ABOUT THIS EPISODE

This month, coffee on the brain, manipulation mismatch, wired for language, and scanning for Christmas spirit.
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TRANSCRIPT

00:00:03this month cautionary note about optogenetics as with any sharp tool you just have to be careful how you use it and how you interpret the results and how it impacts the brain we actually see fairly substantial reorganization of brain networks depending on whether I'm fat and caffeinated or not plus the Neuroscience of early language exposure and evidence of Christmas spirit in the brain hello and welcome to neuropod I merely dog in
00:00:42Russ pull drag has perhaps the most well-studied brain in the world nearly every Tuesday and Thursday for a year-and-a-half the Stanford psychologist would climb into an fmri machine at about 7:15 in the morning the main thing that I should get in the scanner was we called resting functional MRI we're basically I sit and do nothing except for trying to stay awake for 10 minutes the project board rack explains you'll did more than a hundred scans in total creating one of the most detailed longitudinal studies of how different parts of the brain talk to each other as he reported this month in nature Communications is brain connectivity was actually surprisingly consistent overtime we didn't really know how consistent conductivity was over a long. I'm within an individual and so you know that's an important thing to know but at the same time there's a lot of things that are actually changing that are going to riding on top of that relatively stable backbone you one of the things that we showed changed had to do with whether I was
00:01:42bad and caffeinated or not because on the days when I got blood draws on Tuesdays I needed to be fasted and so you know we we have this sort of built-in experiment comparing Tuesdays and Thursdays there we saw that in spite of this sort of relative consistency we actually see fairly substantial reorganization of brain networks depending on whether I'm fat and caffeinated or not did it matter if your morning cup of Joe was a permit espresso or pour-over or drip coffee or God forbid those pods that you get you know when those machines I only drink espresso that's not an experiment that I we did okay good to know that you're a coffee snob like me how do you know that it's the coffee as opposed to the fact that you skipped your bowl of Cheerios we don't actually that's an interesting question and we think it's probably the caffeine driving it simply because we know that caffeine has effect on blood flow in the brain but yeah we can't actually with
00:02:42do you say that we can't Pull A Part whether it's food or caffeine because those are perfectly compounded in the study for future study but assuming it is the caffeine what were the differences that you were seeing in your brain expected to see when we compared days with vs. without breakfast and coffee that everything would just sort of be less connected noisier on the days when I'm uncaffeinated but what we see is actually sort of the opposite that the biggest changes that there's a couple of networks one network involved in visual processing in another Network involved in somatic sensory and motor function that actually became much more strongly connected to one another on the days when I was fasted
00:03:30now that you've created this map of a healthy brain over time can the research Community use it as a kind of Benchmark to study things like schizophrenia and other people's brains I think that's right you know it turns out that the variability overtime within me look quite different from the variability across people and that suggests that we really do need to focus on looking at individuals over time and I think that you're right at the the clear place to go with this is to look at people who have much more variability in their psychological function like people with disorders such as good as Predator by for disorder you've made all the data from this project available to the research Community through a portal called my connectome does it where you at all having that much information about you you out there for anyone to see and possibly hack
00:04:23yeah well I thought a lot about this and talked with colleagues a lot about this going into it and the certainly there are concerns I kind of wanted to do it one because you know I'm generally of the feeling that data should be open and you don't have been involved in a lot of other data sharing efforts but also because I think that something like this needed to happen to babysit like this needs to exist and I was seeing but relatively unique position to be able to do that with much less concerned than a lot of other people would have if they tried to do something at his study up here December 9th in nature Communications that's at nature.com n c o m m s
00:05:07pencil Vats key is a neuroscientist at Harvard University he and his colleagues were studying the ability of rats to press a lever in a certain pattern and they wanted to know the role of the motor cortex so they begin by using a drug called new skin mole which temporarily shuts off and runs but when one particular injection went awry they decided to permanently destroy the motor cortex so it's the Salvage that experiment to their surprise the two types of brain manipulations like two completely different behaviors permanent destruction and the Rats could still complete the liver test but temporary inactivation with the drug and the animals were useless at the task that use optogenetics instead of a drug and came to the same conclusion ditto when they repeated the experiment by knocking out the scene part of a zebra finches brain
00:05:57so it seems that temporary and permanent brain manipulations don't always necessarily yield the same result I met up with benzo Vats key at his office at Harvard to discuss what this song means especially for studies of optogenetics as with any sharp tool you just have to be careful how you use it and how you interpret the results and so what we found is that optogenetics and other techniques that transiently perturb the nervous system might have a consequences on processing in the brain elsewhere other than Target circuits are targeted brain areas generally neuroscientist will look at the behavior of a mouse say after perturbing Sumner on with this technique essentially what you're saying is that we don't know if that behavior is necessarily because of alterations in the Target neuron or some other element of the circuitry that's linked
00:06:57alteration of the target neurons the question is whether under normal circumstances those neurons have those effects would it exercise the capacity to influence the behavior in the way that you have probed I think that's the tricky question and how many careful experiments were you know you can be fairly certain that what you're doing is is likely a consequence of the function of the brain circuits but in our experiments now just talk about our own experience it was a surprise or initial experiments on in activations told me that motor cortex in this case the part of the brain that we study is very much involved and my sumption based on our initial results was the motor cortex was the place where these behaviors that we study are stored and where they are generated from and so for my own experience it was somewhat of a surprise that when we leave and motor cortex we did not see those effects
00:07:57in an accompanying News and Views that appears in nature, suit off the Nobel prize-winning neuroscientist from Stanford he reflecting on your findings rights that it's an exciting but sobering time for Neuroscience exciting because we can manipulate neurons with these sobering because everything is interconnected actually don't know what it all means he's right in a sense but it's frustrating I mean what is the path forward given the that we have these amazing tools but we don't know how much they will reflect true biology
00:08:34I think it's too complex puzzle the brain and any given a technique will give you a window onto solution but you know you will it require a lot more I think then simply transiently turning off part of the brain or a set of neurons I think it's it's a cautionary note to Brett's beware of some of the caveat at the end of the day what's the message that you want the Neuroscience Community to take away from this paper I think they're too many messages one is to remind people of something we know that the brain is a time ago system that's sensitive to initial conditions sensitive this month perturbations and be careful interpreting the outcomes of of transient circuit privations
00:09:24the other lesson that I would like for breakfast at clinical commute to take away is that this might help explain a function recovery after brain injury and only static regulation neural activity that we hypothesized is responsible for the spontaneous recovery of Downstream structures and their function might underlie the recovery that you seen in patients pencil bet-ski his study was published December 9th in nature that's at nature.com / nature will also post a link to it on our website nature.com Neuroscience last neuropod there you can also find the News and Views article I mentioned what's the news story from nature Sarah Reardon
00:10:12as a kid I used to speak Hebrew I've mostly forgotten it now but it's possible that my brain hasn't and wants more according to a new study in nature Communications my early exposure to another language might be influencing how I'm speaking to you in English today to learn more I met up with study author Laura Pearce she started by telling me about the children in her study led the first group are internationally adopted children I said these kids were born in China they are exposed to Chinese language from birth until the point that they were adopted into a french-speaking family in Quebec and so this happened before they were three so the ones we looked at were 6 to 25 months of age when they were adopted and from that point on they speak only French so that's kind of the target population and have to do control groups that's right so one of my groups are French model angle kids who have spoken just French since birth and continue to speak only French and the other group is a group of Chinese French
00:11:12bilingual speakers so these kids started out learning Chinese they started learning French around the same time as the adopted kids so before they were three but they continue to speak Chinese and so at the time that we tested them they spoke both Chinese and French fluently when you tested them inside the scanner what were the children doing and listening to so for this study we gave them a task in French pseudo words are made up words and they just have to make certain judgments about them as they go along so we're looking at how their brain processes the sounds of French can you give me a couple examples yes other things like Shan set vape pen things that kind of sound like French words but are not there. They don't have any meaning
00:11:55things that people who don't speak French in just heard that probably think you're beautiful even myself every now and then have a moment where I wonder if is that really a word nocturnal birds so on the fmri what did you see I see what we found is that when the three groups perform this task all of the groups activated regions that were typical in some ways of processing of sounds the adopted group and the bilingual group showed activation in additional regions that are not necessarily Associated specifically with language processing but more Toto General attention and memory processes the kids who lost their native tongue their brains basically look the same when they're listening to these French pseudo sounds as the bilingual kids who continue to speak Chinese today
00:12:47that's right. They showed a lot of similarities with the bilingual speakers which was really surprising to us because they really only had this very brief exposure to a second language so I think it really says a lot about the role of these early experiences in studying the brain up to process the sounds of language Laura Pearce / study would she completed as a graduate student at McGill was published December 1st in nature Communications again that's at nature.com and c o m m s
00:13:19now in keeping with the season I will describe the next study through song
00:13:31It's the Most Wonderful Time of the Year
00:13:38with those studies to probe the parietal lobe volunteer
00:13:45It's the Most Wonderful Time of the Year
00:13:52it's the hap happiest season of all
00:13:59which scientist planning their and Mariah standing up her protocol it's the hap happiest season of all
00:14:14the crazy actually feel alright well that laughing you hear in the background is my next guess study author Brian haddock from the University of Copenhagen welcome Dr haddock thank you so I had a little fun there with the lyrics to the Christmas carol but did I get the methodology of your study about right the Christmas spirit in the scanner that that is what got you interested in looking for signs of Christmas spirit in the brain very successful study as well on migraine patients and we need to do something for them to look at while they were in the scanner and that's where the idea of showing them images with Christmas images next in what was the Paradigm the pictures that the study
00:15:14it's Roxy looking at what you looking at least a series of every day images of streets buildings rooms and they would be the same type of images with a Christmas theme so streets at Christmas time at Christmas time and you study the brain activity in 20 people 10 of him regularly celebrate Christmas in 10 of them don't what differences did you see in their brains by Cherry was the one group they were to report that they to celebrate Christmas and that they have positive associations to Christmas and their brain we found several areas that whenever the images switch theme from everyday seem to a Christmas-themed activation in these areas of the brain group that said that they do not celebrate Christmas and they have neither positive or negative feelings about Christmas that they feel very neutral. Christmas
00:16:14and this is what you call the bah humbug effect know it's not what we decided to send it into the Christmas issue of British medical journal and I have a criteria is that has to be done in a real research Paradigm everything that we write has to be true but there's a few things that we can kind of play within one is really thought about all of who could benefit from this and that's what we thought of all those people who celebrate Christmas for years misheard of lost their the Christmas motivation or something so we kinda messed up the bah humbug Patient Group but no egg nog was consumed before the patient's went into the scanner how people didn't wear ugly sweaters I mean you just put in all these kind of Christmas cliches I thought it was great but with all the fun in Marion
00:17:14decide there's some real science hear right that is not Christmas finding an interpretation of the two ways you can kind of keep yourself to the fact that they will what we viewed is a physiological effect that happens when people who celebrate Christmas when they see images of Christmas that doesn't happen if people don't celebrate Christmas and leave it at that this is a logical fact and that we don't know how to interpret it or you can kind of build on other interpretations kill people of hat and then you can make a whole theory about exactly what's going on in the brain and that's what we kind of play with in the discussion where we allowed the authors to to attempt to make that broad interpretation and then we allow Grinch and I'll to to come with us to remind you that well that's not what you measured what you measured it is cuz you collected you a lot
00:18:14the response you don't know what there thinking you don't know what they were feeling all those caveat sin limitations the kind of damp in the festive mood today Christmas I'm Jewish and so lights and trees and decorations none of that gets me excited at all and you've now giving me an explanation for this that these things do nothing for me in my cerebal area I find that kind of reassuring that you can actually measure something that you feel yourself for that you know to be true to yourself what if you put me in the scanner and then you showed me images of dreidels and lot cuz and sparkling menorahs do you think that my brain would light up in the same Regents it is possible first of all they depend on there with your sociation to those Traditions are if you have a owner of my family lawyer coming again reaction
00:19:14my wife before this interview possible that it could be the exact same network that this is actually a more General Network that's for dinner or Nostalgia or something like that could be that there's a totally unique Network that's for this celebration I think we can leave it there and just say merry Christmas happy holidays and may the Christmas spirit Network in your brain always be active this holiday season and I wish you could that be MJ. Com the bmj
00:20:05and lastly this month a production note and I'm afraid it ain't good news I don't personally want to be the one to bring you this month of call so I'll let Carrie Smith be there Christmas Grinch hi Carrie. The most welcoming introduction by the good to have you back on thank you very much and what's going on at least 10 years of bring Nero goodies to people's areas around the world it's time for knee report to take a break of indefinite links I have to say so it's not leave for now they will be pneumonia or opposed to know did this have to do with the return of cereal so it just wasn't going to be feasible to let me know seriousness priorities as you might imagine a large group such as nature and for the moment we just have to focus on other things
00:21:05which is incredible I'm at was kind of in the Stone Age of podcasting what were you trying to cheat when you launch the podcast I was trying to achieve getting yours as much as possible and feeding my own curiosity new things nearest science and she studied it for a little while and so it was great to be able to find a medium for it for sure was periodic at first but by 2008 it become a regular monthly thing and you then made something like 75 shows before you hand it off the Ravens to me it seems that emerged over those dozens and dozens of shows surprise anyone to hear this is a technique while you're in bed in two neurons light sensitive proteins and then when you feed line till 7 to the brain of for example of mouth sore right you can trigger those New Orleans to buy the fire will be
00:22:05and that gives you a tool to ready probe networks in greater amount of detail than ever before and in fact it was really great to have in 2007 as a young present to myself to have called dice rules on the show who's the man who really should have kicked off this field so calls first appearance he told us about light activating runs in mice that basically woke them up from sleep so here is what we found was that when we delivered a light activated ION channel to the mouse brains by driving the high between neurons optically that we could favor the sleep-wake transition so we could favor the probability of transitioning to wakefulness yeah not long after I mean the initial reports what kind of 2000 and 5/6 so this was a long enough for you to do some fundamental science experiments with it
00:23:05are you also took a number of field trips for neuropod what was one of the most memorable University a few years ago to meet and your son to school David field and he become interested in a historical paper he's seen from I think the 19th century it was written by an Italian neurophysiologist who claims that if he put a person on a big leave at like a big balance it was tilted say that this folk from a sativa was underneath the middle of the person that he said blood flow to the head when I was thinking more seriously Heisel well believe it should tip and I should see them lean towards the head end of the balance so David scientist in Reading he said well I don't know if I believe this and the little people in the US are in the literature was saying I didn't believe it was all necessary by the furnace historical report so David set out to actually make a brain balance and luckily enough I got to go to reading and he put me on his brain balance
00:24:05I'm so hazy Kip of him by introducing me to the diva and putting me on it that you can Shuffle around a little bit bit more that's some pretty quirky neuroscience and you also learn some pretty quirky fax over the course of reporting the show anything that kind of knock your socks off couch Lee was I think I came on it by accident when I was looking for a reference or source for a number I kept seeing quotes and everywhere that the human brain has a hundred billion neurons and I couldn't really find you know any definitive reference running experimental data it just but people seem to reproduce this number without ready checking so I got in touch with the nearest scientist Suzana herculano-houzel who is
00:25:05space in Brazil and she had done a study why she basically Blended sounds Blended human brains into a kind of brain soup and then filtered them through a cell counter and she came out with the title of 86 billion neurons instead so what she told me on the podcast a few years ago and she doesn't think this hundred be an estimate is anyway yeah right
00:25:29like a small difference the 14 billion neurons amount to pretty much as many neurons as a baboon brain has or almost half the number of neurons in a different actually so few more neurons than we originally thought but this might just be coincidence but for each billion neurons we made an episode of neuropod right so or thereabouts that's pretty spot-on that was always the intentionally wasn't it an absolutely well I'm sure listeners are going to miss the show but there will still be the weekly nature podcast right what's the best way for people to stay on top of that and also to stay in touch with you they can get in touch at nature.com I don't twist at many carry nature podcast and I'm a daily dog in that's it for this episode of neuropod and that's it for the podcast for a while as always you can find links to everything you heard on this show or any of the
00:26:29weather 80 + episodes of the past decade at nature.com Neuroscience / neuropod thanks again to all you wonderful neuro Geeks I Milly dog in thanks for listening

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