How to hijack a brain

Hypnosis, parasites and optogenetics: how minds can be manipulated...
05 February 2019
Presented by Chris Smith, Georgia Mills
Production by Georgia Mills.


Two faces, or a candlestick?


This week, how hypnosis works, the parasites that hijack the brain and behaviour, why we're all being manipulated 24/7, and building remote-controlled rodents. Plus news that we're a step closer to reversible birth control for men, why rocks affect how you vote, plastic makes mussels weaker, and a new device puts thoughts into words...

In this episode

Sperm surrounding an egg cell.

00:50 - Cocktail inspires male contraceptive

A reversible contraceptive technique for males has been developed by researchers in China.

Cocktail inspires male contraceptive
with Bill Colledge, University of Cambridge

A reversible contraceptive technique for males has been developed by researchers in China. So far it’s been tested only in rats, but appeared to be safe. The approach involves injecting into the vas deferens - the tubes that connect the testes to the inside of the body - a small amount of a thick, gel-like substance that blocks the movement of sperm. Injected in a series of layers above this is a solution of gold nanoparticles that can absorb infrared or heat energy, and a chemical that can dissolve the gel plug and reverse the blockage. The idea is that focal heat applied to the area is absorbed by the nanoparticles; this releases the gel-dissolving chemical, which then unblocks the vas deferens. Bill Colledge is a reproduction specialist at Cambridge University’s Physiology Department. He wasn’t involved in the study but agreed to take Chris Smith through the paper describing the work…

Bill - This group are trying to develop a novel method for male contraception because at the moment there are very few opportunities for male contraception, other than using a condom or having a vasectomy. And what they decided that they would try and do is to block the tube - or the duct - that allows the sperm to get out of the testes and out of the body.

Chris - And is that reversible so you could do this for a period of time and then turn the effect off?

Bill - Yes it is. I mean that's one of the novelty of the technique is that it should be reversible. There are other groups that are trying to do a similar approach of blocking the duct, but those are generally irreversible. And this approach that they have developed is incredibly novel in that they believe that, by a simple heat treatment, they would be able to reverse it.

Chris - Talk us through how it works; what's the technique?

Bill - What the group have done, and they've tested this in rats, is they have put substances into the duct that the sperm have to move through; and these substances are in several layers, and one of the substances is a sort of thick compartment that will prevent the sperm from moving. The other substances, when activated by heat, can become liquid and then they can dissolve the compartment that's blocking the sperm, so it's therefore reversible.

Chris - So it's a bit like a "tequila sunrise" then, in the sense you've got these layers: you've got a thick layer that provides the blockade, but then you've got higher layers that are capable of dissolving the blockade but only when they get near it but they're not near it to start with, unless you put some heat in there?

Bill - Absolutely it is just like a cocktail! In fact the people in the paper say that they were inspired by looking at a cocktail with different layers...

Chris - It's ironic that they're talking about cocktails in a paper about a sort of chemical vasectomy!

Bill - Well it is indeed! Yes! But I think it's a it's a very very novel and innovative approach. It needs to be developed; it needs to be progressed to see whether it would work in humans - they've only just tested it in rats, and they've monitored the fertility of the rats after this treatment for a period of 65 days or so. We don't know whether it can last longer than that. And that's clearly going to be important in translating it into the clinic, because you don't want to have to keep having this treatment. You want it to last for a fairly long time.

Chris - In terms of actually how the heat reversibility bit works, how have they done that?

Bill - The different layers have different chemical components and to reverse the blockage what they do is they heat the testes, with just a infrared heat source, and that liquefies one of the layers, which then releases the chemical in a different layer, which will then liquefy the blockage to allow the sperm to progress.

Chris - Does this mean though that if I go and take a hot bath I could accidentally dissolve this? I mean, how hot do you have to make the tissue, because I can't see many people jumping at the chance to have their testicles irradiated with infrared sources in order to reverse this. It might not be comfortable!

Bill - That's an absolutely perfect point and it was one of the issues that when I read the paper came to mind. They are heating the tissue up to about 42 and a half degrees Celsius, which isn't that hot - and certainly one can have a hotter bath than that - so I was concerned that it is possible that you have a hot bath and you inadvertently become fertile again. I think what they can possibly do is modify the different components within this plug - perhaps to increase the temperature at which you could reactivate - and that might get over having hot baths. It's also possible that the way in which they formulated the plug means that, if you you shine a light onto the testes, it will specifically heat up the plug rather than the rest of the tissue.

Chris - Is it easy to get the plug in there in the first place. Would that be an injection into that duct into the vas deferens?

Bill - What they've done is they've introduced it into the duct of a rat. I think the human male duct will be larger and therefore the procedure will probably be even easier.

Chris - Is there any risk to the sperm from the chemicals involved in this. Could you damage sperm or introduce DNA changes into the sperm which might lead to birth defects, for example?

Bill - A bonus of this method is that one of the chemicals that are involved in dissolving the plug is also toxic to the sperm, and they make this point that you if there are any sperm that do manage to get through they are going to be incapacitated by this chemical. I don't think that it will introduce mutations, because the sperm has already fully formed and the the genetic material in the sperm is probably well protected. I think what it will do is it will render the sperm not functional, and you may want to wait after you've reversed the procedure before you try to conceive...

Chicken's eggs

06:06 - Making medicines in chicken's eggs

Genetically modified chickens package up proteins needed for life-saving drugs in their egg whites.

Making medicines in chicken's eggs
with Lissa Herron, Roslin Technologies

Many very important drugs, including anti-cancer and diabetes therapies, contain very large, complex proteins that are extremely difficult to make without using living cells. But this is expensive, and can make the products harder to purify. Now, scientists at the Roslin Institute at the University of Edinburgh have genetically modified chickens so they package up the desired proteins - in very large amounts -  in the albumen - or the whites - of their eggs. Georgia Mills heard how it works from Lissa Herron, head of the Eggcellent Proteins Business unit at Roslin Technologies...

Lissa - The great thing about chickens. Well there's many great things about chickens actually. So one thing is that chickens are very evolutionarily different from mammals. And what that means is you can make proteins for mammals that will have no effect in the chicken at all. Another is that the complex pattern of sugars that need to get attached to the protein for some proteins to be active. The chickens actually do it in a way that's very similar to humans. And then the final main reason is that large scale chicken production for eggs, and then the separating of egg whites from egg yolk and cracking the eggs in everything, is already very scalable. There's already large scale production both in the food industry and in the pharma industry for production of vaccines and eggs. So we can put all these things together and have something that's really scalable very quickly.

Georgia - So you're getting chickens to basically lay eggs with specific proteins in. How have you done this?

Lissa - We used a lentivirus, which is a particular type of virus that can insert DNA into the genome of an organism. That virus was modified so that it can't replicate - all it can do is insert the gene. And we also had another bit of DNA called a promoter and that tells the gene when and where to express the protein. And so we made one that very specifically and very efficiently tells the chicken "express this protein only in egg white in a very large quantity".

Georgia - How then do you get the protein out of the egg?

Lissa - We crack the egg; separate out the egg white from the rest of the egg components, and then we use a technique called chromatography, which is how everyone separates proteins from each other in a mixture. And what we found is that we can actually use basically the identical kinds of methods that people use for purifying proteins from cells.

Georgia - How much can you get out of a single egg? 

Lissa - It depends on the particular chicken line that we're talking about. But in our best expressing line we can get between one point five and three grams per litre of egg white. So, and for the particular protein that we're talking about, a single egg can give us a dose for an adult. Very easily scalable, so you can have it be a single chicken or you can have it be thousands of chickens relatively quickly.

Georgia - What is the effect if any on the chickens?

Lissa - The chickens can't tell. As I say, we were very careful to choose proteins that don't have an effect on the chicken, and because the gene is there from the start, as far as the chicken is aware it's just another egg white protein. So it sees it as a "self" protein and doesn't have an immune response against it. And the modification is made only once. At that point we just breed forward for the next generation. So our interferon chickens, for example, are on something like the seventh or eighth generation.

Georgia - What about the eggs. Could you eat the eggs?

Lissa - You can't eat the eggs because they're from a genetically modified organism. And the regulations say you can't do that if you did accidentally eat an egg. For some reason it's unlikely to have any effect on you because the proteins won't survive your stomach. But the proteins are not intended for eating! 

Georgia - Okay. Good to know! Okay. So what's next and now you've shown that this can be done in ways that you think can be scalable to industry, what's the next step?

Lissa - So now this project has moved out of the Roslin Institute and into Roslin Technologies, which is a company. And, initially, we're going to be marketing these proteins as research reagents so that researchers, these proteins are used widely in research and our hope is that researchers will will buy these and use them; and that will help validate our claims and people can confirm that the proteins are what we say they are. In the meantime we'll be developing - we have a particular interest in - animal health, as we've come out of an animal health institute. And also we're interested in speaking to people who would be interested in developing human or animal therapeutics.

Georgia - Are there any disadvantages to using the chickens? 

Lissa - Yeah. There's always a risk. You know even though we'd have very high spec facilities that have very high biosecurity controls, it is a living organism, so you could always get an infection. But that's something that happens with mammalian cell culture as well - you know you can get infections into in the cell culture tanks. Obviously, you know, some people are not keen on using animals as a tool in general. And it does take a while to get the chickens made - takes about a year to get to a point where you have hens laying eggs...

Mussels on the seashore

12:17 - Microplastics make mussels weaker

How sea life is succumbing to plastic pollution...

Microplastics make mussels weaker
with Danni Green, Anglia Ruskin University

Most of us saw Blue Planet Two and the impact that plastics in our oceans are having on the wildlife there. But it’s not just the obvious large-scale things, like plastic bags, that are causing most of the problems: it’s actually the microplastic particles that these form when they break down. These particles are invisible to the naked eye, but they are steadily working their way through all forms of life in the ocean and appear to be impacting the health and activity of at least some of them. Speaking to Chris Smith, Danni Green is from Anglia Ruskin University; she’s just published a study showing that plastic particles affect the ability of some shellfish to attach themselves to their surroundings...

Chris - So which shellfish have you been looking at?

Danni - So we looked at the blue mussel, Mytilus edulis. This is the mussel that you probably most commonly would eat, the mussel that you would see in on the shelves of supermarkets. Myself and my collaborators from Maynooth University, we wanted to understand how these mussels have been affected in terms of the health but also how they function as ecosystem engineers. These are really important organisms: they form quite complex reefs, and they support a lot of biodiversity of other animals.

Chris - How did you discover that they're struggling to cling on?

Danni - I set up an experiment using an outdoor laboratory system so it's kind of realistic without releasing microplastics into the environment, which would not be very popular with DEFRA, and we dose them with microplastics and run the experiment for quite a long time - 52 days - and after this time I tested their tenacity, which is their ability to hold on to the substrate and you measure the vertical force that is necessary to detach them. And I found that the control mussels that were not exposed to microplastics had double the strength than the ones exposed.

Chris - They make a sticky material that enables them to cling on don't they?

Danni - So they form what's called byssal threads, so it's little tiny threads; and you would have seen these on mussels either on the shore or on your plate and these actually attach onto the rock and allow them to stay in place. And the mussels that were exposed to microplastics, so, they had half the number that they actually produce - they produce less threads. Therefore the strength was reduced.

Chris - And the dose of microplastics that you're exposing them to, was that sort of ocean-realistic? In other words, if I were to go out into the field and take a sample of seawater where mussels would be eating and going about their business, I would probably see levels of plastic equivalent to your experiment or not? 

Danni - I hope not! At the current day! So, the amounts that were used is representative of what we might find in the future, in the next kind of 50 to 100 years depending on which sort of projection you use. But actually, our concentrations were one of the lowest used in experiments to date. So it is quite realistic. These effects aren't happening now and there's still time to prevent this happening. 

Chris - Which is good news isn't it? But how do you think the plastics are achieving this effect? What are they doing to the mussels to mean that the byssal threads are reduced by up to 50 per cent in the affected animals? 

Danni - So it's difficult to tell. It's either that they're making the animal feel full, and it's not getting the same nutritional value from its food because it feels like it's full. We did a technical shotgun proteomics, where you basically take a blood sample (in this case it's called haemolymph but it's the equivalent of blood in vertebrates), and we analysed all the proteins in the organism and found that a lot of immune response proteins were being expressed - stress response detoxification proteins, all these things that are indicating that this animal is trying to get something out of its system. And this was the same whether you had normal microplastics or biodegradable microplastics. So there's an effect from both of these types.

Chris - Do you think this is unique to mussels, or have you started to look at other shellfish that will also be exposed in the same way? They're filter feeders - they'll be drawing in water and therefore potentially bringing these things into their bodies in the same way that the mussels do...

Danni - So it's difficult to tell if the exact effects that we had were unique but from other studies that I've done I found that oysters have also been impacted: they've had alterations to their filtration rate, differences in their biomass, and other people have found that their reproductive output has also been reduced by microplastics. So there are definitely effects happening on other bivalves, not just mussels.

Chris - It's interesting you're seeing this effect with just - if you want - "naked microplastics", because one of the other things people talk about in this context is that these plastics tend to soak up a toxic cargo of other oil-loving chemicals in the sea. So it could be a double whammy for these animals then, because not only are they getting a direct impact physically from the plastic, they could then get the toxic burden that goes with it. So they could be impacted twice?

Danni - Yeah, exactly. So it could either be from the plasticisers that are on the plastic itself, or it could be from the persistent organic pollutants they absorbed from the water that they're in; it could also be biological - it could be microorganisms attaching to the microplastics and then having an effect. And in order to separate these, we would have to do some pretty complex experiments, which I know that these sort of things are being done to try to work out what is it really that's causing this effect.

Chris - And just finally, if this turns out to play out the way you think it is in your experiments, what would be the marine impact of this?

Danni - If mussels can't attach to the rock then they can't form complex reefs; they can live in really exposed environments where the waves are gonna wash them away. So there's a greater chance of them being dislodged and therefore unable to form these really important habitats, which support biodiversity. They're also economically important, and when we farm them as well they're often left out on these kind of pole and line sorts of systems, so they could be dislodged: you could be losing yield. There's economic and ecological consequences...

Child shouting into microphone

17:43 - Translating brain waves into speech

Can technology give a voice back to the voiceless?

Translating brain waves into speech
with Nima Mesgarani, Columbia University

The ability to speak is something we often take for granted; but not everyone can. So can technology give a voice back to the voiceless? Izze Clarke caught up with Nima Mesgarani, from Columbia University’s Zuckerman Institute, who may have found a solution...

Izzie - Speech is the most natural way for us to communicate. It's faster than emails, instant messaging and helps us to connect with those around us. Which is why losing our ability to talk because of an injury or a disease can be so devastating.

Nima - For example, locked in syndrome or ALS. An example of that would be Stephen Hawking; that he was also losing the ability to talk.

Izzie - That’s Nima Mesgarani from the Zuckerman's Mind and Brain Institute at Columbia University.

Nima - So in these cases the brain is fine. The pattern of activity that produces or hears speech is OK. It's just the connection between that and the speech generation muscles that is affected. What we're hoping to do is to directly read speech from the brain of a person so that they do not have to actually say it but we can go one step before that. And as the brain activity is produced we can directly detect and decode it.

Izzie - When we hear or imagine speech, our brain kicks into gear and that generates a specific pattern of neural activity in the brain as it processes this information. That goes on in a certain area called the auditory cortex. That brain pattern depends on who is speaking, what we're hearing and the quality of the sound. What's impressive is that Nima and his team measured those brain signals and came up with a method that decodes them and turns it back into speech.

Nima - We've used a machine learning algorithm. These are models that are loosely based on the properties of neurons in the brain and they are able to learn extremely complex patterns of relationships. We also use the latest technologies in speech sentences and we basically ask the algorithm to learn how to translate, how to go from the brainwaves back to the speech sentences, and from there we can go to the sound itself.

Izzie - That sounds too good to be true. So how did people come into this? How are you able to test that?

Nima - We teamed up with neurosurgeons and whenever they had patients, for example, with epilepsy, the surgeons implant a bunch of electrodes in their brain. And these patients are in the hospital, they're connected to a recording device and we play them sound and we record their brain waves simultaneously.

Izzie - The first part of this experiment involved playing children's storybooks to patients. This helps the algorithm to recognise their all important brain patterns when hearing speech. But then it was time to see if the algorithm could inverse this, turning those brain patterns into something audible.

Nima - We asked them to listen to numbers from 0 to 9 and the algorithm was never trained on numbers but, looking at half hour of the speech, it was able to to figure out what sort of brainwave activity corresponds to what sort of speech sounds.

And then this algorithm is able to reconstruct the sound that is most similar to what the person actually heard.
And of course,because we know what the person actually heard, you're able to compare the two to determine whether it did a good job or not. And when we did that test we found that what we reconstructed from the brain is highly intelligible.

Izzie - How intelligible? Well, using the latest speech synthesize,s the algorithm translated their thoughts into this.

Clear robotic voice - zero, one, two, three… 

Izzie - And those speech synthesizers, similar to Siri, Google assist or any other minion living in your device, helped make this a vast improvement from any previous attempts.

Fuzzy robotic voice - Zero, one, two, three…

Izzie - See what I mean? But Nima seemed in very positive that one day this system could translate brain signals into more complex sentences. So could this technology give a voice to those with ALS,  locked in syndrome or those with any other speech impairment?

Nima - So I would say that this is definitely a big step in that direction but obviously there is a lot more that has to be done. Previous studies have shown that there is a lot of similarity between actually listening to a speech or imagining listening to a speech. But of course it has to be tested and that's also another future direction of our work.

The ideal goal would be to have an implantable device, that is able to detect and decode the brain activity that reflects the internal voice of a person. So when the person tries to say something internally we would be able to decode and translate it into speech so that the person will have the ability to communicate using speech.

Evolution, ape skeletons. Gibbon now shown at natural size.

22:38 - Geology shapes human evolution

How the environment has made us the way we are...

Geology shapes human evolution
with Lewis Dartnell, University of Westminster

The Earth is, to put it lightly, a pretty important factor in humanity’s origin, for a start we live here. But the extent to which features of the planet like rivers, rock type and plate boundaries have shaped our evolution and human history, runs very deeply. It affects everything from our development of intelligence, right up to who you might vote for at the next election. Don't believe us, well Lewis Dartnell from the University of Westminster, has just written a book on the topic, it's called Origins: how the earth made us, and Georgia caught up with him to find out why we’ve been so shaped by our own planet…

Lewis - Humans are an animal species just like any other organism. We have been adapting to our environment, we've been influenced by our ecosystem, by an environment we've been growing up in. So in some sense it's not surprising that as a species we've been crafted by our natural world. And the reason that we evolve such high intelligence in East Africa is because the environment was exceedingly unstable and very quickly fluctuating, because of a combination between the plate tectonics and that interacting with climate cycles to do with Earth's wobbling orbit. So it was our environment that created us to be very intelligent.

Georgia - Why would a changing climate help us become super smart?

Lewis - Because if you have a relatively static environment, so say its environment that's always pretty dry, an animal can evolve a very good survival strategy to that like a camel, and it would store a lot of water in its body and recycle all of that water and have kind of humps to minimise its body fat. But if you've got an environment that is always changing, fluctuating back and forth, there's no no one body solution to that. And the best solution that evolution can come up with in that case is a behavioural solution, it makes complex adaptable behavior, it gave us intelligence.

Georgia - Right. So if we'd had it good and easy and everything stayed the same would have become simple camel type.

Lewis - We probably wouldn't be having a conversation on the technology, in fact we wouldn't have language or tool use had it not been for this wildly fluctuating environment in East Africa. 

Georgia - How about more recently, I say recently, like when humans started to start making civilisations.

Lewis - So we look at the first civilisation and I'm sure everyone is familiar with Mesopotamia. There's a very fertile region between the rivers Tigris and Euphrates and that's where the first large cities popped up. That's where the very beginnings of civilisation began. And again there's something really quirky about the plate tectonics in that region where humanity first built civilisations. And what's happening is the Arabian Peninsula is swinging away from Africa like this great big barn door of continental drift and it slammed into the southern margin of Eurasia, of the other continental plate, and crumpled up a range of mountains called the Zagros mountains. And when you've got a great big heavy mountain range it pushes down the crust, the earth's crust alongside it, and you get what's known as a foreland basin. And we often find rivers like the Tigris and Euphrates flowing through that foreland basin and they fill up with a very fine, very fertile river deposited soil. And so in a sense humans settled and built their first civilisations in the place was easiest to get settled with agriculture and build these big populations and these first cities. And it was plate tectonics again that created that environment for us to settle into.

Georgia - And what about us today just like day to day lives. Is there anything that we've been influenced by that we might not know?

Lewis - Another great example that really jumped out to me when I was writing Origins, was it's not just ancient history. We still bear this deep imprint of the earth and the kind of geology underlying our feet in something as current and free flowing as politics, and there's a couple of examples in Origins. There is a very very clear correlation between Labour-voting constituencies and rocks dating back to the carboniferous era. So looking as far back in Earth's history as 300 million years now, and again that deep link is actually profound it jumps out at you when you just look at the two maps that I put into Origins. And the explanation is is actually quite simple because carboniferous age rocks are where the coal deposits are, and coal is what powered us through the industrial evolution in Britain and it's been, and it still is, an incredibly important energy source in the modern world. And the reason that the Labour constituents map over where the coal deposits is that the Labour political party rose out of trade unions, so that the link there is relatively simple. But I still think is absolutely profound when you think about it that something like the political map of where people just happen to vote for different political parties correlates so strongly with the age of geological rocks that happen to lie beneath your feet.

A woman's eye

28:38 - How does hypnosis work?

What's happening in the brain when a hypnotist gets to work...

How does hypnosis work?
with Devin Tehune, Goldsmiths, University of London, & Jack Blackbourne, hypnotist

When you think of mind control, there’s usually one thing that immediately comes to mind. Hypnosis. This is the spooky phenomenon where people can appear to be under someone else’s control. But is it real? Ever curious, the Naked Scientists decided to give it a go and had their first taste of being hypnotised by stage magician hypnotist Jack Blackbourne…

Jack - I want you to imagine now these magnets going to get stronger and stronger. What's going to happen is its going to start pulling your hands in closer and closer together. Deep breath in with me. These are real big stack of heavy books, imagine your hand now getting heavier and heavier. If you try and pull your fingertips apart, it's going to feel almost impossible to do so; the more you think about it and the stronger these magnets feel, if you try and pull your fingers apart it's going to be really really hard to do so. One, two, three, now open your eyes.

Georgia - Despite being a bunch of skeptics that were definitely a few fingers stuck together and a hand or two floating up in the air. All thanks to the dark arts of Jack Blackbourne, professional hypnotist and mind reader who started getting into it about seven years ago.

Jack - There is a hypnotist school, like Hogwarts but for hypnotists, you can go on a big crash course over a few days and two days later you come out of it and you're a hypnotist. Easy as that really.

Georgia - What was it like for you the first time you actually hypnotised someone?

Jack - Scary as you could imagine, the fear of failing in front of everyone, but the first time it works and you just have this overwhelming sense of wow, I've got like a superpower now.

Georgia - Were you tempted to use your powers for evil?

Jack - I still do. Not tempted, I still do. Yeah I went into a bar and got someone who I had never met to give me all his money in his wallet, for no reason at all other than to make him feel great.

Georgia - Did you give him his money back?

Jack - Of course I did yeah.

Georiga - What's your favourite thing you've ever got someone to do?

Jack - It depends on the situation. There's the situations where we get like a stag party or a hen do and everyone's up for something; everyone's up for a laugh and everyone's up for a bit of mickey taking and you can get them to do whatever you want, you can get them to pretend like they're baby again and they'll just crawl down on the floor and they'll make lots of noises and not talk like a human being. That's kind of fun in front of lots of burly men who are drunk, to see that they're kind of the best man for example, rolling down the floor crying. Yeah that that's always a good one...

But what is hypnosis? Chris Smith spoke with Devin Terhune who researches the subject at Goldsmiths, University of London...

Devin - Hypnosis means a lot of different things depending on the usage and depending on the person using it. Typically in an experimental or clinical context it refers to a set of techniques in which we harness the phenomenon of suggestions. We use suggestions to alter behaviour and experience. So suggestions are just simple verbal communications whereby we're telling you something that you're going to experience something as though it's occurring outside of your control. So I might tell you for example you are no longer able to experience anything in your arm and in very highly suggestible individuals, this can often produce an experience where they cannot feel any pain for example in their arm. Hypnosis is just a technique for using those suggestions.

Chris - And what do you mean by highly suggestible. What does that actually translates into? How would I recognise someone who is?

Devin - They are not necessarily easy to recognise on the street, so they don't have any kind of distinct kind of characteristics that are easily identifiable. Nevertheless they amount about to about 10 to 15 percent of the population. So these are people that are able to experience pronounced changes in their thoughts, their emotions, their perception in response to suggestions kind of one of the most notable features of them is they tend to get very highly absorbed in activities, so people that tend to kind of get really emotionally involved in films or music and activities along those lines, tend to more often not be more highly suggestible.

Chris - And do we understand why, when you make these suggestions to them they are more susceptible to engaging with that message. Is this something about their brain that makes them susceptible?

Devin - Sure, so our understanding of the of the brain mechanisms underlying hypnosis are relatively poor. We do know that suggestibility is fairly stable and so this would seem to suggest that are there are these kind of neuro-physiological characteristics. One kind of idea that there's behavioral evidence as well some neuroimaging evidence, is that highly suggestable individuals seem to have less awareness of their intentions. So normally when I try to suppress pain in my arm I'm aware that I'm intending to do so. So one kind of prominent theory of hypnosis that we would suppress pain in the arm, but a highly suggestible person is not aware that they're doing so, and that's why it feels like it's outside of their control. So this seems to kind of implicate brain regions or brain networks involved in the extent to which we're aware of our own mental states.

Chris - To what extent have people actually done hypnosis in brain scanners to see how it changes brain activity?

Devin - There's been a tremendous amount of research using functional neuroimaging techniques to study various features of hypnosis, has been going on since the mid to late 90s. These studies have largely aimed to kind of validate hypnotic responses and less to study the mechanisms. So basically in other words these techniques have largely shown beyond fairly reasonable doubt that when people are experiencing a reduction in pain in response to hypnosis, you're actually seeing corresponding changes in brain regions supporting pain processing. So basically these kind of studies overwhelmingly indicate that hypnosis is a real, in the sense that's producing genuine changes in the brain.

Chris - And if it's producing genuine traces and changes in the brain what's the application? And in what way can that be used for good not just to make people laugh on stage. Can we use it clinically?

Devin - Yes so the primary clinical application of hypnosis in therapeutic contexts perhaps the most prominent one is in the treatment and management of pain. So since the 19th century hypnosis been reliably used to treat and manage pain. It's important to emphasise it's certainly not a panacea, it doesn't work with everyone and it's not going to work with all conditions and symptoms. It's especially good with pain. The evidence for other conditions such as anxiety and depression is not really as good. That might be because there's not a lot of research on that. So it's really hard to say but particularly in the context of pain it seems to be especially valuable. 

Chris -And to finish do you think it's just humans that are susceptible to hypnosis. Could I for instance hypnotise my dog?

Devin - I would say you cannot know. So I would view hypnosis as largely a kind of a verbal application of suggestion. Certainly you could potentially manipulate your dog in various ways and potentially manipulate their behaviour using various types of tricks, but I would be very cautious about kind of linking that with something like hypnosis.

Signpost showing conflicting directions

36:09 - Are we all being manipulated all of the time?

Meet the subtle signals you miss that alter your behaviour...

Are we all being manipulated all of the time?
with Philipe Bujold, University of Cambridge

Are you being manipulated without even realising it? Georgia Mills got the low down from Philipe Bujold, who studies decision making at Cambridge University...

Philipe - Yeah. So actually I thought I'd give you an example of how easy you are to manipulate. So I'll ask you a quick question which is a very famous question. Daniel Kahneman and Amos Tversky, who won the Nobel Prize in 2003 in economics, did this test and so I'll ask you two sets of questions. Let's say we have 600 people that are infected with a specific disease and I give you the choice of two programmes that you can apply to try and save a few people. So programme A you know for a fact that about 200 people will be saved. Programme B about one third probability everyone will survive, everyone will be saved but then two thirds probability no one will be saved. Which one would you pick? Programme A or programme B?

Georgia - A I think, yeah.

Philipe - Yes. So that's what most people would pick. So you pick the safe option so you try to save 200 people for sure. If I'd asked the question a bit differently and instead basically give you two programmes that are about dying instead of saving. So we say programme C 400 people will die for sure or programme D there is a one third probability that no one will die or two thirds probability that everyone will die.

Georgia - That's trickier, D sounds better in that one, but they're the same.

Philipe - So you follow basically the average. So most people if you present an option as a gain would go with the risk-less option so you go for it the certain the sure options or saving 200 people. But here 400 people will die for sure is considered a loss. And people tend to be a lot more risk seeking when it comes to losses. So you prefer testing tense and so you can imagine this kind of question when you ask this a million times to different people, people have different patterns but everyone seems to follow this type of behaviour.

Georgia - Does this mean governments can use this to try and change our behaviour?

Philipe - Yes so these kinds of tests have actually started a whole new subfield of science called behavioural sciences. Within this we have behavioural insights which are different choice biases that we can use to try and modify people's behaviour. And most of this is actually for good, so I don't want to scare everyone. It's also been happening most of your lives we're just aware of it now. But sometimes it's not as good. And so with the advent of data science there's a lot of different things you can do, and alot of corporations, shops, companies are using that to maximise profit. But then on the other hand you have governments that are really trying to use that, to try and make society better if you want, according to the government that is.

Georgia - Hit me hit me with some examples then.

Philipe - Some examples, well actually I was talking to a group in Canada, my home countries. So their behavioural insights group in British Columbia, were asking question recently which was, how do you reduce the rate of human caused wildfires? For example you've probably heard about California last year very difficult. So that's a really good question and you don't want to force people to stop making fires. You just want to try and nudge them, which we call to try and reduce this risk. So they were asking a bunch of different questions and it seems like low cost messaging which is just reminding people, texting people about it, seems to influence their decision. And so what you want to do is still leave the decision there for people, so they still have the same choices, but the way you asked the choice is basically biasing the choice one way or another. So that's a great example. Another one that we probably all experience is on Netflix, and when you're watching TV on any streaming device really, when they start playing the next episode automatically this is a huge framing effect because if you had to choose that's a little gain. So you're choosing to watch the next episode you're winning, but if you have to stop the next episode automatically that's a loss. So it's a lot harder for people and you just keep watching, you binge watch and that's a very good example of what's happening.

Georgia - And what about sort of out and about in the street. So there are things there that we might come across on a daily basis?

Philipe - Yes actually in London there's a very good example. And that would be the buttons you have to press to cross the intersection. A lot of these actually in a lot of major cities don't do anything. They give you the impression of control which gives people the idea that oh they've pressed so they will wait. But most of the time they don't actually do anything. Now in most villages or smaller towns they actually have some measure of importance. But you can try next time in London or in New York a lot of these things don't do anything.

Georgia - We've been tricked. So what does that mean, it makes us less likely to just run across the road?

Philipe - Exactly so it reduces jaywalking. And there's another great example that would target men specifically if you've been to a urinal recently where you saw a bee or a fly in the urinal, that's people taking advantage of your psyche really to make you aim there so that you don't have spillover.

Georgia - Making it fun I guess as well. Is there a way to you know, shield yourself from this kind of stuff.

Philipe -  So unfortunately like a lot of behavioural effects you can't really shield yourself. So this takes advantage of how our brain is wired and so we're very very efficient at being flexible. That's a key trait of humans, but all this flexibility comes at a price. And it's that we take a lot of shortcuts in our decision making and a lot of what we do is going to be subjective, so relative. So I was talking about gains and losses earlier, a lot of this will be based off what you're seeing in your direct environment. So what's considered a win right now might be a loss tomorrow. And so that's a key symptom if you want of our flexibility of our humanness, but unfortunately it also makes us very risk prone for these kinds of behaviours.

Cartoon of switch turning on a person's head

Parasites: masters of natural mind control
with Jenny York, University of Cambridge

How, and why, do parasites manipulate the mind? Chris Smith hears how from Cambridge University behavioural ecologist Jenny York...

Chris - First of all, tell us why parasites would need to manipulate someone's mind or an animal's mind? Why?

Jenny - Parasites make their living on the inside or on other organisms, said a host species, and they're at complete conflict with these other organisms because they are stealing from them. So in order to sort of transmit to the next stage of their lifecycle or to reproduce, in some cases, they have these adaptations that allow them to manipulate the behaviour of their host.

Chris - Can you give me some examples?

Jenny - I can start with probably my favourite example (somewhat biased) of the common cuckoo which we study up at Wicken Fen in Cambridgeshire, here

Chris - Can you do an impression of one?

Jenny - I wish I could!

Chris - You hear the sound so so infrequently these days, because they were on their way, aren't they? They're not so common as they once were. What do cuckoos do then? We all know they lay eggs in the wrong bird's nest. But what do they do to make that better?

Jenny - So as you say they lay their eggs at the wrong nest. There are there are brood parasite, that means they need to put their eggs in the nest of host species in order to reproduce and produce offspring. And they have a whole variety of tricks in order to make this happen and to improve their chances because it's not at all that the host birds' interest to raise these cuckoo chicks. And one really interesting adaptation they have manipulation of behaviour: the female cuckoo - despite being very secretive and cryptic, and hiding and waiting for hosts to leave the nest so she has an opportunity to lay, and taking as little as 10 seconds to lay her egg in their nest - she then after doing so gets this really conspicuous call. But if it were anything else you'd think: "Why is she giving the game away?" She's alerting the hosts to what she's just done... So we were really interested in this call and we looked at the acoustic structure of it it's very similar to that of a sparrowhawk which is a predator of what she is parasitising. Exactly!

Chris - So is that she's doing that in order to make them stay away for longer, and so that they're distracted worrying about the predator. They're not worried about what she might have done in their nest.

Jenny - Yeah that seems to be what's happening. So this call makes them equally vigilant to hearing a sparrowhawk call. So it does get them off kilter. There's something about this call that makes them feel wary about their own safety and so instead of paying attention to what's in the nest and thinking: "Is there something parasitising me?", they're paying attention to looking after their own well-being.

Chris - How do you think the cuckoo's evolved to do that in the first place because that's pretty complicated. To mimic another bird having evolved to lay your egg in the wrong nest in the first place. To then evolve to mimic another bird. You gotta know that the other bird you're mimicking is a threat to the first bird you're trying to parasitise. There's lots of links in that chain.

Jenny - Yeah so it's probably unlikely that they're doing this consciously and using vocal mimicry that some species do. Some species can hear a call and then imitate that call perfectly. It's more likely with cuckoos, because they're not vocal learners, that they just inherit this as instinctive, this call that they have. And over evolutionary time it's become more and more similar to that of the sparrowhawk.

Chris - Amazing. What about, since we're talking this week about manipulating the brain, rather than just external manipulation; what about things that manipulate from within? Parasites that can actually change the way your brain physically works?

Jenny - So there are some lovely examples of this. I don't know if lovely is the right word, to be honest! I think that if you think of the sci-fi movies, you know, Alien - we have the real world alien in the zombie fungus that infects ants. They'll come across a spore of this fungus on the forest floor, and then it will take several days to develop inside them, and at a certain point it switches and causes that behaviour to change that they move away from the colony and up high in the tree where they then bite onto a leaf and stay still until this fungus erupts 24 hours later; erupts from the head and throws spores into the forest carry on.

Chris - So they make the ant into their, sort of, fruiting body?

Jenny - Exactly. Yeah. Yeah. Amazing. So they're just manipulating the behaviour directly inside.

Chris - Do we know how the fungus is doing that to the animal's brain?

Jenny - This is something that's getting more and more interest at the moment. This exact mechanism of how parasites are manipulating their hosts. So it's a lot clearer in another example: the kamikaze horsehair worm. So there's a worm that lives inside the body of a cricket, and it needs to get to water in order to get to the next stage of its life cycle, so it must burst out of cricket's body. But the cricket doesn't want to go anywhere near water, that's not part of its everyday life. So by changing the neurochemistry of this cricket, it makes it a kamikaze cricket that goes towards the nearest body of water and then is burst open with a giant worm...


A rat grooming

47:34 - Remote controlled rodents

Light can be used to control brain circuits to change behaviour...

Remote controlled rodents
with Kay Maxine Tye, MIT

The technique called “optogenetics” involves adding a light-sensing gene to nerve cells. This makes the nerve cells become light-sensitive themselves, enabling scientists to switch on and off different brain areas by implanting a small light-source into the brain. Georgia Mills spoke to Kay Maxine Tye, who uses optogenetics at MIT to understand how the different parts of the nervous system contribute to brain function and the generation of complex behaviours. She first of all explained how you make nerve cells light-sensitive...

Kay - The first projects well that became really popular was channelrhodopsin and channelrhodopsin is an algal protein so it's found an algae pond scum. And somehow this single-celled organism 'knows' that it needs to swim towards light where, actually, how it does this is that there is a light-sensitive channel and when that light hits that channel it opens. That, in the case of an algae, makes a little flagellum flap so that the algae moves forward. In neurons, it would make the neuron fire an action potential which is the means by which neurons can communicate with each other.

Georgia - Right. So by putting this protein; making sure it's expressed in certain parts of the brain when light is present you can basically switch them on.

Kay - Exactly.

Georgia - How do you get the protein to express only in the neurons you're interested in? 

Kay - A common way is to use a viral vector. There are all different types of viruses and you can express any gene of interest in a virus. The virus infects the cell and then the cell starts producing whatever that gene codes for. So in the case of channelrhodopsin I can package it into a virus and then use the virus to infect certain cells. Based on the cell type we can control the expression of channelrhodopsin.

Georgia - So what kinds of things are people using optogenetics for?

Kay - It's a really powerful tool because it allows us to go in and, you know the brain is just this big grey ball of mush, and how do we know how it works? We can piece by piece test what happens to the rest of the brain as well as to the animal's behaviour when we manipulate the activity of select populations of neurons. We can define those populations of neurons by what they produce, what type of neuron they are, what their connections are, and that helps us sort of dissect the circuitry of the brain.

Georgia - Could you give me a couple of examples of what you've actually made animals do?

Kay - Yes. So in our group, we publish a paper in 2015 and found that if you activate GABAergic, these are inhibitory neurons that project from the lateral hypothalamus to the ventral tegmental area, which is where most dopamine neurons are found... If you activate these GABAergic neurons what you get is - you know, we place the animal in an empty chamber and you start stimulating these neurons and the animal will begin licking the floor and then it will shift its way and engage as if it's picking up food from the ground and eating it, except that there's no food it's an empty cage. So their paws are empty, yet they're sitting back holding it up to their face and engaging in what looks like feeding behaviour. Another result that we've seen is you stimulate certain populations of neurons, for example, in the brain stem and you'll get all sorts of really robust escape-related behaviour: animals leaping out of their cage, jumping off of apparatus. One of my students once called this the popcorn mouse we got popcorn mice because the mice are just leaping all over, and that suggests that we're tapping into an escape related circuit.

Georgia - It sounds like this is quite a young field but there's amazing things being done already. How far do you think this could go? Could we get to the stage where we have like remote controlled mice?

Kay - I don't think remote controlled mice is very far off at all, I mean, wireless stimulation devices exist. I mean, the hardest part would be like the battery life of the wireless control. I mean, that we basically have now. I think that if that doesn't exist now it's, you know, a few months away from making possible.

Georgia - Wow. So you're telling me you could get a mouse and sort of say: "forward, left, right". That kind of thing?

Kay - Yeah, yeah! I mean, we can control motor cortex, we can make mice run in a circle. If we had two different lights on the different sides you could make the mice run left or right, or forward or freeze. I think running backwards is a little bit trickier. I mean, to me, a remote control mouse feels very much within reach.

Georgia - Do you think it could ever be done in humans?

Kay - I think the biggest concern that I would have about using it in the brain for humans - although I believe optogenetics is already being used for retinal prosthetics for people who are blind and to help them see, and for bladder control. Things are on the periphery of cases in which function is already completely lost and so there's relatively little to risk. But I think in terms of using it in the brain we still are just beginning to understand brain function. And so I think that is still quite dangerous because the viral tools that we have for expressing these transgenes which will be the only way to get into a human would be potentially feasible if, and only if, they could become stable and safe. And I think that is a big 'if'. Currently all the viral vector tools that I'm aware of and familiar with and have used have some level of toxicity.

Georgia - All right. So you don't have to worry about being remote controlled humans just this minute?

Kay - No! I think there's all sorts of ethical concerns that I hope will prevent irresponsible exploration!

A lit candle

Why does a candle smoke after it's blown out?

Jenny Gracie has been shedding some light on the problem...

Richard - Why does a candle start to make more smoke and smell when it's blown out?

Jenny - To shed some light on this question I spoke with Duncan Graham a professor of chemistry at the University of Strathclyde, to, first of all, find out how a candle actually works.

Duncan - A candle looks simple enough: a block of wax with the wick, often a piece of string running through the centre. But you need three things to start a fire: fuel, oxygen, and a heat source.

Jenny - I also caught up with Ricky Carvel who teaches combustion and fire dynamics at the University of Edinburgh. He had this to add to how the flame keeps alight.

Ricky - When a candle is burning, the energy from the flames heats up the wax and, while the wick does burn, it's actually the wax that fuels the flame and keeps burning. The melted wax flows towards the wick and is drawn up into the flame. Inside the flame, it's about 800 to 1000 degrees C and the high heat breaks up the big wax molecules into smaller chunks. This process is called pyrolysis. Most of these chunks burn inside the flame and are turned into carbon dioxide and water vapour which are both invisible and have no smell.

Jenny - This process can also be called combustion. Duncan went on to explain it further.

Duncan - If the combustion of the wax is 100% complete, then only light, heat, water vapour, and carbon dioxide will be produced. However, we've all seen the sooty marks that can be left on the edge of a candle holder. On a larger scale, the black marks seen at the back of a fireplace heading up the chimney. This is due to incomplete combustion of the wax, producing small carbon particles which we call soot.

Jenny - So that explains why we see smoke. But what about the smell?

Ricky - The smell you get from a burning candle is due to the tiny proportion of pyrolysis products that didn't burn properly in the flame. When a candle was blown out, the flame stops immediately but the wick and the wax are both still hot, so pyrolysis continues for a few seconds. The solid particles and smelly gases are produced for a moment, but with no flame to burn them, they rise like smoke. This is what we see coming from the wick and this is why the smoke smells more with no flame.

Duncan - It's the same process for burning any type of fuel. By this logic and on a bigger scale if we want a fuel source such as coal to burn more effectively, then we can carefully blow air onto it to increase the amount of oxygen. This, in turn, increases the efficiency of combustion producing a cleaner flame and less smoke.

Jenny - Thanks to Duncan and Ricky for helping us shed some light on that question. Next week we have this question from Leah.

Leah - So why are some people good at imitating accents and doing impressions while others simply aren't? Obviously, you can get better with practice, but why are some people born with the skill of imitation and some aren't?


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