Researchers at the University of Adelaide have discovered a novel and complex visual circuit in a dragonfly’s brain that could one day help to improve vision systems for robots.
Dr Steven Wiederman and Associate Professor David O'Carroll from the University’s Centre for Neuroscience Research have been studying the underlying processes of insect vision and applying that knowledge in robotics and artificial vision systems.
Their latest discovery, published this month in The Journal of Neuroscience, is that the brains of dragonflies combine opposite pathways - both an ON and OFF switch - when processing information about simple dark objects.
“To perceive the edges of objects and changes in light or darkness, the brains of many animals, including insects, frogs, and even humans, use two independent pathways, known as ON and OFF channels,” says lead author Dr Steven Wiederman.
“Most animals will use a combination of ON switches with other ON switches in the brain, or OFF and OFF, depending on the circumstances. But what we show occurring in the dragonfly’s brain is the combination of both OFF and ON switches. This happens in response to simple dark objects, likely to represent potential prey to this aerial predator.
"Although we’ve found this new visual circuit in the dragonfly, it’s possible that many other animals could also have this circuit for perceiving various objects,” Dr Wiederman says.
The researchers were able to record their results directly from ‘target-selective’ neurons in dragonflies’ brains. They presented the dragonflies with moving lights that changed in intensity, as well as both light and dark targets.
“We discovered that the responses to the dark targets were much greater than we expected, and that the dragonfly’s ability to respond to a dark moving target is from the correlation of opposite contrast pathways: OFF with ON,” Dr Wiederman says.
“The exact mechanisms that occur in the brain for this to happen are of great interest in visual neurosciences generally, as well as for solving engineering applications in target detection and tracking. Understanding how visual systems work can have a range of outcomes, such as in the development of neural prosthetics and improvements in robot vision.
"A project is now underway at the University of Adelaide to translate much of the research we’ve conducted into a robot, to see if it can emulate the dragonfly’s vision and movement. This project is well underway and once complete, watching our autonomous dragonfly robot will be very exciting,” he says.
This is magenta, and not pink. Unlike pink, magenta doesn’t actually exist. Our brain just invents magenta to serve as what it considers a logical bridge between red and violet, which each exist at opposite ends of a linear spectrum.
TL;DR this color is fake (and also I hate it)
w
what
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Wait til you learn about Stygean Blue
Your brain is a badly-designed hot mess of bootstrapped chemistry that will tell you that all kinds of shit is happening that has no correlation to physical reality, including time travel. It just makes things up. Your brain is guessing about what’s happening when your eyes saccade, what’s happening in your blind spot, and what the majority of the visible light spectrum looks like, and you don’t know it’s happening because it doesn’t aid your survival to become aware that a lot of what you see is fake.
The human eye only has three types of color sensitive cones, which detect red, blue, and green light. Your brain is making up every other color you perceive.
Let’s have a little fun with that thought. This is the visible spectrum of light.
You will of course note that yellow is on the chart. Yellow has a discreet wavelength, and is therefore a distinct physical color. But we can’t see it.
“Sorry, what the fuck?”
What we call yellow is just what our brain shrugs and spits out when our red and green cones are equally stimulated. We have light receptors that can pick up on the physical spectrum of light we call yellow: that’s why yellow things don’t just look like moving black blocks to us. But your brain has no fucking idea what the color yellow looks like.
Some animals have eyes that can perceive the color yellow! Goldfish have a yellow cone in their eyes. If they could talk, they could tell us what yellow looks like. But we wouldn’t be able to understand it.
What your brain actually sees of the color spectrum:
We can measure the wavelength of light, so we know that when we see ‘yellow,’ we are seeing light in that 550-ish nanometers range. But we don’t have a cone in our eyes that can pick that up. Your brain just has a very consistent guess about what color that wavelength of light could be. We decided to name that guess ‘yellow.’ We can’t imagine what yellow really looks like any more than a dog can imagine the color red.
Here’s the funny thing: your brain is never perceiving just one photon of light at a time. Something like 2*10⁸ photons per second are hitting your retina under normal conditions. Your brain doesn’t individually process all of them. So it averages them out. It grabs a bunch of photons all coming from the same direction, with the same pattern, and goes, “yeah, that cup is blue, fuck it, next.”
That’s how colors blend in our eyes. So sure, if a photon of light with a wavelength of 550 nanometers bounces into our eyes, we see what we call “yellow.” But if we see two photons at the same time, coming from the same object, one of which is 500 nms and the other of which is 600 nms, your brain will average them out and you will still see yellow even though none of the light you just saw was 550 nms.
So how does magenta factor into this?
Well, as we’ve just established, when your brain sees light from two different slices of the visible light spectrum, it will try to just average them together. Green plus red is yellow, fuck it. If it’s more red than green, we’ll call that ‘orange.’ Literally who gives a shit, we’re trying to forage over here. There are bears out here and it’s so scary.
What happens if you take the average of blue and red light, which we perceive to be magenta? What’s the centerpoint of that line?
Fuckinggreen.
Hey, that’s not gonna work? We live on a planet where EVERYTHING IS GREEN. If something is NOT green, that means it’s either food, or a potential source of danger, and either way your brain wants you to know about it.
So your brain goes, WHOOPS. Okay - this is fine. We already made up yellow, orange, cyan, and violet. We’ll just make up another color. Something that looks really, really different from green.
And so it made up magenta.
So, physics-wise, is magenta “real?”
No; there’s no single wavelength of light that corresponds to magenta. But you’re rarely seeing only a single wavelength of light anyway. And even when you are, every color other than RGB is a dart thrown on the wall by your meat computer. This is the CIE Chromaticity Diagram:
Explaining this thing is a little more than I want to take on on a Saturday morning, but I’ve included a link above that goes into it a little more. The point is that only the colors that actually touch the ‘outline’ of the shape actually correspond to a specific wavelength of light. All of the other colors are blends of multiple wavelengths. So magenta isn’t special.
Given that color is just a fun trick your brain is playing on you to help you find food and avoid danger, is magenta real?
Yeah, absolutely. Or at least, it’s just as real as most of what we see. It’s what we see when we mix up blue and red. It would be disastrous from a survival standpoint to perceive that color as green, so we don’t. Because it’s not green. Light that’s green has a wavelength of around 510 nm. Stuff that’s magenta bounces back light that is both ~400 and ~700. Your brain knows the difference. So it fills in the gap for you, with the best guess it has, same as it does with your blind spot.
The perception of color exists within your brain, and your brain says you see magenta. So you see magenta.
So I googled Stygian Blue and…
Yall.
FORBIDDEN.
HOW TO SEE THE FORBIDDEN COLOURS
Hyperbolic Orange is the color my soul is
Dark tumblr show me the forbidden colors
We are back on this again.
Like most things involving the brain, visual processing is one of those weird subjects where the more I know about how stuff works, the more I find myself impressed that it generally works as well as it does.
