THE BRAIN
The Cerebrum
The cerebrum is the largest area of the brain. The surface of the cerebrum is covered in a greyish layer called the cortex (from the Latin word for "bark"). It is split into two halves (hemispheres) by a deep fissure, but the two sides are joined at the bottom by the corpus callosum which connects the two halves and delivers messages from one half to the other. For reasons which, even in the 21st century, remain unclear, nearly all the signals from the brain to the body and vice versa cross over on their way to and from the brain. This effectively means that the right cerebral hemisphere controls the left side of the body and the left hemisphere controls the right. Where damage occurs to one side of the brain, it is the opposite side of the body where the effect is seen.
Each cerebral hemisphere is responsible for different thought processes. The left hemisphere controls the more analytical processes (particularly language), whereas the right is involved in the more creative areas such as art, mathematics and music.
Each hemisphere is further divided into four lobes by fissures (also known as grooves or sulci) and gyri (the "bumps" which can be seen on the surface of the brain).
