The brain is an essential part of the nervous system, a complex, highly coordinated network of tissues that communicate via electrochemical signals. We use our brains in virtually everything we do, from keeping our heart beating to deducing the existence of black holes. Within our brains lie our deepest secrets, our earliest memories, our most amazing capabilities, and the keys to the mystery of consciousness itself.
Hippocrates (460–377 b.c.), the most famous physician of the ancient world, first theorized that our thoughts, feelings, and ideas came from the brain, while others at the time thought the heart and stomach were the seats of emotion. Today, researchers are paying more attention to the roles played by the brain and the hormones that affect it in experiences such as mother-infant bonding, religious ecstasy and prayer, extreme stress, and meditation. Researchers now realize that though our minds and brains may not be exactly the same thing, they are intimately connected.