Isegoria

Insulin resistance may be a powerful force in the development of Alzheimer’s Disease:

In the body, one of insulin’s responsibilities is to unlock muscle and fat cells so they can absorb glucose from the bloodstream. When you eat something sweet or starchy that causes your blood sugar to spike, the pancreas releases insulin to usher the excess glucose out of the bloodstream and into cells. If blood sugar and insulin spike too high too often, cells will try to protect themselves from overexposure to insulin’s powerful effects by toning down their response to insulin — they become “insulin resistant.” In an effort to overcome this resistance, the pancreas releases even more insulin into the blood to try to keep glucose moving into cells. The more insulin levels rise, the more insulin resistant cells become. Over time, this vicious cycle can lead to persistently elevated blood glucose levels, or type 2 diabetes.

In the brain, it’s a different story. The brain is an energy hog that demands a constant supply of glucose. Glucose can freely leave the bloodstream, waltz across the blood-brain barrier, and even enter most brain cells — no insulin required. In fact, the level of glucose in the cerebrospinal fluid surrounding your brain is always about 60% as high as the level of glucose in your bloodstream — even if you have insulin resistance — so, the higher your blood sugar, the higher your brain sugar.

Not so with insulin — the higher your blood insulin levels, the more difficult it can become for insulin to penetrate the brain. This is because the receptors responsible for escorting insulin across the blood-brain barrier can become resistant to insulin, restricting the amount of insulin allowed into the brain. While most brain cells don’t require insulin in order to absorb glucose, they do require insulin in order to process glucose. Cells must have access to adequate insulin or they can’t transform glucose into the vital cellular components and energy they need to thrive.

Despite swimming in a sea of glucose, brain cells in people with insulin resistance literally begin starving to death.

Which brain cells go first? The hippocampus is the brain’s memory center. Hippocampal cells require so much energy to do their important work that they often need extra boosts of glucose. While insulin is not required to let a normal amount of glucose into the hippocampus, these special glucose surges do require insulin, making the hippocampus particularly sensitive to insulin deficits. This explains why declining memory is one of the earliest signs of Alzheimer’s, despite the fact that Alzheimer’s Disease eventually destroys the whole brain.

A recent study looked into the brains of habitual short sleepers:

The team compared data from people who reported a normal amount of sleep in the past month with those who reported sleeping six hours or less a night. They further divided the short sleepers into two groups: Those who reported daytime dysfunction, such as feeling too drowsy to perform common tasks or keeping up enthusiasm, and those who reported feeling fine.

Both groups of short sleepers exhibited connectivity patterns more typical of sleep than wakefulness while in the MRI scanner. Anderson says that although people are instructed to stay awake while in the scanner, some short sleepers may have briefly drifted off, even those who denied dysfunction. “People are notoriously poor at knowing whether they’ve fallen asleep for a minute or two,” he says. For the short sleepers who deny dysfunction, one hypothesis is that their wake-up brain systems are perpetually in over-drive. “This leaves open the possibility that, in a boring fMRI scanner they have nothing to do to keep them awake and thus fall asleep,” says Jones. This hypothesis has public safety implications, according to Curtis. “Other boring situations, like driving an automobile at night without adequate visual or auditory stimulation, may also put short sleepers at risk of drowsiness or even falling asleep behind the wheel,” he says.

Looking specifically at differences in connectivity between brain regions, the researchers found that short sleepers who denied dysfunction showed enhanced connectivity between sensory cortices, which process external sensory information, and the hippocampus, a region associated with memory. “That’s tantalizing because it suggests that maybe one of the things the short sleepers are doing in the scanner is performing memory consolidation more efficiently than non-short sleepers,” Anderson says. In other words, some short sleepers may be able to perform sleep-like memory consolidation and brain tasks throughout the day, reducing their need for sleep at night. Or they may be falling asleep during the day under low-stimulation conditions, often without realizing it.

The old adage about inventiveness is that it stems from necessity:

Based on his studies of orangutans, primatologist Carel van Schaik of the University of Zurich has come to a very different view. “When food is scarce, orangutans go into energy-saving mode. They minimize movement and focus on unappealing fall-back foods,” he observed. Their strategy in this scenario is quite the opposite of innovation, but it makes sense. “Trying something new can be risky — you can get injured or poisoned — and it requires a serious investment of time, energy and attention, while the outcome is always uncertain,” van Schaik explains.

Research on humans faced with scarcity echoes van Schaik’s orangutan findings. In 2013, Science published a study by economist Sendhil Mullainathan of Harvard University and psychologist Eldar Shafir of Princeton University describing how reminding people with a low income of their financial trouble reduced their capacity to think logically and solve problems in novel situations. A subsequent study found that Indian sugarcane farmers performed much better on the same cognitive performance test after receiving the once-a-year payment for their produce, temporarily resolving their monetary concerns. (Farmers who did not take the test previously did comparably well after getting paid, so it is unlikely that the improvement was simply the consequence of prior experience with the test.) People will do whatever it takes to survive, of course, which may occasionally lead to innovations. But as these and other studies suggest, if one’s mind is constantly occupied with urgent problems, such as finding food or shelter or paying bills, there will not be much capacity left to come up with long-term solutions to better one’s livelihood.

So where does creativity come from? Insights have come from the surprising observation that orangutans can be incredibly creative in captivity. “If food is provided for and predators are absent, they suddenly have a lot of time on their hands, free from such distractions,” van Schaik explains. Furthermore, in their highly controlled environments, exploration rarely has unpleasant consequences, and there are many unusual objects to play around with. Under such circumstances, orangutans appear to lose their usual fear of the unknown. In a study published in the American Journal of Primatology in 2015, van Schaik and his colleagues compared the response of wild and captive orangutans to a newly introduced object, a small platform in the shape of an orangutan nest. While captive orangutans approached the new object almost immediately, most wild orangutans, though habituated to the presence of humans, didn’t even go near it during several months of testing — only one eventually dared to touch it. Such fear of novelty may pose a significant obstacle to creativity: if an animal avoids approaching any new objects, innovations become rather unlikely. “So if you ask me, opportunity is the mother of invention,” van Schaik remarks.

Philosophy never seems to be making progress:

One of Gottlieb’s central insights is that, as he wrote in his previous volume, “The Dream of Reason,” which covered thought from the Greeks to the Renaissance, “the history of philosophy is more the history of a sharply inquisitive cast of mind than the history of a sharply defined discipline.” You might say that philosophy is what we call thought in its first, molten state, before it has had a chance to solidify into a scientific discipline, like psychology or cosmology. When scientists ask how people think or how the universe was created, they are addressing the same questions posed by philosophy hundreds or even thousands of years earlier. This is why, Gottlieb observes, people complain that philosophy never seems to be making progress: “Any corner of it that comes generally to be regarded as useful soon ceases to be called philosophy.”

Growing plants on Mars ain’t easy:

Drew Palmer, an assistant professor of Biological Sciences, Brooke Wheeler an assistant professor at the College of Aeronautics, and astrobiology majors from the Department of Physics and Space Sciences, are growing Outredgeous lettuce (a variety of red romaine) in different settings — Earth soil, analog Martian surface material known as regolith simulant, and regolith simulant with nutrients added — to find the magic formula for the type and amount of nutrients needed to grow a plant in inhospitable Martian dirt.

“We have to get the regolith right or anything we do won’t be valid,” said Andy Aldrin, director of the Buzz Aldrin Space Institute.

Unlike Earth soil, Martian regolith contains no helpful organic matter and has fewer minerals plants need for food, such as phosphates and nitrates. Adding to the challenges, real Martian regolith in its pure state is harmful for both plants and humans because of high chlorine content in the form of perchlorates.

The current Mars regolith simulant isn’t perfect. Until a real sample of Mars dirt comes back to Earth, which could happen on a mission estimated to be at least 15 years from now, Florida Tech researchers will spend the next year trying to create an accurate regolith analogue by applying chemical sensing data from the Mars rovers.

Eventually, it may be possible with the addition of fertilizer and removal of the perchlorates to grow various plants in a Martian soil. Florida Tech scientists are partnering with NASA scientists who have experience growing plants on the International Space Station to help figure out ways to make Martian farming a reality.