Lockdown aged young brains, and dealing with nuclear waste
In this edition of The Naked Scientists: How COVID-19 lockdowns affected the brain development of teenagers; how best to dispose of dangerous nuclear waste; and why the UK’s puffin population is thriving despite a rise in avian flu.
In this episode
00:57 - How lockdown affected teen brain development
How lockdown affected teen brain development
Patricia Kuhl, University of Washington
New research has found that COVID-19 lockdowns resulted in significant changes in the brain development of teenagers, translating in some cases into the equivalent of up to 4 years of accelerated ageing. The study - which has been published in the journal PNAS - suggests that the impact was also much more pronounced in girls. The research was the brainchild of Patricia Kuhl at the University of Washington…
Patricia - The original plan was to begin in 2018 and bring teenagers between the ages of 9 and 19 into the laboratory to study many brain measures and behavioural measures to try to understand adolescents. And they were to come back in 2020 for visit two. Of course 2020 hit, and so did the pandemic. And we were all on lockdown. So in 2021, we brought all these teens back, but we understood it's not the same study anymore. We're not looking at them two years later. We're looking three years later and a crisis has intervened. One of the measures that might reflect this change in our lives was something called cortical thickness. At the top of our brains there's this layer of grey matter filled with neurons and synapses and that grey matter thins as we age. So it's known, there are lots of data, showing that the cortex, the grey matter in the cortex, thins from pre-adolescence to until we die. And that thinning over time is associated with slower processing, memory loss. And we also know that you can accelerate cortical thinning based on stress. So we wondered whether or not we would see any differences in the cortical thickness from the 2018 data and the 2021 data.
Chris - How do you know though, that they weren't going to thin their brains like that anyway? How do you know that it was the pandemic that might be making any differences you saw and not just that cohort?
Patricia - Well, answering this question took a special method. We took the 2018 data, We built a normative model for examining exactly what you'd expect based on the data you've collected with just age. So if nothing else had happened just based on age, how much thinning should you expect? So that normative model allowed us to take the 2021 data and go back and compare it to the normative model and say, has it thinned exactly as the model predicts as we'd expect? Or is there more or less thinning? And in fact, it allowed us to say all of the teens thinned faster. Their brains age. This is a measure of maturation or ageing. It thinned more than expected, and the dramatic result is that girls show an effect that's much larger than boys. It's four years worth of advanced ageing in the girls versus one year of advanced ageing in the boys. There's no known data that girls caught the virus more than boys. And when you look at the brains of the girls, the effects are all over. Whereas in boys, it's in just the visual cortex. We're attributing that to one of the known causes of thinning, which is stress and explaining that girls depend more on their social connections.
Chris - If you look at where the thinning has occurred, did that translate into any functional changes, reflecting this increased ageing you've detected?
Patricia - When you look at the particular brain areas, many of them are related to social processing, face processing, mentalising about what other people's statements mean. Areas of the brain that we rely on for social interpretation of our everyday world. So again, the findings we have in girls seem to point to that social explanation. Whereas in boys, we don't see any of those social areas affected. It's only visual cortex. So it does present a puzzle. And would we expect changes, correlated changes, in behaviours in cognition, in measures of social wellbeing? Yes, we do. We have some data. We are still crunching those measures to see whether or not we can see whether girls who thinned much more strongly have more of these measures than we'd expect, reflecting a decrease in the sense of wellbeing or a sense of belongingness. But we can't say anything about that yet. But yes, that's our hypothesis.
Chris - What do you think the prognosis is for these people? Are they basically destined to have advanced ageing for the rest of their life and this may therefore mean that there is more waiting for them sooner down the track than would otherwise have occurred?
Patricia - Chris, that's the key question. When I think about it and think about what we know about the brain, we're not going to see the brains of these teens get thicker again, that's not the biological process. It's always a thinning over age. But what would it look like? So if we brought these girls back now, as their social lives came back, as all of their lives came back, a return to normalcy, what we might see is just a slowdown in the thinning process. And we would point to that and call that recovery. Or the opposite, which would be what you've just asked. Is there a retention of that increased age reflected in the measures in the brain? And it's anyone's guess what it would look like.
Chris - Given that a very significant proportion of younger people are shifting their lives online, some of them are almost putting themselves into a lockdown voluntarily, aren't they, by withdrawing from society. So does this give us an opportunity then to study them and to ask whether we see the same effects in these people who are not experiencing coronavirus, but they are experiencing those same social isolations and see if we've therefore got the correct model, that you've captured the correct outcome, but also work out what the impact might be on people more generally of the life we are tending to see them leading in this era?
Patricia - Again, you're spot on. I think the teens, at least those in America, I think those in Britain as well, are flocking to social media. And it's both a comfort because it means connectivity 24/7, but it's also a negative because bullying, the tendency for extremely negative feedback on social media is just rampant here. And so the teens who are flocking to media have both increased their exposure to the online potential of bullying and removed themself from social face-to-face. I'm a strong believer that our social well being really does depend on face-to-face contact and that media is not as good even when it's positive. It's just not as good. Look at the learning losses that we see here in primary school and secondary school and college students. Reading and maths scores plummeted during the pandemic because we weren't learning well, the kids weren't learning well through a screen. My studies of babies and young children say they can't learn with screens. You need social interaction. So I am a strong believer that we have to monitor and examine why the kids flock to social media and as parents constantly try to keep the line of communication going.
08:45 - What should the UK do with its nuclear waste?
What should the UK do with its nuclear waste?
Claire Corkhill, University of Bristol
The Sellafield nuclear site in Cumbria is the temporary home to the vast majority of the UK’s radioactive nuclear waste. This is the byproduct of nuclear fission: splitting apart the nuclei of heavy elements like uranium and the collecting the energy this releases. But what to do with the radioactive nuclear waste, which can be detrimental to the environment if it isn’t managed properly and can remain hazardous for 100,000 years, is key to its potential future in the UK’s net zero ambitions. Now, concerns have been raised about the safety of the Sellafield site, with the BBC reporting leaking silos and sub-standard cybersecurity. To find out more, I’ve been speaking with Claire Corkhill, a professor of mineralogy and radioactive waste management at the University of Bristol. Claire recently contributed to a BBC article about Sellafield and the UK’s nuclear waste…
Claire - All nuclear waste starts as uranium from nuclear reactors. So this uranium is what has been used to generate energy from the splitting of uranium atoms. What that does is it creates what we call fission products. These are smaller atoms that are unstable and they emit radioactivity. And this radioactivity is what makes the nuclear waste so very hazardous. A lot of people's minds will automatically go to The Simpsons and that green glowing goo that oozes out of barrels around Homer Simpson. But actually it's much more boring than that, I'm afraid to say. Physically speaking, radioactive waste is contained in ceramic materials, in glasses and also in cement. And when I say glasses, what I mean is it's not poured into containers of glasses. It's actually chemically locked up inside the structure of the glass.
Chris - And is it all solid stuff or do we end up with liquids as well?
Claire - Well, it is a mixture. In an ideal world, when everything's working correctly, we have solids, but that hasn't always been the case in the past. So almost all of our waste is stored at the Sellafield site up in Cumbia. Now, some nuclear power stations that are being decommissioned around the country, for example Trawsfynydd and Wylfa in Wales, these have temporary stores, interim stores. But the majority of the waste is at Sellafield. And the majority of it is in safe, secure warehouses essentially, where the waste is stacked up in barrels or drums very neatly. It looks a bit like an Amazon warehouse, but obviously with less people driving around. But some of it has been there for the last 50 years or so, underwater in what look a little bit like large swimming pools, and some of these large swimming pools are exposed to the air, which means it's exposed to all of the elements. It's exposed to birds swimming in it and so on.
Chris - Obviously exposed to the elements and those kinds of constraints, that's not ideal. But once it's in that solid vitrified or concrete like form, is that not okay? Can we not just bury that for example, and then leave it to cook for a few hundred thousand years, just avoiding the area and it will become safe?
Claire - Yeah, that's really the idea. So the radioactivity of the concreted waste is kind of the medium level of activity, if you like. So we are okay with storing that in these warehouses over long periods of time. And we're talking here about decades now. Occasionally you'll need to refurbish the packages if they've started to degrade and so on. It's the higher lived radioactive waste that we're a little bit more concerned about because this is really hazardous to biological life. It's emitting an awful lot of heat, so it needs human intervention to try and keep it cool. Now that's okay whilst we have the technological world that we live in today, but the radioactivity of these wastes will persist for hundreds of thousands of years. So how can we guarantee right now that people in 500 years time or 1000 years time will have the technology to be able to keep these wastes cool? Ideally what we really want to do is take all of these materials away from people forever and isolate them from populations so that we don't have to rely on the populations of the future to try and keep this material safe. And as you quite rightly suggested, one of the best options for this is burial in a deep geological disposal facility.
Chris - Do we have something like that? I mean, is there anything on that site that could accommodate that? I suspect that doesn't go down very well with people who are concerned about the environment or people who have to live near where you intend to do that.
Claire - So the first thing to say: it's important that other countries are already building these types of facilities. So Finland are already well advanced with building their facility. They've not started accepting waste yet, but they will in the next few years. In the UK we have a policy that the government has correctly identified that we can't just keep generating waste and storing it for very long time periods at Sellafield. We need to do something safer with it in the future. And what we are looking for are two things. The first is a site with a suitable geology, and the second is a site that has a willing community. So we are looking for communities to volunteer to have one of these facilities. And you might think that, well, who would volunteer for this? But, actually when you look at the Finnish example, there were communities who were fighting over the facility because they wanted all of the financial benefits that would come from having construction and the financial incentives from the government to have that facility in their local area.
Chris - And these facilities that we are talking about, next generation storage facilities. Is that going to be future proof not just from the perspective that someone in the future won't have to worry about dealing with it, but the sorts of waste we anticipate the next generation of nuclear producing. Because there's a lot of talk about, for instance, SMRs, small modular reactors, being used in various places. Will the sorts of waste we anticipate coming out of those sorts of facilities be able to go into the waste facilities that we are planning today? Or are we going to be back to square one in a few years time because we generate waste and say, 'well, these are not fit for purpose.'
Claire - What we can say is that small modular reactors produce the same types of waste as the large reactors that we're currently building and operating in the UK. So like Hinkley point C that's currently being constructed. We're not worried about those. That waste will be able to go into a geological disposal facility. We're fairly certain of that. The other types of more advanced reactors we're talking about are things like fast breeder reactors and molten salt reactors. These things are a little bit more experimental on paper at the moment. Now is the time for us to really be looking at those designs and thinking about what the waste will look like. We can then start to understand whether the geological disposal facility will be suitable. That's still a question that we haven't got an answer to. And it's something that the people who are designing these reactors, it's something that they really need to have at the forefront of their mind. Because if we take into account waste now at this early stage of design, we could avoid those problems of the past that had us pile waste at Sellafield in not the best way. It's a very timely question and it's something that I hope we can really get to the bottom of before anyone starts to build any of these new nuclear reactors.
16:24 - New sweatband keeps tabs on body biochemistry
New sweatband keeps tabs on body biochemistry
John Rogers, Northwestern University
Scientists have developed a sweat-collecting band that can analyse the fluid and determine what’s actually happening inside the body. It could flag up problems we don’t even know we have. So, how does it work? I’ve been speaking with its inventor, John Rogers, at Northwestern University…
John - Many people are familiar with fitness trackers of various sorts, typically mounted on the wrist, measuring steps and overall activity, sometimes heart rate, temperature as well. But it doesn't tell you everything. It doesn't provide any kind of biochemical information on how your body is performing during physical exercise. And so what we were interested in developing is a wrist-worn device that could complement and extend the kinds of parameters that you can currently measure with fitness trackers into this biochemical regime.
Chris - How does it work? What are you actually measuring to get, effectively, from outside the body, a glimpse into what's going on inside the body?
John - When you think of biochemical assessments, you're typically thinking about blood sampling, or maybe more recently measurements of interstitial fluid, the fluid that exists within the tissue but outside of the bloodstream. And there are various ways to capture those fluids and to monitor them, typically in a hospital setting. But the problem with those approaches is they require penetration of the skin, obviously to collect blood but also for interstitial fluid. And those methods are by definition invasive. You have risk for infection, risk for pain, probably not super useful in a routine way for athletes or people who are interested in fitness. And so we focus on sweat because it's very easy to collect, especially during a physical exercise. Everybody sweats and the sweat turns out to have a lot of biomarkers present in it, various biochemical species, many of which correlate with those same species in blood and interstitial fluid. And what we've designed is kind of an elastic band that couples to the skin at the wrist and has little inland ports. And as sweat moves into our band, we can measure different biochemical species and sweat. And we can also determine the rate at which sweat is emerging from the skin. And the total amount of sweat that's released during a given time period.
Chris - Is the rationale for using sweat that we make sweat from blood and therefore it filters out the liquid to make the sweat, and some of these other biomarkers that you're interested in go with the water?
John - That's kind of the idea. The sweat glands are not directly and intimately interfaced with the blood vessels, but there's permeation through the blood into the interstitial fluids, into the sweat glands. And so it's all equilibrating. In many cases, concentrations of species in sweat will be different than those concentrations in blood, but they're correlated. And so in many cases you can establish calibration factors and that's important because there's a tremendous amount of historical data on how to interpret blood serum concentrations of species. That's the chemistry aspect. But like I said, just the physical processes of generating sweat and sweat emerging out of the body, those are important pieces of information to understand as well, especially in athletic performance. You want to avoid cramping and things like that. You'd like to rehydrate. We also have colour changing chemistries to do that chemical concentration measurement just by quantifying the change in colour. The additional colour changing component of these bands allow us to determine the timing at which sweat fills into various parts of the band along its length. And so from that information, we can determine sweat rate as well as total sweat volume. And then in addition for this particular paper, we are demonstrating the ability to determine the lactate concentration in sweat and its pH.
Chris - Have you given it a real road test, or I suppose I should say trackside test? Have you put this into real world settings with real world athletes?
John - We have, in fact. And the publication includes extensive testing on a cohort of human subject volunteers, some of which have high levels of physical fitness, others not so much. The microfluidic band itself is waterproof. And so you can quantify sweat loss and sweat chemistry even when you're in the pool, which turned out to be pretty interesting because I think there's a limited awareness of how much you're sweating while you're swimming because water from the pool is washing the sweat away. And this provides a mechanism for really quantifying that in a way that hasn't been possible in the past.
Chris - If you show this to people, are they showing an interest and are they finding this is actually adding useful data to a training regime that means you can optimise performance further for people.
John - You talk to endurance athletes, you talk to triathlon competitors, you talk to people on our football team. So Northwestern is kind of a small private school, but we have a pretty high level football programme. They monitor sweat currently. The way they do it, however, is with absorbent pads just taped to the surface of the skin. And they use that information to make informed decisions on how much fluid intake they need to consume to get back to where they started. So they're already doing it. The problem is it's a very clumsy process. You aren't able to visualise the release of sweat in real time because you have to take the absorbent pad off and weigh it and wring it out. I think sweat is a whole new kind of metric to think about in the context of your fitness routine. And so I think it will start with performance athletes, but I think there will be much broader interest in this novel way to track your workout.
22:35 - Farne Island puffins thrive despite avian flu fears
Farne Island puffins thrive despite avian flu fears
Sophia Jackson, National Trust
The Farne Islands lie off the coast of Northumberland. They have been described as “possibly the most exciting seabird colony in England” and are currently home to around 50,000 breeding pairs of puffins. They are doing remarkably well despite concerns around outbreaks of avian flu, which we have reported on this programme. Members of this beautiful and endangered species usually start breeding in May, with young chicks - which are called pufflings - arriving later in the British summer. Sophia Jackson from the National Trust is out there right now, keeping an eye on them…
Sophia - The Farne Islands are off the Northumberland coast in the United Kingdom. It's about 27 islands when the tide is low and we count puffins on 9 of those islands. On Inner Farne, for example, we've got, this year, 26,500 pairs of puffins. This is because the top soil is really ideal for them to burrow into the ground. The island looks like holey cheese. Some burrows do overlap with others because there are so many. And most importantly on that, we've got no ground predators, which means there's nothing that can go into their burrows and get their egg or get their chick when they are breeding. We're in the North Sea, we've got marine protection zones around our islands as well. So it means that their food source is protected.
Chris - Do they have to share their ground space with any neighbours?
Sophia - Yes, so the Farne Islands are really rich for all species. We've got over 200,000 seabirds nest here. Guillemots and kittiwakes and razorbills, shags, all on the cliffs. We've got a really large important population of grey seals as well. So we'll have them lolloping up into the island and pupping in the winter as well. So yeah, they've got a lot of noisy neighbours to deal with out here <laugh>.
Chris - And to what do you attribute the fact that the population has gone up? The 2019 census showed just north of 40,000, now you think north of 50,000. So quite a substantial increase. Is that just because there wasn't an accurate count before or have they genuinely increased in number?
Sophia - So it sounds like a lot, but that increase would've been gradual over five years. We weren't quite sure what to expect because the puffin population is declining globally. We were very surprised that ours has gone up by 15%. But I think just with the ideal habitat they've got here, they are thriving, which is really good. But it shows the importance of constant monitoring. So we're going to do the survey every year and just keep an eye on them and see what's happening.
Chris - We reported on our programme that - in fact, speaking to people from the RSPB and so on - that there was real concern about what bird flu might do to rare species, including puffins in places like the Farne Islands. So it looks like they have weathered the flu storm. Why do you think that, thank God, that what we feared might happen didn't?
Sophia - We're so relieved that puffins managed to weather the avian flu storm on the Farne Islands. They didn't avoid it completely. So in 2023 and 2022, the peak years of avian flu, we did pick up 938 puffins. However, compared to all the other species, that was nothing. Puffins, the way they nest, I think has helped them. Because they burrow into the ground and they've only got a couple of neighbours underground, disease is less likely to spread between the puffins. So unlike the cliff nesting birds, the guillemots nest really close together and they're all sharing a tiny space. There's lots of food around, they're all squishing together. So almost like what we did during Covid when we locked down and went into our own houses, the puffins have their own houses. There was a study done of the Isle of May, which was very interesting as well, and it showed some immunity within puffins. So whether or not that's shared within our puffin population as well would be interesting to know.
Chris - And you're off on your way over there today, are you?
Sophia - Yes. Inner Farne today, so we came over on a very wavy boat crossing, but we are in the North Sea. So that's what to expect. When you come over, you make sure your bags are clear of all potential ground predators. There's a foam mat you walk through when you get onto the island to take any diseases and things off of your feet. So we're doing everything we can to still prevent avian flu coming onto the island.
Chris - Although of course if it arrives with a bird, which is not going to follow those sorts of protocols. That must remain a huge risk. Do you actually have a monitoring system in place so that you are going and sampling to see what is circulating among the birds there?
Sophia - So we have lots of protocols in place. So if we find a dead bird that doesn't look like it's been predated, there's not lots of feathers around it and things like that, it looks like it's just died, we will send that off. So we contact DEFRA and someone comes and collects it and sends it to the lab and they do the tests on it as to why it died. Has it got avian flu? Luckily none of them have had avian flu this year, which is very good.
Chris - That's very encouraging, isn't it? But what guidance is given to protect people? Because obviously if you're in a place where there are tens of thousands of birds and we are having big outbreaks of bird flu, thank goodness not there at the moment, but there is the potential for people to pick things up, isn't there? So are you practising particular protocols to make sure that you are not exposed?
Sophia - We advise when visitors come onto the island that they wear a waterproof coat. So if they do get pooped on, which is quite a high possibility on the Farne Islands because there's so many birds, you can just wipe it off. We've got various antibacterial, hand sanitiser stations around the island as well. When the team does go and pick up a dead bird to send off, even if there's no avian flu this year, we'll still wear full PPE. So we'll wear a hazmat suit, goggles, mask, gauntlets, and wellies to pick up that bird just in case it's got something. But if there are signs of avian flu that do appear, we will close the island to protect people and protect the birds.
Why don't some people enjoy music?
James - Anhedonia is defined as an inability to experience joy or pleasure. It occurs in roughly 70% of people with a major depressive disorder. However, to give us a sense of what's going on specifically with your experience with music, I'm going to need some help, and that's why I've put in a call to Malinda McPherson, Assistant Professor at Purdue University's Department of Speech, Language, and Hearing Sciences.
Malinda - To classify a person as having musical anhedonia, and not a more general form of anhedonia, that person must respond positively to rewarding stimuli like laughter, money, visual art, television, and other types of positive things. But they just don't respond positively to music. There are generally considered to be two types of musical anhedonia. One is acquired following some neural damage or trauma, and the other is present without any kind of neurological damage. The first type can sometimes go away as the brain damage heals, but the other type musical anhedonia, without brain damage, unfortunately, does not have a known cure. But there's also nothing wrong with a person with musical anhedonia. There's simply a spectrum of responses to music. Some people get chills every time they hear music, and others only get pleasurable responses to music sometimes. People with musical anhedonia fall on one extreme of the spectrum.
James - So it's not that they can't identify how a certain piece of music is intended to make them feel, whether that be sadness, joy, tension, etc.. This inability to process the music is known as amusia. It's just that in the case of specific musical anhedonia music doesn't bring them enjoyment. Thanks, Malinda, for your help. I also want to pick out this comment from Alan on our forum. Under the question he writes,
'If you aren't turned on by listening to music, perhaps don't take a formal route involving theory, keyboards and exams, but find a beginner's brass band where you learn to follow the dots and they have instruments you can borrow or rent. You get all the fun of a team sport, especially the pub session afterwards, and you only need to use three fingers. Or take up folk dancing whether music has immediate meaning and relevance. Plus the pub session afterwards where you meet the band.'
Well, we know where we can look for Alan if we ever need to find him. But on a more serious note, he's right to bring the conversation back to why we think most people do derive pleasure from music - as a vehicle for socialising. A tool to communicate emotions, and to encourage us to perhaps dance together even if there's no cure for your specific musical anhedonia, Carl, you can still benefit perhaps from the positive social function it inspires.
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