Look around your house or car at all the amazing inventions that have come along in the past few years: iPods and iPads, GPS devices, satellite TV, those weird little robots that can vacuum a room by themselves. All these technological toys are like Stone-Age tools compared to the amazing wonders of the human brain. Although humans have been studying the brain for thousands of years, in the past 15 years or so, scientists have debunked some longstanding myths about our most vital organ. Here are some surprising facts about the human brain.
5. The Average Brain Uses Equivalent of 20 Watts of Power
Researchers have determined that the brain consumes about 20 percent of the body’s energy. From there, it’s rather simple to take the average daily caloric intake of a human, translate that into an energy equivalent, and then determine the amount of energy an average human brain uses each day. Several different sources have determined the brain’s electric output to be approximately 20 watts. That begs an obvious question: Do the brains of so-called “geniuses” use more energy? We might not know if it weren’t for studies of one of the most famous brains in history. Following Albert Einstein’s death in 1955, his brain was preserved for research, and studies have found that it contained many more glial cells — the cells that nourish and otherwise assist neurons — than other brains, which would require more energy.
4. People Use Much More Than 10 Percent of Their Brains
The myth that humans use only 10 percent of their brains has been repeated so often, by so many sources, it’s widely accepted as fact. It’s certainly one of the most pervasive myths about the human body, dating back to the early 20th century. Researchers have used MRI and PET scans of the human brain to show that far more than 10 percent of the organ is used even at rest. In fact, studies suggest that during any given day, fully 100 percent of the brain’s area is active. Furthermore, individuals with even minor brain damage to any area of the brain can show impaired function, hardly consistent with an organ that according to myth is 90 percent unused. Despite the fact that this myth has been proven wrong again and again — including on a 2010 episode of the popular show MythBusters — it persists in popular culture.
3. The Brain Adds New Cells Throughout Life
Another longstanding brain myth is that a person is born with all the brain cells they’ll ever have, and when the cells die, that’s it. The brain has some 100 billion nerve cells, and cells do die on a regular basis. Cell death can be accelerated by drug and alcohol abuse and even sleep apnea. However, studies in recent years have shown that our brains add new neurons throughout life, as many as hundreds of thousands per month. You can aid this process, known as neurogenesis, by exercising, engaging in mentally stimulating activities and eating a healthy diet. Eventually, scientists hope to learn how to reproduce this natural process of neurogenesis to treat damaged brains.
2. Aging Doesn’t Cause the Death of Brain Cells
Also contrary to popular belief, the process of aging itself doesn’t necessarily kill brain cells. A study at Harvard in the mid-1990s examined the brains of 38 people who had died between the ages of 57 and 90. The study found no age-related loss of brain cells. In other words, the brains of those in their 80s and 90s had as many neurons as those of the 50-somethings. But changes in the brain that begin in our 20s and 30s eventually result in diminished mental function. Researchers have found that the brain shrinks slightly with age, losing up to 10 percent of its weight by age 90. And the brain’s chemistry changes, slowing the connections between neurons. The good news is that a few lifestyle changes can help keep your brain young. Of course, some of these are obvious — don’t smoke, drink alcohol in moderation, eat a heart-healthy diet, and exercise. Most importantly, keep mentally active. Take up a new hobby, learn a new language, and stay active with friends.
1. The Brain’s Storage Capacity Is Astounding
Imagine your brain as a computer hard drive. How much memory would your “system” have? A few scientists have puzzled over this question in recent years, with widely varying results. Syracuse University Professor Robert Birge estimated in 1996 that the human brain had a storage capacity of between 1 and 10 terabytes, with a likely value of 3TB (for comparison, high-end iMacs today come with a 1 terabyte memory).
However, Scientific American posed the same question to a psychologist in 2010, who estimated that the brain’s memory storage capacity is 2.5 petabytes (a petabyte is 1 million gigabytes, or 1,000 terabytes). To put those 2.5 petabytes in perspective, the entire print collection of the U.S. Library of Congress is estimated at 10 terabytes. Even that might be understating the brain’s processing and storage capacity. University of Southern California researchers Martin Hilbert and Priscila Lopez have spent several years researching the combined computer processing and storage capacity of humankind. The two researchers estimated that as of 2007, all of the computer processors (desktops, laptops, servers, PDAs) on the planet Earth combined could process 6.4×1018 instructions per second. As the researchers note on their website, “The maximal number of neural nerve impulses of a group of 64 people is equal to the number of instructions all our computational devices combined can compute (in 1999 it was equal to nerve impulses executed by one human brain).”