 I am Louisa and for the next 15 minutes or so I will talk to you about our brains, how they can be affected by damage and I also want to share with you some of the most recent ideas that we neuroscientists are working on today on how to repair our brains in the future. So, I would like to start by giving you a short overview of what we know about the brain and how it works. Has anybody of you ever wondered why we still, until today, still associate the image of a heart with feelings and even personality? Have you, I'm sure that you're all familiar with expressions like, I love you with all my heart or you have referred to other person as having such a good heart. And don't you just think that this is super weird that we're still using all of these expressions until today even though we all know that the organ in our body that is responsible for producing our feelings like love and for making us who we are is our brains. So, by now, we should already be using expressions like, I love you with all my brains and this person is so good she has such a beautiful brain. But we are still not yet there and so the reason for that is that our brain was misunderstood for a very, very long time and nobody could actually tell really how the brain was working and what it was doing because if you look at it, its structure doesn't tell much about its function. So we needed to really develop new technologies, new methodologies to be able to really take a closer look inside the brain and finally figure out what it's doing and how it is doing it. So it was really over the course of the last 150 years that we got a better idea of this and now we know that the brain is formed by many different cells and that the functional unit, so the most important cell in the brain, the one that actually does the job is the neuron or the nerve cell and this is a cell that can receive process and transmit information and it is doing so by sending these electrical discharges. So nowadays we can look at the brain as just being a very big circuit that is formed by these fundamental parts which are the neurons. And we know, so an analogy to what the brain is doing is that it's working like a computer and this is something that you can relate to because everybody knows what a computer is. So the brain is really receiving information from around us, from the environment, is processing this information and is giving an output. So that can be for example the movement of your arm, it can be controlling your breathing or it can be the formation of a memory. And for these circuits to be working well, all of these smaller parts have to be in place and also functioning. So what happens to the brain upon different types of damage be it like a trauma or a stroke or neurodegenerative diseases like Alzheimer's or Parkinson's is that these smaller pieces of the circuit which are the neurons they die and they get lost and this can lead to a disruption of the circuit and a malfunctioning of the brain. So what are the effects or consequences of brain damage that you can see from the outside? This is very, very variable and to illustrate this I want to tell you the story of these two young men who suffered brain damage. The one to the left is Phineas Gage. He was involved in a railroad construction accident in which this metal rod was driven into his skull and through it and really damaged a huge part of his frontal brain. And the one to the right is Henry Molason. He suffered from epilepsy and to treat this condition he got a surgery in which a small piece of his brain was removed. This was the hippocampus. So now I wanted to ask you by looking at these images, who do you think suffered the most severe consequences from the damage? Who thinks it was Phineas Gage? Show of hands? Okay. Who thinks it was Henry Molason and show of hands? You are a very unreasonable audience or you know what the hippocampus is doing which so he, all neuroscientists. Okay. Yeah. You are actually right. So it was very astonishing at the time that Phineas Gage really showed very little effects of this huge brain damage that he suffered and what you could see from the outside was a weird social behavior and this was really evident only for the people who knew him before the accident. So for his closest relatives and friends they said that he was not the same person anymore. He was being vulgar and aggressive and acting in a weird way but that was actually it. But Henry Molason he had a much more severe effect of this damage in that he was enabled to form new memories. So he had a memory of around 30 seconds. And he also couldn't orientate himself in space anymore. So to go from the room to the toilet or to the kitchen and because of these conditions he had to spend the rest of his days in a nursing home. So it was very, very severe. So what you can see from these stories is that actually the consequences of the brain damage they don't depend so much on the size of the damage but really on the area of the brain that is affected by it. And so here for example if you would suffer a brain damage to the back part of your brain you would probably have troubles seeing or if you would have damage in other parts of your brain you would have problems moving your arms or legs or something like that. So can the brain then repair itself from damage? So we know that other organs in our body can do this pretty well like the skin or the bone. Can the brain also do this? And to discuss this with you I decided to use first a simpler system to explain. So imagine a system that consists on a device which is plugged to a socket through an adapter and it has to be everything there plugged to work. And imagine that this adapter gets broken or lost so now you cannot plug it anymore. How can you repair this system? So now I take advantage of my intercultural background to give you two examples of how you can really repair this system and I term this the German way or the Brazilian way. So the German way is a very simple idea so you just replace. You have your system that you need to solve this problem and what you do you just plug in a new adapter, plug it all in together and it will for sure work in a very efficient manner so we know this. The Brazilian way is a method that you can use when you don't have all of the resources available so imagine you don't have the money to buy a new adapter or you don't have any adapter lying around and you really want to plug these things in. So you use your creativity and you adapt and you end up with something like this. So can the brain use any of these two systems to repair itself after a damage? So can the brain use the German method and replace the new neurons that get lost by new ones so actually no it cannot and this is because we humans we are born with most of the neurons that we will carry out with us throughout our life and old age so there's really not so much that we can do. And I say that we're born with most of the neurons that we will have until we die because there was a huge misconception in the field in which it was thought that after you're born no new neurons are generated in your brain but we know now for about 20 years that this is not the case. So there are specific regions in the adult human brain where new neurons are generated every single day and these are these two regions but the new neurons that are generated here they don't replace neurons that get lost in a damaged area. So yes this German way is not happening in our brains. Can the brain then compensate for damage and go through the Brazilian way and adapt to an injury and yes it can. So here to the left you can see a brain scan of a healthy person while moving the right arm and this is the area of the brain that gets activated by this and here you can see stroke patients while doing the same movement and they had this area of the brain damage and they're having problems moving their right arm. So what you can see is that in these patients many other areas get activated for the same movement so the brain shows a certain degree of plasticity and maybe this is the movement is still not perfect but maybe you can recover part of the movement. So since the brain cannot repair itself in a very good functional way can we then repair the brain and the answer to this is no not yet so but we have made a huge progress over the last decades in science and medicine and we have developed many different treatments and drugs that are being used nowadays in the clinic but these are only able to mitigate or reduce the damage or alleviate the symptoms that you feel. So yes we need to work harder on this but so the reason why until today we have no cure available for brain damage is that number one as I told you in the beginning neuroscience is still at its infancy so we need more time and second our brains are very very complex so an adult human like me and you has around 86 billion neurons in their brains and each of these neurons makes up to 1,000 to 10,000 connections which are called synapses and in total we have around a hundred trillion synapses in our brains. This is a huge number and to give you an idea we have more synapses inside our brains than there are galaxies in the observable universe or than there are stars in our Milky Way galaxy so now you can understand a little bit of the complexity to solve this problem. So what what are our ideas to solve this very complex problem so the neuroscientists of today have many different ideas and this is one of them to go that is called the neuron neuronal replacement therapy which is basically the German method. So the idea here is to replace the neurons that got lost with new neurons and then to get the functional recovery of the circuit and I want to stress here that for this approach it is essential to do basic research so to go to animal models of brain damage and disease because we first need to understand how the system works there before we translate this into a treatment for humans in the future. So there are three requirements for for a neuronal replacement to be successful. First the new neurons they need to turn into the correct neuron type that was lost so neurons come in all different sorts and flavors and we just need to get this right. Second these new neurons need to connect into the circuit and integrate in a meaningful manner so that we get a functional restoration of what was lost and third they have to survive for a long time for you to get a permanent restoration. So there are different approaches in order to to get this neuronal replacement. One of them is to try to attract these neurons that I told to you before that are produced daily in our brains into the damaged area. So this is something that is already happening naturally in our brains upon damage and we now know how to boost this reaction and we know that these new neurons they can even turn into correct neuron types and even integrate to some extent into the circuitry but a problem that we haven't been able to solve so far is that these neurons they end up dying there. So the injured area has a toxic environment for these new neurons and they just die. So this is something that people are working on how to overcome this but we have other ideas. So one of the ideas is the so-called reprogramming. So reprogramming is a forced conversion of one cell type into another cell type and as I told you before in the brain we have many different cell types. One of them is a neuron and we also have other cell types which are called the glial cells and today we have we know how to and we have the technology for example to convert or turn glial cells into neurons. So the idea here is to go to the damaged area where you have for example astrocytes that are these glial cells and turn them into neurons and this is something that we have achieved and we can turn them into the correct neuron type. They survive but we still don't know if they can integrate properly and this is something that that is being worked on and the last approach that has been the most successful one so far is the transplantation. So to transplant new neurons from outside into the damaged area and the cell source can be very different so we can use cells from a fetal source or even use cells from the skin and turn these through reprogramming into neurons and then transplant these into the brain and what we have seen so far is that these cells can turn into the correct neuron type and they can integrate in a meaningful way and this was the most exciting thing to see and they also survive for a long time. So because of these very promising results in basic research this is now being tested and translated into clinical research in humans so there are now ongoing trials clinical trials for transplantation in Parkinson's disease patients and maybe this is an option for the future. So yeah so for that I would like to thank you and I hope that you learned something new tonight and I hope that you enjoyed this talk and this evening from the bottom of your brains and if there's anything that stick to your brain from tonight let it be that your brain is a fantastic organ and it's very complex that neuronal replacement therapies show promising results that maybe you will be able to see in the future and if there's only one thing that sticks from tonight let it be this one and that basic research is very very important so it is important for us to understand well how our brains work and also for us to be able to come up with new therapies that will help and improve our lives in the future so thank you very much. Questions? There's a one. To which one did you mean for the ones that are the the ones that are producing neurons or sorry the ones that are that I showed these two places where we have new neurons that are so yes these neurons have a function. For humans we are not so sure about it so we know that should I go back so for the ones that are being generated in the here in the hippocampus we know that these new neurons are important for learning and memory and they also have a huge relevance for our mood so it has been seen that in patients with depression that they have lower generation of neurons in this area so even the antidepressants they are making this number increase so we are still trying to understand what is happening in humans and the neurons that are generated here in this region in humans we still don't know what they are doing so in mice or in rodents it's different because the neurons that are generated here they go to a place in the brain that is important for of faction and this is very important for for these animals but it's not important for us humans we're not good in of action so we still don't know what these neurons are doing in our brains any other questions this is a very good question so yes the reason so the the neurons that are controlling my right arm moving right now are on the left side of the brain and the reason for that is that so these neurons are on my brain but they send their projections which right it's like a cable which is the axon that goes through my spinal cord and when they reach a certain point they just pass through the other side of the body so that is the reason it's not intuitive but it's just how how we are built any other questions yeah yeah it's yeah this is really hard this is something that we still cannot do so for example in near degenerative diseases like Alzheimer's Parkinson's this is something that we don't know yet how to stop or multiple sclerosis for a trauma or stroke there are ways to like stop the bleeding or like reduce the inflammation and then try to reduce a secondary damage but we still don't know how to stop the damage in our brains yes there are many so inflammation is one thing but other other things like in Alzheimer's for example we still don't fully understand why these neurons are dying there's this accumulation of some protein deposits in our brain which we also don't know how to stop or dissolve but yeah there so for example they are developing antibodies for Alzheimer's that can really stop try to stop these proteins from aggregating but this is still ongoing so far we don't have anything thank you very much thank you