Nature Podcast

Introduction

This is a transcript of the 15th October edition of the weekly Nature Podcast. Audio files for the current show and archive episodes can be accessed from the Nature Podcast index page (http://www.nature.com/nature/podcast), which also contains details on how to subscribe to the Nature Podcast for FREE, and has troubleshooting top-tips. Send us your feedback to mailto:podcast@nature.com.

Kerri Smith: Coming up this week, how the brain learns to read, using a technique cell phone users know well.

Cathy J. Price: It is almost like the predictive text system that we have on our mobile phones and sometimes it gets it wrong, but most of the time it is helpful.

Adam Rutherford: And we have a winner of the much coveted, unit of the week prize.

Steven T. Bramwell: It is measured in very peculiar units, of Bohr magnetons per angstrom.

Adam Rutherford: We discover the charge on the elusive magnetic monopole.

Kerri Smith: And mice become gamers with a new measuring technique using this.

Kerri Smith: Yep, the unlikely fusion of neuroscience and quake, plus moon crashes and an exclusive interview with the freshly crowned Nobel Laureate. This is the Nature podcast. I am Kerri Smith.

Adam Rutherford: And I am Adam Rutherford. Much as though these delectable introductions might sound like I am making it up on the spot, I'm actually reading off a carefully crafted script. Of course, I learnt to read as a child and it is exactly that that makes understanding the neuroscience of learning to read rather tricky. Children are learning all manner of things as their brains take shape, confusing the picture. But this is a problem that Cathy Price from the Wellcome Trust Centre for Neuroimaging at UCL and colleagues have got around with an unlikely group of subjects. A cohort of Colombian guerrillas, militia who had laid down their guns and decided to get educated instead. This gave the researchers a unique opportunity to see what happens in the brain when you learn to read as an adult. Cathy has joined us in the studio. So you have got 20 odd illiterate guerrilla soldiers and presumably a control group. Nature 461, 983–986 (15 October 2009)

Cathy J. Price: Yes, they were all illiterate to start with and then one group of them had already been on the literacy program, but the control group were just about to start on the literacy program.

Adam Rutherford: And so you scanned this cohort's brains using MRI. So what did you find?

Cathy J. Price: So what we found was basically regions that we can divide into four different types. We found areas that are involved in understanding speech, heard speech. We found areas that were involved in seeing objects and we found an area of the brain called the angular gyrus, which we know is associated with reading because if you damage it, then you could have reading difficulties. In the fore brain we found whether the connections between the left and the right hemisphere were increased after in the cohort who had learnt to read.

Adam Rutherford: So in adults who can read, who learnt to read in childhood, did they display the same physical attributes as the guerrillas who learnt to read in adulthood?

Cathy J. Price: Well, that is the difficulty. We cannot say that because we can only identify which brain regions are involved by comparing them to a matched group and we don't, in UK we don't, we are not able to find a matched group of equally educated, same age so we cannot identify them, which is why this group was so important because there was no reason to suspect that they were not capable of learning to read. They had not learned to read, because of socio-political environment that they had been brought up in.

Adam Rutherford: So how do your results change the way we think about reading development?

Cathy J. Price: Well, I think the major contribution here is about what role the angular gyrus plays in reading because this area has been known to be involved in reading for a long time, because if you damage it, you can get reading and writing difficulties. And so the old neurological model of language that was developed about a 150 years ago, suggested that this was like a little dictionary, where you stored what words looked like and then this area, the angular gyrus then translated what the word looks like into what it sounds like. But once we had seen which set of regions were changed together with the angular gyrus we conducted some connectivity analyses to try and see how does the information flow between these areas and what we saw was that the information did not flow from the visual areas into the angular gyrus. The angular gyrus was feeding information to the visual system with expectations of what it was expecting to see. So it is almost like the predictive text system that we have on our mobile phones, where you can type away your message and the predictive text tells you, what it is expecting to see and sometimes it gets it wrong, but most of the time, it is helpful.

Adam Rutherford: And how does this relate to our current understanding of brain plasticity in general?

Cathy J. Price: Well, there are a number of studies that are coming out very rapidly at the moment, showing that the structure of the brain does change when you are learning to do a new task, and it has lots of implications. So, for instance, keeping your brain as active as possible, so that it does not atrophy as you get older and also for people who are recovering from stroke or brain damage, you can see how the brain can start to redevelop itself, in order to support the recovery process.

Adam Rutherford: Okay. Now on the pod, when we interview scientist would like to talk about the stories about how the research came about that fall outside of the natural scope of the paper. So, this is highly unusual in terms of what we publish in Nature. What was it like working with a group of illiterate ex-guerrilla soldiers in Colombia?

Cathy J. Price: Right, that is a difficult one; I cannot answer that because I have not met them. So as a scientist in the UK, you know, I have been given a beautiful sample of data which is fascinating and I can only ask the same questions myself.

Adam Rutherford: So you never met them?

Cathy J. Price: No. So it is all done electronically via email.

Adam Rutherford: I See...

Cathy J. Price: You know, the web, likewise I have a collaboration in China, and I have never met them and everything is via email.

Adam Rutherford: I imagined you trudging around the Amazon trying to hunt down Colombian guerrillas.

Cathy J. Price: Yeah, that sounds very exciting, but unfortunately, nobody paid for my flight to go out there.

Adam Rutherford: Okay Cathy. Thanks for joining us. Find the full paper online at http://www.nature.com/nature.

Kerri Smith: Coming up later, some mice learn to play classic first-person shooter game quake and in the news a certain scientist is charged with being a terrorist. Before all that though, here is Geoff Brumfiel with tales of a one poled magnet.

Geoff Brumfiel: For decades, physicists have been looking for something called a magnetic monopole. The idea is simple, really. Magnets always have a north and south pole, but north and south are never seen by themselves; this really annoys researchers because it is easy to find isolated electrical charges, electrons for example, act as a point negative charge and ions are more or less positive charges. Nobody seen a lone monopole in outer space, but researchers have found monopoles inside a crystalline material known as spin ice. It is all a bit complicated, so I went to see Steven Bramwell at University College London to learn more about spin ice and monopoles. Nature 461, 956–959 (15 October 2009)

Steven T. Bramwell: Okay, so here are some crystals of spin ice. These are not very good ones. The good ones we tend to use for the experiments, but you can see they are a sort of shiny, sort of honey-coloured crystals and it does not look anything particularly special in itself, but it has very special properties, when you get down to very cold temperatures about less than one Kelvin. One of the interesting things about it is which is very unusual is that most magnetic substances, when you cool them to near to absolute zero, they order magnetically, in other words, all the little atomic movements in the magnet line up in some definite pattern, whereas in spin ice, they don't; it remains in a disordered state.

Geoff Brumfiel: So when you say, it remains in a disordered state, I mean, so what is going on then in this sort of crystal?

Steven T. Bramwell: Yes, so each atom carries a magnetic movement. So it is like a little bar magnet and these little bar magnets are interacting with each other via their magnetic fields and usually that causes them to all line up in a crystal, but in spin ice has a special property, what is called a frustrated magnet. It does not allow the lining up of the little bar magnets on each of the atoms and so they get stuck in a rather complicated arrangement. There is about a million, million, million, million tiny atomic bar magnets in there. Now it turns out that when you have got that number of bar magnets interacting, where the magnetic poles are can change, so they are not just locked together and in fact what happens in spin ice is the special arrangement of the atoms and of the little atomic bar magnets means that the magnetic poles form a sort of in space and can move up apart, just like magnetic charges and so spin ice, you can think of as a sort of a box full of magnetic charges that are just free to move. The only caveat on that being that you have to have the same number of positive and negative charges.

Geoff Brumfiel: So, then I guess, to turn to your paper specifically here, there has been a lot of developments in monopoles recently, but maybe you can tell me just how you have managed to measure the magnetic charge, I guess, you called on these little things right?

Steven T. Bramwell: That is right. So if you think about an analogy with electricity, you can measure the electrical current, it is an ammeter for that and you can measure the electron charge. What we set out to do is to see if we could measure the charge and current of the magnetic monopoles in spin ice. So this is the magnetic charge and the magnetic current, in other words, a number of monopoles drifting in a certain direction, in a certain period of time. We found a method of using a theory of electrical current in a solution, an ionic solution, like say water which has some ions in it, which conducts electricity by the motion of these ions, and it turns out that the motion of magnetic charges in spin ice is exactly equivalent to the motion of ions in water. These things conduct magnetic electricity that we have called magnetricity, but they do not conduct it like a piece of copper would, they conduct it like water would conduct electricity.

Geoff Brumfiel: So lay it on me then, I mean, how much charge do these things have?

Steven T. Bramwell: Okay, well it is measured in very peculiar units, of Bohr magnetons per angstrom. Okay, this is a measure of the force of the, that is one of these particle experiences when it is put in a magnetic field. This value of the charge is actually, I think, about a thousand times smaller than that of a cosmic monopole. So it is clear that it is not a cosmic monopole, it does not have the same charge as the cosmic monopole, and in fact the charge is a property of spin ice itself. So, if you got one of these things in another material, which is possible, but it would have a different charge. So there is not any one charge.

Geoff Brumfiel: I know people have been looking for monopoles. Physicists have been looking for evidence in monopoles for decades now, I mean, it sort of been driving them nuts why you can have separated electron charge but not separated magnetic charge. Does this really end the hunt for the monopole, do you think?

Steven T. Bramwell: Absolutely not. I think, if anything it could intensify it in a way because I mean, these are non-cosmic monopoles, they are not the things that the particle physicists have been looking for. However, they do a put rather new and interesting light on the whole question of magnetic monopoles because it shows that it is part of a pattern, a very interesting pattern, whereby materials can sort of reproduce the laws of physics within themselves and nobody really knows at the moment whether this is going to be extremely significant or not, but it is a sort of common sense that if a material can produce things that look very much like magnetic monopoles, then may be this will tell us something about the origin and properties of the real things that physicists think exist, somewhere in the universe, but no one has ever observed.

Kerri Smith: That was Steve Bramwell, talking to Geoff.

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Kerri Smith: We have an exclusive interview with Nobel Laureate, Elizabeth Blackburn, coming up shortly, but before that, a team of researchers have devised a way to play computer games on work time by teaching them to mice. Charlotte Stoddart faced the end of level boss to find out more.

Charlotte Stoddart: You want to investigate how individual cells in the brain process spatial information. This is something you can do in rodents, but to do it properly, your subject's head must stay completely still. So how do you do it? Well, David Tank and colleagues at Princeton University adapted the video game Quake2 to create a virtual environment, in which their mice could navigate around an area without actually moving their heads. I called David to find out more about this unusual setup, but first he told me about the aptly named place cells that were the object of their study. Nature 461, 941–946 (15 October 2009)

David W. Tank: As a rat or mouse walks through an environment, then the cells will fire an increased number of action potentials per unit time, at a particular spatial location in the environment and different cells have different locations that they prefer, their spatial receptive field.

Charlotte Stoddart: What has been difficult about investigating place cells in the brain?

David W. Tank: Place cells were originally discovered using what we call extracellular recording electrodes, these are wires which are inserted into the brain and positioned basically outside of a neuron but nearby and these kind of record what are called extracellular action potentials. But what they don't tell you is what information the neuron is actually receiving on its synaptic inputs that generate those action potentials. So there is always an interest in getting information about the intracellular membrane potential dynamics and this has never before been accomplished with place cells in rodents that are navigating in an environment and so that is really the technical advance that this paper presents.

Charlotte Stoddart: Okay, so this is what you have done, you have managed to make recordings inside cells, while an animal is navigating around an area. So tell us how you did it because it is actually quite clever and quite unusual.

David W. Tank: So one of the central components of our instrumentation is an air-supported Styrofoam ball about 8 inches in diameter, what we call a spherical treadmill, and at the very north pole of this Styrofoam ball, the mouse is situated, in particular its head is held at that position, using a head plate, but the mouse can walk freely on the surface of the ball. The second component is a kind of a mini IMAX theatre screen that surrounds the spherical treadmill and this is a screen upon which the virtual reality is projected and that software is basically a video game. It is actually based on an open source video game engine called Quake2. So anyway, we adapted it to use signals recorded from the motion of the spherical treadmill to change the view angle in the virtual reality. There actually was a third component, which is a reward system. So we actually have water rewards that are under the control of virtual reality game engine and when the mouse walks to particular positions in the environment, it gets a very small water reward.

Charlotte Stoddart: My producer who is more familiar with video games than me wants to know if the mouse has a Quake railgun, I think, it is called.

David W. Tank: Well, that is a very good question. They are actually displayed in the Quake code, but we mask them out, so to speak, and so no, unfortunately, the mouse does not actually see his gun.

Charlotte Stoddart: Okay, so while your mouse is walking up and down this virtual corridor playing this video game, you have got electrodes going into the mouse's brain, into particular cells, so what is it that you are measuring and what did you learn from these measurements?

David W. Tank: So, there were a number of models that made different predictions about what the membrane potential trajectory in time would look like, as the mouse or the rat walked through a place field and what we did was by virtue of our ability to make these recordings. We were able to provide evidence for and against these different models and there were about a half dozen such models.

Charlotte Stoddart: Is it possible to give us a very brief summary and tell us overall than what have we learned about spatial information processing in the brain?

David W. Tank: First of all, let me say that I don't think and we don't present this work as being the final word on the mechanisms of the generation of place cells. I think that is really important to understand. What I do think is that it provides the very first picture, a very first information that allows us to sort of re-evaluate all of these conceptual models.

Charlotte Stoddart: So it sounds like you have got lots more to investigate. What you have planned next? Are you going to do some more of these virtual reality experiments?

David W. Tank: Virtual reality experiments are really expanded in my lab. We have different kinds of environments, we have team ACES, we have SQUARE arenas, we have environments which you cannot produce in the real world, for example, the mouse walks to an end of a court or then it is teleported to another region in space and these are the things that really virtual realities strength are; to do things that really cannot be done in real environments but which could be used to probe some of the mechanisms and coding and so on of place cells and spatial representation in the brain.

Adam Rutherford: David Tank, from Princeton University, talking to Charlotte. And now the headlines from elsewhere in Nature this week.

Kerri Smith: Physicists at the University of Basel in Switzerland have developed a new electronic device that can separate entangled pairs of electrons. The study demonstrates how a superconductor containing electrons naturally entangled in pairs can be used to produce spatially separated electrons. The Y-shaped splitter device is connected to two quantum dots that can only be configured to accept one electron at a time, forcing the electron pair to split and each electron to leave the Y-junction in a different arm. The device might prove a useful way to test quantum theories. Nature 461, 960–963 (15 October 2009)

Adam Rutherford: They may not be the prettiest of creatures, but a team of researchers has discovered a way to make fruit flies super-attractive to other flies at least. Joel Levine and colleagues at the University of Toronto found that fruit flies signal both their sexual and species identity using a single molecule. By genetically destroying the cells that produce it, the team made male and female flies irresistible to normal males. Flies lacking these cells entirely were also hyper-attractive to males of a different species. The team thinks that the signal usually acts as a barrier, preventing flies mating with the wrong sex or the wrong species for that matter. Nature 461, 987–991 (15 October 2009)

Kerri Smith: In a classic case of watching the Watchmen, a new study has tracked white blood cells as they sneak past the brain's surveillance mechanisms. Scientists at the Institute for Multiple Sclerosis Research in Germany have shown how T lymphocytes, a type of white blood cell involved in the immune response can attach themselves to the inside of blood vessels in the brain and crawl in against the blood flow. Because these cells can trigger autoimmune inflammation of the brain, like multiple sclerosis, these results could be useful in devising treatments. Nature advance online publication 14 October 2009,

Adam Rutherford: Now, unless you had your cranium in a bucket of silicon dioxide last week, you will know it has just come out of the media frenzy that is the Nobel Prizes. Over on our YouTube channel and on http://www.scientificamerican.com, you can find our exclusive video interview with the recipients of the chemistry gong, Venki Ramakrishnan, where he discusses the supreme importance of the ribosome and curiosity-driven research.

Kerri Smith: But do not say we never give you anything listeners, here on the pod in another exclusive interview, we talked to medicine and physiology Nobelist, Elizabeth Blackburn from the University of California, San Francisco. She picks up the check and trophy for her work on telomeres, the caps on the end of chromosomes that play critical roles in cell division, aging and cancer. Here she is telling Nature's Elie Dolgin about when the phone call came in. Published online 5 October 2009, 461, 706 – 707 (2009) doi: 10.1038/461706a

Elizabeth Blackburn: Well, I was fast asleep on early Monday morning and the phone rang around 2 o'clock and so I just groped around and tried to find it and my husband was groping, trying to find it and I managed to find it and we did not know if it was a family calling or something like that and so I pick up and then somebody identified himself as being on the Swedish, The Nobel Prize Foundation, and then he explained that I have been awarded, the prize and then he advised me to get a cup of coffee. He said that people would be calling very very soon; you know, this was 2 am in the morning and I guess he could hear that I was pretty groggy feeling. So, and then it started very gradually sinking in that this really was true.

Elie Dolgin: So, I guess you did not get back to bed after that.

Elizabeth Blackburn: I did not get back to bed and I think I have not slept; I think I finally got some sleep about, you know, 4 or 5 days later, which were about right now, in fact.

Elie Dolgin: Well, maybe we can go a little bit further back and you can tell me about the early days of when you first discovered telomeres.

Elizabeth Blackburn: Yes, well, I was a graduate student with Fred Sanger in England and it was in the days when DNA sequencing was just being worked on and so I was really very interested in DNAs and what you could sequence from them and at that stage, pre-cloning days, remember, there wasn't a whole lot of DNA you could get your hands on, but you could get at the end of linear DNAs and so I thought wouldn't it be interesting to look at the ends of DNAs in the actual nuclei and Joe Gall at Yale had discovered very short linear high-copy number minichromosomes in a ciliated protozoan. So I thought, this would be a good system to look at the ends of DNA, you know, real nuclear DNAs, not just viral DNAs or bacteriophage DNAs, and so I got these DNA sequences and they were just already very surprising, sorts of, molecular behaviours and so they were clearly, you know, there was something quite interesting at the ends of these DNAs.

Elie Dolgin: And at this point, what were you calling these things?

Elizabeth Blackburn: Well, we called them the ends of the chromosomes and so they were telomeres, you know, it struck me as a bit grandiose and over extending the concept a little bit.

Elie Dolgin: So what are the big outstanding questions then for the field of telomeres?

Elizabeth Blackburn: Yes. So you might think it is all over, but it is emerging from various observations and we did some of them that the telomerase can do things in cells which is not related to telomere maintenance and an unpopular idea initially, but now the data are coming in and it really compels us that there is more to telomerase than its function, which it clearly has of being a polymerase that elongates chromosomal telomeric DNA. No question, it does that, but like so many, it has, you know, it has got a nested stage orbit, it has been moonlighting to and...

Elie Dolgin: You can save those discoveries for your next Nobel Prize.

Elizabeth Blackburn: Well, I am so excited because I still have exciting things to chase up because it is not over yet.

Elie Dolgin: Well, more than a 100 years since Alfred Nobel first started giving all these prizes and this is the first time that two women have won the physiology or medicine prize at the same time. What do you see is the significance of that for female scientists?

Elizabeth Blackburn: Well, I think, what I hope it makes become very normal is the idea of well, two women would become as likely to win the Nobel Prize as two men might be, you know, so what I hope, you know, this shows a trend that women are clearly in science, doing science and you know, we are able to be successful in doing science. As I say my hope is that it becomes just so normal that we won't even comment on it anymore.

Kerri Smith: Elizabeth Blackburn talking to Nature reporter, Elie Dolgin.

Adam Rutherford: Now this week's news jamboree features smack down on the Moon and terrorism at the Large Hadron Collider. Geoff Brumfiel has been all over these stories like a cheap suit and here he is in the studio. First this is what eager sky watchers were tuning into on Friday at 12:30 Greenwich Mean Time.Comment Flight November IR2 to OPR10.Stand by for spacecraft impact.We confirm a thermal signature of the crater from IR cameras. Over.Copy Science. 535.054 seconds.The shepherding spacecraft has hit the surface of the moon and this marks the end of the LCROSS flight mission.Mike I wonder if you could give us your impressions of what we just saw and mission success.Well it's hard to tell what we saw there...

Adam Rutherford: That was the final seconds of the LCROSS mission smacking down on the Moon as described by mission control and followed by the NASA commentator. Geoff, so what did happen, was it a damp squib?

Geoff Brumfiel: Well, LCROSS obviously would like it to be a damp squib because they were looking for water but the real question is what did they see and I think the jury is still out on that. They were expected to see I think a 6 kilometre high plume of dust coming out of the Moon and all they saw was a little flash and one pixel on one camera on the moon that scans the orbit or so.

Adam Rutherford: So what made them think that we are going to get this 6 kilometre plume and why did not it happen?

Geoff Brumfiel: Well, these are all questions I am sure the LCROSS people will be hoping to answer in the coming days and there is a number of things out at the moment. It is all pretty much speculation perhaps the rocket stage that was supposed to kick up all this dust and hit at the right angle or perhaps they did not really understand the geology of the crater that they were striking. It is really just too early to tell.

Adam Rutherford: So it doesn't mean that it was a mission failure then.

Geoff Brumfiel: Not at all and in fact mission managers are saying that they have data, they are analyzing it, I think it is just too early to say really what they saw but it certainly was not the sort of spectacular success that NASA had hoped for in the big photo up, I think that they were looking for.

Adam Rutherford: And when are we going to start seeing some of the scientific results?

Geoff Brumfiel: It could be several weeks from now before NASA convenes a press conference.

Adam Rutherford: And in the other story you have been covering this week a disturbing development at the LHC.

Geoff Brumfiel: Indeed there is a physicist who was working on the Large Hadron Collider, the big particle accelerator near Geneva, Switzerland who has been arrested on charges of communicating with terrorists.

Adam Rutherford: So, tell us who is this guy and what was he doing at CERN?

Geoff Brumfiel: Well, the guy's name is Adlène Hicheur and he is a post doc at the Swiss Federal Institute of Technology in Lausanne. He was working on an experiment called LHCb which is one of the big four detectors at the Collider.

Adam Rutherford: So this is pretty serious, what are the charges?

Geoff Brumfiel: Well, the charge is criminal association in relation to a terrorist undertaking and what Hicheur specifically being accused to doing is e-mailing to al-Qaeda in the Islamic Maghreb which is the North African wing of al-Qaeda. He supposedly had been communicating with them about targets to strike within Europe and specifically France.

Adam Rutherford: When you say targets to strike, he works at the biggest scientific experiment of history of mankind, was CERN a target?

Geoff Brumfiel: Well, there is no evidence at this stage that CERN was either a target or a possible source of material. All indications are right now that this was unrelated to his activities at CERN and CERN is denying that he could have gained any sort of nuclear material or any sort of equipment that would have aided him in any alleged terrorist activities. I should emphasize alleged because I have just spoken to Halim Hicheur who is his brother who is also a scientist and he says that these charges are totally spurious and without cause and he believes that his brother is completely innocent.

Adam Rutherford: So more bad press for CERN but when are we going to hear more about this story.

Geoff Brumfiel: Well, in terms of the court case, I imagine that that will be developing in the next few weeks and months and already there is a lot of information out there about the supposed intelligence and things that have led to the arrest and there will be much more to come. In terms of CERN, the LHC is still on schedule to start up in late November or early December. So hopefully, finally we will actually get some particle physics instead of the arrests and accidents and all sorts of other news out of CERN.

Kerri Smith: Okay, thanks Geoff. All those stories as ever on http://www.nature.com/news and take a look at our vids as well. That's it for this bumper show. Next week, 250 years of botanic gardens. 40,000 generations of bugs and how our brain deals with very loud noises. I'm Kerri Smith.

Adam Rutherford: And I am Adam Rutherford. Toodle pip old chap.