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Summary

This hybrid session is perfect for medical professionals looking to enhance their understanding of the topographic anatomy of the brain. It'll provide an introduction to the different planes of imaging, anatomical features, setting context for epilepsy surgery, and more. Attendees will also have the opportunity to ask questions and fill out forms at the end of the session to qualify for a certificate of attendance.
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Please Note: As this event is open to all Medical professionals globally, you can find out how to access closed captions here.

Aswin Chari is a neurosurgical trainee and a PhD candidate at Great Ormond Street Hospital & University College London's Institute of Child Health.

Learning objectives

Learning Objectives 1.Describe the three planes of imaging. 2.Recognize the differences between gray matter and white matter of the brain. 3.Name and explain the significance of the interhemispheric fissure and the Sylvian fissure. 4.Describe the various gyri and sulci of the frontal lobe. 5.Explain the significance of the anatomy of the brain in cranial neurosurgery, with particular reference to epilepsy surgery.
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The following transcript was generated automatically from the content and has not been checked or corrected manually.

So we've got a hybrid session, you, so we have some people in person and those of you online. Um So if you haven't done so already, uh we'll put the link for the Precose form. Um If you could fill this out, please. Um And then at the end of the session, we'll put the link for this um the questionnaire for this session. Um Please fill this out as we'll use this as a marker for attendance and those who have attended over 70% of the sessions at the end will receive a certificate. Um So without further aie, I'd like to welcome our um mister K, sorry. Uh Sorry. Um Who will be talking to you about the topographic anatomy of the brain? Mm Thank you. Um So, yeah, so I'm a neurosurgical trainee um at, based at UCH at the moment at Queen Square. Um And I uh I have been asked to talk to you about kind of cortical uh and surface anatomy of the brain. And hopefully I'll put it in a context as to why it's important, not just, you know, boring teaching the anatomy because that's a bit dull. Um But before we, um, start off in any, um, any kind of anatomical to, I always want to make sure that people have their basics up to scratch and I'm sure you guys will have. So I'm going to pick on people in the room because they're bothered to turn up. Um, and so I'm going to pick on some people. So, um, what are the three planes of imaging? Great. And when you move one side to the other on these planes, what are some of the terms that are used to describe those directions? Yeah. And for which one is that so natural? Yeah, mel natural is in the sagittal plate. Yeah. Yeah. Superior, inferior, yeah, or anterior uh posterior for the coronal plane. So yeah, so you can move up and down. And when it comes to the brain, obviously, when you, I guess the the main way in which we look at the brain uh is through imaging and a very important part of imaging MRI scan. So this is a a flare MRI scan of a patient that I had when I made the slides uh who had a brain tumor. Um And I kind of mapped out what uh the different planes are in different directions are. So obviously, when you're looking at an MRI scan, remember that it's always flipped around left to right, um anterior and posterior is the front of the brain, the back of the brain. And then in the axial plane, you've got superior and inferior. So it's always useful to have this in mind. Um Because if you're describing the relationship of a particular gyrus of the brain to the tumor or the tumor to some other structure, you want to be able to describe it really clearly as to where that is. So, yeah, basics and I guess uh you know, this lecture won't do it because I I I'm not covering it, I'm choosing not to cover it. Um But it, it's a good idea to know where some of the kind of surface landmarks of the brain are uh in relation to the skull. Um So you have a kind of understanding of when you look at the patient roughly where something is gonna be. So if you see an intracerebral hematoma on the scan, you often don't get a chance to get uh a detailed MRI scan and put it on to your neurone navigation system. And so you have to guess you have to say, I think it's here and make a hole in the skull there and you hope it's gonna be there. And so yeah, you should develop some and as you get through kind of neurosurgical training, you know, I think people get better at, at trying to do that and say yes, it's somewhere here based on what they see on the scan. Cool. Um So basic different parts of the brain in terms of the nervous structures in the brain. Um This has a dark gray bits which are here somewhere has some white bits and some lighter gray bits. Um Anyone can name these bits for me. Yeah. So this is cortical gray basal. Yeah. So these are the subcortical gray matter. So the basal ganglia, um the cordate, the putamen and the thalamus, they all subcortical gray matter structures. Yup. And what's the white bit? That's the white matter. And obviously the, the, the, the the difference between them is that your gray matter is where all your neurons are, your neuronal cell bodies. Um There are six different layers in most parts of the cortex. Again, I'm not covering the layers of the cortex. I don't think they're particularly uh at the moment. Um But yes, this is where all of your, your, your neuronal cell bodies are. Um It's where I guess the action happens. Um And then your white matter uh underneath is where all the cabling is. Um And you've got different types of fibers um which connect the brain to the spinal cord and distally brain to the different parts of each other. Um and the two hemispheres. So, yeah. So I'm gonna start with a little bit of context and cover why knowing your anatomy and knowing your scal and gyral anatomy. Your cortical anatomy is important from the perspective of epilepsy surgery. I think it's relevant to any form of cranial neurosurgery that you do. But this is just my area of interest. And so I'm gonna kind of set it in the context of epilepsy surgery. So, in epilepsy surgery, we aim to find out where the seizures are coming from uh and remove that area of the brain, we call that the epileptogenic zone. Uh and it's defined as the area that we need to remove, to rid the patient of their seizures. And so it's a bit of a circular definition there. And so all our other tests like, you know, we go through uh we put patients through a presurgical evaluation um and all these other things that we do with them. So we take history, find out about what their seizures look like, uh uh history, uh family history, uh history, et cetera, uh clinical examination, the MRI scan, which we use to try and find the lesion. And you can see on these images here that there's a very, very subtle abnormality in the cortex. Here, you can see it's a little bit brighter going down to here. And this is a developmental abnormality called a focal cortical dysplasia. Um And an MRI is a very important part of our presurgical evaluation. Uh We use eeg um including scalp and video eeg. Um And at the end of all of this, we say, OK, we think the seizures are coming from here. We need to remove that part of the brain and it's really important once we do that to actually know exactly where in the brain that is, that we want to remove because we wanna make sure that that doesn't have functional consequences. Ie you're not gonna chop up the primary motor cortex and leave them with their arm, not moving. Um And so it's really important that we know exactly where we are in the brain. And sometimes when all of this doesn't give us an area like that thing over there, uh we sometimes have to put electrodes into the brain seg uh And this is an example of an SCG plan where we've put, I don't know, 12, 15 electrodes into your brain. And here as well, we really need to know where we are putting these electrodes um because we want to find where the seizures are coming from and also find functional areas of the brain. So, you know, putting an electrode into motor, if you stimulate it, they'll move their hand. Uh And so, so, you know, not to go there with the per se. So really, really important from a cranial neurosurgeons perspective to know uh their anatomy. And here's an example of uh one of my bosses putting an electrode uh with the help of a robot. So um here's the, here's the meats. And um so this is hopefully what we're gonna learn. Um How many lobes do we have in the brain for any advances? Yeah, that the V Yes. Yeah. So firstly, we have two sides. So that's a minimum of eight. Ok. Ok. Uh, and then I put it to you guys that we actually have 10 in terms of cortical lobes, uh because you've got the insulin and it's not something you kind of learn about every day. Um, but you, I certainly think that you've got five lobes on each side. Um And so hopefully over the next course of the next, I don't know, half an hour, 40 minutes. Um, we will find out a little bit more about all of these lobes, including um the borders. Um the gyri involved in each one, the Sulci, um some of the fun anatomy of, of these lobes, um how we map them uh and also co cover some of the deficits that you get if you take out those areas. So we're gonna start with a super easy question. Um What separates the two hemispheres of the brain? What CCU so the central sulcus will get to, yeah. Anyone. So, yeah. So what, what is the, what is the thoughts in? But it's the interhemispheric fissure. So, firstly, you've got the two hemispheres and you've got interhemispheric fissure between them and basically a fissure is a big sulcus. And so we've got two fissures really that, that come to my mind. So you've got the interhemispheric fissure and then you've got the Syb fissure. So, um so the Sylvian fissure is here. Uh And we'll come to what it helps us border in a second, but essentially, that's that's formed by the kind of um brain bending over as it develops into this sort of c shape. Uh And so you've got two big sca which are the Sylvian fissure and the interhemispheric great. So now that we've separated the two hemispheres from each other, let's start the biggest lobe which is the frontal lobe. Uh And obviously, in terms of, of volume area, et cetera, this is the biggest. Um And so what what are its borders? So let's start with all the different bits of it. So name names and things that where the uh borders of the frontal lobe are the um place. OK. Hello, the frontal pole. Uh ok. Great. Um So at the, at the back of the frontal lobe is is the primary motor cortex. What gyrus is that? So that's still part of the frontal lobe. So that's the precentral gyrus. And so what is the sulcus that therefore makes the posterior border? So the frontal lobes, the central sulcus, exactly. And so what is the inferior border of the frontal lobe? The skull base up to a certain point and then part of the Sylvian fissure? Good. And what is the medial border of the frontal lobe, interhemispheric fissure? Good. So you now you know clearly how to define the frontal lobe. It's bordered inferiorly by the Silvia fissure posterior by the central sulcus and media by the interhemispheric fissure. And everything else is skull, right? Great. Anyone know the bits of it. So we've already said that this is the precentral gyrus. So you have area as well. Ok. Good. So those are, those are kind of functional definitions and I'm looking for anatomical. So I'm looking for the gyri and the sca yup. Perfect. So you, you'll, you'll figure out through the, through the course of this to the anatomy is very simple. People have made it easy for us. The frontal lobe is divided into in front of the precentral sulcus, which is here, you've got three frontal gyri which la run anterior posteriorly and they are the superior frontal gyrus, the middle frontal gyrus, and the inferior frontal gyrus and the inferior frontal. And the, and they are separated by it's OK, which are called the superior frontal sulcus and the inferior frontal sulcus super simple. Um And you'll notice that a lot of the gyri II, I split that way. The pre and the postcentral gyri are really weird because they're at a strange angle compared to the rest of the brain. Self. Gyra. Ok. Good. Uh Now, what do they do? So you said that this is primary motor cortex? So, from here, your corticospinal tract comes down and allows you to control contralateral motor function. Um and maybe even a bit of ipsilateral function cause there's a few uncrossed fibers. Um And what about the rest of the frontal lobe? What does it do? Yup. Ok. Good. So the, we'll come to that at the end, what did the superior middle frontal gyro do? Yeah. So you can have lots of different things there. So the, the kind of, I guess the important bits that I that are in the front of my mind are pun intended. Um are the supplementary motor area which is up here in the superior frontal gyrus just in front of the motor strip, um which is involved in kind of planning of movement. You've got kind of all the all the personality things of your auto frontal cortex uh uh uh here in your prefrontal cortex or the decision making, executive control, all that sort of thing. And we often see patients with big meningioma, for example, which have been compressing the auto frontal cortex, their personality changes, they become more irritable intolerant of their relatives, et cetera. And that's how they are picked up um good. And then on the dominant side, which is most commonly on the left hand side, you've got some language function in the inferior frontal gyrus, the inferior frontal gyrus is split up into some bits. Um The uh it's called the pars uh orbitalis which is in front of the orbit, the pars triangularis because it looks like a triangle and the pars Acular because it is in front of the insula. So the insula is called insular because it's an island. Uh and the UUM is uh whichever Greek Latin name for curtain and it covers the insula. So this is pars alaris of the uh of the inferior frontal gyrus. Uh And so, somewhere in the pars triangularis and the front of the pars Acular is thought to be broker's area uh which is responsible for kind of um production language is probably a lot more complex than that, but that's the kind of yeah, base level to start up. Um So yeah, so three gyri plus the precentral gyrus uh and your inferior frontal gyrus can be split into uh pars uh orbitalis, pars, triangularis and pars ocular. And it's always very easy to localize the bottom of the central uh of the precentral gyrus because from the pars Acular, there's this U and this U bend takes you automatically into motor strip. Uh and down at the bottom here is face motor. Um So mo your motor organization is um uh leg in the paramedian bit in the, in the interhemispheric fissure your hand up here. Um uh fe and then face coming to face down. Um And the, the key thing about the face motor area from a clinical context is that you can afford to take it out in most cases because your facial innervation is bilateral. Um And so taking out one side doesn't have a massive effect, cool frontal lobe. Uh So we've done borders G I si we've talked about function. Um We'll come to mapping later and we'll come to defer later when, when we talk about the kind of surgical context of things. OK. Next lobe which lobe parietal? OK. So what are the borders, you know the anterior border, central circus good, medial border transfer. Yup. Uh posterior border parieto occipital sulcus. Yup. Um And then inferior border is the, yeah, the posterior part of the sail in fish. Good. OK. And then any idea of the, the, the gyri and the ska involved here, you know, two for sure. One gyrus, one sulcus that's function. So what, what, what is the location of it? Yeah. So you've got the postcentral gyrus which is here and behind that, the sulcus is the postcentral sulcus. Yeah, perfect. Uh And then anyone else? Um OK. So you, the parietal lobe is split into two by the, by this intra parietal sulcus. The top is called the superior parietal lobule and the bottom is called the inferior parietal lobule. Um And the inferior parietal lobule is split into two gyri. Uh one is a continuation of the Silvia fissure as it goes up. And this Gyrus around it is called the supra marginal gyrus. And the second is this sulcus that goes up and comes back up like this. And the gyrus around it is called the angular gyrus. Um supra marginal and angular gyra are very common areas for glioblastomas to kind of begin and start. So, um we're, we're kind of there relatively regularly. Um And uh let's talk about function. So the pre the postcentral gyrus is important for primary somatosensory cortex. Um Any ideas about parietal lobules, visual it. Yeah. So the parietal lobe to me is very much a a sensory integration area. Um And so there are a list of kind of tasks which uh may be affected if you have a parietal lobe tumor um which involve kind of integration of the different senses. Um There's a specific syndrome which I can't remember the four bits of called Gusman syndrome, which you get from something that affects your dominant parietal lobule, uh dominant parietal lobe. Um So have a read. I I can't remember them off the top of my head, but at some point I will OK. Um We really don't do very much to map uh in the parietal lobe. Um Sometimes you can have people awake and get them to do some of these tasks like line bisecting um because they get neglect of one side. Um But it's not something that we do very often. Uh And certainly from the, the kind of day to day neurosurgical assessment of outcomes, you know, we can take out someone's parietal lobe without affecting their function. I'm sure their function is affected in, in many, many ways. But our way of assessing is so cruel that we don't pick them up in kind of routine clinics, cool occipital lobe borders. There's only really an anterior border. Yeah, it's the right occipital surface. Um And again, it's organized into three gyri the superior middle and inferior uh occipital gyri. Um and uh the sulci in between are the superior and inferior occipital sul super simple Ventola. Anyone know anything about insular anatomy? Oh, anyone even heard of the insulin before? Yeah, cool. So it's an area that we don't go very often because it's dangerous and it's dangerous. Not because it is, the function is particularly eloquent, it is dangerous because over the surface of the insula, you've got the distal branches of the middle cerebral artery. And if you damage them, when you are going to operate on the area that can then affect things like your corticospinal tract. So they can cause strokes of the white matter tracts in the sub, in the area that they are supplying. And therefore, that is why it is a risky area to operate on. Um So the uh the insula is bordered by something called the circular sulcus that goes all the way around it. Um And it is split in two by the central sulcus of the insula. And what's really cool is that the central sulcus of the insula lies exactly deep to the central sulcus that you can see on the surface. Um anterior to the central sulcus. You've got three usually short gyri, the short gyro of the insula, anterior, middle, posterior, short gyra, uh and behind it, you've got two long gyri, so anterior and posterior long gyra of the insula. Uh so circular sulcus, two bits, three short gyra at the front, two long gyra at the back. And that is the insular uh is that, is that all uh did we do the temporal lobe? It's good 30 minutes, the temporal lobe. Ok. So temporal lobe also very important for, for especially for epilepsy surgery because it's probably the most common cause of surgically treatable epilepsy, temporal lobe, epilepsy, um gyri some kind. Yup, superior borders uh Sylvia fisher anteriorly and inferiorly it's skull. Um there's a temporal occipital surface at the back, that's the kind of posterior border of it. Um And gyri super super superior, middle, inferior, and again, you've got superior and inferior uh so cool. So here's a summary of everything that we've been through. Basically, here's all the, the gyri and I think we've mentioned all of them here. Uh The the other thing is the medial view of the brain. So there's an extra sulcus here which I've made for you, which is the cingulate uh Gyrus uh important for things like motion and pain processing um which is not really visible on any other surface of the brain and it kind of traverses all of the um all of the lobes. So it's not particularly, you know, you can't say the singular is only part of the frontal lobe or only part of the front lobe kind of goes across them. Um And above the cingulate gyrus uh is the cingulate sulcus. Uh what is this? Uh it says there? So, this purple structure here is a focus callosum um which is your main area of white matter fibers instead of crossing between the two hemispheres. Um where else do white matter fibers cross between the two hemispheres, right? Between the two cerebral hostess. Yeah. And it friend the posterior. Exactly. Yeah. But the main B is is through the book. Cool. Um Any other important uh fissures that you can see here? I guess it's this one here. I don't know what this is. This sulcus is. So through the middle of the occipital lobe. So this is the Calcine uh Sulcus uh and basically straddling the Calpine Sulcus at the very back is your primary visual cortex. And so anything above Calcine will supply your lower visual fields and everything below Calpine will supply your upper visual fields cause everything crosses great. Um And then in terms of um me other medial anatomy. So this bit above the Calcine, but in the occipital lobe is called the cuneus. So this triangle over here, it's called the cuneus. Uh and this, which is the medial bit of the uh parietal lobe is called the precuneus uh when you're looking at the midline. So if you hear those, those terms, that's what they're referring to. Um you've also got some sca and some gyri on the bottom of the skull. So here is your inferior temporal uh gyrus down here. You've got something called the fusiform uh or parieto-occipital gyrus in the middle. Uh And here you have your parahippocampal gyrus. So there's the, the, the two additional pain from the temple. And on the bottom, here's a quick summary of all Pasa. And I think again, we, we've named them all uh relatively straightforward enter, right? So I'm just checking that I've got everything great. Uh And here the medial surface. So this uh marginal ramus of the cingulate gyrus uh of the cingulate sulcus is important because it is an important way in which we localize where the primary motor cortex is. So we'll come to this later, I'll, I'll pick on one of you. Um But uh seeing on a scan on a, on an image like this, that's really readily labeled is really easy. But when you see it on an MRI scan in two D, it can often be really difficult. And so, one of the ways in which we localize the primary motor cortex is this the first ascending bit of the cingulate uh sulcus. When you look on a, on a sagittal image, on a midsagittal image, uh it is the marginal ramus and the marginal ramus basically continues as the postcentral sulcus. And so just in front of it is uh so somatosensory and it goes as a continuous U and therefore, this bit just anterior to it is the primary motor cortex uh and this whole thing together. So this the medial bit of the primary uh sensory and the primary motor cortex uh are called the paracentral lobule. Um Here, you also have uh a, a kind of straight looking gyrus at the bottom of uh the occipital lobe, which is called the lingual gyrus. Uh and you have a very straight gyrus at the front uh of the frontal lobe which is called gyrus rectus, straight. Cool. So why is, why is all of this important? And I'm gonna give it, give you kind of context in two different ways. First is from a research context. So you can, you can envision that if you're doing research studies and you want to localize the function of a particular area of the brain, you want some homogeneity, you want to be able to assess that same area across many different patients. And so you have to have some way of saying this is, I don't know the anterior bit of the superior, superior temporal gyrus. And I took it out and I assessed all of these patients and these are deficits that I got. But you want to make sure that that is the same area that you've taken out in all these patients or monkeys or whatever it may be. Um And so you, you wanna have some way of uh homogenizing your localization across patients. And the first person that started to do that is a guy called Rodman who came up with all these areas. So they're called Rodman's areas. Uh And he did it based on Cyto architectural anatomy. So he took them looked at different areas of brain down a microscope and said these are the different areas in which which the layers of the cortex look different. And therefore we split it up into certain areas. And so this is how the kind of first bits of of cortical localization came about. Um So area four is the primary motor cortex. Area 123 are the primary somatosensory cortex. Um I remember area 17 being important uh as a primary visual cortex. Um And so he did it all cyto architecturally. So looking at things down a microscope and looking at the relative abundance of neurons in different layers of those six layers. Um Yeah. So I understand down it's important to have this like, yeah, but in actual patients, individuals, do you see a lot of um yeah, cool. Um and things have moved on a little bit. So now I can readily take a brain. I think this is a template brain and put it through a piece of software and say I want to split it up into 250 different pieces and it will do that and it will do that reliably across different patients. Um And you can use this for, for anatomical studies. In this case, I've tried to build networks using um using these different parcells. And there's a lot of science that's gone into what parcells to use. So there's so many, so many different ways of splitting up the brain into different areas that different people have developed for different specific purposes. But if you want to then split it into multiple areas, you've got to then, you know, see what you're doing it for which one of these atlases, uh what features you're looking for and therefore, which Atlas you're gonna use to split into different areas of the brain. What's more interesting is probably the clinical context. Uh And as I mentioned, I mentioned one way of localizing the primary motor cortex. Um And so what I'm gonna do now is take a pause from PPO presentation and pick on maybe they can cloud cloud, cloud Claus. Yeah. Costa costa sir. Uh So can you see my screen? OK. So this is uh my MRI scan. Uh you can see from the big nose, this is definitely me. Um And so I want you to try and uh find my primary motor cortex. So come up here have a play so fine primary motor cort fine. So this is a T one weighted MRI image. Uh And as you can see on this gray matter is gray, how do I scroll it? It's like, yeah, you should be able to just um with the uh yeah or, or the skull here. Yeah. So I just start on the top. Yeah, I think that is your central sulcus. OK. So then, and I think so then yeah, so an anterior to that somewhere here will be here. Ok. And do you have a way of recognizing which is the hand area, which is the hand air? No, I have no idea. Ok. Cool. Anyone have any ways they know of localizing most 10? I, I've, so I've heard of the Omega sign but I, I can never actually see it. I've only seen it on raped, but I can never find it in real life. So, I think you found it on the other side. Is that here? No? Ok, cool. Anyone know the well, no. So as you can see going from the lovely colored pictures that we have to this, you know, if I told you to say where is the um you know, the, the occipital and the Calpine Fis on that sale? You don't need to move it. Um Can you find them the what? Sorry, the right occipital fissure. So this probably around and then the urine taran probably bu Yeah. Uh And so it's a lot more difficult to kind of localize. Thank you. Um So it's a lot more difficult to localize on a two D thing than it is on, on 3d. So for example, for the primary motor course, we have like four different ways of trying to look it. Um And this is on a normal, I'm saying it's normal because it's mine, this is on a normal brain, right? So if you've got a tumor in the way that's distorting the athlete, it can be even more difficult and often you have to use the contralateral side to say this is what it looks like on the normal side. And therefore, I think this is where it is and you still may not be correct. So here, for example, I think this is the omega sign. Yeah. So, so this is hand area. Um So I think this is central focus one way that so I'm gonna go through a couple of different ways. So one way is that the superior frontal sulcus runs all the way back and stops at the precentral sulcus. OK. And so I think then this is the precentral gyrus, there's the omega sign, there is something called the, the bracket sign, the pas bracket sign, which is just behind the sensory cortex. And so the thing in front of it is sensory and therefore the thing in front of that is motor, it's all pointing to the same. And then there's a thing that I showed you on, on the medial view of the brain is that the singular goes up, goes up, goes up and then the first bit at which it takes off up is the marginal. And so this is sensory and therefore the thing in front of it is motor. And so all of the things that we've done have told me that I think this is my primary motor cortex. Um and at the time at which I had the scan. They were also testing at the F MRI and it fits. So that is my motor cortex cool. OK. So you've done the hard job of localizing on an MRI scan. And you realize that the thing that we want to remove that little cortical dysplasia thing that we want to remove is just in front of the motor cortex. So here is uh an epilepsy patient who um I operated on a few months ago. So you can see that this patient has had some seg electrodes and um and basically this one here is the motor cortex and we have put in all of these electrodes and figured out that these ones are in motor cortex. So we shouldn't remove them. This is where the seizures were coming from the bit that I marked out in blue. This is where all the important blood vessels are. And therefore you think OK, that's really easy. It's just a question of following the plan. This thing is on our ne neuron navigation system. So you can just literally just do what it tells you to do and follow it and do it. So then you go get to the operation and you do. Uh so this is slightly backwards cause this, we've already done the craniotomy and closed it. But I want to show you the side of the hole that we made. So you make a cut in the skin, you make a hole in the, in the skull and you expose this bit of brain. Now, you're exposing this much because the operation you need to do is this much. Um How do you know what Gyrus is? What, what sulcus is, what there? So you can use your navigation uh and you can try and uh and localize based on that. Um But sometimes you get it wrong. So you, sometimes you think what is the precentral sulcus is actually the postcentral sulcus. And so you, you think you're in front of it, you resecting something safe, but actually, that's primary motor cortex. So you use mapping. So there's different ways of intraoperative mapping. Uh And broadly, I split them into two ones that are that you do um in the operation, the ones that you do before the operation. So the things that you can do before the operation is a functional MRI scan uh which uh and a diffusion imaging scan which uh localizes white mere, the functional MRI will localize areas of cortex and you can get like I did to move your right or left arm in an MRI scanner. Uh and the blood flow to your right hand area will go up. And therefore, you know, that's, that's what the bit that's controlling your hand. Um And you can also do intraoperative mapping. So you can do evoked potentials like you said, or, or stimulate cortical stimulation and subcortical stimulation to try and find important areas that you don't want to remove. So in this case, we did cortical stimulation uh and we found that the area that we wanted to resect was somewhere up here. Uh And this is the uh arm, hand and tongue, I think, or torso, maybe I don't remember what it was. But yeah, anyway, we, so we localize different areas of the um based on the, on the mapping. Uh And therefore we preserve those areas so that the child doesn't have deficit at the end. Um So this is a sleep mapping. Um You can also do mapping a week so you can get them to, you can stimulate a certain area of the brain, uh get them to move their hand as you're doing that. And if they suddenly stop moving, it means you've stimulated their hand area and you shouldn't re um m for, for purely motor reasons. Um I think a sleep mapping is really good because you don't have the added pressure of the patient being awake during the operation. Um And actually from an efficacy point of view, it's really, really good. Um And so I don't see the, the reason to have someone awake for that, but for language mapping, there is no way of doing that asleep. And so you have to have the patient awake. Um You have to have a really good neuropsychologist that helps you uh do specific uh verbal tasks depending on where in the brain you are. Um They also work very closely with the patient to ensure that they're comfortable. Um, and they're performing as well as they possibly can because you don't really want a false, you don't want to say, oh, they couldn't perform that repetition task when actually it's because they were uncomfortable, they were in pain. They didn't, they weren't bothered to cooperate with you, et cetera. You wanna make sure that you're picking up true positive so that you maximize what you're removing in terms of tumor. Um and also preserving function. That's all I had. Cool it. Yeah, I have a, I I have a question about the in cases that you can't that you struggle to find. Yeah. Is that what sort of um Yeah. So um so, so you do the, the, the I guess the in, in America, they like to split it up into phases. So the phase one is called the noninvasive presurgical evaluation where you do MRI scan, eg blah, blah, blah. The phase two is they're sticking the electrodes into the brain. And if you still can't find where they're coming from, you may have missed it. Uh Or it may be that it's coming from multiple areas. In which case, there is no like one single operation that you can do to remove the area. Um So they go ahead with continued medical management. So uh medication, anti seizure medication, um you can have ST neurostimulation. Um So things like vagus nerve stimulation is very established. Um there's emerging indications for deep brain stimulation and responsive neurostimulation breath as well. Um And so those are options but the latter two aren't really done in the UK. Yeah. OK. Yeah. Yeah. Yeah, that was it. I I'm just, yeah, I'm just trying to mm and also the five steps and um I have a question in terms of recovery, post um post resection. Um I know I just to make sure that is a decision. Yeah. Um So in terms of recovery patients, how does that happen? I mean, the question is that CNS doesn't really. Yes, very well. Um Yeah. So I'm going to paraphrase the question because someone said, can you please paraphrase questions from the live audience? Um um So the, the question is about like, how do patients recover when you remove a bit of their brain? Um And actually remarkably well is the answer um especially in Children. So adults are a lot less forgiving. Um because I guess everything has developed and um there's a lot less plasticity. Um but kids are remarkably resilient so you can. So there's a, I guess the most drastic thing that is done in probably all of neurosurgery is an epilepsy operation called a hemispheric disconnection or a hemispherectomy where you basically disconnect half the hemisphere or half the brain. So one whole hemisphere from everything else. Um So you don't disconnect the, the thalamus and the basal ganglia, but all the cortex that we talked about. So every single gyrus and sulcus that we spoke about today, you disconnect from the other half of the brain. Uh because the whole half of the brain is involved in generating seizures. And actually, they do fine, you know, some of them will continue to have normal speech, continue to have normal motor function. Most will have kind of subtle motor deficits on the other side. So especially the fine movements and things like that will be affected. They will definitely have a hemianopia. Um But actually the the risks of continued seizures affecting brain function is so high that we say that this is something that is worth doing for for this time. Yeah. And you said that you um you have no, we so we take them out before surgery. So um there's different ways of of monitoring in uh to find where the ses they are coming from, you can do uh kind of extra operative things. So the sed that I showed you was they go down to theater, they have the electrodes put in, they come up to our monitoring unit and then they have cameras on them and we wait for them to have seizures. And then when we see it on the camera that the seizure is starting. The neurophysiologist who are literally amazing. They look at all of these like 200 different squiggles and say, ah that's where the seizure is coming from. Um And then we map it out based on like that scan that I showed you and say, OK, that then this is the area that we need to remove. Um you can do intraoperative uh localization as well. You can just put an eeg electrode on the surface of the brain and see where the spikes are. But when they're under an anesthetic, they can't have a seat or they're very unlikely to have a seizure. Um And you don't want them having a seizure when they're under an anesthetic. Um And so you can't, you can't say that this is where the seizure is starting from in. So I see. Yes. So it, it, it really depends on what you want to do. Um In a brain tumor, it's very easy to say where the tumor is. Um And so what you are mapping for intraoperatively is for function. So, re reality in uh in reality, what I mean by function is motor and language. Um people have done monitoring for other stuff like parietal lobe function or um even some frontal lobe, like more, more further front frontal lobe, like executive function um mapping when patients are awake. Um But I don't think they're mainstream and I don't think they, they will be anytime soon. Uh I'm just gonna see if there's anything on here and then I'll come to you. Uh I got a question. Do you do a weeks, surgery, sources of epilepsy in the non-dominant hemisphere, usually not. Um In Children, definitely not. Um in adults also probably not. There's no need to. What question? Yeah, sure. If it does a good job, why not? Um Yeah. Uh I need a good reference recommendation to read about brain map more. Uh So um there is an amazing book uh by a guy called Reba um called like Cortical Anatomy or something, something similar. Um It's amazing read it. Um get it if you want to. Um But all of these colored images that I showed you are from raped and if you go to raped ass anatomy like neuroanatomy section, it, it's genuinely amazing and they've got all these beautiful diagrams that make it really easy to kind of get to grips with um with, with anatomy. It's one of these things that's really boring. Um But it's all about repetition and so, you know, I could give the same lecture to you four times and every time you heard it, you would pick up something different from it. Um Don't expect to know all of it. It's OK to forget. Um But as you hear it more and more you'll pick stuff up. So there's also this thing called the Cambridge Lectures in Neurosurgical Anatomy, uh which I've been to like three times and I probably will go to another three times. Um Just because every time I pick up something different, I pick up, you know, the next level of stuff. Uh I have a question about complications of SS eg and subdural grid. So different ways of localizing where the disease are coming from. What I've shown you seg is basically, you make a very, very small hole in the skull like this uh like this. So it's literally like, you know, a two millimeter hole in the skull. You put in a bolt and you put a wire through it. Um Previously, they used to do lots of operations where you make a big big massive window in the, in the brain. And you put a, a subdural grid on the surface, you put the, you put the bone flap back and then you take them up to the epilepsy monitoring unit. Uh As you can imagine, that's a much bigger operation. Um The patients took a lot longer to recover from it. Um Infection rates are higher because you've got basically a massive skin incision and then a massive amount of wire coming out of the of the skin incision. Um And so essentially, it's all moved to seg and there's very few indications left for subdural grid. So pretty much it, it it doesn't really happen anymore. I question, which was, I mean, it's just a question. How many sort of anatomical variants do you typically see in animals? Yeah. So sometimes we'll, you know, we won't be sure which the central sulcus is or which the precentral gyrus is. And sometimes, you know, this is a question about anatomical variants for this online um uh and you know, there'll be two gyri where you expect only one to be and there may be like an abnormal sulcus somewhere there. And that may be an indicator of, that's where your pathology is. That's where your developmental problem is, especially in epilepsy. Um And so that's why in addition to studying the scan, you also need some form of, of functional localization in addition to the anatomical localization because there's only so much you can do with the anatomy, but you have to confirm that with your function. So that can be in, in in the form of F MRI or T MS where you, you localize it outside of the scope of the operation or you can localize it with the scope of the operation, with mapping. Yeah. Yeah. Thank you. That book um Applied Cranial cerebral anatomy is awesome. Is, is there, is there a lot of um ultra ultrasound? I have no idea. Yeah. Uh I probably yes but don't know, don't know anything about ultrasound? Yeah, they use uh I mean there, there's, there's one or two focused ultrasound machines in the UK. Um And they're being used for kind of, yeah, thalamotomy for, for movement disorders mostly uh for tremor, but I, I don't know anything about it. Cool, cool. I stop here. Thank you very much, everyone for coming. Um and everyone online. Thank you for giving such an excellent talk. Please get everyone fill out this uh feedback form just so we know how to make these sessions better. Uh Thank you very much, everyone.

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