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9 Nervy Facts About the Vagus Nerve

What happens in the vagus nerve, it turns out, doesn’t stay in the vagus nerve. The longest of the cranial nerves, the vagus nerve is so named because it “wanders” like a vagabond, sending out fibers from your brainstem to your visceral organs. The vagus nerve is literally the captain of your inner nerve center—the parasympathetic nervous system, to be specific. And like a good captain, it does a great job of overseeing a vast range of crucial functions, communicating nerve impulses to every organ in your body. New research has revealed that it may also be the missing link to treating chronic inflammation, and the beginning of an exciting new field of treatment that leaves medications behind. Here are nine facts about this powerful nerve bundle. 

1. The vagus nerve prevents inflammation.

With a vast network of fibers stationed like spies around all your organs, when the vagus nerve gets wind of the hallmarks of inflammation—cytokines or the inflammatory substance tumor necrosis factor (TNF)—it alerts the brain and elicits anti-inflammatory neurotransmitters via the cholinergic anti-inflammatory pathway. A certain amount of inflammation after injury or illness is normal. But an overabundance is linked to many diseases and conditions, from sepsis to the autoimmune condition rheumatoid arthritis.

2. It helps you make memories.

A University of Virginia study showed success in strengthening memory in rats by stimulating the vagus nerve, which releases the neurotransmitter norepinephrine into the amygdala, consolidating memories. Related studies were done on humans, opening promising treatments for conditions like Alzheimer’s disease.

3. It helps you breathe.

The neurotransmitter acetylcholine, elicited by the vagus nerve, literally gives you the breath of life by telling your lungs to breathe. It’s one of the reasons that botox—often used cosmetically—can be potentially dangerous, because it interrupts your acetylcholine production. You can, however, also manually stimulate your vagus nerve by doing abdominal breathing or holding your breath for four to eight counts.

4. It’s intimately involved with your heart.

The vagus nerve is responsible for controlling the heart rate via electrical impulses to the sinoatrial node of the heart, where acetylcholine release slows the pulse. The way doctors determine the “tone” or “strength” of your vagus nerve (and your cardiac health) is by measuring the time between your individual heart beats, and then plotting this on a chart over time. This is your “heart rate variability.”

5. It initiates your body’s relaxation response.

When your ever-vigilant sympathetic nervous system revs up the fight or flight responses—pouring the stress hormone cortisol and adrenaline into your body—the vagus nerve tells your body to chill out by releasing acetylcholine. Its tendrils extend to many organs, acting like fiberoptic cables that send instructions to release enzymes and proteins like prolactin, vasopressin, and oxytocin, which calm you down. People with a stronger vagus response may be more likely to recover more quickly after stress, injury, or illness.

6. It translates between your gut and your brain.

Your gut uses the vagus nerve like a walkie-talkie to tell your brain how you’re feeling via electric impulses called “action potentials". Your gut feelings are very real.

7. Overstimulation of the vagus nerve is the most common cause of fainting.

If you tremble or get queasy at the sight of blood or while getting a flu shot, you’re not weak; you’re experiencing “vagal syncope.” Your body, responding to stress, overstimulates the vagus nerve, causing your blood pressure and heart rate to drop. During extreme syncope, blood flow is restricted to your brain, and you lose consciousness. But most of the time you just have to sit or lie down for the symptoms to subside.

8. Electric stimulation of the vagus nerve reduces inflammation and may inhibit it altogether.

Truly breaking new medical ground, neurosurgeon Kevin Tracey was the first to prove that stimulating the vagus nerve can significantly reduce inflammation. Results on rats were so successful, he reproduced the experiment in humans with stunning results. The creation of implants to stimulate the vagus nerve via electronic implants showed a drastic reduction, and even remission, in rheumatoid arthritis—which has no known cure and is often treated with the toxic cancer drug methotraxate—hemorrhagic shock, and other equally serious inflammatory syndromes.

9. Vagus nerve stimulation has created a new field of medicine.  

Spurred on by the success of vagal nerve stimulation to treat inflammation and epilepsy, a burgeoning field of medical study, known as “bioelectronics,” may be the future of medicine. Using implants that deliver electric impulses to various body parts, scientists and doctors hope to treat illness with fewer medications and fewer side effects.

Original image
iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
Original image
iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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iStock
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Why Your iPhone Doesn't Always Show You the 'Decline Call' Button
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iStock

When you get an incoming call to your iPhone, the options that light up your screen aren't always the same. Sometimes you have the option to decline a call, and sometimes you only see a slider that allows you to answer, without an option to send the caller straight to voicemail. Why the difference?

A while back, Business Insider tracked down the answer to this conundrum of modern communication, and the answer turns out to be fairly simple.

If you get a call while your phone is locked, you’ll see the "slide to answer" button. In order to decline the call, you have to double-tap the power button on the top of the phone.

If your phone is unlocked, however, the screen that appears during an incoming call is different. You’ll see the two buttons, "accept" or "decline."

Either way, you get the options to set a reminder to call that person back or to immediately send them a text message. ("Dad, stop calling me at work, it’s 9 a.m.!")

[h/t Business Insider]

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