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The Blink of an Eye — And More Wonders of Human Body Design

Evolution News

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Darwinists insist on your body’s “poor design.” By contrast, a prediction of intelligent design for biology is that phenomena should appear more functionally complex and elegantly coordinated the closer one looks. Evolutionist cavils aside, this is certainly true for the human body.

Vision

We blink all day long, once about every 5 seconds. Why doesn’t the world go dark in those moments? How do we perceive a continuous image? “The brain seems to remember the percepts that have just happened,” an article in Science Daily says. “Scientists have now identified a brain area that plays a crucial role in perceptual memory.” At the German Primate Center, they found the spot where visual information is stored briefly during each eye blink. “Our research shows that the medial prefrontal cortex calibrates current visual information with previously obtained information and thus enables us to perceive the world with more stability, even when we briefly close our eyes to blink,” says the lead author of a paper in Current Biology. (Emphasis added.) This implies a process of calibration, interpolation, and calculation happening literally in the blink of an eye.

“Ghost images” can be detected by the human vision system, an article in Live Science says. These are not direct images that we are familiar with, but rather computed images arrived at by multiplying the light in each pixel from a projected scene onto a background scene. The product produces the ghost image, but it can only be perceived under the right circumstances.

Experiments with participants viewing a superimposed checkerboard on a background photo showed that the ability to see the ghost image is a function of the eye’s refresh rate. The photo only became visible when a single-pixel detector collected the light from each pixel and then fed it into a projector at the right speed. Reporter Stephanie Pappas says this is akin to the optical illusion of seeing a movie when the frame rate matches the eye’s refresh rate. 

The reason this works, [Daniele] Faccio said, is that the human eye has a slow refresh rate. It’s not unlike the reason that movies work: When images are flickered on the screen faster than this refresh rate, it creates the illusion of smooth movement.

The eye “is very fast in acquiring the information,” Faccio said. “It’s just very slow in getting rid of it.”

The researchers figured out that the flickering patterns remained in the eye’s “memory” for about 20 milliseconds, slowly fading out over that time. If the 20-millisecond patterns overlap, the eye sums them up like a movie, allowing the ghost image to emerge.

Although ghost images are unlikely to appear in natural settings, the experiments provide a new way for neuroscientists to understand vision. For design advocates, they open windows into the moment-by-moment calculations that our eyes and brain have to perform to give us a smooth picture.

Olfaction

What we perceive as odors are collections of molecules. Why similar molecules produce very different perceptions of smell has long been a puzzle to physiologists, making odor classification difficult. Is there a way to classify odors, the way audible tones can be classified by frequency? The Salk Institute looked into this “unsolved problem,” hoping to find a pattern that might allow scientists to predict how a molecule (or combination of molecules) would smell. They found that mapping molecules in 2D was too simplistic. Patterns emerged only when they mapped the molecules onto a hyperboloid, a shape similar to a Pringles potato chip.

When the team looked at how the molecules clustered on this surface, they found there were pleasant and unpleasant directions, as well as directions that correlated with acidity or how easily odors evaporate from surfaces. These observations now make it easier to construct pleasant odor mixtures to use, for example, in artificial environments (such as a space station).

The paper in Science Advances explains why this pattern makes sense in nature:

In the natural environment, the sense of smell, or olfaction, serves to detect toxins and judge nutritional content by taking advantage of the associations between compounds as they are created in biochemical reactions. This suggests that the nervous system can classify odors based on statistics of their co-occurrence within natural mixtures rather than from the chemical structures of the ligands themselves.

Meanwhile, at the Monell Center in Philadelphia, scientists learned something new about “mysterious sensory cella” in the nose adjacent to the olfactory sensory neurons, called microvillous cells. “The findings suggest that the so-called microvillous cells (MVCs) may protect the vulnerable olfactory epithelium by detecting and initiating defenses against viruses, bacteria, and other potentially harmful invaders.” MVCs may also helped regenerate damaged cells in the olfactory epithelium. This suggests “multiple levels of protection in the airways,” says a co-author of the paper in PLOS ONE that, fortunately, appears more interested in the function of these cells than their evolution. 

Mother’s Milk

Two news items show the benefits of human milk for newborns. Scientists at the University of Edinburgh find that “Breast milk may help babies’ brain development.” Pre-term babies showed better brain development when fed breast milk instead of formula. Brain scans were performed on 47 pre-term babies at 40 weeks that had been delivered at 33 weeks.   

The team also collected information about how the infants had been fed while in intensive care — either formula milk or breast milk from either the mother or a donor.

Babies who exclusively received breast milk for at least three-quarters of the days they spent in hospital showed improved brain connectivity compared with others.

The effects were greatest in babies who were fed breast milk for a greater proportion of their time spent in intensive care.

HealthDay reports on a paper in the journal Pediatrics where scientists compared the “healthy weight trajectory” of babies who were fed directly from the breast, or by pumping, or by formula. Healthy weight gain was best for those babies with direct breast feeding, scientists found. “Researchers stressed that breast milk, in any form, is better than formula,” they said. “But they said the findings support the notion that the method of feeding matters, too.” Often this is difficult for mothers having to work. A healthy society should promote this natural function of mother and baby.

Liver

The liver is appropriately named; it wants to live. It has an uncanny ability to regenerate itself, and can regrow 70 percent of its mass in a few weeks if damaged, and function like new. Researchers at the University of Illinois wondered how it does that at the molecular level. The secret involves signaling and alternative splicing that puts the liver back into a neonatal state:

“We found that the liver cells after birth use a specific RNA-binding protein called ESRP2 to generate the right assortment of alternatively spliced RNAs that can produce the protein products necessary for meeting the functional demands of the adult liver,” said graduate student Sushant Bangru, the lead author of the study. “When damaged, the liver cells lower the quantity of ESRP2 protein. This reactivates fetal RNA splicing in what is called the ‘Hippo signaling pathway,’ giving it instructions about how to restore and repopulate the liver with new and healthy cells.”

Conclusions

Many non-living objects, such as crystals and metals, look the same practically all the way down. Living things, by contrast, become more wondrous as you zoom in from organism to organ to tissue to cell to nucleus. New imaging techniques are bringing wonders into focus that were unimaginable for most of human history. If ever there was a heyday for intelligent design, it should be now.

Photo credit: Deeped Niclas & Amanda Strandh, via Flickr (cropped).