The human brain is one of the most complex organs in the body. It controls everything we do, from simple movements to difficult problem-solving tasks. Scientists say that the brain contains billions of nerve cells that communicate through electrical signals. Although the brain makes up only a small part of our body weight, it uses a large amount of energy every day. Modern technologies allow researchers to study how memory works and why people sometimes forget information. Moreover, doctors use advanced equipment to diagnose brain diseases and help patients recover more quickly. Sleep also plays an essential role in brain function, because it helps the body restore energy. Even today many processes inside the brain remain a mystery, and scientists continue exploring this remarkable organ.