Tag Archives: vision

Are dogs color blind? Not exactly

For decades, scientists thought that dogs view the world in plain black and white. However, relatively recent research into canine anatomy and behavior shows that man’s best friend actually sees things in color, albeit not as well as humans.

Credit: Pixabay.

The notion that dogs have poor vision and can only see in shades of gray can be attributed to Will Judy, the former publisher of Dog Week magazine in the 1930s.

“It’s likely that all the external world appears to them as varying highlights of black and gray,” Judy wrote in a highly popular 1937 manual called “Training the Dog.”

This myth surprisingly persisted for decades until research in the 1960s examining the structure of the canine eye shed more light on the matter.

The human eye perceives color when certain wavelengths of light are reflected off objects and into the lens. The refracted light is then focused on the retina where photoreceptors called cones and rods interpret the message in order to be processed by the visual cortex in the brain. There are millions of these photoreceptors throughout the human retina.

Rods are responsible for our ability to see in low light levels, or scotopic vision, allowing us to perceive shapes and motion even in dim light or almost no light at all. Cones are made up of three different types of receptors (short, medium, and long-wavelength cones) that allow us to perceive color.

The most important difference between the cone and the rod is that the cone is more light-sensitive than the rod and requires much more light to enter it in order to send signals to the brain. This explains why we can’t see colors in the dark.

Initially, it was thought that dogs lack cones, which led to the conclusion that they can’t see color. Anatomical dissections, however, showed that dogs also have cones, but much fewer compared to humans. Additionally, humans and other primates are trichromatic, meaning they have three kinds of cones, whereas dogs are dichromatic, only having two types of cones. Dogs are missing red-green cones, so they can’t see these colors.

On the upside, dogs have more rods than humans, allowing them to see much better in the dark than us. Dogs are essentially domesticated wolves, nocturnal predators that need to have good eyesight in the dark to track and catch prey. The canine eye also has a larger lens and corneal surface, as well as a reflective membrane behind the retina, called the tapetum lucidum, which further enhances night vision. The tapetum reflects back the light that has already entered the eye, giving the dog’s eyes a boost. This is the reason why your pet’s eyes may sometimes appear to glow at night.

Although dogs aren’t as good as humans in the vision department, they more than make up for it with their noses and ears. Canines’ hearing is keener than ours and their sense of smell is about 1,000 times more sensitive than the human nose.

How dogs see colors

Left: Human view. Right: Same scene seen through canine eyes. Credit: Dog Vision.

All of this is to say that dogs aren’t fully color blind. In fact, in many ways, dogs probably perceive color similarly to humans with various forms of red-green color blindness. Certain colors aren’t vivid and different hues of the same color are difficult to differentiate between.

That’s because for the two types of cones dogs have, one is for blue while the other absorbs wavelengths between a human’s version of red and green.

But how exactly do dogs see color? That’s impossible to tell without swapping eyes with them, but judging from their anatomy it’s likely they see best in shades of yellow, blue, and green. When these colors are combined, a dog’s brain will likely process these wavelengths in dark and light yellow, grayish yellows and browns, and dark blue and light blue. This may explain why dogs go nuts over chasing yellow tennis balls. They probably can see the tennis ball light up, especially against a green grass background which, to them, comes across as rather dull.

The people at Dog Vision took this information about the canine eye and used image processing to offer a momentary glimpse into how dogs see the world. The blurry images below are not a perfect reflection of how a dog truly perceives shapes and colors, but they do a good job at illustrating how different their eyes are from ours.

The reason why these images are blurry is that dogs tend to be nearsighted.  A poodle, for example, is estimated to have 20/75 vision. However, dogs are much more sensitive to motion at a distance — anywhere from 10 to 20 times more sensitive than humans.

If you’d like to learn more about how these images are processed, you can read András Péter’s technical explanation, who programmed the app. You may also use the tool to upload images and create your very own dog vision pics.

Credit: Dog Vision.
Credit: Dog Vision.
Credit: Dog Vision.
Credit: Dog Vision.
Credit: Dog Vision.
Credit: Pixabay.

How blindness alters the way we process sound

Credit: Pixabay.

Credit: Pixabay.

It’s widely known that blind people compensate for their lack of vision by amplifying their other senses. The incredible musical talents of Stevie Wonder and Ray Charles immediately come to mind or even Marvel’s Daredevil, if we’re to take a leap into fiction. But these improvements in the remaining senses are not just learned behaviors — they’re the result of a plastic rearrangement of the brain, which undergoes a sort of makeover following the loss of a sense. In a new study, scientists investigated how people who have lost their vision at an early age process sound, finding that they have more refined auditory cortex responses.

Amplifying sounds

The human brain is traditionally divided into six main areas: the frontal, parietal, occipital, temporal, limbic lobes, and the insular cortex. Smell and sound are controlled and processed in the temporal lobe, sight is typically confined to the temporal lobe, taste and smell share olfactory nerves, touch is generally detected by the parietal lobe, and sight is handled by the occipital lobe.

Studies suggest that the loss of vision prompts the brain to reorganize the way it processes sound. In a new study, researchers at the University of Washington and the University of Oxford compared the auditory cortex response to pure tones in blind people who lost their vision at an early age and sighted individuals.

The results suggest that although the two groups had similarly-sized auditory cortices, this brain area was more responsive to certain frequencies in blind people. These findings published in the Journal of Neuroscience add more weight to the idea that the occipital cortex adapts to the loss of sight by becoming more specialized to support an individual’s increased reliance on sound to interact with the world.

A 2014 study found that adult mice kept in total darkness for just onef week compensate for their loss of vision with an improved sense of hearing and more auditory connections in the brain. Researchers found that the rodents’ neurons responsible for processing sound fired stronger and faster and could pick up on a wider range of tones.

Tonotopic maps in auditory cortex for four example subjects. Credit: Huber et al., JNeurosci (2019).

Tonotopic maps in auditory cortex for four example subjects. Credit: Huber et al., JNeurosci (2019).

It works the other way around too. A 2012 study published in the same Journal of Neuroscience showed that people who are born deaf use areas of the brain typically devoted to processing sound to instead process touch and vision. The authors of this study previously also showed that people born deaf are better at processing peripheral vision and motion.

In the future, the researchers would like to perform a similar experiment with people who lost their vision as adults, but then recovered it. The aim is to reveal the mechanisms of how these brain areas manage to communicate, which for now remain a mystery.

Barn owls (Tyto alba) took part in an experiment which tested their behavioral and neural responses to moving objects. Credit: Yoram Gutfreund.

Owls perceive moving objects like we do, suggesting bird and human vision are quite similar

Barn owls (Tyto alba) took part in an experiment which tested their behavioral and neural responses to moving objects. Credit: Yoram Gutfreund.

Barn owls (Tyto alba) took part in an experiment which tested their behavioral and neural responses to moving objects. Credit: Yoram Gutfreund.

Differentiating a moving object from a static background is crucial for species that rely on vision when interacting with their environment. This is especially true for a predator such as an owl. Now, a new study found that owls and humans share the same mechanics for differentiating objects in motion.

Individual cells in the retina can only respond to a small portion of a visual scene and, as such, send a fragmented representation of the outside world to the rest of the visual system. This fragmented representation is transformed into a coherent image of the visual scene in which objects are perceived as being in front of a background. Previous studies, mostly performed on primates, found that we perceive an object as distinct from a background by grouping the different elements of a scene into “perceptual wholes.”

However, these studies left some important questions unanswered. For instance, is perceptual grouping a fundamental property of visual systems across all species? At least, this seems to be true for barn owls (Tyto alba), according to the latest findings by Israeli researchers at Technion University’s Rappaport Faculty of Medicine in Haifa.

Yoram Gutfreund and colleagues studied both the behavior and brain of barn owls as the birds tracked dark dots on a gray background. The owls’ visual perception was tracked by a wireless “Owl-Cam”, which provided a perceptual point of view while neural activity was mapped in the optic tectum — the main visual processor in the brain of non-mammalian vertebrates.

“In behaving barn owls the coherency of the background motion modulates the perceived saliency of the target object, and in complementary multi-unit recordings in the Optic Tectum, the neural responses were more sensitive to the homogeneity of the background motion than to motion-direction contrasts between the receptive field and the surround,” wrote the authors.

Caption: An example of owl DK spontaneously observing the computer screen. The target is embedded in a static array of distractors (singleton). The left panel shows a frontal view of the owl and the right panel the corresponding headcam view. The red circle in the right panel designates the functional fovea. The color of the circle changes to green when it is on target. Credit: Yael et al., JNeurosci (2018).

Caption: the same setup as above only now the target is embedded in a mixed array of moving distractors. Credit: Yael et al., JNeurosci (2018).

The two experiments conducted by the researchers revealed that owls seem to be indeed using perceptual grouping, suggesting that the visual systems of birds and humans are more similar than previously thought. More importantly, the study provides evidence that this ability evolved across species prior to the development of the human neocortex.

The findings appeared in the Journal of Neuroscience. 

Acuity Kitchen Photo.

There are huge differences in how animals see the world — we’re among the crisp-eyed

Not all eyeballs are created equal.

Acuity Kitchen Photo.

Image credits E. Caves, N. Brandley, S. Johnsen , 2018, Trends in Ecology and Evolution.

If seeing is believing, humans probably believe a lot more than other animals, according to new research from Duke University. Our eyes perceive the world in much sharper detail than those of most other members of the animal kingdom, the results suggest.

To see or not to see

The researchers measured the visual sharpness of several species using a method called ‘cycles per degree’. Basically, what this method ascertains is how many pairs of parallel black and white lines an eye can distinguish in a single degree of vision. The human eye, the team writes, can resolve around 60 cycles per degree. Anything above 60 line pairs starts to look a blurry grey to us.

These measured visual acuity levels were then fed into software that transformed a reference image to give us a taste of how other animals see the world (the image above). Compared to most other organisms on the planet, our eyesight is actually crisp:

Eyesight sharpness.

Image credits Image credits E. Caves, N. Brandley, S. Johnsen , 2018, Trends in Ecology and Evolution.

The team writes that chimps and other primates see roughly as well as we do. That’s not very surprising, given that they’re our closest living relatives. There are a few species that can boast higher visual acuity than us the team notes that some birds of prey, such as the Australian wedge-tailed eagle with 140 cycles per degree, can see nearly two times more detail than we do. Given that they need to spot small prey from thousands of meters away, that’s not very surprising. Apart from these, however, we humans seem to have quite good eyesight.

Fish and most birds, the team reports, can only distinguish about 30 cycles per degree. Elephants can only see a paltry 10 — which is actually the level at which a human is declared legally blind.

The team also explored the implications of their findings. It’s easy to assume that every living thing sees the world roughly the same way as we do, but the results show there’s an incredible variation in visual acuity. They note the case of the cleaner shrimp, which “likely cannot resolve one another’s colour patterns, even from distances as close as 2 cm”. Then what’s the point of sporting bright colors and waving your antennae or your body around? For context, it looks like this:

The team believes that this behavior isn’t meant to communicate anything to other cleaner shrimp — it’s meant to signal fish: “both [the shrimps’] colour patterns and antennae are visible to fish viewers of various acuities from a distance of at least 10 cm,” they write.

“Thus, these distinctive colour patterns and antennae-whipping behaviors likely serve as signals directed at clients, despite the inability of cleaner shrimp themselves to distinguish them.”

They make a similar point about butterflies. Based on the team’s results, these animals probably can’t even distinguish each other’s patterns. Birds, however, can.

“The point is that researchers who study animal interactions shouldn’t assume that different species perceive detail the same way we do,” Caves concludes.

While I do find the findings fascinating, it’s important to note that animals may actually see better than their visual acuity alone suggests. The team’s research only focused on how their eyes work, but ‘seeing’ is mostly handled by the brain. It may very well be that these relatively dim-sighted species have neural systems in place to improve the final images they perceive.

For now, we simply don’t know. Judging from the amount of data each species’ eyes records, however, it may be that we are some of the sharpest-eyed animals out there.

The paper “Visual Acuity and the Evolution of Signals” has been published in the journal Cell.

Doctors restore patient’s sight with stem cells, offering new hope for cure to blindness

Scientists have developed a specially engineered retinal patch to treat people with sudden, severe sight loss.

The macula lutea (an oval region at the center of the retina) is responsible for the central, high-resolution color vision that is possible in good light; when this kind of vision is impaired due to damage to the macula, the condition is called age-related macular degeneration (AMD or ARMD). Macula lutea means ‘yellow spot’ in Latin.

Picture of the back of the eye showing intermediate age-related macular degeneration.
Via Wikipedia

Douglas Waters, an 86-year-old from London, had lost his vision in July 2015 due to severe AMD. After a few months, Waters became part of a clinical trial developed by UC Santa Barbara researchers that used stem cell-derived ocular cells. He received his retinal implant at Moorfields Eye Hospital, a National Health Service (NHS) facility in London, England.

Before the surgery, Water’s sight was very poor, and he wasn’t able to see anything with his right eye. After the surgery, his vision improved so much that he could read the newspaper and help his wife in the garden.

The study, published in Nature Biotechnology, shows groundbreaking results. Researchers could safely and effective implant a specially engineered patch of retinal pigment epithelium cells derived from stem cells to treat people with sudden severe sight loss from wet AMD. This is the first time a completely engineered tissue has been successfully transplanted in this manner.

“This study represents real progress in regenerative medicine and opens the door on new treatment options for people with age-related macular degeneration,” said co-author Peter Coffey, a professor at UCSB’s Neuroscience Research Institute and co-director of the campus’s Center for Stem Cell Biology & Engineering.

Douglas Waters was struggling to see up close after developing severe macular degeneration, but 12 months on he is able to read a newspaper again

AMD usually affects people over the age of 50 and accounts for almost 50% of all visual impairment in the developed world. The condition disturbs central vision responsible for reading, leaving the surrounding eyesight normal. Wet AMD is caused by hemorrhage or liquid accumulation into the region of the macula, in the center of the retina. Wet AMD almost always starts as dry AMD. Researchers believe that this new technique will be the future cure for dry AMD.

Scientists wanted to see whether the diseased retinal cells could be replenished using the stem cell patch. They used a specially engineered surgical tool to insert the patch under the affected retina. The operation lasted almost two hours.

Besides Water, another patient, a 60-year-old woman who also suffered from wet AMD, underwent the surgery. The two patients were observed for one year and reported improvements to their vision. The results were incredible — the patients went from being almost blind to reading 60 to 80 words per minute with normal reading glasses.

“We hope this will lead to an affordable ‘off-the-shelf’ therapy that could be made available to NHS patients within the next five years,” said Coffey, who founded the London Project to Cure Blindness more than a decade ago.

 

 

Nightjar bird.

A more limited range of color vision might help predators see through camouflage, research finds

Most animals can perceive fewer colors than humans can — while others can see many more. Scientists at the University of Exter have looked at the comparative advantages of di- and trichromatism in finding camouflaged birds in pictures to understand why so many species rely on this limited range of color vision.

Basic colors.

Sometimes less is more — but that doesn’t really stand for color receptor cells. Humans have three kinds of these cells on our retinas, so our vision revolves around three basic colors, making us trichromats. But a large number of other animals, including the majority of mammals today, are dichromats who only have two kinds of color receptor and see everything as a mix of only two colors. On the other hand, many bird species (and this one lady) are tetrachromats, and some invertebrates can pick up on many more colors.

But back to dichromats. Most of them are red-green color blind, and that’s also the most common type of color blindness in humans. Moreover, some primate species show color vision polymorphism, meaning certain females are trichromats but most individuals are dichromats. Add all this evidence together, and it begs the question — is there an evolutionary advantage for seeing only two colors instead of three? To find out, a team from the University of Exter has created an online computer game and unleashed it upon the web, where more than 30,000 people played it.

The concept was pretty simple: players were shown photographs either in normal color or in simulated dichromatic vision. There were camouflaged nightjar birds or their nests, containing eggs, somewhere in the image — and the players had to find them.

Nightjar bird.

Example of a nightjar seen in trichromat (left) and dichromat (right) vision.
Image credits University of Exeter.

Seeing a more limited range of colors should make dichromat predators more adept at finding prey since there’s less color, so to speak, to help hide a well-camouflaged dinner. Dichromats should thus have an easier time differentiating between light and dark areas and finding hidden objects, for example — an advantage any aspiring predator would want.

But the team was surprised to find that participants looking at trichromat photos were actually faster at finding the nightjars and eggs that their counterparts. There were large variations in the performance of dichromat players from photo to photo — depending on factors such as camouflage patterns or brightness. Furthermore, over the course of the game, dichromats improved their game faster than trichromats, and by the end of the game, both groups performed equally well.

So it is possible that their performance was worsened as their brains learned the ins and outs of dichromatic vision. It may be that, given a longer period of time to adjust, they could become even better than trichromats at spotting the eggs.

” These results suggest there are substantial differences in the cues available under viewing conditions that simulate different receptor types, and that these interact with the scene in complex ways to affect camouflage breaking,” the team concludes.

 

The paper “Relative advantages of dichromatic and trichromatic colour vision in camouflage breaking,” has been published in the journal Behavioural Ecology.

New App Shows How Dogs See the World

It’s common knowledge that dogs don’t see the world the same way we do, but there are a lot of misconceptions about how dogs see the world — now, a new app simply called Dog Vision shows us just how dogs see.

dog1

Dogs are nearsighted, and they’re not good with different brightnesses (shades). Below is how a dog would see this firework show.

dog1b

 

Many people believe dogs see in black in white, which is simply not true; their vision is more similar to blurry color-blindness, with less sensitivity to shades of grey. Dog Vision takes into consideration what we know and transforms images into their “how doggy sees this” equivalent. The differences are evident.

dog2

dog2 - DogVision

First of all, dogs see less colors than we do. The cone cells in our eyes are responsible for day vision and color perception; each cone detects a different wavelength of light, so we can see a broad spectrum of colors. Dogs have cone cells too, but unlike humans who have three types of cones, they have only two, like red-green colorblind people. This makes their color vision very limited.

Dogs are also very short sighted – a special test, custom-made for dogs, puts them at around 20/75 vision, according to Psychology Today. This means a human could barely see at 23 metres (75 feet) is what a dog can just about make out at 6 metres (20 feet).They are also worse than us at detecting brightness differences (shades).

dog3

dog3 - DogVision

But don’t feel bad about our canine friends – while sight may not be their best sense, they more than compensate with their other senses.

So, head on and experiment with your own pictures – maybe of yourself – to see how your dog sees the world around him!

abe_lincoln

Why you look ugly in photos – and some ways to solve it

Let’s face it,  if you’re not a rare photogenic beauty or if you don’t have good photographers as friends, you most likely look terrible in photos. So, does that mean you’re ugly? If so, why is it that you look so much better when looking at yourself in the mirror? Let’s explore these questions and try to find out how we can look our best in photos.

ugly_photos

A window into a flat world

Your eyes capture the visual essence of the outside world. Simply closing your eyes and imagining what it would be like to be blind is terrifying in and of itself. But have you ever thought about what it would be like to live with only one eye? When we try to focus our view on something really small or far away, we close one of our eyes. However, there’s something missing when we utilize this technique –– it’s the stereo vision!

Human eyes come in twos, but unlike horses which have one on each side, we have both of them right in front of our heads. Thanks to the close side-by-side positioning, each eye takes a view of the same area from a slightly different angle. The two eye views have plenty in common, but they also complement each other — each eye picks up visual information the other doesn’t. You can easily see what I’m talking about by closing each of your eyes for a second and then comparing the views. So, each eye takes a separate view, but in the end, both images are combined after processing occurs in the brain. The small differences between the two images add up to a big difference in the final picture! The combined image is more than the sum of its parts: it is a three-dimensional stereo picture. The brain also ignores the nose which would have been a drag to always see for the rest of your life. Thank you, brain!

I’d recommend you follow the story of Susan Barry, a woman who, for 48 years of her life, was stuck in a flat, 2-D world.

So, the main point here is that we see in 3-D. A camera has only one eye, so photography flattens images in a way that mirrors do not. Also, depending on the focal length and distance from the subject, the lens can create unflattering geometric distortions. For instance, if a photo is taken with a short focal length (zoomed out) and at the same time the subject is also close to the camera, then you’ll get a fisheye lens effect that skews the portrait, making the nose and forehead look bigger. A good photographer knows he needs to position himself farther away and then zoom in if needed. Indeed, this amplifies the shaking effect, but keeping the camera still using a tripod does the job.

Then there’s another factor – unless your face is perfectly symmetrical, people see it differently than you do in a mirror. This is because mirror images are reversed, as opposed to what photos capture and what others see directly. Watch these two photos of Abe Lincoln below to get an idea of what this means:

abe_lincoln

Also, when looking yourself in the mirror, you have the advantage of always correcting the angle in real-time. Unconsciously, you’ll always look at yourself from a good angle. In contrast, photos always seem to catch you at a bad angle. Everybody, no matter how ugly they are, has a good (or at least, better) side.

Flash ruins everything

photo flash

Photo: all-things-photography.com

When you look at a real-life object, you have the advantage of automatically compensating for lighting as your eyes adjust to see better, while your brain also processes the image for the best contrast. When mental calibration is absent, a photo will often turn out with shades and lights that not only look unnatural but also unflattering as well. Things get a lot worse in the dark when you need to turn the flash on. The flash makes the skin look shiny and greasy and sharpens the edges of your face, making you look like a polygon troll. For your best pose, try to take photos outdoors under natural lighting. In fact, according to OK Cupid, a camera’s flash adds seven years.

The fake smile

fake smile hilary

Photo: mindthebrain.net

“Say cheese!” Oh, boy, that always ruins it. Really, whenever I have to ‘pose’ for a photo, I always wind up looking like I’m about to get my driver’s license. If someone tells you to smile for a photo, don’t do it unless you really want to. Just stay as relaxed as possible, so your face muscles won’t grind into an unnatural and unflattering pose. It’s just a photo there’s no need to become too self-conscious about it. Also, it’s best to keep your eyes open and chin up. This will get rid of double chin, up the nose shots, asymmetry caused by muscles twitching in the face, and shoulders pulled all the up to your ears and, most importantly, it will make you focus on something other than your horrible photographic past.

The instant shot

look_photos

Photo: zoznam.sk

Tests with Air Force pilots have shown that they could identify the plane on a picture that was only shown for 1/220th of a second. While most of us aren’t fighter jet pilots, we’re capable of distinguishing between minute differences in highly succeeding frames. As far as people are concerned, however, the brain doesn’t pay attention to each individual facial expression that arises from moment to moment. Instead, the brain averages these out and discards momentary deviations, so when you’re talking to another person you’re actually looking at a corrected, fluid representation of that person’s face. Imagine consciously feeling every twitch of an eye or facial muscle, with hundreds of these every second. Thank you, brain!

A camera is a lot different though. It freezes a sub-second instant in time, complete with all the deformity you wouldn’t notice in average mode. Push the shutter multiple times, and choose your best photos. Good photographers might take even hundreds of photos before settling on the perfect one.

Do photos surprise reality?

reality

Another way why photos make you look ugly is by comparison. Like we pointed out above, we’re used to seeing faces in real life that are moving in a fluid manner. Guess where you see the most photos on a day to day basis: billboards. Yup, those perfectly photoshopped faces. When you look at a photo, you’ll automatically compare it in your head with other photos you’ve seen, and most of these are of celebrities — photos of extremely graphically altered celebrities. It’s hard, but please stop comparing.

The takeaway is that you probably don’t look that bad in your photos, and you’re judging yourself too harshly. As long as you refrain from making stupid poses while taking pictures, you’re halfway to the perfect portrait.

NASA to conduct unprecedented twin experiment: one twin will spend a year circling the Earth, while the other stays grounded

It’s something that puzzled me for years now: consider a pair of identical twins; say, one gets a job as an astronaut and rockets into space. The other is also an astronaut, but he decides to skip this one and stay home. After a while, they reunite, but are they still identical? That’s exactly what NASA wants to find out!

In March of 2015, NASA astronaut Scott Kelly will join cosmonaut Mikhail Kornienko on a one-year mission to the International Space Station. Their lengthy mission is part of a study which will document the effects of long-term space flight on the human body. But here’s the cool part: Scott Kelly also has a twin brother, Mark Kelly – who is also an astronaut, albeit retired. We wrote about his retirement here. While Scott, the test subject, spends one year circling Earth onboard the ISS, his brother Mark will remain home as a control.

“We will be taking samples and making measurements of the twins before, during, and after the one-year mission,” says Craig Kundrot of NASA’s Human Research Program at the Johnson Space Center. “For the first time, we’ll be able two individuals who are genetically identical.”

So what will they be studying? The ISS doesn’t go at high enough speed for an age difference to be noticeable (according to Einstein’s theory, if you travel at fast enough speeds, comparable to that of speed of light, time will slow down for you – so if this were to happen, one twin would be younger than the other). The main focus will be the subjects’ health.

“We already know that the human immune system changes in space. It’s not as strong as it is on the ground,” explains Kundrot. “In one of the experiments, Mark and Scott will be given identical flu vaccines, and we will study how their immune systems react.”

Another experiment will look at telomeres—little molecular “caps” on the ends of human DNA. Telomeres have been linked to aging, and in space, telomere loss could be accelerated by the action of cosmic rays. Researchers will study if space travel accelerates aging. Meanwhile in the gut, says Kundrot:

“There is a whole microbiome essential to human digestion. One of the experiments will study what space travel does to [inner bacteria] which, by the way, outnumber human cells by 10-to-1.”

Another study will focus on how vision changes in outer space, and on “space fog”—a lack of alertness and slowing of mental gears reported by some astronauts in orbit. But these aren’t separate studies – it’s just a big one with many aspects.

“These will not be 10 individual studies,” says Kundrot. “The real power comes in combining them to form an integrated picture of all levels from biomolecular to psychological. We’ll be studying the entire astronaut.”

 

 

 

walk_exercising

Exercising helps preserve vision for the elderly

walk_exercising

Physical workouts, be it simple home fitness, represent a golden standard for living a healthy life. Researchers at Emory University recently proved another key benefit to exercising, one especially useful to the elderly, after they found that even taking a few short walks a day can vastly curb  macular degeneration – the leading cause for loss of vision.

Studies that focus on the therapeutic or beneficial effects of exercising are usually centered around neurodegenerative diseases or injuries, and less on vision. Dr. Machelle Pardue and colleagues wanted to see whether there was any significant improvements in vision through exercising. Age-related macular degeneration – the progressive loss of vision with old age – is caused by the loss of light-sensing nerve cells in the retina called photoreceptors. It’s a bit like loosing pixels on a huge resolution TV, only instead of blank spots, your display becomes more blurry.

With this in mind, the team conceived a study where an animal model (mice) was subjected to exercising before and after exposing the animals to bright light that causes retinal degeneration. The researchers trained mice to run on a treadmill for one hour per day, five days per week, for two weeks. After the toxic light altered the mice’s vision, another two weeks of the same program was studied. Remarkably, the exercised animals had nearly twice the number of photoreceptor cells than animals that spent the equivalent amount of time on a stationary treadmill, and their retinal cells were more responsive to light.

“This research may lead to tailored exercise regimens or combination therapies in treatments of retinal degenerative diseases,” Pardue says. “Possibly in the near future, ophthalmologists could be prescribing exercise as a low-cost intervention to delay vision loss.”

Just one hour a day of exercising can have dramatic positive effects on your vision, later in life

Previously, similar studies also showed that exercising can significantly improve vision, however these followed energy intensive workouts like long-distance running. The present study suggests that even light exercising, like walking an hour a day, may provide a dramatic improvement for your eyes’ health.

“One point to emphasize is that the exercise the animals engaged in is really comparable to a brisk walk,” Pardue says. “One previous study that examined the effects of exercise on vision in humans had examined a select group of long distance runners. Our results suggest it’s possible to attain these effects with more moderate exercise.”

What are the mechanisms that link exercising with prolonged vision, though? The researchers were able to identify a certain growth factor called BDNF, which was thought to be involved in the beneficial effects of exercise in other studies. Mice that ran on  the treadmill a full four weeks had higher levels of BDNF in their blood, brain and retina than the mice that hadn’t exercised. Also, when the researchers blocked BDNF receptors, exercising didn’t render any visible improvements for eyesight. Next, the researchers are looking to find whether  other exercise regimens are even more protective and whether exercise is beneficial in models of other retinal diseases such as glaucoma and diabetic retinopathy. 

The results were published in the Journal of Neuroscience.

(c) Nickolay Lamm

How cats see the world (with pictures)

As a cat owner myself, I’ve often wondered how feline vision differs from that of humans. Clearly, with their huge pupils and crocodile-like eyes, their view of the world must be truly different from ours. Artist Nickolay Lamm recently showcased a project that features various photos from two points of view: the human and the cat. While not the most realistic take on how cats see, these photos offer an interesting glimpse on how felines see.

(c) Nickolay Lamm

(c) Nickolay Lamm

To alter his photographs in a way similar to how a cat would see, Lamm consulted with ophthalmologists at the University of Pennsylvania’s veterinary school and a few other animal eye specialists. For each photo, the top view is an unfiltered photograph that portrays what we humans normally see, while the bottom view shows the same photo from the cat’s perspective.

(c) Nickolay Lamm

(c) Nickolay Lamm

You might notice that cat vision is much more blurry than ours. Cat’s see really well in the dark, but for this, they had to sacrifice fine details and some colours to be able to see well in low-light conditions. Also, notice that the cat’s vision is slightly broader than ours.  That’s because cats see 200 degrees compared to our 180 degrees.

(c) Nickolay Lamm

(c) Nickolay Lamm

Cats don’t see very well at a distance. While human vision is perfectly adapted for seeing sharply 100 feet away, cats barely can distinguish fine details past 20 feet. Apparently, kitties miss out on the beauties of foreground landscapes.

Nickolay Lamm

(c) Nickolay Lamm

But no matter, kitties are fine with seeing in the dark. Cat eyes have much more rods than humans – photoreceptor cells in the retina – which allows them to absorb more light and see better in low-light conditions. Their elliptical pupils can open very wide in dim light, but contract to a tiny slit to protect the sensitive retina from bright light.  Ever took a picture of a cat only to see afterward that it looked like the spawn of Satan, with fire blazing from its eyes? This Terminator-feel happens because cats have what’s called an atapetum lucidum – a reflective layer that bounces light that hits the back of the eye out through the retina again for a second chance to be absorbed by the rods, which allows them to see even better at night.

via PopSci

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