 And I hope it's going to work. So now the preview is working. Okay, hello everybody, sorry for the delay. We had some technical issues. So hello everyone, and welcome for another episode of this third season of SITUX Vision. This is an online web seminar series for vision and vision neuroscience. These talks are part, as you know by now, they are part of the worldwide neuro-initiative, which is a platform for neuroscientists in the virus field to exchange on the most recent work. And we're still doing that because, well, as a woman traveling to conference, still remains complicated. My name is Maxim Ziememann. I'm a former PhD in computer science lab. And today I'm very happy to receive a seven-file analyst. First of all, I received this PhD in animal ecology and conversation ecology from the University of the University of Madrid in Spain. He then got some post-doctoral experience at Oxford in the UK and then at the University of Minnesota in the US, respectively in the Department of Zoology and Department of Ecology. He next moved to the West Coast, where he accepted the position as an assistant professor at the California State University Long Beach to finally move inland in Indiana, where he's now a full professor in the Department of Biological Science at Purdue University, and that since 2014. Esteban's group aims at, and I quote, and ends our understanding of the mechanism underlying animal behavior using an evolutionary framework in order to develop predictive models that can be applied to solve conservation biology problems. Currently, they are interested in the evolution of visual systems and behaviors in vertebrates. And today we are really eager to hear more about their work on predatory direction from a bird visual sensory perspective. Hello, Esteban. How are you doing today? I'm doing very well. Thank you very much for the very nice introduction. Can you see my screen? Yeah, we can see. Okay, hold on one second. Okay, and you can still see my screen. Perfect. Awesome. So ready to go? Ready to go when you are. Okay, thank you. So first of all, I'd like to start with acknowledging the real makers of all the data that you will see throughout my talk. These are my wonderful grad students, technicians, and postdocs that have been working with me and it has been a pleasure to have them in my lab. Basically, most of all that you're going to see today is because of them. We are interested in understanding how visual perception affects behavior, particularly in birds. To do so, our sort of overall approach is to measure different visual traits with different techniques, then use that information to inform some perceptual models that give us the opportunity to generate predictions that then we test in behavioral experiments using a different set of behavioral techniques. So basically what we're trying to do is to bridge the gap between visual perception and behavior in birds. And our research has implications for evolution sensory mechanisms, as Maxime said a few minutes ago, conservation ecology, and to certain degree, biomemetics. So over the years, we have been collecting information on different visual traits in birds. And that led us to a very interesting comparative data set. So today, instead of going deep into a few studies, what I'm going to do is do a more of a synthesis of some of the work that we have been doing. And that starts basically with the idea of spatial vision. As you know, at least in humans, spatial vision defines our visual experience and it certainly affects our behavior. We have frontally play-sized, we have a single center of acute vision, which is a phobia, relatively close to the center of our eyes, and our binocular field and our phobia fields somehow overlap. That is a very interesting visual experience. But one of the interesting things is that other animals may have a fundamentally different visual experience. So many authors have posed the idea that if we understand that spatial vision experience in other animals, maybe we can be in a better position to predict their behavior, right? And there are many examples, this is one of them. So our interest in spatial vision is related to predator-prone interaction. So here we have a beautiful predator, that animal detected a prey item, right? And it's flying very quick. And here we have our prey item that it's not going to be happy, although the predator will be very happy, as you can imagine, right? So that sums up a classic predator-prone interaction. But when we think about predator-prone interactions, there are different stages, right? At an early stage of this predator-prone interaction, there is a component called detection, by which if the prey detects the predator quick, then the prey will be able to, will increase these chances to escape. But if the predator detects the prey earlier than the prey, then the predator will have higher chances of a successful attack. Obviously, detection in birds, because they're visually oriented organisms, is highly influenced by the process of visual search. And this is basically what we are, we have been studying for some time now. Now, detection itself has a very important role in multiple predator-prone interaction models. This is one of them, right? So depending on who detects first the predator-pray, these sort of sequence of steps can change the probabilities of capture and of course, of escape. So the question that I'm going to try to pose today is what are the key visual specializations in avian predators and avian prey related to that early detection? We can rephrase that question in this way. What is the degree to which vision varies between avian predators and avian prey? And obviously, to start thinking about that, we can use the framework of mammals, right? And this is one example, right? And we have the zebra that has a really wide visual coverage, not so much of binocular vision, whereas the lion has reduced visual coverage, a lot of binocular vision and so forth. So the question is, is the same going on with avian predators and prey? So you can imagine that for practical purposes, defining a predator and a prey, it's pretty close to an animal, right? So because obviously any avian prey species, to some degree, is also a predator. So throughout the talk, when I say prey, what I really mean is species that detect food at close distances, right? And when we say predator, what we really mean is species that detect food at far distances. So that difference in detection is sort of reflected in the use of the word prey and predator. Okay, so let's go quickly through some basics of spatial vision, right? So here we have a bird, here's the eye of the bird, right? If we hemisec the eye, we'll see here the retina and here's the pectin of the bird. If we extract that retina, usually we have to flatten the retina. So that's why you see these guts around the retina. And the retina of birds, it is amazing, right? Because it has a series of single cones for in particular that are associated with the processing of color signals. And it also has something called double cones that are thought to be associated with the processing of achromatic signals and motion. So if we look across the retina, we'll see areas that we usually call the periphery of the retina with low density of these photoreceptors that lead to lower spatial resolution. Whereas other areas within the retina have high densities of these photoreceptors, also called centers of acudition, which lead to higher spatial resolution. Also in birds, they have oops, sorry. Can you see my PowerPoint? Yeah, we do. Thank you. Also in birds, we have some, they have an organelle called old droplet. And the old droplet is ripe. So light comes through the photoreceptor in this direction. So light goes first through the old droplet and eventually reaches the visual pigments where phototransaction takes place. So if you take a fresh avian retina and put it under the microscope, this is what you're going to see. Each of these dots represents an old droplet. And each type of comfororeceptor has a different type of old droplet. Now, I told you before birds have visual pigments. They're in the outer segments, of course, and they have a certain type of sensitivity. Now, the old droplets do something really magic, which is filtering the light in a way that they block light up to a certain point. And after that point that we call the lambda cut, they allow light to go into the visual pigments. So basically the old droplets change the sensitivity to some degree of the visual pigments, right? In other words, the old droplets are, we thought, are meant to enhance color discrimination in birds. Okay, so I told you there are areas of the retina with high density of these cones and they are called centers of acute vision. In birds, there are different types of centers of acute vision. I'm showing you in this slide just two, but there are more. The phobia is the one that we usually think of because humans also have a phobia. So it's an invagination of the retinal tissue that allows a greater packing of photoreceptors. But other bird species might also have something called an area, which is an enlargement of the retinal tissue to accommodate that higher number of photoreceptors. Now, the centers of the center of acute vision appears to be also the center of visual attention. So we developed these eye tracker for small birds that allowed us to measure what's going on in the right and the left eye simultaneously. So we were able to present in different screens different types of visual stimuli, right? So here's a starling, right? With, and I'll show you a video in a second with the camera looking at its eyes. So what we do is we map out the retina of the starling and then we tell the software, hey, the phobia of the starling is right here, okay? So the software goes and say, okay, let me project that phobia, which is that these two red dots into the other screens, right? And that's what you see. So I'm going to play a video, focus on the lower panel right here. These are starlings, so we decided to show them and here's the phobia moving around. We decided to show them a millworm and look at that starling, amazed by that millworm, right? So the bottom line here is that the brain somehow in bird seems to be talking to these centrifugal vision, right? To direct the center of visual attention, okay? So here's our bird back, the projection of the center of vision, right? We can create a sphere around that bird and project the right and the left eye into that visual field, right? And if we do that, then we will get these different landmarks around the visual field, the lateral fields, the binocular field with the projection of the bill, and of course, the blind area at the rear of the head. And here we have the projection of the center of our vision, right? So we can represent these into dimensions, right? And this is a classic graph representing all that I told you. And the reason I'm explaining that is because I'm going to be showing you several of these graphs. Whatever is not blind area is what we call visual coverage in birds, okay? So here's a list of visual sensory traits that are to different degrees associated with that early detection by avian prey and avian predators. Remember what we mean by these two terms, right? So a few years ago, most of the research in the literature was focused on trying to understand vision in falcons and hawks, eagles, vultures, right? And what, you know, most of the literature was reflecting when it comes to prey were pigeons and chickens and things like that, right? And this is sort of a view of at that time, our understanding of these visual traits. There were a lot of question marks, there were a lot of assumptions and so forth. So the interesting thing is that all these orders of birds represent about 40% of the species. But what we decided to focus on is on the order of passeriforms that represents about 60% of existing bird species. So we did a lot of sampling on prey in those orders. And for predators, we also sample a lot of falconiforms and accipitiforms, but also predators within the passeriforms. So the bottom line is that before I continue, you need to know that this talk is heavily, heavily biased towards some passeriforms. But hopefully you got the idea as to why we decided to bias in that way. Now, if you want to gain a better understanding on the predator's visual perspective from the perspective of non-passeriforms, I strongly recommend that you take a look at these reviews that have been led by Simon Poteer. There are excellent, excellent summaries of the literature on the predator visual perspective, again, from the perspective of non-passeriforms. Okay, so here's our table. So what I'm going to do now is I'm going to start filling out the different cells based on what we learned from this term. So in terms of visual acuity, this is pretty obvious, right? Species that detect food at far distances, the so-called predators have higher, much higher visual acuity than the prey, right? This is more of an assumption associated with our operational definition of what a predator and prey mean. And here is sort of a view of different examples of different species of birds relative to humans, cat and goldfish for you to see that trend. Okay, so visual acuity established, how about visual coverage, right? Remember the zebras and remember the lions. What's going on with birds? Well, pretty much the same thing. So in terms of visual coverage, songbirds tend to have wide visual coverage. So this is sort of a snapshot of what it would be around the visual field of a typical songbird, right? So wide visual coverage again, whereas the predators that we sampled tended to have more reduced visual coverage, which makes sense because if you have a wider visual coverage, then the chances of detecting a predator coming from somewhere around your head are going to be high. So that's established. When we started studying binocular vision, this is when our heads turned completely around because that expectation in mammals went completely away. So what we found is that prey or birds that detect food at close distances have much wider binocular fields than their predators repeatedly. So there is something going on with these species that detect food at close distances that apparently they need a wide binocular field. And we'll continue talking about that in a few slides. So the bottom line is binocular vision, wider in avian prey, narrower in avian predators. So in terms of the center of acute vision, I just as a refresher of the two that I'm going to be talking about today. What we found is that species that detect food at close distances tend to have a single center of acute vision. This is just one example, the brown-headed cowber. This is a topographic map of the retina showing the variations in the density of retinal ganglion cells. And here's a picture, a cross-section of the phobia of these brown-headed cowber. If we have these represented in a three-dimensional view of the visual field, here we have the binocular field, and here you have the phobia projection of the left eye and the right eye, of course. So we found these configuration in a bunch of different species, these so-called avian prey species, right? In the case of predatory species, which is not a surprise because it has been found in many raptors, we found that they have two centers of acute vision, right? In this case, the tree swallow, it has two phobias. Other songbirds that are a predatory species tend to have a phobia in an area or two phobias in whatever combination, but it's usually two. Now, in the tree swallow, the phobias, here's the visual field and here's the projection of the four phobias two per eye into the visual field of the tree swallow. So centers of acute vision, one phobia for avian prey, which usually projects laterally, we'll talk more about these, and in the case of avian predators, two centers of acute vision, whatever combination, and it usually projects laterally and frontally. Eye movements was also something extremely interesting that we found out differs between these two groups. So the degree of eye movement is higher in avian prey species than avian predatory species. And it's pretty amazing, I would say. So here's just one example of the many species that we looked into, the Carolina chickadee. So these species can converge its eyes to a point it can generate a binocular field of about 76 degrees. But at the same time, it has a degree of eye movement that it can diverge potentially its eyes and create kind of a small blind area where the binocular field is. And there are obvious functional implications of these. So you can think, well, these really wide binocular fields could be associated with the process of exploring the food substrate to detect food items. Whereas these visual configuration could be related with, oh, is there a predator around and checking quickly around his head whether a predator is attacking. Now the interesting thing is that we also found that these avian prey species with a single phobia, the degree of eye movement varied depending on the configuration of the retina. So to explain that, imagine we have a bird and the bird is looking at a lizard, right? And what we're going to do is we're going to explore different retinal configurations that vary across species, right? So here is our retina, right? And here is an axis that goes through the retina. So imagine that we go and sample the density of retinal ganglion cells across that retina, right? And we can identify if we look at different species at gradient. On one extreme of the gradient, we'll have species that the cell density profile will look more or less like this. So from the nasal to the temporal, we'll find low densities and suddenly a really abrupt increase of cell density that ends up in the peak at the peak of cell density in the fall. And then it comes down. If we assume that there is a threshold cell density above which the animal perceives as high resolution, then we can hypothesize that these species with a pronounced change in cell density will have within its visual field a relatively small center of acute vision in terms of angular distance that it covers. But the interesting thing is that there are other species in which the cell density profile is very different. So instead of finding a steep increase, you find a more gradual increase. So if we assume that if we make the same assumption, right? That a certain threshold cell density will provide that perception of high visual acuity, then these species will have a relatively wider in angular space center of acute vision in terms of visual experience than these species. If that's the case, then we can make some predictions if both species needs to capture a certain amount of high quality visual information by moving their eyes per unit time. And what we can predict is that these species would tend to have more pronounced eye movement behavior than these other species. So we decided to test these hypotheses by looking at the topographic maps of a bunch of different species of birds, right? And basically we looked at the retinal ganglion cell density across different axes, right? And we associated the slope of change to these different sort of cell density profiles, the high slopes and the small slopes. And we control for phylogenetic effects and basically we found what we predicted, right? That species with a more pronounced rate of cell change across the retina tend to have a higher degree of high movement than species that have a less pronounced degree of change in cell density. Of course there are a bunch of other alternative hypotheses that could be explaining this, but that's a very interesting finding showing how eye movement behavior in these species, these prey species might be quite dependent on retinal configuration. And of course, this finding has a lot of implications for the evolution of anti-predator behavior because we also find, I don't have time to tell you, a similar result related to head movement behavior, not just eye movement, but also head movement behavior. So we can talk about that in the Q and A if somebody's interested. Okay, so eye movements variable in avian prey, but depends on retinal configuration and limited in avian prey. Let's talk now about frontal spatial vision, which is the most interesting finding of all, right? But I will invite you to try to put yourself in the head of a bird. I know it's tough, I know it's tough. We try to do that all the time here in my lab. And if you think about that, the beak is the element, the most important element that birds use to interact with their environment. So whatever happens visually around the beak is extremely important for the bird in order to obtain food, in order to drink, in order to interact socially with other individuals all the time. So you can imagine certain evolutionary pressures for frontal spatial vision to be tuned to the ecological needs of those species. At least that's the hypothesis. In species that detect food at close distances, our avian prey, the single phobia prey does not project into the binocular field. You might say, well, but they move their eyes a lot. I know, but even when their eyes are converged, those phobias don't get into the binocular field. In other words, these animals have a visual experience that is fundamentally different from the human visual experience. Remember in our case, phobia vision and binocular vision overlap. In their case, they don't. So the implication is when they are exploring their substrate to find food with their beak perpendicular to the substrate, they're looking at the substrate with low acuity vision. But they have these wide binocular fields. So what's going on? Obviously, we don't know what's going on. But here are some ideas, which are a little bit of speculation with a little bit of data to entertain these products. So what we decided to do was using the house parrots. We decided to look at the retina at the area that subtends the centrifugal vision and the area that subtends the binocular field. That is the temporal portion of the retina. And I'm going to go a little bit quick for the interest of time with these results. Happy to answer more questions later. So one of the things that we looked into house parrots is the ratio of achromatic to chromatic cones in these different portions of the retina. Now is in the binocular portion of the retina, there was a higher better in a few minutes in the binocular field going on. Oops, can you hear me? Yes, sorry, we lost you for at least 30 seconds. Oh, but now I'm back now. Yeah, you were talking about the ratio of achromatic and chromatic cones. That's good news that I'm back. Sorry about the technical difficulties today. Right, so basically there might be some kind of achromatic trend going on into the binocular field of these house parrots, right? So in terms of the lambda cap, remember the old droplets that I mentioned to you before, this is the wavelength in which they start allowing light to go through the photoreceptor, sorry, through the visual pigment. We did some micro spectrophotometry and what we found is that in the achromatic cones, when we were looking at the achromatic cones, the lambda cap was higher in the binocular, within a given individual in the binocular portion than in the foveal portion of the retina, whereas the lambda caps of the chromatic cones were higher in the foveal portion than in the binocular portion of the retina. So following some of the literature, one potential translation of these trends is that these findings might suggest possible enhanced chromatic discrimination in the foveal portion of the retina, that's expected. We knew that for years, but this is what it was unexpected, a possible enhanced achromatic discrimination in the binocular portion of the retina. So the bottom line here is that in birds, in this avian prey, binocular vision might be anatomically different from foveal vision, and these anatomical differences might lead to some functional differences, right? So we posed the hypothesis, and again, it's just a hypothesis we're speculating here, that binocular vision might handle better achromatic cues, whereas foveal vision might handle better chromatic cues. And if this is the case, we would predict that birds would increase the investment in gathering binocular or foveal information depending on which visual dimension is challenged. So we decided to do an experiment. Figures are missing here. Wow. Okay. Let me stop sharing because let me share again. We seen a couple of slides. So the slide without sharing looks perfect, but when I share it, the figures disappear. So I'm trying to share it again. Sorry about that. I'd like to remind the audience that they have questions that can use a tap, and if he has a question, we will answer that at the end of the book. Let's share. Maxime, would you mind letting me know if you can see my screen? I see. Oh, perfect. The figures are back. That's good news. So we decided to run a behavioral experiment with these house parrots in which we had food trades, and because we did some work on the readiness, we were able to project their foveal vision and their binocular vision, right? So we were able to find out the body postures in which the chances of using binocular vision or foveal vision would be high, right? So then using the physiological information that I showed you before and some visual models that are available in the literature, we modeled how these house parrots would be perceiving these seeds against these background, and what we found out is that from the perspective of chromatic contrast, which is color vision, pretty much the same between the fovea and the temporal retina, but when it comes to achromatic contrast, look what we found. That these seeds would have a higher achromatic contrast, even that anatomical configuration that I showed you a few minutes ago, higher achromatic contrast in the temporal portion of the retina than in the foveal portion of the body. So then we developed this manipulation of different substrates, the same seeds varying the achromatic contrast and the chromatic contrast of the seeds. And I'm about to show your preliminary results, we're still doing the analysis, so this might change completely as we analyze more and more behavioral dimensions, but basically the preliminary results show that the proportion of time using foveal vision tends to increase when the animals were challenged chromatically more to find the seeds. In other words, when in the chromatic dimension, it was more difficult to distinguish the seeds from the background. But when the animals were challenged more achromatically in terms of finding the seeds, then the animals tended to use more binocular vision before pecking into the seed. So the bottom line here is that species that detect food at close distances, we think or we're proposing that their frontal vision is likely tuned to enhancing that achromatic visual discrimination. And maybe that's why they have these really wide binocular fields to optimize the process of using visual contrast, achromatic visual contrast in order to find the seeds. So what about the species that are more predatory species, right? Well, one of the things I didn't tell you when I showed you this graph is something related to the distance between the different centers of acute vision. So what we found out is that they're almost equidistant. So one interpretation is that if you need to detect prey items far away, maybe concentrating four spots of high acute vision in your frontal view might be a really good idea if your prey moves because it would allow you to estimate and predict the potential, estimate the speed and predict the position of that prey in space much better and consequently increase the chances of catching that prey. So the idea that we're putting forward is that species that take food at far distances, these predatory bird species, their frontal spatial vision is likely tuned to enhancing visual acuity, but not just overall acuity, although that's happening, but also having these four spots with high localized visual acuity. So if we try to put all these together, right? Going back to our predators and prey, this is more or less what a snapshot in their visual field will look like. More or less, I mean, we're taking a leap of the imagination that is pretty big here, right? So avian prey species have this wide visual coverage, one set of acute vision per eye, these wide binocular fields, maybe there is a heavy emphasis of acromatic vision going on here, whereas the avian predator species have more reduced visual coverage, four centers of acute vision reduced binocular field. We haven't studied what happens here, so this is an assumption that we're making in this graph. And we need to, at the end of the day, relay that back to behavior, right? So this is the way we are sort of imagining the vision exploration behavior of species with a single center of acute vision, one of these prey species, right? And this is the sort of filtering that happens that might be happening in the eye, no idea what's going on in the brain, right? And we can do a similar exercise for these species, that these predatory species that sit and wait, and eventually once they detect the food item, they go after it. So in wrapping this up, I have to tell you about the exceptions, right? Because that's when the cool stuff pops up. And there are tons of exceptions, right? So what we have done here is to try to, you know, throw a line, a single dimension, which is at which distance they might be detecting food. But of course, there is little generalization when we start looking at a bunch of other species. So I'm going to tell you about two examples. One is the, there are many more, but just two. One is the eastern meadowlark. This is an avian prey species. It inhabits open environments. You can see the animal here trying to look for food. You can also see the animal checking out what's going on around itself, right? So if we step back and we ask the question, what is the phobia in these avian prey species usually located? And the answer to that question is right here. So the phobia in these prey species is a little bit off the center, more towards the temporal side. But the most important thing that I would like you to pay attention to is relative to the temporal nasal axis, which should be aligned with the horizon. It's above that axis, right? And what that means is if we see one of these prey species from this point of view, the phobia is going to be projecting in this way, more or less, right? Basically, aligning the projection with the horizon. Eastern metal arcs are not like that. So here is the axis I was telling you before. Look where the phobia is, is below that axis. So what that means is the projection of the metal arc phobia is going to go above the horizon relative to other prey species. So what we believe might be going on is that in a species like these, this might be a really good idea when you are quickly scanning the environment trying to check what's going on to try to detect these potential predators or even conspecifics that are trying to occupy your territories because they're very, very territorial, right? So here we have for the Eastern metal arc sort of an exception to the pattern that I've been telling you about. But probably the most interesting exception to that pattern is the flycatchers, right? So flycatchers, they're seed and weight predators. Is this working? Yeah, they're seed and weight predators, right? They look around, they take food, they go after the food, they come back, eat the food, okay? So I told you about the old droplets. Here's a picture of the old droplets. When you see old droplets, when you put a fresh retina, as I said before, of all these species, this is what you're going to see. And I'm going to show you all droplets of other species, right? This is what you see, old droplets. So now whoever is listening to this, you have become an expert in old droplets in the identification in births. Congratulations, okay? So when my grad students were looking at flycatchers of the genus NPDonax, one of the things they found out, because this is a predatory species, they have two centers of acudivision, what I told you before, instead of two phobia, they have a central phobia and an area in the temporal area of the retina. So they were looking at old droplets in the retinal periphery, and there you go. You're experts now, you're like, yeah, sure, no problem, those are old droplets. When they turned the microscope to the central phobia, they found this. So now that you're experts, hopefully you're like, whoa, what's that? Something is not the same. Let me zoom in, this is what they found. The interesting thing here is that you can see the old droplets, so they're there. But suddenly you see these triangular structures which are red, orange-like or some sort. What's going on here? So this is a long story, of course, I don't have time to tell you the whole story, but let me tell you what they are. So here's a picture from the bright microscope and this is the picture with the electron microscope, right? So this is the structure, this is the structure in the electron microscope. Just for reference points, this is the usual old droplet that you will see here, here, here and here, right? Just to give you a sense. So what these structures are are actually giant mitochondrias that are residing within a single cone. And these giant mitochondrias are surrounded by hundreds and hundreds of small lipid droplets that give the giant mitochondria these structures, these orange-reddish coloration. So we decided to call these the mega-mitochondria small old droplet complex or MMOD complex, right? And if you're asking right now, because we have been asking the same question, what are they for? We don't know, but what we do know is that if you look at different families of births from which we have pictures on the old droplet layer, they all look the way I told you, but only two species of flycatchers, of a new world flycatchers have these MMOD complex. It's likely that many more have, we haven't sampled all of them, right? So only those two species. So we don't know what's going on, but in the paper, we put forward some potential hypotheses to try to explain in the future what's going on. So these mega-mitochondriacs have been associated with high energy production within a cell. And that high energy production could be associated with faster responses of the photoreceptors, which somebody could take the leap and say, well, if they have a high response rate, maybe that gives those photoreceptors higher temporal visual resolution. On the other hand, the red-orange light might actually synergize the high energy production through some enzymes in the photoreceptors. And also they might have some optical effect because that coloration actually can enhance chromatic contrast of moving prey against blue and green backgrounds. So maybe what's going on here is that this complex is aiding these fly catchers in motion detection and tracking. And they use this all the time. Here's a video of a fly catcher and insect flying quickly and the animal, boom, right away was able to detect and capture, oh my gosh, this prey item. So we think that functionally, these MMOD complex might lead the animal to have a really specialized slow-mo vision. So here is the sort of picture that I showed you before, a little bit more completed, right? So what are the take-homes? Well, hopefully you realize that an eye is not an eye, it's not an eye, right? Avian vision is very different from Amelia vision. I showed you some evidence supporting that. But most interestingly, the eye of an avian predator filters information differently from the eye of an avian prey. And we put forward some new hypotheses about spatial vision in avian predators and prey that we would love to start testing and if somebody else is interested, please do not hesitate to contact us. But probably the most interesting thing is that where this is going. And obviously the frontier is how this information in filtering and the level of the eye that I told you about today is integrated in the avian prey to eventually influence behavior. And we have no idea whatsoever what might be going on here. And with that, I would like to thank all the funding sources. And if you have questions, please let me know. I'm happy to answer them if there is time. Thank you. Thanks a lot for that. That was really interesting. Like at the same because of your MMOD complex. I'd like to remind the audience that if they want to join us, I'll share the link on the YouTube chat. So if you want to join us, join the discussion and ask your question yourself. If you are most welcome to do so. We have a couple of questions. Actually, we have one from Erin Dedek from Udalenburg. Hello, Karin. She's asking a question about your sparrow figures. Do you see a difference in lambs that in both members of the double cone? Do I see a difference in the lambs that cut off? Can you repeat the last part? Sorry. In both members of the double cone. Good, excellent question. Just in one. And the reason is that it's pretty difficult sometimes, even though we have been able to measure the accessory old droplet in the accessory cone, sometimes it's quite difficult to find that second old droplet. So the results that I showed you are mostly associated with the primary cone, the old droplet in the primary cone. Sorry. I think you can answer this question but have one from, okay, I'm going to say that wrong. Madine Savestani, do you think your findings on visual abilities in prey predator apply to mammals? For example, primates prey because why binocular vision field plus single foveal specialization? Right. Great question. I don't know. That's the short answer, right? So there has been a lot of research on the mammalian side. I'm not an expert by any means. But I think the interesting thing here is that some dimensions seems to align, the visual coverage, the lower acuity and all that. But other dimensions are quite different, right? So all the story I told you about frontal spatial vision, we I think, or I didn't read anything along those lines but there might be a paper or many more. I don't think I've seen that in mammals but I may be wrong, but that's a wonderful question. Yeah. Which mammal? You have a comment from Greg Schwartz. He's thanking you for your talk and for all those many fascinating hypotheses. Okay. Thank you, Greg. I have a question from Luisa Ramirez from Brazil. Is the eye movement shooting? Did you consider a second size? I will expect to observe large saccades in the case of broad acuity zone and small saccades, otherwise, do you think it is the case? So I understood the saccades. The eye movement, yeah. Right, right, right. But I didn't understand what the question was exactly about the saccades. She's asking if you consider it and if you will expect to observe large saccades in the broad acuity zones. I see, I see, got it. Right, okay. The answer is complicated. And the reason the answer is complicated is because one of the things that we found out is that the saccades vary depending of where the eye is. So I don't know, can I share a blank screen here? Can you see my, that blank screen? Yeah, you can. Right, so here's the eye, right, of a bird. I'm really bad at drawing, so I apologize. This is awkward. Yeah, this is awful, but you get it. Right, so what we found out is that in some bird species, the eyes seem to move more in some axis than others. So for instance, starlings have these axes of oblique eye movement. So most of the large saccades occur here. Our expectation was that they might be randomly distributed, but they're not. Which might be related to the anatomy of the eye muscles, which might be related to a bunch of different things, right? But we haven't been able to find a pattern of small and large saccades in terms of eye movement. So what we found is that most of, irrespective of whether they're small or large, most of them in starlings occur in sort of this plane. But in other species, it's different. So for instance, in cardinals, which is a North American species, they oscillate. And we have no idea why they oscillate, but they oscillate. So they have an oscillatory pattern of eye movement. So I think this is the tip of the iceberg, trying to find out what might be going on. And it's a fascinating area of research because it can have a lot of connections with how animals scan their environment. Using eye movements. Yeah, so I'm sorry. I cannot answer that question at the level I wish, but we don't have the information yet. A great question. Very great. A couple more questions if you'll do it. I have one from sitting by Shwee. I hope, I guess, sorry for the name. It was a fantastic talk. Thank you. How much of the avian vision will you say is developed through in it learning and how much as a genetic basis? Oh, wow. Great question. I'm going to be so honest with you. No idea. I'm sorry, it might be a frustrating answer, but that's the truth, right? So we don't know, but that's an area of future research that if somebody's interested in taking in that direction might be fascinating, right? What we know is that there is between individual variation within a species in some of the traits that I've been talking about. Could that lead to differences in behavior? Could that prime some individuals to be able to learn certain things? Could it be individuals to be able to learn certain visual exploratory behaviors than others? Fascinating question, but I don't think we know the answer to that up to this point. Thank you. I have another one from Companen. Your four fovea predatory disease for catching things seems to rely on the pre-passing several foveas in sequence. Do the birds, therefore, align their head axes accordingly? Yeah, so great question. It's likely, but I don't think we have enough information to be able to answer that question. Now, something I didn't tell you, because there is not enough time, right, is that birds move their heads quite a bit, and there is evidence showing that they prefer to move their heads rather than their eyes. So when it comes to visual exploration behavior in different parts of the visual scene, a regular bird will tend to move its head more than its eyes. So one of the questions that we have no idea about in species other than pigeons is how they allocate their head versus eye movement behavior to the different tasks. There are studies in pigeons looking at that question when it comes to orientation in three-dimensional space, right? And we have some idea of how pigeons are doing that. And as I said, the answer is they tend to prefer the head movement most of the time, but there are some situations in which both are important. But in other species, all the species that I told you about today, no idea, right? So we need to have some technology to be able to answer those questions. Cameras that could be used as eye trackers while the bird moves, we showed you our eye tracker and the head is fixed for technological reasons, is fixed. So as we develop more technology, hopefully we will be able to determine in wild birds or in more natural situations how that process is completed. Great question, great question. I think it's thinking about here. Okay, I'm just going to ask a couple of more questions and then I will close the light stream if you want to join us. Please use that note because after that we will join the Zoom talk. I have a question from... I'm from Hamburg from Brisbane University in Australia. Okay. Do you find anatomical or behavioral evidence of lateralization and does it differ between raptors and prey? Thank you for the question. Alright, so people found, like Nathan Hart, found evidence of lateralization in the relative densities of comfortable receptors in stalling. So there is evidence that that is the case, at least in that species. That study was followed up by other scientists looking at that lateralization from a behavioral point of view and the results matched with the anatomical evidence. We looked at lateralization in how sparrows, in terms of relative densities of single cones, and so far we haven't been able to find any evidence. One of the potential explanations is that our sample size is not enough to detect a signal. What we did find is evidence of between individual variation in the relative densities of photoreceptors that could potentially affect visual perception between individuals. We have data on a few other species when it comes to relative density of single and double cones, but we haven't got the chance to analyze those data for lateralization. We need to acknowledge that the effect sizes are pretty small. That doesn't mean that being small in terms of number of photoreceptors, that small effect size doesn't have an actual effect. We have to differentiate these two scenarios. The implication of small effect sizes is that we need a really large sample size to be able to detect a signal in some other species. Maybe that's the limitation that we have had that our sample sizes may not have been huge to be able to detect that signal. There is evidence in the literature, as I said, that we need to be able to identify that signal. Once again, thank you everyone for being here and thanking you for your talk. One last question. I'm saying that right. Based on the red color of the M-M-O-D complex, we assume that it is expressed in the red and single cone only, but it is not. One of the limitations of that study was that we were trying to catch a different bird species as part of this project, and the fly catchers fell into our catching method. The good news was that we had that species that we were not able to catch a fly catcher because we didn't have the permit and all that. That was good, but we were not prepared to study fly catchers. This was an accidental finding. Once we found that, of course, we went like, we need to catch fly catchers because the life of a biologist is very different. There are many stories related to that, but I can tell you that my grad students put an immense amount of effort to try to change that. We were limited in the number of samples and because of that limitation, we were not able to find out what is the identity of what we believe in the MMOD complex. We do think it's a single cone because in the electron microscope, we only found the MMOD complex associated with single cones, but we couldn't do any micro spectrophotometry on those cones to determine the identity of that single cone. Is it the long wavelength sense? It's the long wavelength sense. It's the long wavelength sense. I promise you it's not because we were not interested in, it's because we couldn't get more fly catchers. We're planning on doing some follow-up studies and have a network of people that will help us in the catching process if we get the permits and whatnot. If we get the grant, of course. Thank you, everybody. Thank you for giving this talk today. Thank you very much for inviting me. It was a pleasure doing the talk. We will follow up now with a more formal discussion. I will close the stream if you want to join us. This is your last chance. Thanks again, everybody. We have another talk next week with Nick Steinmetz. Thank you very much. If you have any questions or questions, please follow us or follow trans. Subscribe to this channel. As usual, all the relevant information in the comments below this video. Thank you all. Goodbye. And we are now off. Good.