Brain

The brain is a pinkish-grey, wrinkled organ that fills the skull — looking, for all the world, like a huge walnut. It is hard to believe, from its appearance, that this ugly lump of jelly contains the mechanisms of thought, perception, will, and consciousness, that it is the seat of our personality. Its 100,000 million nerve cells, each with an average of 100,00 connections from other neurons, makes the human brain the most complicated and least understood object in the known universe. The vertebrate brain is the large anterior portion of the central nervous system . The "cranial vault" of the skull encases the brain in most vertebrates. In invertebrates, the enlarged and specialized anterior ganglion of the central nervous system is often referred to as a brain, although not all scientists regard it as a true brain.

Hyperactivity

Hyperactivity means there is too much muscle activity. Hyperactivity is also used to describe a situation when a part of your body is too active, such as when a gland makes too much of a hormone. Hyperactive behavior usually refers to constant activity, being easily distracted, impulsiveness, inability to concentrate, aggressiveness, and similar behaviors.
Typical behaviors may include:
1. Fidgeting or constant moving
2. Wandering
3. Talking too much
4. Difficulty participating in quiet activities (such as reading)