I’m calling this neuromythology, meaning false beliefs about the brain and nervous system. I thought this would a fun and informative post to make, debunking many of the myths people have about the brain, and showcasing some surprising truths. This will be the first in a four-part series just to disseminate hopefully interesting information. In most cases I’ll be taking my info straight from a recently published textbook on Biological Psychology (also called Neurobiology) by doctors Breedlove (heh), Watson and Rosenzweig. These will be statements that are been generally believed, some of which are true, some of which are false. As you might expect, some of this info will be already known to you and some of it will come as a surprise. Enjoy.
- Some human nerve cells are more than 3 feet long. True! In humans we have neurons that connect the spinal cord to the rest of the body that can be more than a meter long. In giraffes they can be up to 15 feet long!
- Nerve impulses travel at the speed of light. False! “Depending on the type of fiber, the neural impulse travels at speed ranging from a sluggish 2 miles per hour to, in some myelinated fibers, a breakneck 300 or more miles per hour. But even this top speed is 3 million times slower than the speed of electricity through a wire.” Still, over 1/3 of the speed of sound is pretty fast!
- More people die each year from the use of legal drugs than illegal drugs. True! Alcohol and smoking kills more people than all other drugs combined.
- Only humans seek mind-altering substances. False! The self-administering of intoxicating substances is one that we share with a variety of animals. Elephants like alcohol when it’s provided to them, and on game preserves have been shown to seek it when stressed. Intoxicating mushrooms are eaten by cattle, reindeer, and rabbits.
- Our bodies make chemicals that are similar in structure to heroin and marijuana. True! Endorphins are similar to opiates, as are enkephalins and dynorphins. There are a whole class of endocannabinoids that are compounds our bodies make that have similarities to THC, the active ingredient in marijuana.
- Testosterone is made only by males, and estrogen is made only by females. False! Both genders produce both hormones, in different amounts. The testes produce testosterone and converts a small proportion into estrogen, while the ovaries convert most of their testosterone into estrogen.
- Only humans have created cultures. False! Culture has been observed in primates. A population of Japanese macaques developed a set of behaviors that included washing food, playing in water, and eating marine food items; and they transmitting this culture of water-related behaviors from generation to generation.
- Once our brains are developed, we can never grow new nerve cells. False! It’s true that nerve cells–virtually all of the approximately 100 billion–have grown before age 2, new nerve cells do continue to grow in the hippocampus area of the brain throughout our lifetimes, a region involved in learning and memory. In other words the more you learn and experience, the more neurogenesis occurs, and exercise & socialization can boost neurogenesis too. So get back to exercise and keep some good friends!
- Some people are incapable of feeling pain. True! The technical term is “congenital insensitivity to pain.” These folks can discriminate between the touch of the point and head of a pin, but they experience no pain when pricked with the point. Unfortunately they also tend to die young from their injuries, which sucks. The earliest known example worked as a ‘human pincushion’ in the 1930’s at a circus and had–get this–a crucifixion act!
Stay tuned for part two, where among other things I’ll be discussing whether or not dogs are actually color-blind, if different parts of the tongue are specialized to recognize certain tastes, if one half of our brain actually controls the opposite side of our body, and if we can lose weight permanently by surgically removing fat!