The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals—only a few invertebrates such as sponges, jellyfish, adult sea squirts and starfish do not have a brain, even if diffuse neural tissue is present. It is located in the head, usually close to the primary sensory organs for such senses as vision, hearing, balance, taste, and smell. The brain is the most complex organ in a vertebrate's body.

In a typical human, the cerebral cortex (the largest part) is estimated to contain 15–33 billion neurons, each connected by synapses to several thousand other neurons. These neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells.

Any abnormal activity in the brain can cause a person not to be in proper condition. Many common illness and diseases that may be associated with abnormalities of the brain such as autism, cerebral palsy, bell's palsy, paralysis, coma, syndrome down, stroke, alzheimer's, parkinson's and so on.

For brain coma, it was caused by lack of oxygen and blood flow to the brain. Generally, the brain which was not functioning cannot be recovered and lead to brain coma. Some patients, they will suffer from brain coma before their heartbeat completely stop.

To treat brain coma, we need to stimulate back the blood flow so that they can carry the oxygen to the brain. One of the recommended methods by the experts is acupuncture treatment. This is the best and safest method in treating brain-related problem.