The brain has two halves or hemispheres: right and left. The right hemisphere controls the left side of the body, and the left hemisphere controls the right side. In most people, the left hemisphere regulates language and speech, and the right hemisphere controls nonverbal, spatial skills. If the right side of the brain is damaged, movement of the left arm and leg, vision on the left, and/or hearing in the left ear may be affected. Injury to the left side of the brain affects speech and movement on the right side of the body. Each half of the brain is divided into main functional sections, called lobes. There are four lobes in each half of the brain: the Frontal Lobe, Temporal Lobe, Parietal Lobe, and Occipital Lobe. Other important sections of the brain are the Cerebellum and the Brain Stem. Although not usually divided into lobes, the cerebellum and brain stem both have different parts. Each of the brain hemispheres and lobes, cerebellum, and brain stem has specific functions, and they all work together:
Frontal Lobe: most anterior, right under the forehead; the frontal lobe controls intellectual activities, such as the ability to organize, as well as personality, behavior, and emotional control.
Parietal Lobe: near the back and top of the head above the ears; the parietal lobe controls the ability to read, write, and understand spatial relationships.
Occipital Lobe: most posterior, at the back of the head; the occipital lobe controls sight.
Temporal Lobe: side of head above ears situated immediately behind and below the frontal lobes; the temporal lobe controls memory, speech and comprehension.
Brain Stem: lower part of brain, leads to spinal cord; the brain stem contains nerve fibers that carry signals to and from all parts of the body. The brain stem also regulates body functions such as consciousness, fatigue, heart rate, and blood pressure. Damage to the brain stem can cause loss of consciousness.
Cerebellum: located at the base of the skull; it is a curved mass of nerve tissues that regulates balance and coordinates fine motor skills; it enables us to move quickly and smoothly.
Grey and White Matter: The brain is made up of two types of tissue, grey matter and white matter. Grey matter is involved in analyzing information. White matter conducts information between grey matter areas. The ratio of grey to white matter changes over the lifespan.