Evolution of the Human Brain: Pasko Rakic Lecture at UC Davis

[00:00:03]okay just about time good afternoon uh for those of you who don't know my name is Leah chalupa I'm chair of neurobiology physiology and behavior and I'm acting as host today and Ted Jones will be host for tomorrow's lecture so it's a great pleasure and we say this quite often but in this case it really is a great pleasure and honor to introduce pashka rakish who's here from Yale University where he's professor of neurobiology and neurology as well as founding chairman of what is now the department of neurobiology I think it'd be fair to say that Dr rickisha's the preeminent Developmental neurobiologist and he's held this position for at least 30 years he has a knack of kind of asking fundamental questions and doing these tremendously creative experiments so that his work is been in the Forefront of whatever particular issue he's addressed and for those of you who are in development biology you know what I'm talking about let me give you a little bit about his background it's a very interesting background he was originally trained as a medical doctor in uh what is now Croatia was Yugoslavia at that time and he came to Harvard the Mass General in 1966 to do a fellowship in neurosurgery and the chair neurosurgery department after interviewing him said you know your accent is a little bit strong and you'll see what I mean in a minute then maybe you shouldn't be dealing with patients right now and go and do some research for a while and for about 40 years now he's been in research so he was at Harvard for about 12 years and then he came to Yale University as a full professor and founding member what was in a section of neurobiology and he's been there ever since and he's made that department although it's a very small Department he and the late Pat Goldman Ricky made the department one of the preeminent departments in the world so let me introduce him by uh telling his title and the evolution of this should be a space that evolution of the human brain lessons from Radiology archeology but it's okay maybe I can see that did you see misspelling there yeah all I'm glad to be again here in University California Davis and when the Ted and Leo called me uh to come and I was glad to but then they said you have to give it two batches and they say uh one would be like a public lecture and the other will be scientific lecture so I was very glad that public lecture doesn't have to be scientific and I I knew I knew that uh that water is going to be my second lecture on my favorite subject on neural migration but what would be the first one and I gave to Leo actually a choice I said could you I talked about medical implications of that or Evolution if you talk about evolution and I see now why you know he was hoping that some of the presidential candidates would come uh you know and they can maybe learn something about uh uh Evolution but I actually like the talk I'm not evolutionary biologist but I like to talk about that and I don't have a chance very rarely uh uh people talk about that but I did spend all my life you know on these three species working and it's very fortunate because I started with a human brain as Leo said working in your surgery and then went to Mouse at that time was a spontaneous mutation and now continue with transgenic mutation and then start to make like a transition between Mouse and human and working in the monkey and it's kind of appropriate here because you have primate Center should take advantage of it and now since it's very popular transitional Neuroscience you know transitional medicine research I try to say that really Monk Is transitioned between Mouse and human and you will see at the end or even that I actually go back and work on a human a little but you know it is interesting working just on these three species you start to appreciate the evolution and I was thinking if only Darwin didn't come to this idea before you know just looking at that I could make that point so but actually Evolution you will see in the moment have also medical implications and videos animal models we should recognize what are evolutionary implications now this is my second lecture and I mentioned just because I was afraid after my first lecture nobody will come so I just to tell you that I hear very Dynamic things over there going on and I'll talk to you our latest stick of migration even someone published data what's that going on oh I can go to my internet okay okay so I will when I talk about Evolution I'll just talk about cerebral cortex I have passion for that I think this is the part that make us different from any other species it's not liver and I'm sorry to those who work in spinal it's not even spinal cord it is really cortex that makes it possible I give a lecture and you to listen and and so how it develops and how is cortex different and when I give lectures and I repeat that very often even to my medical students how is cortex or for that matter brain In fairness other parts are very similar different from any other organ and I would say that it's a map in which position a neural defined connection and function that's not the case for any other organ the clever a little lower part of upper part doesn't matter and you can take one kidney and you know give it as a transplantation and still other work a little harder but in the brain it is very precise map and this is what is so fundamentally different it's not only laminar position there how they're interconnected but in um not just aerial position here how they're interconnected in a specific way but Ariel only this for example cells in the layer two or three are those which make those connections when Fairman and Vanessa did appear mapped and that is known here and looking at differences earlier here okay okay then I will not mention her work uh uh uh so how it's made and how it's related to to uh to evolution um and I would like to devote that to to my professor yako at that lecture because it's an evolution and he was a professor at Harvard Medical School in neuropathology but he introduced me in the joy of doing developing brain human in that case he gave James Arthur lecture it's a kind of a prestigious lecture in New York museum of natural history and on brain evolution and he said that he was 34th lecture every biomedical question can be reduced developmental questions so if you are working on some problem either this is schizophrenia or bipolar disorder you end up looking of how a brain was developed and when susceptibility for example for the disease occur and so on and then he was more put his path by the way at that time this was politically correct to smoke a pipe and this by the way he devoted to me that was a painting we will ask artists to do for his 70th birthday and he said in every developmental question can be reduced to evolutionary questions and I was so happy that you know when I was invited many years later to give James Arthur lecture and I gave a talk and I wish he was still alive to hear because I was inspired by his uh talking to him he likes to discuss that and so on and I learned I named it lessons from embryo archeology and don't look at the Oxford dictionary for that word as yet because it's not yet there but I think maybe one day will be and you will see why reason is and I put that on that painting uh Rene mcgregate I did my great did Belgian painter which many people think is French because most of the painter things are over there in Paris I do not know he was complex man what he meant but what I thought he was saying by looking at this egg and looking in DNA on this egg there is a secret for every detail of this which kind of birds will be which kind of feather every little color and every feather all that was already there predetermined only if we knew how and I was thinking since this is what I call our embryo archeology since we in archeology we can look empty skull and we just see how brain become bigger because skull is bigger we don't know what happened on molecular cellular level if we ever have a hope to learn how our cortex become say bigger or how become different it is to look during what happened during embryological stages the brain is made because everything would happen in evolution through gene mutation left some imprint and this is how we will learn if ever and I was just thinking that that would be a great thing to do and at that time I added here actually just the newer number what is the difference when you look obviously brain is bigger a cortex become bigger and rhesus monkey but hundredth time and human about thousand times in surface area than Mouse and this is number of genes now you will ask me why I put 29 in each I do not know exactly how it's about the same time a same number in all of these species by the way the biggest deflation was not in the stock market or anywhere else this is in in genes because people were saying we have hundred thousand and eighty thousand for a long time was 79 and then was it 30 and now they said 29 it doesn't matter really but the number of genes are about the same I by the way try to get it from Francis Collins and uh he was very evasive and I can tell you later on during interception about our conversation okay now people say well that's people even who believe in evolution said very simple and this I borrow slide from um from colleague in Sweden when I was there and some Symposium Evolution a few years ago and uh this is that if you breed chicken take always bigger and bigger in 40 generation 41 you have nine times bigger chick I said this is Revolution you just select and this is not a very good way to look at that because this is still Chic this is big but it is still check it's maybe good for Kentucky Fried to have that but this chick can is not smarter than this chicken and everything is same but just a bigger this is not Revolution work and when you look there are qualitative differences and I put that slide I'm not going to that because otherwise you will leave even not only it will not come tomorrow but it will even in today's lecture these are some of the differences that I myself looking at the human brain phone this is a qualitative differences and Ted know many of them that some of this we discover actually all of this we did in my lab you know so on and so forth International new cell type other people have shown there's some exist in human you know Sister letters type of cells and so on and I'm not going to do that it would be if we had a course but I will mention the word rest of my truck the one part and this is size how that that we have time larger surface area of the cortex then maps and I think I think it's very fundamental because this is the first step all of this other thing couldn't happen if you don't have these neurons and so the difference between Mouse and human and I'm not that naive that I think that you know monkey evolve from elaboration of rodent brain and then human father elaborate I recognize these are different branches of evolution have a common ancestor but they go their own way in specializations but we could learn from that and the one thing that makes a difference and possible is to to us to be different from other and unique with our symbolic thinking I said no speech because it's symbolic thinking you can be deaf mute and still think this is our ability that's because areas are modified and added and I show here also results I will show you because I mentioned that number of genes didn't change so much I will show one example from nematode and here is reservila with all its wings so it's actually much smaller brain uh two examples of the genes that in the context in the mouse we could modify cortex and how this could work now when people say well how this occur how we have like some areas become bigger frontal lobe become bigger visual for example stay same in monkey and human in absolute size and there are several you there are many opinions many modifications of those opinions or subtypes but basically one is selectionism versus environmental construction theoryism and this is lamarchism that's called and that function gradually create organ because you need it and you kind of work on that and it's okay this is kind of uh basically proven incorrect by long ago but then came Darwin and the selection of functionally useful inherited I put in red changes this is very important because what you do would never affect your children I mean their inherited characteristic an environment this is what lisenko Isa was and I was as Leo mentioned in Belgrade we were in Eastern Europe and that was the official at that time politically correct thinking that environmental environment create phenotype through change of genome you know famous thing and this is like to give that lecture I don't have to prove anything just to remember what I read in your in newspapers even um and uh it is you know he said how we will beat America in in you know food production we have big severia it's not good for weed because it's too cold but will be planted wheat and over years with Will accustomed to you know to call the next year will be better and until it will grow in cold because cold would make future Generations stronger and stronger by experience of the cold and you know where they went with their uh their food program whereas here by doing selection genetic selection we made much better in high production of Ethan we we have to not only to sell them but to give them okay so that was defeated but I think that here in this country in Neuroscience I see something and this is another word that I created that people think that environment creates brain new brain connections and over time that effect so that and this I call okay now when I gave that lecture I prepared that lecture when when I gave this uh James Arthur lecture in um in New York and so I kind of made that drawing and I was intimidated because I a member of their committee was still alive I was um Steve J Gould who's American the most at that time prominent evolutionary biologist and what he would say that and I tested that with my secretary actually Carol because she believed in evolution she was actually a teacher of evolution but this is what most people made mistake and this is I say what the I made this drawing and say what is correct and she looked she believed that you know she said obviously this second is correct because um you know giraffe this is common once yesterday of giraffe um you know was standing and over thousands of years every year in a couple of quarter of inch and so on and then it transferred to the Next Generation this is called continuous variation slow transition and making longer and longer neck because it's Advantage to the giraffe to eat the leaves whereas this guy here couldn't find enough food could not reproduce this longer head was advantage for for getting a female and getting off sprinkle survive but actually it is uh what is happening sudden giraffe have the same number of uh like in a predecessor like most mammal 32 vertebrates is just that at one point this vertebrates were three times longer and then extended it and it was the advantage for this animal occur once and if this occurred by the way in Sweden you wouldn't see giraffe because it's too cold probably will freeze their their neck and but in Savannah of Africa was Advantage under more and more giraffe and they survived I was very glad that that Steve good like this and said that's correct and I was very glad because you know he was a controversial figure even though he was the best in that but I think he was often right and I was always thinking he was right when he did Ingrid with me and um and what what he taught me I was thinking well what people say what is the chance that is that this occur and he said this that is slow occur every you know thousands of years or every hundred thousand a year on the same gene and then each time for quarter of of inch it is millionth time or maybe more less likely than it occur once and it's big and it's big an advantage however there are many mutations that didn't work on environment didn't work I put that because I think what happened there maybe is how it's happened with with the question of enlarging our own cortex so I said how would this apply to areas now I mentioned that this connections are made in a specific way and this is what makes a difference between us and other species but if you go to Society of Neuroscience most of people study how connections are made 98 and so on but let's reduce it how connections are made between say Visual and I remember you remember that that map of Vanessa and others how connections are interconnected you could study how this make so I kind of reduce like this other area so if a contact B and B contact C and so on this is this a reciprocal connection with some area if you want to make these connections before you make connections you have to have neurons so you have to in make enough neurons for a human you have to have a thousand times more neurons and neurons are a larger number okay you have to a b and c then if you since these connections are not random a must be different from B must be different from C and D you don't even have to do experiment there was a controversy at one point where there are all neurons and cortex initially are equal this is so-called tabular as a hypothesis people who are thinking about that in conceptual way or theoreticians say you don't have to do experience it's impossible that if neurons are equal you couldn't have a brain in which all of you have occipital lobe here in front of here and all of these connections repeatable from individuals to individual and neuropathologies look at the brain don't see difference between two individuals so this basic thing had to be there however and you will see this has come to what I'm studying in my scientific life is that none of these neurons are generated in the cortex you will see that and this is how cortex is different from other organs because liver neurons are generated in the liver next to each other here the none of them in the cortex so this is just a little for public lecture and actually I have a evidence maybe tomorrow we'll show some of this the progression of cortical neurons stem cell from embryonic stem cell to neural stem cells then go to neuronal progenitors and this would be like a for progenitus uh projection neurons like pyramidal neutrons one two three over time there are different progenitors and then some of them diverge from neural progenitors to interneurons progenitors those projectors which Pro intramurals don't make pyramids ourselves so there these so-called stem cells are different and then of course then the the religion becomes astrocytological so actually we all hear about stem cell and many are interested how they could be maybe used for replacement therapy but I'm interested that in stem cell is a secret how you made that cortex in the first place and so I'm adding here not all neuron cells are created equal tomorrow when you talk a migration you will see significance of it today I just go and tell you that there are many labs we show now and this is now generally accepted I put just here I don't know does names the progenitors over time generated different classes of neurons now could we follow the journey that would be tomorrow yes we can but and we can study neurogenesis in Vivo but now how they are generated I have to say that if I want to talk about evolution I mentioned cortic as a map in which position defines function but it's interesting the time of neuron origin defined position and this is how we could study when I entered the field it was not yet there only through about late 60s and 70s introduce time eating studies I see H3 time within it's one of the nucleotide go to the dividing cells and then if it is radioactive one electron is a little different uh then uh it in the molecule so that uh you could detect that these cells was generated at the time when timing is available and it's available only for 10 minutes then we can destroyed and this was generated either before or after because after is diluted and this may be divided once more time so it's very quantitative and you see you can stain this is glial cell this is Neuron that's labeled that's not and then in that field you see how cells are labeled later on people start to use deproma urine it's now very often used this is different molecule it's a substitute for timing and they have different structural formula but could be incorporated in DNA can be detected like that with fluorescent it's a kind of easier but you will see have some problems so I know some of my colleagues like Leo and Ted have seen that slide many times and he has to travel all the way to Barcelona to see that slide last time but I think the point is I'm showing that for those maybe who are not since this is public lecture for me it was fascinating when I so it first time is still fascinating if you for example inject monkeys pregnancy last 165 days 50 embryonic day you label this pyramid of cell but if you take another animal inject you know 20 days later you label these stalet cells okay so this every cell have a different time and in visual system you go first this each line represents one animal and then I plotted the cell and 54 label 5 62 6 and like that and the last cells generated in Monkey was this is bird it's 165 days two months before birth around 100 days and this is last cells because they are around here in layer 2 On the Border layer one which is the time margin of Zone this is labeled cells countered to embryonic day and later on we made injections we can label glial cells but not neurons so I kind of thought that this is something that is interesting and you don't have any more neurons we looked very hard other people did and then come discovery of the century and you will see that it has relevance to Evolution this is why I put it there that neurogenesis thousands of new neurons daily just in the principal sulcus and you see here cells migrating to to the cortex how we could miss that many cells and by the way they should be seen even in a Golgi method or even light microscopy so then but it it was published in science must be truth but then I read that in a scientist this was about two years later the fact that an article makes the Supreme should not cause us to lower our analytical senses when attempting to build an information provided in that article regardless of the perceived quality of the journal I said okay so when you look we published three papers in in science and couldn't find it so how you look at that this three times more than that so we repeated actually yeah but this is all from our lab but we send that we published this is with conduct uh in French science did publish it and you see we have seen here that actually it could look a label cell but when you look in the Deep going through the Deep optical density that this disappeared that's why a good blue not blue I mean yellow is not in that cell it's above that cell but it looks like so it is like looking from here you see these cells you'll hear you see it it looks over new clothes so it is one of the errors there are several this look like a label cells and it turns out is not and then when you turn out at 90 degree you see that this cell is not labeled this is glial cell this is Neuron blue green so there are technical there are other problems with that paper but I think I then since they are devoted that to my professor he when he would smoke Pike he would say some other words and he say people wanted to see that we have more neurons so he said desire is not substitute for knowledge and enthusiasm is not substitute for information so why this is I want to mention because you will read so many of those papers vrdu is not marker of new neural many people label and they publish the paper it only marked DNA synthesis it is true it labeled dividing cells but it's true it could label DNA repair it's very slow but if you do multiple injection you could label them I think you have here lecture I saw somebody's daughter gave a DNA repair okay but even more so before sell that I'll show you some decent slide abortive S phase this is not just a repairing either strength it's a totally new Strength S phase you label with a single injection can increase rate of proliferation that otherwise would not occur his mutagenic effect induced aberrant gene expression phenotype you take two dishes and put safe even bone marrow and then in one ad directed and you have more divisions and cells have more variety than in the other one effects cell function it's because this disturb migration obviously if you have one of the four nucleotide in many genes change with different shape of molecules that is a havoc can be incorporated in dying neurons and new new neuroglial cells from neuroglial cells so for example if glial cells is labeled and then die it can be incorporated in the neuron because there is a so-called Fusion that people now prove and can be incorporated in Engineers hypoxia drug neurodegeneration I just want to show you our study this was with my former student Austin professor in Cincinnati you put hypoxia's hemia and that neuron by legally getting one side artery you have dead cells in the ca and you could label them before dying almost very well and then tunnel this is a method for cell death and you double able so these cells will go down all of them are labeled with the occipital manure if you are not careful you could say look you get a lot of neurons in hypoxicillin or if you put toxic substance or animal does too much exercise and so now you can say three of those are just the exhibromo uridine so there may be new neurons but don't forget the tunnel is not 100 sure method maybe there are new neurons maybe not we do not know and difficult to find something new so you're happy you publish that and then my friend George saying send me that when he was still undergraduate in akun lab he uh published in 1972 they showed you see you can incorporate even time it in the cell is not dividing just damaged by ultraviolet light so I just want to say this technical thing and is retrovirus safe no Ackerman another show that it could be that providers could go to microgreer they'd be microfia this is Ackerman his first daughter Ahman but the first senior author is Joe La Turk University of Connecticut and then these are my graduate students who wrote general of Neuroscience this opinion and so on it goes there and it labels cell so this cell is retrovironly labeled but it's not new neurons it's all neural and then finally of that before I go to the next stage is that we looked at nuclear DNA synthesis bldu could be labeled in dopaminergic neurons in substantial Niagara after mtpt injection okay we just published that two months ago in pnas so some people thought that this substantial not gonna get new neurons when they die but actually they those which die actually incorporate the oxybroma unit than we did in humor and in human with substantia Niagara neurons this was done with a very sophisticated Metals called fish DNA you see have two this is a male with two X chromosome and four I forgot 18 chromosome 18 yeah so in human Parkinson's disease patient before cell died it doubles DNA synthesis you have two times more chromosome in the cells and then die and then that so-called marker that many people use pcna also label this is human cells we just published so if you look cell cycle all of this that I put in red this is from somebody's work energy at all these are different molecules in Volo cell cycle including S phase all of them are now proven to be engaged in cell debt so each label cell so I was just in Stockholm feel uh man not human two months ago and the thesis defense of uh bartway in the Jonas recent lab in which the c14 there very clever experiment c14 labeling and they show that c14 was very high in the atmospheric in Sweden and in other countries at the time of up atmospheric Atomic blast testing and so all cells which were at that time created would have C molecules on the level that was at that time in atmospheric as well as in vegetables and everywhere and this way you could see people born before 1968 and after and so on and they found that many cells glial cells in brain are there but they came to conclusion the cortical neurons as as old as the individual at that kind of made me happy because but this time it didn't study we did come to that conclusion and published that in you know uh in uh in 1985 but here what I did have in that paper is you see this is got this skin this is cornea why all this this animal this is new skin not last year's skin you know my cornea even change certainly uh well my care doesn't change that much uh but but not brain cells and this is will come how I I put that there is because I think has significance for evolution of the cortex one other reason why we have decreasing capacity on neuronal Terminal during evolution you see from fishes amphibians you know salamander can generate all new spinal cord but we cannot mammals cannot rat cannot do that either rodents but more and primates which is accomplished by reduction on adult neurogenesis and regenerative capacity why is that occur and by the way to prove that this is so I did actually how I'm doing with time maybe I will skip over that just to mention too that we looked and we found that in primates it's like 10 times less than in rodent this is monkey and here is in the olfactory very few cells and so why should we during human evolution lose such seemingly useful functions this is what I did right it lost a neuronal turnover and continuous neurogenesis has evolved to retain memory or land behavior that is essential for the survival of our species in other words it is important that you keep your neurons because this is over a long time this are we are not faster than this zebras or giraffe or stronger than Lions but we learn something and we use over time and the storage of our knowledge is a synapses and connections and and store and if you change that you would lose that was the hypothesis that I put in that paper okay however price was that it is accompanied by the reduction of originality capacity okay now so how then you form that you make and not only that you make neurons the class or life but you don't make it in the cortex what a kind of difference and this by the way I did when I was still in Yugoslavia and make that experiment in which we put the timidine in the in the medium and found the cells are proliferative only near ventricle but not in the cortex itself this confirmed what people knew from the mouse work like Angie van Sydney and other but put me to see how they migrate and this is how what happened if you inject monkey you label cell Neo ventricle three days later you put another animal cell migrate and up here so they go from The ventricle and and migrate and inhuman and in monkey that is much longer than in mouth speaking on Evolution you see here is a long track that cells have to migrate all the way from ventricle to come to the cortex and how they do that you see there are three so-called radio which was discovered Long Ago by scientists at the Turner of the century including kahal and others let's use in Stockholm and I don't know magin in Italy and you see I found using em that these cells migrate along this light process already ugly so this is what happened they are moving you will see tomorrow I'll talk a molecular mechanisms and how this occur on the other this level but today I just want to say that we could see those cells and I mentioned how this occurred in evolution instead of doing that static and sacrificing three animals to prove it you could see in the slice preparation using confocal microscope and you see cells divide and then here is the vision near ventricle and could be asymmetrical division this green one will become neuron and go up and you see now I'll show you this on the way to the cortex this is where they divided this is cortex as an individual go to the position you see it was inside out first generated and then second third one above the other and this is now in the color the seven Cent this is pseudo color just for those who are sitting back to see they come to the top so that is in Mouse but you in human monk is even more difficult because cell from this position have to go to the proper position here and that is provided by this radial glia which do not divide for a while so as cortex grow they keep these highways and here you see many cells moving along the same path so this is how we could then label those cells using maybe I leave it for tomorrow to show you that so I wanted just to show you model so more this is model based on you know 125 monk is injected different time and sacrifice so this is piece of the cortex this is ventricular Zone here where they divide in two zones ventricular subventricular they go and migrate along these Pathways and you see first layer six and here is the time age 50 60 and a letter 5 come I don't know but I could see that many times when I give a lecture it gets still impressed thinking to which extent Evolution went to to make it possible that one cell bypass previous generative cells and come so that layers six generated and five and four then three and in that order I do not deny that there are a lot of connections there that have to be done after but this is the first step they'll have to come there then now they will make corticocortical connections but they have to be in their position I just want to stress that up and on basis of this type of work I formulated this hypothesis and I will test it in front of you the two-dimensional Mosaic or ventricular Zone which is here where cells are proliferative is transformed into three dimensional cortical architecture in which X and Y axis that is here position of cell aerial depend on the site of origin here these cells make this column and this cells make this call so by side of their origin whereas the z-axis that is within the layers is provided by time this is first the second third fourth in fact I cannot now resist not to show you okay so this is what you do you put retrovirus label one cell because it's very small percentage you're labeling and then you see how they go and then number one cell number two number three number four these are all cells come from the same from the same mother okay now how this is related to evolution cortex is spent by increasing the surface we discuss that a number of radial units you see this is human monkey and mouse and cortex is thicker but not so much but thousandth time in service how this occur because there are more radial units how this could occur first step is to increase number of units that could occur several ways and one of this is mode of cell division and I got the video if cells are always symmetrically divide in evolution or our brain fact that we have that map is one step the most important but second most important in evolution is that cells at one point could make asymmetric division so the two cells are not equal when you have two equal cells you increase their number of equal cells and then later on you make different types of cells in each division that occur during cortex in early stages in monkey say before 40 embryonic day cells are dividing like that each progenitor symmetric will make two progenitors symmetrical means the two cells are equal and then at one point this projector produced one daughter cell another stay by asymmetrical division so number two number three now you see that how many of these units you have depend how many of these projectors are doing there and you see if it's human it monkeys start here if you prolong that just allow three more divisions you have a time bigger cortex just three more division it could be just one gene we said divide three times more and you have three times not three times eight times bigger context you get that okay so this is called header honey that small timing could produce big changes phenotype this is kind of used in evolution very often but I will now do experiments in mouse that show that you could increase larger cortex I will use one this is Gene from nematode caspase 3 nematode is called said three that is killer Gene and what happened in amateur is that this is people who work on that like Bob horvitz showed that if that Gene is deleted or incapacitated inhibited nematode have more cells because cell do not die by up doors you hear about up of doses so we were first with my colleague to muted the gene but so theoretically what would happen you see cells are dividing each time symmetrical make double double if this is normal apoptosis this cell die then you have that big cortex if this you prevent that cell dying you have two times bigger cortex just one cell one so people say well there is a very few cell dying can you explain a thousand times bigger code one cell could make a double okay and you have molecules and I mentioned to you so more radial columns are produced by symmetrical division if you prevent that and then later on radial if you asymmetrical division interfere you would have dollar column or shorter columns now with my colleague actually Richard Flavel who is molecular biologist at Yale we were first to take that Gene and mutated equivalent of that Gene in in a mouse and look you have a bigger Mouse with it that's not quater Montage okay it's a real Mouse here and when you look this is control in the in the same uterus and this is one which have lack to to uh copy of that Gene it became convoluted that have a bigger cortex and we published that initially and that took us three years to really fully recognize what that means is that you prevent yourself that you have more cells producing and so you have more columns and then the brain start to combo this is how it could occur I do not say that it occurred by we have bigger cortex because we interfere with with a car space it's just that how it could occur it could be by interfering with proliferation and I will show you studies that we did with my colleague Nana chestnut with not Gene Notch is and it it is affecting mode of cell division so cell could divide and give two new neurons and a continue divided in neuron or it could go and go asymmetric will start to produce glia and stop neurogenesis and we did show that Notch this is just impressed now in a Nature Neuroscience just accepted last week after a long time here is that its present Notch and its inhibitor numb is inhibitoral Notch and it's asymmetric we produce there in dividing cells and you could interfere with that you could Force expression of Notch this is intracellular domain of Notch active notch and you stop neurogenesis and sells the touch and become glio or you could force Nam which is inhibitor or not then you continue neurogenesis and cell continue to divide so you that that's tremendous Powers position use a gene discovered in resolvedila and then you use it in the ventricular Zone on the mouse and you can make a cortex bigger and smaller and so you see we can put cells to go this direction and produce more neurons more of these disease or to produce more glue so what you have normally the mouse produce neurons but we when we force is track a neural stem cells to stop producing neurons it glia become earlier and we have no neurons so we have more glia and less neurons opposites occur when we do Nam I'm a little rushing tomorrow I will mention that molecule in different contexts but just for evolutionary purpose think of that but by expressing or over expression of none you continue longer time production of neurons and you delay formation of Glee and finally I want to say another molecule which is beta-catinine this is the only slide that was known for my lab this is from my lab upper we published that this is control and start to have convolution but this is from Chris Walsh lab Harvard they did this beta Catalin which is molecule involved in cell proliferation and they manipulated that and forced it prevented increased number of proliferation of cells and this is their control Walter and look at that how they have convolution Mouse is smooth control and convolutions I was so jealous when he published that because this was really you see cortex is formed because all other Machinery is there you just have more columns and you have larger cortex I thought and Chris said well pashko after that I start to believe in radial unit hypothesis so when I did uh start that work before this we we have that proven we um this is where I kind of suggested possible model before we had the Gene and I said well it could be genes it could be just one Gene and it could determine larger size of the cortex these are radial units in the in the monkey these are actually photographs and these are ventricular Zone which is also radially organized tomorrow I'll show you how this is and what make that possible and molecular level but today I just wanted a more General picture uh of that and you see that you could increase that number in evolution but just prolonging number of symmetrical divisions and so I don't know they let me get away with that said one small step for cell one John step for mankind this is my title in teens and I suggested that it could be some genes I didn't dream that since then we did and I show you three examples that we could manipulate with these genes to produce a cortex large now this mice are little they are not smarter than anything like that and sometimes when I give that people say well you know how you you know couldn't this if you have more sales more radio units like human monkey have more when the mouse be smarter they said no because this is a revolution happen this actually is my foreign brand brain and they cannot even survive many other things have to work well this is how small chances are and I said I just produced few of those mice but if you give me you know Grand 10 million years long Grant I I could produce smarter math because I make every day you know 20 100 miles and maybe 10 million years from now one of them will be smart smarter this is how I thought of Evolution occur in a way to make it popular but then you could say well okay so what determines the number of units and I just show you I went back all the way to study now human brain and what we by looking these early stages we found and this is a human brain actually 29 days post-conception and this is before neurons in ventricular zones are ever formed and you save one big cell here we couldn't see the cells in mouse in fact you we see some of them but not so impressive like in human in the monkey so far and this is how they come you see we don't know actually where they come but it seems to come here and our working hypothesis is that this cell if existing human or not in Mouse could influence proliferation here and determine when and how this number of units are formed there so I go back at the end of my talk to to the pictures that I showed beginning I don't think that we know enough yet but we I believe that we look hard then we continue and this way and the young people now with the monkey genome is also published just two weeks ago in science Human Genome Mouse genome we could go and look and find out how this occurred how this become bird and how our cortex become cortex and that would show us you know Who We Are where we come from and maybe even where we are going so I think Leo is right that uh presidential candidates should actually read a little about that because that we could learn more about human nature by studying human cortex and that every question even in medicine could be reduced that to to evolutionary question and we have to take in contact into account those differences between Mouse monkey and human in order to design proper therapy to understand diseases so that is the story of the how I try to convey what I thought by looking at these three species over a year and how cortex May evolve this is just a small piece of it just how it become bigger I know many people study how connections are made that's not enough it's more complicated story but one have to make first step thank you [Applause] what happened to the animal that has a much bigger Vortex are are there cortical areas enlarged equally [Music] no it's not you see it's not and Ted know here very well and also Leo and probably Leah and others because you have here a strong uh uh background in anatomy cortex uh is not a mouse is not just a just a bigger Mouse in fact some area of the monkey for example area 17 in Monk Is about absolute similar size to Human and so our vision is not better than monkey vision and even analysis of what details in the primary visual area but our prefrontal cortex or parietal cortex is much bigger it is what we do with this information so Mouse see same thing but we know much more about those things that we see because we then develop further this part of the cortex analysis and I kind of decided and Leo told me I said the talk should be like about 50 minutes and I am known to make it too longer so I didn't I took out some slides but we have ideas and that how these areas are differentially uh enlarged and you remember one slide at the beginning when I said when I saw when I show are different uh different stem cells and they are different for layer four or five and so on people have shown that but now they are showing that they are different from frontal and for other cortical air and there is a paper that is uh impressed now by from Rubinstein lab it will be in tnas probably within a month or so because I kind of communicated that to the pnas I knew that in advance and I fortunately don't have his slides he showed that there is he has a molecule fgf 18 or something like that and it is expressing the ventricular zone of the fruit Frontalot but not on that and by manipulating you could make it bigger and smaller front a little without affecting the others so areas are therefore mutations of different areas could test that and in large frontal lobe without enlarging visual say occipital because occipital is good enough for us but we should have a little more frontal lobes you know thinking and planning for the future and and so so that's I'm so happy to see that paper will be out in a in a month or so but I was just thinking whether to show you where I thought even in my own talk I have more slide than I you know sure uh okay well it doesn't matter is there any more questions to ask I can do two things in the same time you see that what I saw here when you make um narrow stem cell for projection neurons then I put this and that two projections this could be say frontal lobe and in frontal lobe then letter five six I mean six five four and so on and this would be some other areas so all neural is not this is a problem for for example take a substitution therapy and this was now shown also by Tom Jessel another in spinal cord it's not just to take neural stem cell and inject and think they would just substitute for those that are missing in some neurodegenerative disorder or in trauma each of these cells have a its own type of neuroprogenitor which is different from each other tomorrow I maybe mentioned something out no I think they have more radial units oh yeah they have more exactly okay let's go back I was rushing at the end so maybe didn't show that exactly more radial units in our we have only maybe 30 40 percent more but I think in um out here it is you see this is from here to here that's wild type here when you look from here to here but you look like that it has much more radial units here this is in in Walsh Walsh have more than two times more radial units and if I go now back where I that um okay because okay here is this you see I should put less and and explain better I don't know okay you see normally you see AP apoptosis this is why I said at the beginning you see occasional cell debt in the ventricular Zone and that controls the number you see and if you prevent that there will be more units here because this produces additional at this at this point then you see more radial cells Okay so in in the in this scheme you see there are more because they didn't die there are more and you see if you you uh that maybe you think I'm you see here these are radial units and here radial unit so you have here more of that they go like that and this is the thing okay so this is one cell there so I have that argument actually one was in England with Lewis wallpaper he said well there are only a few I will end up with the only I like running dots but this is true story okay so he said well there are only a few cell deaths and how you could explain thousand times and I said look there is a one cell here and if you prevent that cell will be two times bigger so Robert he's from Scotland says how many are in you know Walters Clan now like 175 he said okay supposedly somebody was killing the war a couple century ago it would be one grave and there will be no 175 wallpapers so you don't have to see a lot of that you you you prevent future generation and this is why this model fits to now several experiments either by preventing cell death or making more proliferation of symmetrical division you increase in this case this is Chris Walsh experiments more columns because he have more of these symmetric divisions we have more uh columns because prevents cell and then by the way we did you could anti-apoptotic Factor you can inhibit propofocus factors so this is more than one this is BLC another mice so you can do it very sophisticated way so other people are doing that and Richard navakovski have mindset here and then if you prevent that then you have a thicker cortex because you have more cells in the column but you don't have more columns so you have two times of of uh speaking of medical implications two times of malformation if they occur early you could have a poly microgiarity a more but cortex is thinner if a correlator you have thicker cortex but a few fewer Gyra it feeds almost mathematically in is that answer your question he is kind of said yes but not completely we have to talk later there is somebody there might have an evolution of reduced it was related to the needs for long-term memory yes actually if we could do it or other organisms do it to whatever degree they do it that it actually does disrupt long-term memory adding new neurons because we do have a world where neurons die tomorrow okay well okay I I don't tomorrow maybe I'll talk a little about that but I don't have slide with me which I wanted to show you see point is there that if somebody now remind me something what happened 30 years ago I can reproduce whole picture of what happened even when I go back to Yugoslavia I didn't see somebody 35 years oh yeah I remember we were sitting there and you know having cappuccino and you remember details what happened and for that you don't have one cell or one memory you engage whole brain and it has to be there new neurons would not be able to incorporate into that and you will see why because tomorrow when I show because you have to have layer five before you make layer 4.

[01:11:05]in a realer Mouse if you are aware I should slide tomorrow one day late cell is not in a proper position is kind of mentally now if you inject Now new cell in 52 years old person you're 52 years late for that and you don't put that cell before maybe one day we will be able to understand the differentiate the cortex but their cells would not have only any experience that you as an individual have so when we have this discussion sometimes you know if I have new neurons in America since I left I would not have an accent but I would not recognize my mother when I go back because these neurons didn't see my mother yeah so I don't think that the new neuron in Alzheimer would make somebody to recognize their daughter if they don't he said we don't have time to discuss that interesting question okay well thank you very much [Applause] I think that this is not good for you please