When I took my first neurophysiology course, my professor asked everyone in class to hazard a guess on the number of neurons in the human brain. 100,000? 1 million? 10 million? A billion? Some of our guesses were close to the correct answer, whereas others were miles off. In fact, there are about 86 billion neurons in the human brain. I was still trying to comprehend the number when a student questioned how scientists determined the exact number. It was a great question! The brain, as seen in images, appears nothing more than jello molded in the shape of a skull, then how would it be possible to count individual neurons? Our professor explained that the earliest studies conducted to investigate the brain’s structure involved making brain soup and counting individual neurons one by one.
Scientific research has proven that human brain is a fascinating organ. It constitutes only 2% of average human body weight, yet it regulates how you breathe, eat, sleep, move, not to mention which movie you watch on Netflix – in short, it does basically everything! The human brain consists of two hemispheres, where left hemisphere controls the right side of the body and the right hemisphere controls the left side. Each hemisphere is in charge of jobs essential to our well being and normal function.
Previously, the scientific community believed a complete brain with both hemispheres intact is necessary to live a normal life. This popular belief was challenged by the case of Jody Miller, who suffered from a rare condition called Rasmussen’s Encephalitis. This condition caused Jody to have frequent life-threatening seizures originating from the right side of her brain. The defect in the right side of the brain also led to severe paralysis on the left side of her body. When every known treatment failed to cure Jody, the only choice Jody’s doctors had was hemispherectomy, a procedure where half of the brain is surgically removed. Although unsure about the success of the procedure, surgeons went ahead and removed the right half of Jody’s brain in an attempt to alleviate her seizures.
To their surprise, the surgery was successful. Jody’s seizures ceased, and she recovered from the surgery incredibly well. Immediately following the surgery, she had slight paralysis on the left side of the body, which was later treated with physiotherapy. Her left hemisphere was able to take over the role of the missing right hemisphere. This phenomenon is known as neuroplasticity: the brain is actually capable of rewiring and modifying its connections to restore lost function. Today, Jody has graduated college, won multiple scholarships and awards, and is living a normal healthy life — all with only half a brain!
Following Jody, multiple children have undergone successful hemispherectomies, and are living with only one hemisphere of the brain. In these cases, the human brain demonstrates a miraculous ability to self-heal, reconnect the brain network, and restore lost body function. The neuroplasticity of the brain makes it possible for individuals like Jody to live a normal life, which is otherwise not possible for Rasmussen’s Encephalitis patients. No wonder why the brain is called the boss of the body!