Lab–grown brains and the debate over consciousness

Host: Benjamin Thompson

Welcome back to the Nature Podcast. This week, could consciousness arise in lab-grown brains?

Host: Noah Baker

And the impacts of cuts to a pioneering diversity initiative. I’m Noah Baker.

Host: Benjamin Thompson

And I’m Benjamin Thompson.

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Host: Noah Baker

First up on the show this week, reporter Ali Jennings has been asking whether lab-grown mini-brains could become conscious and exploring the ethical concerns that question raises.

Interviewer: Ali Jennings

A dull, grey blob the size of a pinhead floats in a petri dish on a lab bench. The blob is made up of thousands of living, communicating brain cells. This is a cerebral organoid, and neuroscientists across the world are growing these structures in the lab to better understand the human brain.

Interviewee: Madeline Lancaster

The way that we accomplish this is by starting with stem cells, and then we essentially provide the right sort of environment to support growth of brain tissue but not other organ types so that what ends up happening is you have these 3D balls of tissue that look a lot like the developing human brain in certain ways.

Interviewer: Ali Jennings

This is Madeline Lancaster, an organoid researcher from the University of Cambridge in the UK. Madeline was the first person to grow a brain organoid back in 2010, and now she uses them to study brain development and disease.

Interviewee: Madeline Lancaster

The human brain is hugely enlarged and very complex, and that gives us our unique cognitive capability but it also makes us more susceptible to neurological conditions that are not very well modelled in, for example, mice. So, brain organoids are especially useful for looking at human-specific features of the brain and for modelling those types of neurological conditions.

Interviewer: Ali Jennings

Right now, researchers can’t grow brain organoids more than a centimetre in length, and they lack much of the complex internal structure of fully formed brains, even those of simpler creatures like fruit flies. But as the field matures, some researchers are working on ways to increase these organoids’ size and complexity, which raises an important question. Could such bundles of brain tissue ever become complex enough to be conscious?

Interviewee: Anil Seth

I don’t think it can be ruled out that a cerebral organoid could achieve consciousness. I think it’s entirely possible that as organoids develop in complexity and similarity to human brains that they could have conscious experiences.

Interviewer: Ali Jennings

Anil Seth works on cognitive and computational neuroscience at the University of Sussex in the UK. Anil thinks that if organoids were to become sufficiently complex, the activity they display could become more similar to that of conscious humans. The problem, according to Anil, is that we don’t know exactly what kind of complexity could lead to consciousness.

Interviewee: Anil Seth

You could say that being more similar in terms of neuroanatomy and neurophysiology to human brains, well, that’s the right kind of complexity. But then there’s also the possibility that you can have organoids of some kind of complex structure that’s different from the human brain but that is also sufficient for consciousness.

Interviewer: Ali Jennings

And this raises an even bigger question. If a future organoid were to develop consciousness, how could you tell?

Interviewee: Anil Seth

The real challenge with organoids, of course, is they’re just isolated mini-brains. They don’t have any natural behaviour, so the only way to make an inference about whether an organoid might be conscious is through the analysis of its brain dynamics. We can measure the electrical activity of a cerebral organoid and compare it to the kinds of patterns that we see in different conscious states in humans.

Interviewer: Ali Jennings

Assessing consciousness in humans is tough. Alongside measuring electrical activity, brain imaging of patients in vegetative states has also revealed conscious-like brain activity. But neither method is completely fool proof. And even if there were a clear marker for consciousness in humans, that same marker might not indicate consciousness in organoids. That said, were organoids to exhibit the kind of activity seen in the brains of conscious humans, Anil would be concerned. Although an organoid’s experience of consciousness might be very different to our own, they might still be able to experience some form of suffering and be unable to communicate it. That possibility leads Anil to believe that the field should consider guidelines for this kind of research.

Interviewee: Anil Seth

Because organoids are rapidly developing and not only in how sophisticated the technology is but in how many labs are conducting this kind of research, and because we don’t know any definitive way of assessing the kind of status of organoids, there is an imperative for ethical frameworks to be developed pre-emptively.

Interviewer: Ali Jennings

Anil is by no means the only researcher calling for guidelines in the field. Already, a committee of the National Academies of Sciences, Engineering, and Medicine in the US is examining the ethical issues associated with organoid technology. They will publish their conclusions on any possible oversight mechanisms in 2021. But Jeantine Lunshof, a philosopher and neuroethicist from Harvard University, thinks it would be premature to regulate the current field based on concerns around possible organoid consciousness.

Interviewee: Jeantine Lunshof

I do not believe even remotely that cerebral organoids have anything that would even approximate what we call consciousness. There are regulatory questions and those are the old ones, the classical ones like, ‘Where do you get the tissue from, the cells with which you start the process? Do you need to tell people for what experiments you’re going to use it?’ But it is not in any sense specific for the question of consciousness.

Interviewer: Ali Jennings

Any meaningful regulation of the field, she says, would have to rely on a firm definition of organoid consciousness, which we currently don’t have. Jeantine also points out that the very appearance of organoids – the fact that they look like mini brains – can trigger our moral intuitions where perhaps they’re unwarranted.

Interviewee: Jeantine Lunshof

Where we see something that looks very much like a human brain in this case, we start to ascribe properties of the human brain and our ethical considerations about human brains, so I think that is important to consider and to bring us back to the reality of research when we talk about ethical appraisal of such experiments.

Interviewer: Ali Jennings

There are plenty of opinions as to how this field should be regulated. Back in the lab, Madeline welcomes conversations about where ethical boundaries might be drawn in the future so as to safeguard against organoids achieving consciousness. But she’s cautious about imposing regulations on the field too soon.

Interviewee: Madeline Lancaster

I think it’s also very important to remember we’re having these discussions about organoids being potentially conscious or not but there are millions of actually conscious human beings out there who are actually suffering from neurological conditions that have no treatment because we don’t understand them, because the animal models have not given us the answers we need.

Interviewer: Ali Jennings

What’s clear is that cerebral organoids allow researchers like Madeline to study human brain cells in ways they never could before, and while future organoids could become concerningly complex, there’s plenty still to learn from the comparatively simple ones we have today.

Host: Noah Baker

That was reporter Ali Jennings. To read more about the potential for consciousness in brain organoids and the ethical discussions going on in the field, look for a feature article in the show notes.

Host: Benjamin Thompson

Time now for Coronapod, our weekly update on the latest coronavirus news, and Noah, you and I are joined this week by Brendan Maher, features editor here at Nature. Brendan, hi.

Brendan Maher

Howdy.

Host: Noah Baker

Hi, Brendan.

Host: Benjamin Thompson

Today, we’re going to talk about something that we’ve not actually discussed on Coronapod before and that is herd immunity. It’s seen by some as a fairly straightforward way of getting the world back to normal, but there’s lots to unpack about why that might not be the case. But before we get into it, I do think we need to define ‘herd immunity’ as it’s a phrase that’s been thrown about a fair bit. Brendan, maybe you can help us out with that?

Brendan Maher

Well, sure. At its most basic level, herd immunity is when the population that you’re talking about has reached a certain amount of immunity, usually through vaccination, so that a new infection really can’t be sustained. As soon as the infection tries to jump to one person, it suddenly hits another person that’s protected, so you don’t really have any sort of sustained transmission and any sort of new outbreaks will just peter out.

Host: Noah Baker

Now, it’s also probably worth mentioning that immunologists often don’t like the phrase ‘herd immunity’ at all. This is something that came up when we were making a video about vaccines recently, and all of the immunology editors we were working with that were helping us write that script were saying, ‘Ugh, it’s not really herd immunity because what it really means is that the vulnerable people in the population are protected from the virus because they never encounter it.’ It doesn’t mean that they’re immune to it. It means that enough people have been immunised that people that can’t be immunised are then protected. But ‘herd immunity’ is the vernacular, which I think it’s worth us going with because that’s what everyone is going to talk about.

Brendan Maher

Some of the experts that my colleagues have talked to are saying that herd protection is probably a more appropriate response, and it’s true because you’re just kind of protected by the fact that people around you are protected. It’s almost like an insulation.

Host: Benjamin Thompson

Well, Noah, you mentioned the word ‘vaccine’ there and, obviously, in the pandemic as it stands, there isn’t one, as we’ve touched on many times, so why is this phrase – correct or otherwise – being thrown about now?

Brendan Maher

Right, so a colleague of ours, Christie Aschwanden, a great freelance writer, she wrote a fantastic article for us last week about herd immunity and I mean really the premise is like why are we still talking about this? Because even in the very early stages of the pandemic, people were saying, well, we can just let enough people get infected so that they’ll be immune and then you’ll have herd protection. But the problem is that that’s never ever been a strategy that’s ever worked. We’ve only ever reached any sense of herd protection through vaccination for things like measles. And even then, herd protection is sort of a labile state. It’s a spectrum. It kind of comes and goes. It depends on how many people are protected in a population and that number can go up and go down, not just with the number of people who are potentially immune but also with potentially other measures that are being taken to keep infections down. So, things like wearing masks and social distancing, they actually lower the number of people that need to be vaccinated to provide herd protection, but without really that vaccination tool, you’re looking at lots of people getting sick and potentially lots of people dying, and that’s a big problem for health officials.

Host: Benjamin Thompson

So, it would be a very bold gambit then, I think it’s fair to say, and yet policymakers around the world do keep raising it. Do we think it’s something that governments will consider?

Host: Noah Baker

I mean there are governments that have been thinking about this, but I think that not many governments would actively say that it’s their policy, right. There’s been discussions among governments about how herd immunity might factor into their response. So, the UK government, for example, very, very early on, this was something that was proposed to great dismay at a lot of scientists and then they sort of backed down and said, ‘No, no, that’s not it.’ And there’s a lot of discussion about how the Swedish government is following a herd immunity approach, but the Swedish government themselves, in a note to Nature this week, said, ‘That’s not our approach. That’s something that could result from this sort of approach but we do not rely on herd immunity going forward. We just want to try to find a way in which we can protect people in a way that doesn’t damage other things like the economy too much.’ But it is something that is being mentioned. Donald Trump quite notoriously talked about what he described as ‘herd mentality’ in a bit of a misspeaking moment, but it has been mentioned by various policymakers around the world. People do keep sort of holding on to this idea that, ‘Hey, what if herd immunity is a way forward.’ And there’s so much to unpack as to why that is not necessarily a way forward until such a time as we have a vaccine and even after that perhaps.

Brendan Maher

A key example of what you’re talking about is this fellow, Scott Atlas, who is very high up the food chain in the US management and response to COVID-19, who has repeatedly said things in public about letting the virus run its course, and to be fair, they have at least sort of ideals and perspectives in these plans, if you can call them plans, that would protect the elderly and protect people who are higher at risk, immune compromised and such, while you open up certain parts of society and allow people to return to normal. But the problem is that there’s no really strong plans for how to do that, and you create sort of great imbalance in that you’re potentially cloistering away certain segments of the population and you can never really even do that entirely because there’s just so much need for people to interact generally.

Host: Noah Baker

And I think it’s also difficult, if you were to employ that sort of approach, you really want to have a sense of when you have achieved your goal, right, and that’s something that people just can’t agree on. It’s hard to know what percentage of a population needs to be ‘immune’ to achieve herd immunity, and that’s calculated based on the R number, but the R number changes based on other measures, and it’s really hard to get a sense of exactly what you’d be aiming for. So, if you suggest that high-risk people lock themselves away and then you test everyone and do antibody tests across the country until you hit a number, when do you know that you’ve got to the number that means those people are being protected? It’s kind of very hard to know that. Epidemiologists often say that studying herd immunity is something you do after studying infection for ten years, and you do it after the fact. It’s very hard to do it before you’ve got to that place. And this also relies on a really kind of fundamental assumption which is that after you’ve been infected by COVID-19, you have some kind of long-term immunity at all, and even that is in question and herd immunity relies on some degree of protection.

Host: Benjamin Thompson

Yeah, I mean just this week actually there’s been some reports coming out in the UK of quite precipitous drops in antibody levels a few months after infection, and we have seen cases where people have been re-infected already.

Brendan Maher

Right, well, on reinfections, my understanding is that it’s not something to get too terribly worked up over. You see this with most kinds of infectious disease, that there’s going to be certain amount of reinfection. So far, epidemiologists, and immunologists particularly, that my colleagues have been speaking with are telling me that the virus looks like a lot of other viruses and you do seem to get some levels of protection. But you’re absolutely right, we don’t know how long that’ll last because we’re still pretty early into this outbreak, just about coming up on a year, I suppose. So, we haven’t really tracked individuals long enough to know if they are indeed immune to infection for very long after having been infected. So, yeah, I think there are a lot of missing variables to really understanding herd immunity and again, as a public health programme, it’s just not a strategy.

Host: Noah Baker

Absolutely, I think one of the sources in the feature described it as giving in to the virus, which I think is something that no one wants to actually agree to, to sort of just hold your hands up and say, ‘Look, we’re not going to beat you, we’re just going to let you kill a percentage of the population until the rest of it can continue.’ That’s a really hard sort of moral standpoint to take as an epidemiologist, as anyone giving a recommendation to policymakers, because it could result in one of the resources suggested 1-2 million deaths in the United States, which I think is a number that no one is willing to accept.

Brendan Maher

And I know that a lot of the counter argument is that closing down society as it were, shutting things down, is also causing a lot of hardship, also causing some untold death, in terms of people not necessarily being able to get medical treatment that they would otherwise have been able to get. I don’t really see the numbers bear that out in any real, appreciable way, although I know a lot of people argue very loudly that they are. Largely, I think what we’re seeing is a greater percentage of excess deaths that we are recognising in the pandemic are really sort of indirectly related to COVID-19. So, as it turns out, this pandemic is more deadly than the death counts would potentially tell us.

Host: Noah Baker

Brendan, there have been some very small sections of the scientific community, along with libertarian think tanks and other sort of people of note, I suppose, that have suggested that this kind of herd immunity approach in which you protect the most vulnerable is a way forward because of these other sort of various tangential ways in which the effects of lockdowns and so on can cause problems or death for people. What is the reaction among the scientific community at large to those small sections of the community that are promoting this kind of concept?

Brendan Maher

Yeah, I get the sense you’re talking about the Great Barrington Declaration, which sort of stated that again, if we kind of return society to normal and cloister away some segment of that society that is at higher risk of death from COVID-19, that we can potentially return to normal. It was based on a lot of strange assumptions that we’ve kind of gone over already talking about, but one of them is that it sort of puts up that we’re in these complete lockdown conditions right now. At least in the US, that’s not true. Most parts of our society have really opened up and unfortunately, we do see escalating case counts in the United States right now, and it’s kind of difficult to watch, and I think we’re going to have to probably see some scale back in the ways things are opened right now to sort of reign in the spread of the virus. But just sort of allowing it to run its course is not something that anybody really agrees is a viable plan and indeed, just a few days after the Great Barrington Declaration, I forget if it was the Jon Snow report that chimed in from a competing group of epidemiologists saying that this is not a strategy that is going to be beneficial to anyone and it’s going to cause untold death.

Host: Noah Baker

And I think it is safe to say that if you were to think of these two declarations by groups of scientists, they don’t represent half of scientists on one side and half of scientists on the other side. That’s not really the way that this distribution works. The majority of epidemiologists are not in favour of a herd immunity strategy. In fact, I don’t think any of them would even consider that to be a strategy that should even be considered.

Brendan Maher

Yeah, we live in this unfortunate time where everybody is always finding two sides to every coin, when sometimes there just is a side that makes sense and a side that doesn’t make sense. At least from the epidemiologists I’ve been hearing from, the side that doesn’t make sense is a strategy that looks at herd immunity as a goal without a vaccine. Let’s get the vaccine in place first.

Host: Benjamin Thompson

And yet it seems so seductive. I guess you can see why maybe it will turn the heads of politicians. Do you think there’s any chance that it could be introduced somewhere in the world?

Brendan Maher

No, I mean, I think you’re right that herd immunity is just a really seductive idea, but when you really look at the numbers of what would potentially happen if you just let the virus run its course, it would be dramatic and painful and deadly.

Host: Benjamin Thompson

Well, not much left to cover on this one, I don’t think. All that’s left to say is, Brendan, thank you so much for joining us today.

Brendan Maher

Well, thanks for having me. I hope I can talk about more cheerful things next time.

Noah Baker

Thanks, Brendan.

Host: Benjamin Thompson

More from Coronapod next time. Coming up in this week’s show, we’ll be hearing what a UK government decision to cut research red tape might mean for gender diversity in academia. But before that, keep your eye on the Nature Podcast feed, as later today, we’ll be publishing the first of a special series called Stick to the Science. Now, this show came out of feedback from you and it’s all about science and politics. As the US election draws near and the pandemic pushes science on to the front pages every single day, reporter Nick Howe has tried to get to the heart of what science’s relationship with politics actually is and perhaps more importantly what it should be. Now, though, it’s time for the Research Highlights, read by Dan Fox.

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Dan Fox

The volcanic debris that buried the ancient city of Pompeii nearly 2,000 years ago could be wreaking even further destruction, as the ash that preserved the city may also being eroding its famous murals. Artworks in many of the city’s buildings are degrading, and often have white crystals precipitating on their surfaces. To investigate how these crystals could be causing damage, a team of researchers analysed their composition, as well as that of ash and pumice collected in Pompeii. They found that both the volcanic materials and the salts on the murals contained fluoride and chloride ions, which could have migrated from volcanic deposits on to the paintings. The team suspect that when excavations exposed Pompeii to rain and humidity, this led to an acceleration of the ions’ migration, causing the murals to degrade more quickly. The researchers hope that they can now identify any more volcanic residue on the paintings so it can be removed. Uncover the rest of that research at Angewandte Chemie International Edition.

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Dan Fox

160 million years ago in what is now China, two species of feathered dinosaurs – Yi qi and Ambopteryx longibrachium – took to the air where they glided very poorly into extinction. A team of researchers analysed fossilised remains of the two species, using an imaging technique called laser-stimulated fluorescence. This revealed details of the skin between Yi qi’s elongated digits that suggest the creature had membranous back wings. However, mathematical models of Yi qi and Ambopteryx wings based on these details suggest that the dinosaurs would have only been able to glide short distances and that they’re unlikely to have been capable of flapping or powered flight. They would probably have walked slowly on the ground and lived their lives in trees. Perhaps unsurprisingly, this lineage quickly went extinct, leaving the skies to the ancestors of today’s birds. Take a short glide over to iScience to read that research in full.

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Host: Benjamin Thompson

Back in 2005, the Athena SWAN charter was announced, with the aim of boosting gender equality in UK academia. Institutions or individual departments could apply for gold, silver or bronze status based on a self-assessment of their efforts to hire, promote and retain female staff. Although voluntary, the Athena SWAN scheme has been effective, and has been exported in some form to countries around the world, including the US, India and Australia. But it’s not without its critics. For example, a recent review said that results are inconsistent and that the application process is arduous. And in the past couple of weeks, as a result of a UK government call to cut red tape for researchers, the UK National Institute of Health Research (NIHR) has dropped what had proved a huge driver for the scheme – it’s requirement that medical schools secured silver status before they could apply for certain grants. Nature reporters Holly Else and Lizzie Gibney have covered the Athena SWAN scheme for years. Lizzie gave Holly a call to find out more about this decision from the NIHR and what it could mean for broader efforts to increase gender diversity in UK academia. Holly started by laying out some numbers on the uptake of the scheme.

Interviewee: Holly Else

It really has been quite well embraced. I think about 160 universities or departments have signed up to the scheme, so that’s a lot of people putting a significant amount of work into proving that they’re doing something about gender diversity within their teams. Whether it’s popular in terms of the people doing the work, whether they like doing it and whether they think that it’s doing the best job it could, is debatable, but people have engaged with the process and we’ve seen some real differences because of it. A success story might be one university has changed their proportion of female professors in their department from 30% to 50% in three years. That’s quite a significant change.

Interviewer: Lizzie Gibney

And another reason why it’s been quite successful, many people might say, is that ever important money has been tied to it.

Interviewee: Holly Else

Yes, so, back in 2011, the National Institute of Health Research (NIHR) decided that specific grants that go to medical schools would only be allowed to go to departments within a university that had a silver award, and this was quite ground-breaking at the time. It was the first time ever that a funder had tied a condition of getting the money to working on gender equality. As a result of that move, universities couldn’t really ignore this anymore. They had to start doing something about it if they weren’t already, and following that announcement, actually, applications to the programme quadrupled. That’s how many universities said, ‘Hey, we still need to keep getting this money. We need to do something about this.’

Interviewer: Lizzie Gibney

Wow, so a pretty successful scheme. What was the latest spanner in the works in the last few weeks?

Interviewee: Holly Else

So, last month, the UK government announced a new initiative to cut red tape to reduce the amount of time that researchers are spending filling in forms and ticking boxes in order to give them more time to actually do the work they’re supposed to be doing, and this could be seen as a really good thing. But one of the consequences of this was the NIHR decided that they would now remove this requirement for universities to have an Athena SWAN award in order to get their funding, and this has caused a bit of friction really because this funder putting their weight behind the programme and saying, ‘Hey, you’re not getting any money until you’ve done this,’ got people start taking it seriously. Now that’s been taken away, there’s a fear amongst some researchers that actually, this is now going to slip down the priority lists of universities, so if nothing is going to happen if they don’t retain their award or move up the ranks in terms of gold, silver and bronze awards then are they going to continue to invest so much time and energy in the preparation of these documents but also actually in the department themselves with regards to supporting women?

Interviewer: Lizzie Gibney

So, yeah, this has come as part of what some people are calling a bonfire of the red tape. There’s this sign from on high that things are really changing for UK researchers and yeah, it might be seen as a benefit for some as the scheme can be quite a burden for the researchers who are having to actually fill in all the self-assessment and a lot of them are women themselves and they’re taking on the brunt of it.

Interviewee: Holly Else

Yeah, you raise a good point there, Lizzie. So, what tends to happen in a department and obviously, this doesn’t happen everywhere, is that it’s the women in the departments’ job to do the Athena SWAN things, and this then ironically means that they’re spending so much time doing their application for Athena SWAN, they’re not actually doing any of their own research. And actually, earlier this year, an independent committee released a report. They’d been doing a big review into the programme to see what its strengths were, what its weaknesses were, and they found that this was actually a very burdensome exercise for departments. And also, lots of people who contributed to the review said they didn’t really have much faith in the decisions that were being made by the panels who assess the assessments that departments send in because there wasn’t really much transparency in how these decisions were made. And so, although people support the imitative, think it’s good and it’s done some really, really great work to improve gender equality in UK universities, there was sort of an undercurrent of dissatisfaction.

Interviewer: Lizzie Gibney

And do you think that fed into this decision at all to get rid of it as a requirement?

Interviewee: Holly Else

Well, officially, we hear, ‘No, it’s an independent thing,’ but obviously, these ideas about Athena SWAN being quite burdensome and disadvantaging female academics in particular have been around for years, so it can’t go unnoticed but I don’t think it would have had necessarily any impact in the decision to cut the red tape and set the bonfire going. It’s just perhaps an unintended consequence.

Interviewer: Lizzie Gibney

So, they’re getting rid of this requirement to have Athena SWAN for this particular health research scheme, which was quite big, I think. It was like hundreds of millions of pounds worth of money. Are they replacing it with anything? Are we just going to completely scrap having to consider gender diversity?

Interviewee: Holly Else

No one’s really clear on this. I mean, the exact wording for the announcement is a bit ambiguous. I’ll read it out to you if you like. ‘Moving forward, the focus for us will be on ensuring applicants provide evidence of their broader commitment to the principles of gender equality rather than on compliance with a specific standard.’ So, that kind of gives the impression that they’re not going to want specifically Athena SWAN but they might want something else or even just a mention of it. But one of the things they might be thinking about doing, I don’t know, is perhaps bringing together something that looks at all different types of diversity. So, one of the arguments with Athena SWAN is there’s so much focus on gender diversity with this award that other aspects of diversity maybe get sidelined, so we’re talking about race, disability, sexual orientation, and maybe something that comes in will be something that looks at diversity more broadly across all those different aspects, which would be seen as a positive thing.

Interviewer: Lizzie Gibney

And what about the kind of message and the timing of this? To some people, it might seem like its watering down the scheme just when women and minorities in science are finding that their careers are being disproportionately disadvantaged by this massive pandemic that we’re living in. Is now really the time?

Interviewee: Holly Else

Well, that’s a really great point, Lizzie. I mean, is there ever a time to remove this kind of requirement on such an important issue? Most people would say probably not. But the other interesting thing is that Athena SWAN has been so successful in the UK that it’s actually been exported to other places. So, in Ireland, the scheme exists and research funding there is tied to these requirements. It’s also in the early stages of getting going in Australia. There’s a similar scheme in the USA. And actually, the EU is considering not necessarily Athena SWAN but some other kind of gender award or gender action plan as a term for its grants in the future as well. So, you could argue that the rest of the world is careering ahead with this and the UK is now pulling behind.

Host: Noah Baker

Nature reporters Holly Else and Lizzie Gibney there. For more on this, Nature has an editorial, and you can find a link to that in the show notes.

Host: Benjamin Thompson

Finally on the podcast, it’s time for the weekly Briefing chat where we discuss a couple of articles that have been highlighted in the Nature Briefing. Noah, why don’t you go first? What’s got your attention this week?

Host: Noah Baker

Yeah, so I’ve been reading an article in The New York Times which is all about something I find shocking and surprising, that there could be a set of organs in the human body that we didn’t know about up until right now and, in fact, more specifically, about a month ago.

Host: Benjamin Thompson

I mean, I imagine that the human body is one of the most studied things on Earth. But you’re saying there’s more secrets to be uncovered?

Host: Noah Baker

Yeah, that’s exactly what I thought, and you would expect that after literally centuries of medicine, of anatomy, we would have found all of the bits that make us do the stuff, and it turns out that perhaps there was another bit that we didn’t know. So, researchers, specifically oncologists, have found what they’re claiming to be a brand-new pair of salivary glands buried deep in the middle of your head, kind of underneath the skull where the nose connects to the ear.

Host: Benjamin Thompson

Right, so presumably then if these are only just discovered, they must have been pretty hard to find.

Host: Noah Baker

Yeah, and that’s kind of part of the reason that people haven’t come across them before. They’re very thin and they are really hard to see with standard imaging techniques. You have to use quite specialist imaging techniques. And in fact, they weren’t looking for them when they came across them. They were trying to understand a bit more about why people who undergo radiation therapy sometimes struggle with dry mouth and problems swallowing, and they were imaging the head and they saw these two sort of bodies show up, about an inch long covering these tubes, and they thought, ‘That’s odd, what is this?’ Then they went into some cadavers. They dissected them, and they found tissue that really closely resembles salivary glands. So, I should mention that other researchers are questioning whether or not these are indeed large salivary glands or perhaps just collections of micro salivary glands, which we know already exist throughout the mouth, and so that could possibly be what they’re looking at here. But the researchers are arguing that this is actually a brand-new way in which saliva is produced, and they want to call them the tubarial salivary glands.

Host: Benjamin Thompson

Well, still some debate then seemingly, Noah, but you said that these glands were found by oncologists. Does this have any relevance to their work to cancer treatment?

Host: Noah Baker

Yeah, and the reason this is important, according to the authors, is that it could change the way that radiation therapy is given, and it could also help to explain why these symptoms of dry mouth and problems swallowing could often be seen by people that undergo radiotherapy. So, when you have radiotherapy, radiation is beamed into your body, and often it’s very deliberately designed to converge in a particular way to only give the highest doses to the area you’re trying to attack, often a tumour. And if you have a good understanding of the anatomy inside your body, then you can try to ensure that you don’t eradiate in a damaging way the parts of your body that you don’t want to be damaged, such as salivary glands. But if you don’t know that the glands exist, you don’t know to avoid them, and so now these glands have been found or they’ve been posited to exist, it means that people administering radiotherapy can try to avoid them in the future and hopefully avoid these symptoms of dry mouth and problem swallowing for those patients.

Host: Benjamin Thompson

Well, for my story this week, Noah, I’m going to ask you a question. What baby animal the size of a Chihuahua has a long tail, is between 71 and 75 million years old and would ruin your day when it grows up?

Host: Noah Baker

I don’t know. Some kind of crocodilian, something like that, a big old crocodile?

Host: Benjamin Thompson

Well, it is something with a lot of teeth, Noah. You’re absolutely right. And I’ve been reading a story in National Geographic about a discovery or a potential discovery of some embryonic tyrannosaur fossils.

Host: Noah Baker

Tyrannosaurs… you’re saying that embryonic tyrannosaurs are the size of a Chihuahua?

Host: Benjamin Thompson

Well, it seems that the researchers reckon that when they hatch, that’s the sort of size they are, about two feet long or three feet long, and what’s intriguing about this is although sort of older juvenile tyrannosaurs have been discovered and, of course, full-sized examples of the genus have been found, these tiny, tiny examples, this early stage of life, not much was known about it to be honest with you. And what’s happened is that two fossils were discovered – one decades ago and one relatively recently in the last few years – of a foot claw and a lower jaw. And with some sort of clever techniques, the researchers put forward that these are from the tyrannosaur genus. Now, not Tyrannosaurus rex, I have to say. It’s an unknown relative, and this work hasn’t been peer reviewed yet.

Host: Noah Baker

So, you have adorable baby tyrannosaurs the size of Chiahuahuas, but how big are they going to get? If they’re not Tyrannosaurus rex, are these never going to get that much bigger? Is this like a new adorable little mini tyrannosaur that they’ve found?

Host: Benjamin Thompson

To begin with, yes. They reckon that these tiny dinosaurs are about a tenth of the size of the adult tyrannosaurs, but I will say that these things can grow to up to 30 feet in length. So, it may start off small and cute, but it will grow up and be quite furious later on.

Host: Noah Baker

Is this the first time that baby tyrannosaurs have been seen? Is it something that’s going to shed new light on the tyrannosaur life cycle?

Host: Benjamin Thompson

Well, yeah, I think sort of up until now, researchers were kind of mystified about what happened in tyrannosaur early years, and what this work is helping to suggest as well is maybe how big tyrannosaur eggs were because so far, there’s been no confirmed findings of one of those. And in this case, researchers think that the tyrannosaurs were curled up into these eggs, pretty big eggs, that measured about 17 inches long.

Host: Noah Baker

So, fairly big eggs but I guess these are pretty big creatures, certainly eventually.

Host: Benjamin Thompson

Yeah, they might be Chihuahua-sized to begin with, but they get pretty big as they get older. Anyway, let’s leave it there, Noah, for today’s Briefing chat. Thank you so much. Listeners, if you’d like to know more about the two stories we discussed today then you’ll find links to them in the show notes. And if you want even more stories like this delivered straight to your inbox then make sure you sign up for the Nature Briefing and, once again, head over to the show notes where you’ll find a link to do so. And now, for a quick humble brag – we’ve been nominated for an award. The Nature Podcast is a finalist in the Lovie awards, and we need your help to win a People’s Lovie award. If you’re a fan of the show, and if you’ve listened this far through I really hope you are, please take two minutes to vote for us. We’re finalists twice over in the video category too, and you can find links for where to vote for us in the show notes.

Host: Noah Baker

And speaking of videos, we’ve made another one, this time about the Philae lander’s rather bumpy touchdown on a comet back in 2014. The crash landing meant that Philae ended up on its side and couldn’t quite finish its mission, but now, thanks to some very clever detective work, scientists have turned the crash to their advantage and got the first ever look inside a comet. Find out how in the video. You can find a link in the show notes. I’m Noah Baker.

Host: Benjamin Thompson

And I’m Benjamin Thompson. Thanks for listening.