > 0:01:54- Receptors in muscles and tendons - tell the brain were the arm is...
0:01:54 > 0:01:56- ..to lead it to the nose.
0:01:56 > 0:02:01- Those who lose their proprioceptive - sense will struggle...
0:02:01 > 0:02:06- ..as they must think about their - body parts' position before moving.
0:02:10 > 0:02:15- Our sense of proprioception - is vital but difficult to quantify.
0:02:15 > 0:02:18- At the SoBA Lab, - Bangor University...
0:02:18 > 0:02:23- ..Dr Emily Cross's research team - can offer clues on how it works.
0:02:25 > 0:02:28- Students and myself - were interested in knowing...
0:02:29 > 0:02:31- ..how you learn new movement...
0:02:31 > 0:02:34- ..and how your brain changes - as you pick up a kinaesthetic...
0:02:35 > 0:02:39- ..or a motor sense of what a new - action might feel like on your body.
0:02:39 > 0:02:42- What that means is I have to dance!
0:02:46 > 0:02:49- I must perform - the same movements...
0:02:49 > 0:02:53- ..as the dancer - in the computer game on the screen.
0:02:54 > 0:02:59- My score depends on how closely - I can match the dancer's movements.
0:02:59 > 0:03:04- I'm not a great dancer, but I'm - doing this in the name of science!
0:03:06 > 0:03:10- Proprioception - allows my brain to keep a record...
0:03:10 > 0:03:14- ..of the position of my legs - and arms are while I dance.
0:03:18 > 0:03:23- I just danced for the first time and - it was hard to follow the dancer.
0:03:23 > 0:03:28- I had no idea what would happen next - and the movements were tricky.
0:03:28 > 0:03:29- It felt unnatural.
0:03:31 > 0:03:36- Dancers have greater awareness - of the position of their body.
0:03:39 > 0:03:44- Emily invited Rhys Jenkins, who's - a tap dancer, to do the same test.
0:03:46 > 0:03:51- This computer game uses a special - camera to measure body movement...
0:03:52 > 0:03:56- ..giving the researchers - an unbiased score.
0:03:56 > 0:04:00- We study dance, not because - we care about dance per se.
0:04:01 > 0:04:06- What we're really interested in is - how people learn complex movement.
0:04:07 > 0:04:11- The team looks at the effect - a complex task like a dance...
0:04:11 > 0:04:12- ..has on the brain.
0:04:13 > 0:04:16- Next, Rhys and I dance again...
0:04:17 > 0:04:21- ..to see if the fact we've done - this before affects our score.
0:04:29 > 0:04:33- Emily's team usually monitors - changes over a far longer period.
0:04:40 > 0:04:42- The practise run helped.
0:04:42 > 0:04:45- I knew what I had to do next - and I knew how to move.
0:04:46 > 0:04:48- It was easier - and it felt more natural.
0:04:50 > 0:04:55- That's because I didn't have to - focus so much on the screen...
0:04:55 > 0:04:57- ..and on every single movement.
0:04:59 > 0:05:02- My score doubled - but Rhys outperformed me.
0:05:02 > 0:05:06- Rhys, you trebled your score. - How was it for you?
0:05:07 > 0:05:12- It was hard at first, but once I'd - done it a few times, it was easier.
0:05:12 > 0:05:14- Did your dance background help?
0:05:16 > 0:05:17- Yes, I think so.
0:05:17 > 0:05:20- I could keep the rhythm - when I was dancing.
0:05:21 > 0:05:24- That's a skill which I learned - when I took up dancing.
0:05:25 > 0:05:26- I think it helped.
0:05:27 > 0:05:31- The fact that both Rhys and I - improved our scores...
0:05:31 > 0:05:35- ..demonstrates that our brains - adapted in a short space of time.
0:05:36 > 0:05:39- The research carried out - by Emily's team...
0:05:39 > 0:05:43- ..shows that areas of the brain - associated with proprioception...
0:05:44 > 0:05:47- ..become more active with practise.
0:05:47 > 0:05:51- Rhys outperformed me as he's used to - moving his body through dance.
0:05:51 > 0:05:53- Proprioception is malleable.
0:05:54 > 0:05:57- When you have different experiences, - it will change.
0:05:57 > 0:06:01- This is a motor learning - and a visual learning task...
0:06:01 > 0:06:05- ..so your sense of proprioception - is changing.
0:06:05 > 0:06:07- It's a multi-sensory task.
0:06:08 > 0:06:13- Sight, hearing and balance play a - part, in addition to proprioception.
0:06:13 > 0:06:15- They all work together.
0:06:15 > 0:06:21- Emily's team is interested in - what part individual senses play...
0:06:21 > 0:06:23- ..in complex movement tasks.
0:06:23 > 0:06:28- This will help us understand how - senses like proprioception work...
0:06:28 > 0:06:32- ..and understand how the brain - combines the senses...
0:06:32 > 0:06:37- ..to allow us to perform - movement tasks in everyday life.
0:06:42 > 0:06:44- How does balance work?
0:06:44 > 0:06:47- There's a vestibular system - in the inner ear...
0:06:48 > 0:06:52- ..which includes three semicircular, - hair-lined tubes...
0:06:52 > 0:06:57- ..and a fluid called endolymph - and tiny stones called otoliths.
0:06:57 > 0:07:01- When you move your head, - you move the endolymph...
0:07:01 > 0:07:04- ..thus moving the hairs - and the otoliths.
0:07:04 > 0:07:09- This tells the brain you're moving - sideways, up and down or spinning.
0:07:09 > 0:07:13- The brain responds to messages - from the ear, the eyes...
0:07:13 > 0:07:17- ..and proprioception receptors - all over the body.
0:07:17 > 0:07:20- It constantly adjusts our balance.
0:07:24 > 0:07:27- Feeling dizzy isn't pleasant.
0:07:27 > 0:07:31- It happens because our body has - a clever way of keeping us upright.
0:07:32 > 0:07:33- Why do we get dizzy?
0:07:33 > 0:07:37- First, we must look at the part - the ear plays in balance.
0:07:38 > 0:07:42- The body senses if we're lying down, - standing up...
0:07:42 > 0:07:45- ..moving or standing still...
0:07:45 > 0:07:50- ..by using the vestibular system - in the inner ear.
0:07:52 > 0:07:55- It's full of a thick fluid - called endolymph.
0:07:56 > 0:07:58- Imagine this bottle is my head...
0:07:59 > 0:08:02- ..and the water - is the endolymph in my inner ear.
0:08:02 > 0:08:07- If I spin it, the water moves in the - same direction as the bottle...
0:08:07 > 0:08:10- ..but if I stop, - the liquid keeps moving.
0:08:11 > 0:08:15- Once I start to spin, the movement - of the liquid tells my brain...
0:08:15 > 0:08:17- ..that my head is moving.
0:08:17 > 0:08:20- The brain gets used to that signal.
0:08:20 > 0:08:25- When I stop spinning, the liquid - still sends signals to the brain...
0:08:25 > 0:08:28- ..and it decides - that I'm still moving.
0:08:28 > 0:08:30- That's why I feel dizzy.
0:08:30 > 0:08:35- This system is important because it - tells me how far, how quickly...
0:08:35 > 0:08:38- ..and in what direction - the head is moving.
0:08:38 > 0:08:42- The brain uses this information - to keep us upright.
0:08:47 > 0:08:50- How good is my sense of balance?
0:08:51 > 0:08:56- Rhian Halford from NoFit State - circus has a challenge for me.
0:08:59 > 0:09:01- Rhian, what must I do today?
0:09:01 > 0:09:03- You're going to walk on a wire.
0:09:04 > 0:09:08- Choose a line across the floor - and stand on it on one leg.
0:09:10 > 0:09:14- Don't look down. - Look at the end of the line.
0:09:14 > 0:09:16- Imagine the wire ends there.
0:09:17 > 0:09:19- Hold your hands up.
0:09:19 > 0:09:23- The leg which is in the air - will feel for the toes.
0:09:24 > 0:09:27- Slide that foot along - and lift your other leg.
0:09:29 > 0:09:32- Toes down, then slide across. - Lift the back leg.
0:09:32 > 0:09:36- Why must I look straight ahead - rather than down?
0:09:38 > 0:09:42- When you go on the wire, - you'll have two platforms.
0:09:43 > 0:09:45- You start on one - and end on the other.
0:09:46 > 0:09:48- That's where your focus must be.
0:09:50 > 0:09:52- Also, the head is quite heavy...
0:09:52 > 0:09:57- ..so if your head tips down, - your body weight will follow.
0:09:59 > 0:10:00- Are you ready for the wire?
0:10:00 > 0:10:01- Are you ready for the wire?- - I think so.
0:10:03 > 0:10:04- I'll help you at first.
0:10:05 > 0:10:06- Focus on the end.
0:10:08 > 0:10:10- The eyes are important for balance.
0:10:11 > 0:10:15- Keeping the head up and looking - at the end of the wire...
0:10:15 > 0:10:18- ..tells the brain - the body is straight.
0:10:18 > 0:10:21- Remember to breathe. - Breathing is good for you!
0:10:22 > 0:10:23- Breathing is important.
0:10:25 > 0:10:29- If the head turns or I look down, - the body wants to follow...
0:10:29 > 0:10:31- ..and I'm likely to fall.
0:10:32 > 0:10:38- I'm concentrating hard but I'm glad - Rhian's holding my hand.
0:10:40 > 0:10:45- That wasn't too bad - but Rhian was holding me.
0:10:46 > 0:10:47- It's time to go it alone.
0:10:48 > 0:10:50- No! I've gone.
0:10:51 > 0:10:52- Focus.
0:10:53 > 0:10:56- It's far more difficult - without Rhian's help.
0:10:57 > 0:11:00- I'm thinking about everything - at the same time.
0:11:05 > 0:11:08- This is one of the hardest things - I've ever done...
0:11:09 > 0:11:11- ..but I'm getting better.
0:11:11 > 0:11:12- Oh, no!
0:11:23 > 0:11:24- I made it, at last...
0:11:26 > 0:11:28- ..with a helping hand!
0:11:31 > 0:11:35- Rhian had another challenge for me.
0:11:35 > 0:11:36- I must try to do this!
0:11:40 > 0:11:41- Easy!
0:11:45 > 0:11:46- .
0:11:51 > 0:11:51- Subtitles
0:11:51 > 0:11:53- Subtitles- - Subtitles
0:11:56 > 0:11:57- How many senses do we have?
0:11:58 > 0:12:00- Five, according to Aristotle.
0:12:00 > 0:12:03- It's a hot topic among scientists...
0:12:03 > 0:12:06- ..but we may have - between nine and 21 senses.
0:12:07 > 0:12:11- For something to be a sense - requires a receptor...
0:12:11 > 0:12:14- ..like pain nociceptors - or taste buds...
0:12:14 > 0:12:19- ..which supply the brain - with information about our world.
0:12:19 > 0:12:23- There may be heat receptors - and itch receptors on the skin.
0:12:23 > 0:12:28- Receptors in the bladder tell - the brain when we need the loo...
0:12:28 > 0:12:32- ..receptors in the bowel - tell the brain when it's full...
0:12:32 > 0:12:37- ..and receptors tell the brain how - much oxygen there is in the blood.
0:12:37 > 0:12:40- What about - hunger and thirst receptors?
0:12:40 > 0:12:45- Research and new techniques - may find a definitive answer.
0:12:45 > 0:12:47- The important thing...
0:12:47 > 0:12:51- ..is that brain reads and combines - information from the senses...
0:12:52 > 0:12:55- ..to give us a detailed, - complete picture of the world.
0:12:56 > 0:12:59- Do animals - have the same senses as humans...
0:13:00 > 0:13:02- ..or do they have additional senses?
0:13:03 > 0:13:07- Zoologist, Dr Gethin Thomas, - will tell me more.
0:13:08 > 0:13:12- We're feeding pigeons. - What's so important about them?
0:13:12 > 0:13:17- Pigeons can see magnetic fields, - thanks to a protein in their eyes...
0:13:18 > 0:13:20- ..which reacts with light.
0:13:21 > 0:13:25- They can see differences in - the magnetic force of the earth...
0:13:25 > 0:13:29- ..in the same way - as we see contour lines on a map.
0:13:31 > 0:13:34- Why can they sense magnetic fields?
0:13:35 > 0:13:39- Being able to work out where you are - is advantageous to an animal.
0:13:40 > 0:13:43- The earth's magnetic field - isn't uniform.
0:13:43 > 0:13:46- There are strong areas - and weak areas.
0:13:46 > 0:13:50- Animals can use this - to navigate themselves.
0:13:51 > 0:13:53- During migration...
0:13:53 > 0:13:56- ..they use magnetic fields - to guide them.
0:13:57 > 0:14:00- What other additional senses - do animals have?
0:14:01 > 0:14:04- Sharks are sensitive - to electric fields.
0:14:04 > 0:14:07- Muscles or a beating heart - create electric fields.
0:14:09 > 0:14:13- Pores in the shark's nose, - known as ampullae of Lorenzini...
0:14:13 > 0:14:18- ..can sense electric fields to - bring the shark closer to its prey.
0:14:21 > 0:14:26- Why have animals developed - different senses from ours?
0:14:26 > 0:14:31- Each sense must allow the animal to - find something in its environment...
0:14:31 > 0:14:36- ..be that its prey, a mate or - a predator which must be avoided.
0:14:36 > 0:14:40- Animals must adapt physically - to sense their surroundings.
0:14:40 > 0:14:44- It all depends on the pattern - of the animal's life.
0:14:58 > 0:15:01- Like around four percent - of the population...
0:15:01 > 0:15:04- ..Rachel Howells has synaesthesia.
0:15:05 > 0:15:08- I like these. - They're the correct colour.
0:15:17 > 0:15:20- It was hard to find this S - because S should be yellow.
0:15:20 > 0:15:23- It's difficult for me - to find a green S.
0:15:24 > 0:15:28- I'm struggling because - so many of these are wrong.
0:15:29 > 0:15:34- Synaesthesia is often described - as a joining of the senses.
0:15:34 > 0:15:37- We all sense the world - in a different way...
0:15:38 > 0:15:42- ..and every synaesthete's experience - is unique to them.
0:15:44 > 0:15:47- Some hear colours - and others taste words.
0:15:47 > 0:15:50- Synaesthesia - is different for everyone.
0:15:50 > 0:15:54- For me, letters, numbers, - days of the week, months...
0:15:55 > 0:15:56- ..and pain...
0:15:56 > 0:15:59- ..have some sort of colour - in my head.
0:16:00 > 0:16:04- When I think of a letter, - I don't see just one colour.
0:16:04 > 0:16:08- H isn't just a strong blue. - There's more texture to it.
0:16:11 > 0:16:15- It's as though you painted it blue, - then put the brush in water...
0:16:16 > 0:16:19- ..and you see the blue - mix into the water.
0:16:19 > 0:16:20- Grass isn't just green.
0:16:21 > 0:16:25- The brown of the soil comes through, - there are flowers in it...
0:16:26 > 0:16:30- ..the grass itself is yellowing - and there are shadows on it.
0:16:30 > 0:16:33- All colours are complex to me.
0:16:34 > 0:16:39- Many people go through life not - realizing they're synaesthetes.
0:16:39 > 0:16:43- They assume everyone - senses the world like them.
0:16:43 > 0:16:47- I knew I was a synaesthete - when I was seven years old.
0:16:47 > 0:16:50- I remember talking to my mother...
0:16:50 > 0:16:54- ..and telling her - that number five is green.
0:16:54 > 0:16:58- She didn't know what I meant - and I knew then this was unusual.
0:16:58 > 0:17:03- Years later, I watched a - TV programme about synaesthesia...
0:17:03 > 0:17:06- ..and I finally put a name - to what I had.
0:17:06 > 0:17:09- It helps me remember dates - and phone numbers.
0:17:10 > 0:17:13- It also helps me plan ahead, - into the future...
0:17:14 > 0:17:17- ..because I can see - days of the week and months.
0:17:17 > 0:17:22- They're a specific colour and they - stretch in a timeline into space.
0:17:23 > 0:17:26- If I think about next Wednesday...
0:17:26 > 0:17:28- ..it's a specific colour.
0:17:28 > 0:17:30- I know that's the pink day - next week.
0:17:32 > 0:17:35- It's thought synaesthesia - is genetic...
0:17:36 > 0:17:41- ..so it may be passed down - from parents to their children.
0:17:41 > 0:17:44- My daughter's five years old...
0:17:44 > 0:17:48- ..and she's started to talk about - numbers and colours.
0:17:48 > 0:17:51- I think I've passed it down to her.
0:17:51 > 0:17:53- It's great. I'm so excited.
0:17:54 > 0:17:59- She can experience the world - through colour and it's fantastic.
0:17:59 > 0:18:03- It's likely we all have a degree - of synaesthesia as infants.
0:18:04 > 0:18:07- As the brain develops - and organizes itself...
0:18:07 > 0:18:09- ..connections are broken.
0:18:10 > 0:18:15- In synaesthetes, it's thought - some connections remain...
0:18:15 > 0:18:19- ..meaning messages from - different senses become jumbled.
0:18:20 > 0:18:23- I enjoy having this - different dimension in my life.
0:18:24 > 0:18:28- I experience the world - through the medium of colour.
0:18:38 > 0:18:40- I kept my balance...
0:18:40 > 0:18:43- ..and walked across a wire - one foot off the ground.
0:18:44 > 0:18:49- Rhian Halford has a challenge which - will test my balance to the maximum.
0:18:50 > 0:18:52- I should be able to do this today?
0:18:52 > 0:18:55- I should be able to do this today?- - Yes, before the end of the day.
0:18:56 > 0:19:01- The low wire was difficult at first. - It was difficult, full stop!
0:19:01 > 0:19:04- I found it hard to keep my balance.
0:19:04 > 0:19:08- Once my shoulders - had tipped to one side, I fell off.
0:19:11 > 0:19:13- The wire - is six feet above the ground...
0:19:14 > 0:19:17- ..so my head is over 11 feet - off the ground.
0:19:17 > 0:19:21- This has had a massive - psychological effect on me.
0:19:22 > 0:19:24- I can't let go!
0:19:24 > 0:19:25- I can't let go!- - You're fine.
0:19:25 > 0:19:27- Right. Come on, Anwen!
0:19:29 > 0:19:31- Right.
0:19:34 > 0:19:36- Move your arms.
0:19:37 > 0:19:39- Concentrate. You're fine.
0:19:45 > 0:19:46- Remember to breathe.
0:19:47 > 0:19:50- I'm glad Adie's here - to hold the rope.
0:19:57 > 0:19:58- Shoulders up.
0:20:00 > 0:20:01- Concentrate.
0:20:01 > 0:20:03- Shoulders.
0:20:03 > 0:20:04- Focus.
0:20:05 > 0:20:07- You're nearly there.
0:20:07 > 0:20:10- Once I'd fallen off, - I felt happier...
0:20:10 > 0:20:14- ..and I got used to - ignoring the distance to the ground.
0:20:15 > 0:20:16- Oh, no!
0:20:19 > 0:20:23- I had to keep my centre of balance - precisely above the wire...
0:20:23 > 0:20:26- ..which is only half an inch thick!
0:20:26 > 0:20:31- If my centre of balance moves a - little, I'm very likely to fall off.
0:20:34 > 0:20:38- Stretching put my arms and legs - lowers my centre of balance...
0:20:39 > 0:20:40- ..making it easier.
0:20:41 > 0:20:44- But it's still incredibly difficult.
0:20:46 > 0:20:48- Rhian, I reached the platforms...
0:20:49 > 0:20:52- ..at the other end of the high wire - and the low wire.
0:20:53 > 0:20:54- How was my balance?
0:20:55 > 0:20:59- Your balance is good - and you can correct mistakes.
0:20:59 > 0:21:03- The biggest mistake you made - was dropping your shoulders.
0:21:04 > 0:21:06- You realized that and you improved.
0:21:06 > 0:21:09- That really helped your balance.
0:21:11 > 0:21:14- It may have been a case - of my brain...
0:21:15 > 0:21:19- ..getting used to the position - of every part of my body...
0:21:19 > 0:21:22- ..so I understood more - about balance...
0:21:24 > 0:21:28- ..or the fact that I stopped - thinking about being on a wire.
0:21:28 > 0:21:30- Do you want to go higher?
0:21:31 > 0:21:33- I don't think so!
0:21:33 > 0:21:34- That was enough for me.
0:21:38 > 0:21:41- In order to stay on the wire...
0:21:41 > 0:21:45- ..my brain took heed of messages - from my eyes and my inner ear...
0:21:45 > 0:21:49- ..about the position and movement - of my head.
0:21:49 > 0:21:54- It also took heed of proprioception - receptors in my arms and legs...
0:21:54 > 0:21:57- ..about the position of my body.
0:21:57 > 0:22:01- It corrected every deviation - away from normal to keep me upright.
0:22:01 > 0:22:03- Practice makes perfect.
0:22:03 > 0:22:07- The brain can prepare the body - and control it.
0:22:07 > 0:22:12- We take our sense of balance - for granted but it's truly amazing.
0:22:15 > 0:22:19- During the series, we've looked at - all the familiar senses...
0:22:20 > 0:22:25- ..and some unfamiliar ones like - balance, proprioception and pain.
0:22:26 > 0:22:28- It's your turn, Katie!
0:22:30 > 0:22:34- It's amazing how much information - our senses give us about our world.
0:22:35 > 0:22:37- The brain - juggles that information...
0:22:38 > 0:22:42- ..to decide what's important - and what can be ignored.
0:22:42 > 0:22:44- Oh! The other side!
0:22:45 > 0:22:49- The senses can work together - or against each other...
0:22:50 > 0:22:52- It looks the same - and it tastes the same.
0:22:53 > 0:22:57- ..to influence the way - we experience our surroundings.
0:23:02 > 0:23:04- Katie, what did you enjoy the most?
0:23:04 > 0:23:07- Katie, what did you enjoy the most?- - I didn't enjoy the dancing!
0:23:09 > 0:23:13- I enjoyed meeting - the blind football team.
0:23:15 > 0:23:18- I spent a day - learning about echolocation.
0:23:18 > 0:23:20- It was an incredible experience.
0:23:21 > 0:23:22- The left.
0:23:22 > 0:23:23- The left.- - Well done.
0:23:24 > 0:23:26- I think we both had a favourite bit.
0:23:27 > 0:23:30- Seeing our producer do a pain test!
0:23:30 > 0:23:35- Yes, I enjoyed that, - after everything he made us do!
0:23:36 > 0:23:38- Ugh!
0:23:55 > 0:23:57- S4C subtitles by Eirlys A Jones
0:23:57 > 0:23:58- .