 So my name is Birgit Blantinga, and as I said, I'm a PhD student at the Eindhoven University of Technology and Maastricht University, both in the Netherlands. And I would like to present something of my PhD project, which focuses on Parkinson's disease. So it's a little bit more clinical than most of the presentations I've seen today, yesterday. Parkinson's disease is a motor disease, or it's a neurodegenerative disease that mainly has motor symptoms. And I think, unfortunately, many of you will actually be familiar with it in your surroundings, because the prevalence is quite high. 1% of the people in over 60 years suffer from it. It's a disease of the basal ganglia, which is a group of structures deep in the brain, a group of grey meta structures, and one of these structures is the subthalamic nucleus, which is a very small structure located in blue here. And that's actually what my research focuses on, but I'll come back to that later. For patients with Parkinson's disease, the first treatment is usually medication, and in the first years of the disease, this usually works fairly well. But after a while, since it's a progressive disease, the symptoms worsen, and often patients also develop side effects to the medication. And at that point, surgery becomes, if possible, an option for these patients. And this surgery consists of deep brain stimulation. And this is also where the subthalamic nucleus comes into play again. Because with deep brain stimulation, during the surgery, an alec throat is placed into this subthalamic nucleus, and it's connected with a wire underneath the skin to a stimulator. And this stimulator gives electrical pulses to the subthalamic nucleus. And this also relieves some of the motor symptoms of Parkinson's disease. It's not really understood why it works, but as long as it does work, well, people are happy to apply it. However, unfortunately, there's also a problem associated with this procedure. And that is that some of the patients still develop some side effects to this procedure. And the side effects usually manifest as behavioural problems or mood problems. So they may become depressed earlier than Parkinson's patients without deep brain stimulation. And we think that this is caused by this very small subthalamic nucleus being divided into three different functional zones. It's the motor part, the associative part, and the limbic part. And we think that the alec throat should be placed into the somatomotor part for the surgery to have the best outcome. However, if the alec throat is placed in this associative part or in the limbic part, then we think these behavioural changes may occur. So the question now, and also the goal of the research is how is this subthalamic nucleus divided into these functional zones and can we find them? So to this end, we scan four healthy subjects on an ultra high field. So seven Tesla MRI scanner, which is located in Maastricht. And we performed sort of standard anatomical imaging and diffuser weighted imaging, which can be used for tractopathy of the brain. So tracking the fibers in the brain. So this is an example of the results. Can you still hear me properly? Okay. This is an example of the results. No, not right. Okay, it felt like I was dropping off. Okay. On your right, you see the anatomical imaging that we have in our study. And on the left, as a comparison, you see a three Tesla image from the literature. And on these anatomical images, we can quite neatly by hand delineate the subthalamic nucleus. And from this subthalamic nucleus, we performed fiber tracking with the diffusion weighted images. And we see that the fibers going upwards from the subthalamic nucleus can actually be divided into three major fiber bundles. There's a fiber bundle in green, which goes to the premotor area. One in red that goes to the inferior front area. And in blue, you can see a fiber bundle going to the internal globus pallidus. So if we know this, these three locations or destinations have different functions. So if we then can look back in the subthalamic nucleus where these three fiber bundles originate, we have an estimate of the functional subdivision. So we did this. And for one example, this looks like this. I can zoom in on this. So this is the axial plane like this. And then we also have a coronal plane like this. And what we see is that the fibers that go to the premotor area actually originate from the posterior lateral part of the STN. Those that go to the inferior front area originate from the dorsal lateral part of the STN. And those that go to the internal globus pallidus originate from the anterior medial part of the STN. But this is the example of one STN, but we have four subjects, so eight STNs. And in general, we see that in seven out of those eight STNs, the fibers that go to the premotor area, the part of the brain that's involved in movement, originate from the posterior lateral part of the subthalamic nucleus. Those that go to the inferior frontal area, which is among other things involved in motion inhibition, so more complex motor control, they originate from the dorsal lateral part of the STN. And the fibers that go to the internal globus pallidus, which is involved in limbic processing, they originate from the anterior medial part of the subthalamic nucleus. So in conclusion, this, although they are preliminary results only in a few healthy subjects, suggests that there is indeed a functional subdivision of the subthalamic nucleus, and that this way we may be able to separate between limbic and motor processes within the subthalamic nucleus. And of course, we hope that in the end, this may lead to improved targeting on the individual subject level for deep brain stimulation. But our first step for the future is to also validate if we can still find this subdivision if we scan patients instead of healthy volunteers. So I'd like to thank my supervisors and my colleagues who also work on this research. And of course, I would like to thank you for your attention. Yes, go ahead. I'm just wondering, what's the dimensions of the electrode compared to the size of the subthalamic nucleus? I was wondering whether maybe another possibility is that the stimulation is quite fierce that it sort of leaks out into other tissues. Yes, yes, that's actually a very good possibility. And there are also research that suggests that you should actually not stimulate the subthalamic nucleus but some of the adjacent areas. Some research suggests you should stimulate the subthalamic nucleus. Some research suggests you should stimulate just outside of it. So that's actually a very good point. And I think in effect, you don't only stimulate the subthalamic nucleus but also some of the surrounding area. The electrode itself is, I think, about one millimeter in diameter and the subthalamic nucleus is about five, six millimeter in every dimension. But the potential field is bigger, of course, yeah. Are these electrodes currently MRI safe? So could you, for example, go back to patients that either have side effects or don't have side effects and then retrograde to check where the electrode was placed? Yes, officially, they're not MRI safe but you can put patients in an MRI scanner of 1.5 Tesla. That's being done. So if you read the mctonic guidelines, they are very ambiguous and whether you can do it or not, but it's being done. And otherwise, you can also do CT post-operative.