If this year's iPhone release taught us anything, it's that we're a society which craves new technology, jumping at the chance to replace last year's breakthrough advancement with one that's a millimeter thinner. But what we often forget is that we already own the most dynamic, efficient machine ever created: the human brain.
The (roughly) three-pound supercomputer inside your skull simultaneously processes facts and faces, stores memories, sweeps out toxins, controls movement and speech and makes decisions. And over the last few years, thanks in part to advancements in neuroimaging techniques, scientists are discovering even more about how remarkable our brain really is.
So what do we know today? Here are 43 facts about the wondrous, weird and incredibly powerful human brain:
1. There are somewhere between 80 and 100 billion neurons (nerve cells) in the human brain. They look something like this:
Image Credit: YouTube
2. The left hemisphere packs in almost 200 million more neurons than the right side.
3. Neurons vary in size between 4 and 100 microns wide. To get an idea of how small that is, the period at the end of this sentence measures about 500 microns in circumference, meaning more than 100 of the smallest neurons could fit inside it.
4. Despite the small size, scientists can actually measure the activity of a single neuron by inserting microelectrodes into the brain, a process called "single-unit recording," often used to refine epilepsy diagnoses.
5. Sex differences in the brain are controversial, but according to a 2014 study published in the Journal of Neuroscience, gray matter takes up a higher percentage of women's brains.
Image Credit: OpenStax College via Wikimedia Commons
6. Greater proportions of gray matter may account for superior performance on language tasks.
7. If you want more gray matter, hit the pavement. Research suggests that regular exercise may lead to increased gray matter inside the hippocampus.
8. Gray matter, which makes up 40% of the brain, only turns gray after death.
9. The brain of a living person has a more pinkish hue and, according to scientists, feels something like tofu.
10. Men may not have as much gray matter, but they have more white matter and cerebrospinal fluid.
Image Credit: Rick Madonick via Getty Images. White matter fiber (left) and fMRI images of reporter Jennifer Wells' brain on April 25, 2014.
11. White matter (which makes up the other 60% of the brain), gets its color from myelin, which insulates axons and increases the speed at which electrical impulses travel.
12. Fat may hurt the heart, but it's good for the brain. More than half the brain, including myelin, is made of fat.
13. When it comes to fuel consumption, the brain is like a Hummer in the body of a smart car. Weighing in at around 3 pounds, a brain makes up just 2% to 3% of the body's mass, but consumes 20% of the body's oxygen and between 15% and 20% of its glucose (estimates differ).
14. Brains also put out an astonishing amount of energy. The sleeping brain could power a 25-watt lightbulb.
15. Your neural hard drive could store somewhere between 1,000 gigs (that's about 50 copies of Taylor Swift's 1989, for those who are curious) and 2.5 million gigs (125 million copies). It depends on whom you ask — when it comes to the brain's storage capacity, scientists aren't exactly on the same page.
16. The number of glial cells in your brain puts your 80-plus-billion neurons to shame. You have at least 10 times as many glia, which means "glue" in Greek. As of 20 years ago, scientists thought glia basically just held neurons together, but certain types, like astrocytes, are now thought to play a role in complex thought.
17. Albert Einstein's brain contained an unusually high number of astrocytes. National Institutes of Health researchers discovered his high glia count while analyzing chunks of his brain tissue 40 years after he died. He also had an extra-thick corpus callosum, according to photos of Einstein's (posthumous) brain that went missing for more than 50 years.
Imagine Credit: Miguel Medina/AFP via Getty Images. A model of Albert Einstein's brain on display during a preview of the Wellcome Collection's major new exhibition "Brains: Mind of Matter" in London on March 27, 2012.
18. But the theoretical physicist's brain proves that size doesn't matter. At 2.71 pounds, Einstein's brain was a tad smaller than average.
19. In fact, our brains as a species have shrunk over time, all the while getting more efficient. Of course, some scientists are convinced that we're getting dumber, because thanks to societal advancements, we can be pretty dim and still survive.
20. The axons in your brain could span a distance of 100,000 miles. That's four times around the Earth.
21. The brain lacks pain receptors, which is why brain surgeons can slice into the cerebral cortex of fully conscious patients.
Image Credit: AIIMS/Barcroft India/Getty Images. A wooden splinter measuring 8 centimeters in length is extracted from the eye of 11-year-old boy Rahul Dev by surgeons during a six-hour long operation on April 28, 2010, in Delhi, India.
Image Credit: BodyParts3D via Wikimedia Commons. Left frontal lobe in red.
23. But while the frontal lobe can take a lot of wear and tear, the brain stem can't. Even moderate damage can be fatal.
24. This is because the brain basically developed front-to-back. Older areas of the brain, which control life-sustaining processes like respiration, are less hardy than (comparably) new areas.
25. In fact, people can survive on half a brain.
Credit: YouTube. A segment from the Today Show featuring a girl with half a brain.
26. But removing certain parts of the brain may have consequences even neurosurgeons don't anticipate. After undergoing amygdala removal surgery to treat severe epilepsy, a woman developed "hyper-empathy," an unexpected result, given the amygdala's role in emotion recognition. Taking out the almond-shaped structure would presumably dull one's sense of empathy, but 13 years later, the amygdala-less woman continues to feel every emotion happening around her, surprising scientists around the world.
27. Don't believe the silly 10% myth — the percentage of our brains that we use is closer to 100. Sorry, Limitless, Lucy and any other movies whose box office sales got a boost from exploring the possibilities of "the unlocked brain."
Credit: YouTube. Bradley Cooper discovers the depths of his mind in Limitless.
28. Texture matters — a lot, according to experts. The wrinkles in our brain, called gyri, increase surface area, letting us pack in more memory-storing, thought-producing neurons. (The folds between the gyri are called sulci.) Here's a photo of an entirely smooth brain, recently discovered by a photographer in a (literal) closet of old brains at the University of Texas, Austin.
29. Want more wrinkles? Try meditation. Years of channeling inner peace has been linked to greater gyrification (the process of wrinkling) in the right anterior dorsal insula, which may correspond with focus, introspection and emotional control.
Image Credit: Bloomberg via Getty. Blood vessels and membranes from a human brain removed at the Radiology Imaging Laboratory of the Brain Observatory at the University of California, San Diego on April 19, 2011.
30. Probiotic bacteria, the "good" gut bacteria, may have the potential to alter neurochemistry and help lower levels of the stress hormone corticosterone.
31. Feeling tired from reading this list? Go ahead and yawn. Yawning cools down the brain, research suggests. Sleep deprivation raises brain temperature.
32. But even exhausted brains are pretty prolific. Some experts say we have 70,000 thoughts a day, while others insist the number is much higher. It all depends on how you define a thought. Here's one formula.
33. Think fast: Information travels through different types of neurons at different speeds, ranging from 1 mile per hour (hopping in stilettos might be faster) to about 270 miles per hour (comparable to the fastest car in the world).
34. Our brains can scan and process complex images (e.g., a subway platform at rush hour) in as little as 13 milliseconds, according to recently published research from MIT. That's pretty fast, given that a single eye blink takes a few hundred milliseconds.
35. By blocking particles from entering the brain, the blood-brain barrier protects against injury and disease, but it also makes it really hard to treat neurological disorders.
36. Scientists in the nanomedicine field, however, are working on creating devices smaller than a billionth of a meter to transport drugs past the brain's frontline defense.
37. The brain region that controls vomiting, the area postrema, is the only area immune to the blood-brain barrier. This useful function lets your brain detect (and signal to throw up) noxious substances in your blood.
38. Playing a musical instrument, the equivalent of a full-body workout for the brain, forces the visual, auditory and motor cortices to work in concert. Whether you're pounding keys like Mozart or slapping the bass like Flea, playing music pulls from linguistic and mathematical skills from the left hemisphere, creative content from the right hemisphere and fine motor skills from both spheres.
39. Your brain doesn't have a very good poker face. Though incredibly controversial, some neurolaw experts are pushing to see fMRI in the courtroom. Arguably, brain scans could help biased humans better assess guilt and innocence, but the jury's still out.
40. Despite what you put on your resume, most people's brains are not built for multitasking. In fact, research has linked media multitasking to lower gray matter density in the brain's anterior cingulate cortex, an area involved in cognitive and emotional processing.
41. But our brains are built for navigation. Scientists took home a Nobel Prize in October for discovering a complex network of cells that’s been dubbed the brain's "inner GPS."
42. Yup, teenagers are actually the worst, but it's not necessarily their fault — their brains are still changing. As of 15 years ago, scientists believed that the vast majority of brain development occurred during the first few years of life. Through structural and functional MRI studies, however, researchers have discovered critical brain changes during adolescence, especially in the prefrontal cortex and limbic systems, which are involved in social decision-making, impulse control and emotional processing. Learn more from this TED talk:
43. When it comes to your brain, arrested development is totally normal. Sure, adolescence legally ends at 18. But based on recent brain-imaging studies of thousands of young adults, neuroscientists say your brain isn't mature until age 25. Fast-forward a few decades and there may even be another developmental period lurking in your future, but research is still fuzzy. Stay tuned.
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