The brain is the most important organ in our body. We operate our entire life through the functioning of the brain. It makes our life exciting or dull, joy or sorrow, meaningful or worthless. It plays a fantastic and marvelous role in our life.
The most sophisticated computer in the world cannot have the storage capacity and information processing ability of the brain of an ordinary person. Unfortunately, no one utilizes the full capacity of the brain. Even geniuses have used only a fraction of their brain capacity. Everyone uses his/her brain but no one has tapped its full potential.
Many old notions about the brain and how we learn have been overturned during the past Decade of the Brain. It was commonly thought, for example, that we had only a fixed number of brain cells and that when we lost them to disease, trauma, or old age, we did not replace them in the way we renewed other body cells. We believed that brain cells could be destroyed but not replaced. We also anticipated that we would lose some of our mental agility as a normal result of the aging process. Brain research in this decade reversed those notions. Research just recently indicated that we can grow new connections between the brain cells at a rapid rate if we use our brains in new and novel ways, regardless of our age.
You probably have a general idea of what the brain looks like. We’re going to probe deeply into the structure of the brain so that you will know precisely why we want you to practice certain strategies and techniques and exactly what is happening as you reinforce your mental agility. Let’s start with some of the vocabulary and imagery needed to talk about and visualize brain structure.
The neuron is the basis of the brain. It is estimated that the brain contains 100 billion neurons. This huge number of interconnecting neurons makes the brain intelligent. Each neuron is a nerve cell composed of a center, named the nucleus, with long, slender axons and short, bristly dendrites. Neurons communicate with each other by passing nerve impulses down the axon of one neuron. At the end of each axon is a minute gap called the synapse (gap between axon and dendrites).
As the nerve impulse reaches the end of the axon, a chemical, called a neurotransmitter, is released by the axon to send and store messages across a synapse. On the other side of the synapse is a dendrite of another cell that acts as the receiver for the signal.
(Connections between brain cells)
The path the message follows from one neuron to another. This message travels from one neuron out its axon, is transmitted over the synapse, and travels up one of the dendrites of another neuron on its way to its destination. The message may be passed from neuron to neuron until it reaches the final destination. On the other hand, the neurotransmitters released into the synapse may alert multiple neurons at the same time. These message pathways are called connections. Trillions of glial cells are present in the spaces between the neurons. These cells upport, sustain, and safeguard the neurons and may have a communications system of their own.
The neurotransmitter performs a critical function in the creation of these communications connections. Each time a message is transmitted between cells, the chemical that is released into the synapse physically changes the receptor dendrite. Bristly spikes build on the dendrite as a result of the interaction of the chemical neurotransmitter and the dendrite. It is the repetition of this chemical reaction along the message route that strengthens the connection.