Tag: senses

Brain Connections Contribute to Our Unique Personalities

By Breanna Draxler | February 7, 2013 10:30 am

Brain differences between the 23 participants were quantified at each surface vertex. Values below the global mean are shown in cool colors while values above this average are shown in warm colors. Image courtesy of Sophia Mueller et al.

Every person thinks and acts a little differently than the other 7 billion on the planet. Scientists now say that variations in brain connections account for much of this individuality, and they’ve narrowed it down to a few specific regions of the brain. This might help us better understand the evolution of the human brain as well as its development in individuals.

Each human brain has a unique connectome—the network of neural pathways that tie all of its parts together. Like a fingerprint, every person’s connectome is unique. To find out where these individual connectomes differed the most, researchers used an MRI scanning technique to take cross-sectional pictures of 23 people’s brains at rest.

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CATEGORIZED UNDER: Mind & Brain, Top Posts

Insects Clean Antennae to Sharpen Sense of Smell

By Breanna Draxler | February 5, 2013 10:16 am

Image courtesy of Barnaby Chambers / shutterstock

Insects constantly clean their antennae, even when they appear to be clean. A group of researchers decided that the phenomenon warranted a closer look, and they used American cockroaches to see what was going on. It turns out that the obsessive behavior is actually the way many insects keep their sense of smell sharp—though it may also lead to their eventual demise.

Cockroaches use their front legs to stick their antennae in their mouths and essentially lick them clean. In the lab, researchers prevented the cockroaches from performing this self-cleaning ritual to see what would happen. A waxy substance accumulated on the insects’ antennae, which turned out to be a mix of environmental pollutants and cuticular hydrocarbons. The latter is a fatty substance the cockroach produces as a sort of moisturizer to prevent water loss through its antennae. After just one day, the non-grooming cockroaches had amassed three to four times as much of the wax as compared to the control group.

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CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: grooming, insects, senses

Bat's Very Strange-Looking Nose May Be Used For Echolocation

By Sarah Zhang | February 27, 2012 1:01 pm

spacing is important
Whatcha looking at? This is just my face.

This new leaf-nosed bat species was recently discovered in Vietnam. What’s with the strange nose? Scientists think that its protuberances and indentations help the bat in echolocation. Come to think of it, it does kind of resemble another excellent sound detector: the inside a cat’s ear.

As strange as the Hipposideros griffini’s nose is, it’s really got nothing on the star-nosed mole.

[via National Geographic News]

Image courtesy of Vu Dinh Thong / Journal of Mammalogy 

CATEGORIZED UNDER: Living World

Does a Chinese Boy Really Have "Cat Eyes" That See in the Dark?

By Sarah Zhang | February 2, 2012 6:23 pm

The strangest thing about this Chinese boy’s light blue eyes is not their color. It’s the purported fact that he can see in the dark. His eyes are just like cat eyes, glowing blue-green when you shine a light in them, says this clip from China’s state-run English TV channel. The boy can catch crickets in the dark without a flashlight and even completes a writing test in a pitch-black stairwell. True, or too good to be?

Natalie Wolchover at Life’s Little Mysteries has rounded up some experts and their collective reaction seems to be, “Hmm…” (It doesn’t help that this video has been posted on YouTube under the name, “Alien Hybrid or Starchild Discovered in China? 2012.”) One possibility they consider is whether the boy has a mutation that produced something like a tapetum lucidum, an extra layer of tissue that helps cats see in the dark. James Reynolds, a pediatric ophthalmologist at State University of New York in Buffalo, puts a stop to that idea:

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CATEGORIZED UNDER: Living World, Mind & Brain

A Vibrating Glove That Actually Enhances Your Sense of Touch

By Joseph Castro | August 8, 2011 5:43 pm

spacing is important

What’s the News: Georgia Tech researchers have now created a glove that heightens your sense of touch. Presented in May at the IEEE International Conference on Robotics and Automation, the glove—which applies high-frequency vibrations to the side of an exposed fingertip—can improve a wearer’s motor skills and tactile sensitivity. “This device may one day be used to assist individuals whose jobs require high-precision manual dexterity or those with medical conditions that reduce their sense of touch,” Georgia Tech assistant professor Jun Ueda said in a prepared statement.

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CATEGORIZED UNDER: Technology
MORE ABOUT: fingers, IEEE, senses, touch

Chemical in Predator Pee Scares the Pee Out of Rodents

By Joseph Castro | June 23, 2011 10:54 pm

What’s the News: In the animal kingdom, prey species must follow one rule above all others: keep away from predators. To do this, some animals take chemical cues from the urine they stumble upon. Now, new research published in the Proceedings of the National Academy of Science has identified a single molecule in the urine of many mammalian carnivores that causes rodents to scurry in fear. This chemical could eventually help scientists understand instinctual behavior in animals.

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CATEGORIZED UNDER: Living World, Mind & Brain
MORE ABOUT: animals, mice, rats, rodents, senses

Visual Virtual People: A Better Model for the Behavior of Crowds

By Veronique Greenwood | April 25, 2011 2:37 pm

crowds
A new model of crowd behavior uses simple visual rules.

What’s the News: When crowds go wrong, they go really wrong—more than 300 people died in a stampede in Cambodia last year during a festival, and hundreds more have been crushed to death in periodic disasters near the Muslim holy city of Mecca. A major flaw of computational models describing how people behave in crowds is that they are often too simplistic or too specific to a situation to explain both normal and disastrous behavior. A new model manages to recreate both types of behavior, working from two basic visual rules: (1) each person will move in the least crowded direction in their line of sight, and (2) they will adjust their speed to maintain a safe distance from visible obstacles.

“This work is an extremely important step in pulling together our fragmented understanding,” says behavioral biologist Iain Couzin, who was not involved in the study (via ScienceNOW). “We’re now approaching a sort of unified understanding of human behavior in crowds.”

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CATEGORIZED UNDER: Mind & Brain, Physics & Math

Scientists Use Bird-O-Vision to Learn Why Some Cuckoos Are Expert Counterfeiters

By Patrick Morgan | March 24, 2011 2:47 pm

What’s the News: The reproductive life of a cuckoo is both easy—it lays its eggs in others birds’ nests, and lets them feed the young—and difficult: cuckoos are involved in an “evolutionary arms race” with other birds, finds a new study. Even as cuckoos improve their counterfeiting skills—producing eggs that look more like others birds’—the host birds get better and better at identifying the forged eggs.

How the Heck:

  • Knowing that birds have four types of color-sensitive cone cells in their eyes, allowing them to see ultraviolet wavelengths, researchers used a spectroscope to measure the amount of light reflected from hundreds of cuckoo and host-bird eggs. They then fed this data into models to produce images showing how birds see the different types of eggs.
  • They discovered that while cuckoo and redstart eggs have a high degree of color overlap, cuckoo eggs targeted for dunnock nests did not.
  • Here’s the kicker: Redstarts and dunnocks don’t spot forgeries equally. Redstarts are more discerning of foreign eggs and readily kick out cuckoo forgeries, while the dumb dunnocks accept even the most mismatched eggs. So these findings suggest that cuckoos targeting redstarts evolved the ability to create better forgeries because the redstart has such a good eye. With dunnocks, that evolutionary force wasn’t at play because the birds are so accepting of forgeries; why bother?

What’s the Context:

The Future Holds: Scientists still aren’t sure why some hosts, like the dunnock, are so accepting of cuckoo eggs. Some scientists argue that this is because the risk in mistakenly rejecting a real egg outweighs the cost of raising a cuckoo egg. The jury’s still out.

Reference: “AVIAN VISION AND THE EVOLUTION OF EGG COLOR MIMICRY IN THE COMMON CUCKOO” Mary Caswell Stoddard and Martin Stevens. DOI: 10.1111/j.1558-5646.2011.01262.x

Image: NHM

CATEGORIZED UNDER: Living World

Labrador Retriever Sniffs Out Bowel Cancer Patients

By Eliza Strickland | February 1, 2011 2:23 pm

The latest diagnostic tool for oncology comes on four paws and is defined by its very effective nose. In a small study, Japanese researchers found that a dog could detect cases of colorectal cancer by sniffing patients’ breath or stool samples. Previous experiments have shown that dogs can sniff out cases of skin, lung, bladder, and breast cancers; researchers think the tumors give off chemical signals that the dog can detect in bodily substances.

The cancer expert in this case was an eight-year-old black Labrador named Marine who was trained to search for disease traces at the St. Sugar Cancer Sniffing Dog Training Center in Chiba, Japan. She must have been a good student. The research, published in the journal Gut, showed that she had a high success rate:

The Labrador retriever was at least 95 percent as accurate as colonoscopy when smelling breath samples, and 98 percent correct with stool samples, according to the study…. The dog’s sense of smell was especially effective in early-stage cancer, and could discern polyps from malignancies, which colonoscopy can’t. [Bloomberg]

Lead researcher Hideto Sonoda says it would be impractical to use dogs for routine bowel cancer screenings, but adds that further research into dogs’ diagnostic ability could lead to the development of an electronic nose.

Dr Sonoda told the BBC: “The specific cancer scent indeed exists, but the chemical compounds are not clear. Only the dog knows the true answer. It is therefore necessary to identify the cancer specific volatile organic compounds [smells] detected by dogs and to develop an early cancer detection sensor that can be substituted for canine scent judgement. To complete the sensor useful in clinical practice as a new diagnostic method is still expected to take some time.” [BBC]

Related Content:
80beats: In Controversial Scent Lineups, a Dog’s Nose Picks Out the Perp
80beats: New Research Points Toward Artificial Nose Based on Human Smell Sensors
80beats: Sniffing Out Sickness: Mouse Noses Respond to the Urine of Diseased Mice
DISCOVER: Lassie–Get the Oncologist!
DISCOVER: 20 Things You Didn’t Know About… Dogs

Image: flickr / pmarkham

CATEGORIZED UNDER: Health & Medicine, Living World
MORE ABOUT: cancer, dogs, senses, smell

Scientists: Sharks May Be Colorblind. Now Let's Talk About Swimsuit Choices

By Andrew Moseman | January 19, 2011 1:20 pm

When you’re nature’s ideal killing machine, perhaps color vision is merely an unnecessary affection. New research argues that sharks could be completely colorblind.

An Australian team led by Nathan Scott Hart investigated 17 shark species, peeking at the structure of their rod and cone photoreceptor cells in the retina. Human eyes come with red, green, and blue cone variations, allowing us to see in color. But not shark eyes. They appear to have just one kind of cone.

“Our study shows that contrast against the background, rather than color per se, may be more important for object detection by sharks,” Hart said. [CNN]

That, Hart says, may explain the common wisdom that sharks love yellow (and therefore you ought to avoid sunny swimsuits). It may be the reflective quality of yellow that catches a shark’s eye, not the hue itself.

“Bright yellow is supposed to be attractive to some sharks, presumably because it appears to the sharks as a very bright target against the water,” said Dr Hart. “So perhaps it is best to avoid those fluoro-yellow shorts next time you are in the surf.” [BBC News]

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CATEGORIZED UNDER: Living World
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