PARTS OF THE BRAIN

Your brain has three main parts: the cerebrum, which is the largest part, the brain stem, and the cerebellum. Each part of your brain has its own special jobs, but the different parts also work together.

Cerebrum

The cerebrum sits at the topmost part of the brain and is the source of intellectual activities. It controls your movement and senses; sight, smell hearing, touch and taste. It is also responsible for memory.

The cerebrum is split into two sides by a deep groove. The sides are called the right and left cerebral hemispheres. Despite the split, the two cerebral hemispheres communicate with each other through a thick tract of nerve fibers that lie at the base of this fissure. Although the two hemispheres seem to be mirror images of each other, they are different. For instance, the ability to form words seems to lie primarily in the left hemisphere, while the right hemisphere seems to control many abstract reasoning skills.

Nearly all of the signals from the brain to the body and vice-versa cross over on their way to and from the brain. This means that the right cerebral hemisphere primarily controls the left side of the body and the left hemisphere primarily controls the right side. When one side of the brain is damaged, the opposite side of the body is affected. For example, a stroke in the right hemisphere of the brain can leave the left arm and leg paralyzed.

The most well-known part of the cerebrum is the cerebral cortex, or the surface of the brain. The cerebral cortex is the part of the brain that makes human beings unique. It controls and integrates motor, sensory, and higher mental functions, such as thought, reason, emotion, and memory.

The cortex is divided into four lobes: the parietal, temporal, occipital, and frontal lobes.

The frontal lobe is located at the front of the brain just behind your forehead and is associated with problem solving, organization, attention and concentration, personality, and expressive language. The frontal lobe receives information from various lobes of the brain and utilizes this information to carry out body movements.

Trauma to this portion of the brain can cause paralysis, the inability to focus on a task, mood changes, changes in social behavior, changes in personality, or the inability to express thoughts.

The parietal lobe is located in the middle section of the brain and is associated with processing tactile sensory information such as pressure, touch, and pain. The functions of the parietal lobe are sense of touch, identification of size, shape and colors, visual perception, and the manipulation of objects.

If trauma is sustained to this portion of the brain symptoms include the inability to name an object, difficulty with reading and writing, difficulty doing mathematics, or difficulties with eye and hand coordination.

The temporal lobe is located on the bottom section of the brain. This lobe is also the location of the primary auditory cortex, which is important for interpreting sounds and the language we hear. The functions of the temporal lobe are memory, hearing, understanding language, sequencing, and organization.

Trauma to the temporal lobe can present with difficulty recognizing faces, selective attention to what we see and hear, short-term memory loss, seizures, or increased aggressive behavior.

The occipital lobe is located at the back portion of the brain and is associated with interpreting visual stimuli and information. The primary visual cortex, which receives and interprets information from the retinas of the eyes, is located in the occipital lobe.

Because of its location at the back of the brain underneath the occipital bone, it is not as susceptible to injury as other portions of the brain. However, trauma to the occipital lobe cause defects in vision, such as difficulty identifying colors, or difficulties with reading and writing.

Cerebellum

The cerebellum is about the size of a fist and is located just above the brain stem and toward the back of the brain.  It is the part of the brain that is involved in the coordination of voluntary motor movement, balance and equilibrium and muscle tone.

 If a person sustains trauma to their cerebellum, motor movements become slow and uncoordinated. Individuals with lesions on the cerebellum tend to sway and stagger when walking.

Located in the medial temporal lobe of the brain, the hippocampus is a horseshoe shaped sheet of neurons which is part of the limbic system and is in charge of transferring information into memory. It functions as the gateway through which new memories must pass before entering permanent storage in the brain. In addition, the hippocampus is responsible for spatial orientation, navigation, and emotions.

Hippocampal damage can result in amnesia: loss of ability to form new memories, although older memories may be safe. Thus, someone who sustains an injury to the hippocampus may have good memory of his childhood and the years before the injury, but relatively little memory for anything that happened since.

If the hippocampus is deprived of oxygen, such as in the case of a heart attack, respiratory failure, or sleep apnea, damage could occur. The hippocampus is also a common focus site in epilepsy, and can be damaged through chronic seizures. In addition damage can occur from diseases such as herpes encephalitis, and is one of the first regions of the brain to suffer damage in Alzheimer's disease in which memory problems and disorientation appear among the first symptoms. People with extensive hippocampal damage may experience amnesia, that is, the inability to form or retain new memories.

Brain Stem

The brain stem is located in the lower part of the brain where it adjoins with the spinal cord. Neurological functions include those necessary for survival such as breathing, digestion, heart rate, blood pressure, and the ability to be awake and alert.

The brain stem provides the main motor and sensory functions to the face and neck via the cranial nerves. Though small, this is an extremely important part of the brain as the nerve connection of the motor and sensory systems pass from the brain stem through to the rest of the body.

Injury to the brain stem is considered to be a serious brain injury. Because the brain stem is involved in attention and short term memory trauma to this area can lead to disorientation, amnesia, frustration, and anger.