Nearly every vital activity necessary for survival, as well as all emotion—anger, fear, joy, love and happiness—originates inside the brain. The brain also receives and interprets a multitude of signals sent to it by other parts of the body and by the environment. Weighing in at a mere three pounds, the brain resembles a gray sea sponge—hence the term “gray matter,” and it is the central control system for the entire body.
Four Main Parts
The four main parts of the brain are the cerebrum, the cerebellum, a central core region called the “between brain,” and the brain stem.
The cerebrum is the rippled tissue commonly imaged as the brain. It is both the largest and most developed area of the human brain. It has two sides, or hemispheres—right and left—and includes four pairs of lobes: frontal, parietal, temporal, and occipital.
• The frontal lobes control thinking, planning, organizing, problem solving, short-term memory and movement.
• The parietal lobes interpret sensory information, such as temperature and touch.
• The occipital lobes process images from your eyes and link that information with images stored in memory.
• The temporal lobes process information from your senses of smell, taste and sound. They also play a role in memory storage.
The cerebrum is the most recent part of the brain to evolve, and positioned on top of the more evolutionarily ancient portions of the brain, such as the brain stem. The “star” of the cerebrum is the cerebral cortex—the outermost layer of the brain.
The cerebral cortex is like the bark on a tree—it forms the surface of the cerebral hemispheres. Despite a thickness of less than 0.2 inch (5 mm), the cortex is responsible for most higher brain functions, including language, memory, and consciousness.
One of the most visible features of the brain is the division between the left and right hemispheres of the cerebral cortex. This division applies to function as well. The left hemisphere is specialized to control language skills, such as talking, reading, writing, spelling, and speech communication. The right hemisphere is associated with spatial processing, such as perception of faces and patterns.
The cerebellum is the second largest area of the brain. The cerebellum's primary function involves the coordination of voluntary and involuntary body movements. The cerebellum guides body movements in a smooth and coordinated fashion.